Just a quick note on the EF86 tubes used in my amps.  These are now all NOS.  The best place to get these is from www.kcanostubes.com
Updated 07 JUL 07
Amplifiers and Guitars most commonly used of mine - many are out on loan that may not be shown here at times
This was in response to somebody asking what rig I am currently using or what I play through.  I typically play through only a handful of
amps.   Click on most of the amp names for a larger photo.

Some of this you can see all at once by
clicking here

I play mostly blues, so I have the amp at one setting, and basically use my guitar volume control and touch, as my "effects".  Its pretty easy to do when
you are as stuck in one style as I am :)  ... Actually two styles .... Blues and 1965-1969 San Francisco acid rock ....

65 Amps London - I mention this amp on the first main page of the website where I also have a few photos.  My two favorite amps on the planet
are this amp and my Dr. Z Carmen Ghia.  I guess behind those would be a Dr. Z SRZ-65 (the best Marshall type amp ever made), a Fender Tweed
Deluxe (Pierson Amps), and tweed 4x10 Bassman.   I cannot say enough about this amp and would suggest that you look at their website.   Better yet
... if you are in my area feel free to contact me and you may borrow mine for a studio gig or live show.  You will also see lots of these amps on major
tours.   If you want even MORE look at their newest Marquis.   I cannot put into words how these amps play and feel.    Current tube compliment is as
follows:   V1 - Dario Miniwatt EF86.   I will be replacing this with a Mullard from KCA NOS Tubes shortly to see what happens.  V2 is a great long silver
plate Ei 7025.  V3 is a Tung Sol reissue 12AX7 for the phase inverter.   I will be trying a GT-12AX7M long plate phase inverter in the future.   Output
tubes are GT-EL84S in a #5 rating.   I was going to toss in a set of #7s for a bit more clean headroom before I even played the amp.   I don't think this
will be necessary as the amp has very nice clean headroom as delivered.  
Tube compliment as of 8/8/06 - V1; Mullard EF86, V2; NOS Tesla
(V1 and V2 from Mike at www.kcanostubes.com) and V3;12AX7 Tung Sol Reissue (to be changed for a long plate phase inverter at a later
date.  The stock V2 Ei 7025 when replaced with the Tesla 803S yielded smoother tone, less peaky high end, and much wider range in the trem due to
much better current output than the Ei.

Pierson-Rose - In late June of 2005 I contracted Pierson Amp to build an amp of my own design.  This is a 20 watt cathode biased amplifier about
the size and of similar layout of the 1955 Tweed Deluxe.  The amps wattage allows the use of large diaphragm microphones without overloading the
mic or console.  The gain structure is in the area of the great rock amps when cranked of the 1960s and early 1970s.  This is the sound of hard blues
and rock from my own personal viewpoint and this was the target of this amps design.  This class A amp have very high levels for it's wattage and it's
use in medium clubs unmic'd is no problem.  I picked Pierson to build this amp based on his construction methods used on his other hand wired
amps.  As all Pierson amps, this amp uses USA CTS pots rather than Mexican Alpha pots.  The used of industrial Belton tube sockets which do not
rattle and take take thousands of tube insertion and removal cycles was another plus.  Pierson uses stainless steel for his chassis.  If you listen to his
Tweed amps such as his Champ, Deluxe, and Tweed Twin you will notice how quiet the amp is compared to a magnetic steel chassis amplifier.  
Custom Mercury Magnetics transformers were specified.  In the tone circuit high end Jensen oil/paper/foil silver lead capacitors were specified.  The
desired smooth character was obtained in part with these capacitors.  Fresh hand selected carbon comp resistors were used.  The amplifier utilizes a
Jensen P12N AlNiCo 5 speaker rated at 50 watts.   The tube compliment was hand picked and traced.  V1 is a Telefunken 12AX7.  V2 is a GE 12AX7.  
Output tubes are trace matched Sylvania 6V6GT tubes.  Pierson will be selling these amps on special order as each is tuned to the player.  The price
of the amp is $2795.   I use this amp either alone or in a two amp rig (a Fender Tweed Bassman for the clean tones and this amp for the crunch and
hard rock tones).  I will have more photos in the near future but for now you can see this amp in the rear row of the photo in the Pierson page on this
site by clicking above at Pierson-Rose.  It is the only non tweed amp in the photo.   The gain structure of this amp can be quickly custom tailored to a
player's desires and to pickups in their guitars.  For people in the Los Angeles area - this amp will be available for audition and recording projects.

Fender Tweed Bassman 4x10 - This is an amp which I have more than one of.   This amp is a classic - a standard, and the amp I have found
which is one of my all time favorite amps with a Gibson ES-335 or Rickenbacker 360-12 for rhythm guitar.  It is also a classic lead rock amp for many
folks.  I have a Fender made model and am currently having Rick Gessner at Valvetrain Amps build me another one with a few twists.   You can see
more on this Valvetrain amp and it's progress in building and development by
clicking here.   The Fender 4x10 Bassman is considered by many to be
the finest sounding guitar amp ever produced.    I am also having Pierson Amps build me a dead reproduction of an original version.

Victoria Sovereign - Perhaps one of the finest rock modern amps I have played.  As of mid August 2005 the amp is in use with Carl Verheyen.  
There is too much to write here, and a review is in progress.  Current output tubes #6 GT-EL34R2.  For a copy of this review, just

Victoria 20112T - (Fender Tweed Deluxe).   I'd say this amp gets played on average, 10 hours per week at the least.   This amp may look like a
simple amp (two volume controls, one single tone control), but it is the most complex amp I own.  Every tube in this amp sounds different.  It shows the
most out of any tube, as it's simple complex circuit has very little coloration.  The carbon comp resistors, proper transformers, and caps, are all period
proper.   This amps is a master of balanced saturation, where the transformers and output tubes reach saturation in a complimentary fashion.  This is
something lost in so many amps made today. The reason I say this amp is complex, is one gets use to one sound they love, but then experiments,
using a 5751 in V1 rather than a 12AY7.  The amp changes completely ... not in a subtle way where you have to strain to hear the difference, but the
difference is right there for even the most blazee listeners to hear.  Different 12AX7's in V2 change the feel, sound and dynamics too.  The there are
the many 6V6's that go in and out of this amp....  RCA, GE, Haltron, Sylvania, Mazda, Raytheon, Vissaeux.  Even the years that differ an RCA 50's to
60's will change the amp in a major way.  The amp is a joy to play, and a joy to carry.  If I could have only a half a dozen amps, it would be a Victoria
Deluxe, Victoria Bassman, a Victoria 2x10 Super, a Black Face Fender Deluxe Reverb, a Marshall JTM-45, and a GT Solo 45 (as I can get any sort of
high gain out of that with pedals).  By the way, the "stock tubes" in this amp as supplied by Victoria were NOS GE 6V6's, an RCA Command 5751, and
a wonderful 12AX7.  As of December 02, the 20112T tube compliment is an NOS RCA 12AY7 in V1, a Telefunken 12AX7 long smooth plate in V2 (or
a 12AX7C in V2)  and either GE NOS Oval Smoked 6V6's or RCA 6V6GT's.
 As of January 03, there is a 6072M in V1, an RCA 7025 in V2, and
GE 1960's 6V6GT's in the output section.

Dr Z. Carmen Ghia - picked up in May of 2003, this is a magic amp in many ways.   I now use this amp with a K&K Audio ported 1x12 cabinet where
the speakers are changed around per need of the moment.  Speakers used are Celestion G12-100, G12-70, Jensen P-12R.  This amp is also used
at times in a dual amp setup with an A/B/Y switch and a Victoria 20112T (Tweed Deluxe), as my current blues and rock setup for smaller venues,
although the Ghia is a very loud amp for it's size.   This is a typical "less is more amp" that is very versatile and dynamic to the touch as are all the Dr.
Z amps.  Tube compliment as of May 15th are a 5Y3 NOS JAN Philips rectifier (although with a GZ34 the amp will have a LOT more plate voltage and
is way too strong for my tastes) ... the power transformer is more than happy with any rectifier, and will just put out more voltage with out a hint of
complaint.  Current tubes are a GT-12AX7R3 SAG 92/100 in V1 (a touch less gain on the A side and a hint more compression and slower rise time on
the A side), and a bit more gain after the tone stack with a very fast rise time.  V2 is an RCA Command Series NOS black box plate 5751 that was
trace matched by my SAG group at GT.  Output tubes are GT-EL84S in a #6 rating as supplied by Dr. Z in the amp.  Many internal photos will be
posted on this amp in the near future.  
3/04 - Tube compliment is V1=GT 12AX7M.  V2=GE 5751 5 star SAG-MPI.  9/8/04 - V1 changed to NOS
Telefunken 12AX7 for a brighter tone for a recording session.

Dr Z. Mazerati - This became my primary performing amp late 2003.  This amp covers all the Vox AC-30 duties, many Marshall and Fender duties,
and is am amp that needs no tweaking to sound and play amazing.  It's single tone knob covers a much wider range than two or three tone controls in
other amps.  With only a single tone pot in the circuit, there is much more articulation and definition that in other amplifiers.  When there are a lot of
pots, caps, and resistors in the tone stack and front end, you need to recover the loss of these components.  There is generally a recover stage in
most amps.  This recovers the loss of level, but can do nothing to recover the loss of harmonic content and detail.  This amp does not have these
problems.  Listen to Brad Paisley and any of his guitar work and you will get the picture.  I cannot say enough about this amp.  If you want another
point of view, check out Guitar Player Magazine Marsh 2004 issue for a full writeup on this amp and the Doctor's Z-28.  They may be the most
complimentary reviews I have ever read on any guitar amp.

Dr Z. Prescription "Extra Strength" - This amp was acquired in May of 2004.  About a half a dozen or so of these have been built.  The official
release date of this amp will be in July 2004 if all goes to plan.  This is now my primary  "rock amp" and may have the most aggressive tone of any
amp I own.  This is not to say it's gain is totally over the top or compressed.   It is articulate at any level.  This amp, with it's quad of split load biased
EL84's puts out wattage, tone, and levels far in excess of it's expectations based on wattage ratings alone.   While the low end is huge, the highs can
be dialed in to give you all the sparkle that any AC-30 could supply.  You can also have the lows and sparkle at the same time!  This amp may not be
in the stores at the moment but should be in short order.  This amp differs from the original Dr. Z Prescription with the use of new transformers, some
design changes and an EF86 Pentode in the V2 position.  The expand switch is something like an afterburner on a military jet.  Watch out!  The high
and low level inputs are very different and give you two very different amps.  Plugging into the low level input will yield a lot of clean headroom if
desired.  This may be one of the strongest sounding amps I have ever played regardless of wattage.  Folks in the Los Angeles area are more than
welcome to come and play this amp at my facility on request.   This particular amp is the first prototype.  The second amp is now being used by a
pretty well known master Tele player and well known recording artist.  
Tube compliment as of 5/04;  V1 - RCA Command Series 5751.  V2 - NOS
BVA (Mullard) EF86/6267 (8/1/04).
 V3- GT-12AX7M (Mullard reissue) MPI.  Output set - GTEL84S #6.  5AR4 Rectifier.

Dr Z. Delta 88 - This amp shares the same front end as the Z-28, Route 66 and KT-45 amps from the good doctor.  This is another new amp from
the design board of Dr. Z.  There are a few things to note here.  This amplifier has a VERY efficient output transformer.  You do NOT bias this amp as
you might normally bias a class A/B amp.  The KT88 output tubes are very easily driven and have a very wide range.  Keeping the bias at a mere 28
milliamps per tube even at plate voltages approaching 500 plate volts with it's solid state rectifier will still yield about 100 watts out of this amp.  The
amp will sound and play great at ALL levels with no trace of grain or harsh tone.  Use it with a single 12 " cab (with a pretty strong speaker) in small
gigs or with big cabs in larger venues, it covers it all.   This amp is a very strong and versitile amp.  Listen to Michael Burks (killer hard blues player) to
get an idea of what these amps can do.  At the 28 mA bias the tubes will last for years.  I think five to ten years you not surprise me at all.  V1 - EF86,
V2 - Phase Inverter, and a duet of KT88SV output tubes in a #5 rating.

Dr. Z Mini Z - This amp is just a blast.  The word on the amp from the Brad Paisley camp is that the Mini Z was used all over the place on the
upcoming CD which follows Brad's "Mud on the Tires" CD.  The amp is built A+1 as all Dr. Z amps.  PTP with a great Weber 8" speaker.  The amp
records just wonderfully.  This may be the Doctor's most agressive and gainy amp!

Dr. Z Z-28 - Added to my amp inventory in January 2004.  This amp is a 6V6 based amplifier.  This amp has the same sort of front end as the Route
66 and KT-45, that is, an EF-86 Pentode.  This front end is extremely articulate and will not buzz like some typical triode front ends.  There is a huge
amount of reserve headroom.  The tone controls also act on the front end gain, so for more front end drive, just drop the volume and raise the tone
controls in unison to a degree.   These front ends are perhaps, the most pedal friendly front ends around, another big plus.   Due to more "Fender"
work and working with Nashville folks wanting Fender sorts of tones, I was lead to this amp.  This is another amp in Brad Paisley's rig, and also is used
by some folks for acts such as Brooks & Dunn and more folks.  I wanted a 6V6 based amp to augment my Fender Deluxe Reverb and Tweed Deluxe.  
This amp covered both bases very well, so nicely in fact, that the Fender amps have been put into my back line rather than my front line of amps.  I
normally prefer a single 12" speaker for Fender tones, but the Dr. Z 2x10 cab was suggested, and as that turned out, was a top notch idea.  The Z
2x10 has more low end, is more focused, yet has wonderful dispersion.  The drivers are Z specific with a few twists.  The cabinet incorporates lens
technology and has some interesting damping materials implemented.  The speakers have lighter cones than a 12" driver, so they are very articulate
and responsive with out being high end overbearing.  This amp also has more headroom than a Fender amp of the same wattage.  This is due in part
I believe, to a clean front end design that does not loose level and harmonic content from a tone robbing circuit topology.  This is my new "Fender"
 4/04 tube change: V2 = GT-12AX7M SAG MPI.  8/1/04 V1 change - NOS GEC EF86.  This amp and the Z KT-45 are my two favorite
grid biased amps in my entire inventory.

Dr Z. KT-45 - Think of this amp as capable of a lot of clean headroom that can go into high level territory like an old Hiwatt.  This is a great hard
core rock amp and also a clean player's dream for steel or rhythm guitar.  The tone controls also control the gain of it's EF86 front end.  This amp
reminds me very much as a Vox AC-50/2 with more headroom and even tighter.  A very versatile amp.  There is more data on this amp and some
photos in the Dr. Z area of this website in the Amp Makers section.  This is my performance amp for any size venue at this point.  It is bigger and
louder than anything I own, easy to carry anywhere, pedal friendly, and loves any speaker setup.  The amp can be bigger and cleaner than my
Fender amps when I want it to be, more articulate than my Fenders, and for huge hard rock from the 60s or 70s styles without the use of pedals, can
not be under estimated as a first pick.  Most amps I tweak with as much as I play.  The Dr. Z amps are not really tweaked by me (they come great right
from the factory), so when I want to really play guitar, I generally grab a Z amp.  With an A/B setup, a Z Ghia wide open and a KT-45 or Route 66
would satisfy most folks requirements.  I tend to use the Ghia at lower levels for a great blues amp, and this KT-45 when I want to flash back to the
60s at the Fillmore or Avalon ... back in the days when the levels filled the room, ashtrays and drinks were slid off tables from the levels (yes, back
then you could smoke inside, so there were ashtrays), and sound reinforcement was generally just for the vocalists.... so the players had to provide
their own "wattage" and levels.   Stock tubes in this amp ... Svetlana EF-86, 5AR4 rectifier ( you can go solid state if you want even more output),
12AX7, and two GT E34LS #6 output tubes.  I am not sure why the amp is called a "45", as on the bench in stock form, it puts out about 70 watts
pretty easily.   
4/04 tube change: V2 = GT-12AX7M SAG MPI.   8/2/04 - V1 NOS Mullard EF86.  This amp and the Z KT-28 are of  my two
favorite grid biased amps in my entire inventory.  One stereo rig I love is a Z-28 and Z Carmen Ghia.  A larger stereo rig I love is a Z
KT-45 and a THD Flexi 50.

Dr. Z MAZ Senior - This is an all around performance and studio amp.  It has very high output and seems to be very happy on any size stage or
venue.  Most Doctor Z amps may seem a bit unconventional to many, as they are not just copies or modifications of other designs such as Marshall,
Vox, and Fender.  Z amps use things like conjunctive tone filters, split load biasing, fixed bias phase inverters, Pentode front ends, etc., in many of
their designs.  The MAZ Jr and Sr have a more "conventional" layout.  There are controls for Bass, Middle, Treble, and they are Master Volume
designs.   This is a very versatile amp that can cover the Fender and Vox bases.  In output it is somewhere between a Fender Super Reverb and a
Twin Reverb.  If you head to the Dr. Z Website and listen to the sound clips of the MAZ Sr. You will hear it cover things from hard rock to SRV tones,
Texas Blues and mellow sounds.  It is a very versatile amp.  My current tube compliment in this amp is
V1 GT-12AX7M in a 1.4/1.4 (changed 4/04)  
rating, V2 a GT-ECC83S in a 1.0/1.0 rating, V3 a GT-12AT7C in a matched rating, V4 a Sovtek 12AX7WA in a 0.9/0.8 rating, and V5 a
matched phase inverter (NOS JAN Philips 12AX7).  
10/9/04 - V1 NOS Tung Sol 12AX7, V2 - GT-12AX7M, V4 GT-12AX7R (WC), V5 NOS GE 5
star 5751 MPI (scope trace matched at GT).  
This amp may be my favorite live performance amp where I want a cathode biased amp.   
This map can give me all the tones of a Matchless DC-30 amp but  also for some unknown reason it can cover the tone bases of a
Fender Super Reverb.   I guess four of my favorite amps seem to be the Z-28, KT-45, MAZ, and my favorite of all, the Carmen Ghia.  All
of these are very different but all excel at what they were designed to do.

Dr Z SRZ-65 - In the center of this group of Z amps is the SRZ-65.  I will not be saying too much about this amp as it is quite straight forward and
easy to understand by any player that has ever played a great Marshall.   Think of a classic 2204 JCM 800 that has been tweeked a bit by somebody
like Caesar Diaz and you come close to the idea.  This amp is biased at 37mA with a set of E34LS #7s.  Preamp tubes are still being played with at
the moment.  So far we have put the amp up against a Diaz Marshall, my own Marshalls, a Komet and a Dr. Z 6545.   The SRZ-65 is more aggressive
by a bit than the 6545.   The master (volume) is smoother than the other Marshalls and the amp is very quiet.  It is a simple amp to understand:   If
you are a fan of classic Marshall tones this is the amp for you.

Fender Deluxe Reverb.  This is one of my favorite "blues" amps, along with the STP-G and the GT Solo Single, and the Victoria.  It is a very
portable amp, so for gigs with friends or to just toss in the car, its a bit easier than the STP-G.  Tube compliment:  Two Groove Tubes GT-7025's  (in
V1 58/65 rating with a slow rise time for blues) and in (V2 85/92 rating for rock from the 60's),   two GT 12AX7-C's (both with medium ratings), two
GT-12AT7's (one with a high fast rating of 116/120) and the MPI with a rating of 100/100) and one duet of GT-6V6R's with a #4 rating.  (as of 7/02,
the output set was replaced with a set of NOS RCA Black plates that gets swapped with a set of #6 GT-6V6C's (the new Chinese tube made off new
tooling and with updated materials.  The Chinese are now showing a preference over the 6V6R (Russian Electro Harmonix) in sound quality and amp
feel and touch).  The Chinese and the Electro Harmonix are both preferred over the Sovtek 6V6's currently.  The Chinese and EH also hold up to
higher plate voltages in the late July 2002 testing.
April  03;  (V1) Gone (V2) RCA Command Series NOS 5751, (V6) GT SAG-AT7-MPI, power
tubes NOS Tung-Sol; 65% ID @ 415 volts B+.  All other 12AX7 tubes are GT-SAG 12AX7R3.  
4/04 V1, V2, V4, V5 GT-12AX7M.

Fender Twin Reverb There is not much to understand about this amp, as it says in the book "Tube amps ... the other half of rock and roll", you
either get it or you don't, as the caption in the photo reads.  The single amp that has probably been on more stages than any guitar amp in history.  
This is a pretty stock example.  V1, V2, V4, and V5 have been fitted with Groove Tubes 12AX7M tubes.  The output tubes are being changed to
GT-6L6GE's in a #6 rating and will be biased at 30mA.

Pierson Tweed Champ - What can I say about a tweed champ?  Everybody needs one of these classics in their tone arsenal.  This may be one
of the very best if not the best.  Totally hand built, Belton sockets, NOS tubes, and the best components available.  Perfect workmanship.  After
testing at least a dozen of these over the last year or so I guess I finally thought I had to have one of my own.  More info

Groove Tubes Solo Single with various tubes.  This is a much played and borrowed amp, with  it's larger output transformer than the Univalve,
which gives a sound I prefer when I use a 6V6 configuration.  Information on this amp including the owner's manual can be found by
clicking here.  
This amp is a class A single ended Class A amp that can use any sort of preamp and power tube set with no adjustments required.  This amp is a little
different in some way to the Univalve.  One difference is that is it available in a head or combo.  It also has a parallel effects loop, which the Univalve
does not have.  It also has a midrange tone control, a presence control, and a master volume configuration.  It is capable of very high gain if needed,
and has a pull function on the volume knob, for an additional 20 dB increase in gain.  This pull function is also foot switchable, so this amp is suited to
live performance use as well as recording.  It is a class A amp, which is very loud for it's power output, so in live applications, it is very adequate for
smaller venues, or when mic'd in larger venues.  (Remember, the Vox  AC-30 at 30 watts (class A), was as loud as the Fender Twin Reverb (class
A/B) at 85 watts).  As of
August 02. the configuration in use in a GT-12AX7R3 in  V1, an NOS JAN Philips 12AT7 in V2, and an NOS 6V6GTA in V3.  
Using an ECC83 in V1 and V2, and the GT 928 adaptor with an EL-84 in V3, this amp is being used for a recording session to replace some AC-30,
AC-15 type amps.  It is also being used with a 5751 in V1, 12AT7 in V2, and a 6550C as the power tube in a Jazz project.
 NOV 02; Tung Sol 6V6,
RCA NOS 7025 (V1), NOS JAN Philips 12AT7WC (V2).  DEC 02;  V1-12AY7 NOS, V2-7025 NOS Wurlitzer Organ pull, V3- NOS 6V6 RCA Gray

Groove Tubes STP-G studio preamp.  Most people do not realize that even without the emulator feature, this is one of the best sounding and
most versatile guitar amps ever made.  It is a 25 watt amp.  Think of it as a Fender Deluxe circuit with mods such as very effective tone controls,
mid-range control and mid-range boost with 5 different EQ slopes, the ability to use EL-34 tubes as well as 6V6 tubes, a gain pad, and the ability to
have either a normal gain structure ala Fender, or a cascaded gain structure with more front end gain than my Boogie Mk. 1.   I use this amp for live
use and recording.  When live, I use different cabinets and speakers.  I most commonly use a Jensen P12R 12" in a Fender cabinet, or a Celestion
12" 70 or 85 in a K&K Audio ported cabinet(s).  This amp with a ported cabinet has as much bass as one would ever want.  It is perhaps the most
versatile amp in my inventory.   
 Current tube compliment:  two NOS 7025's rated at 83/92 and 90/108, two NOS 12AX7A rated at 100/100,
and 100/100, and two NOS 6V6 black plates which on the GT test equipment came out with a #7 rating.

Modified Rivera 100 watt Fandango head with 6L6's with a ported CS-410 cabinet from Rivera and a SUB system.  The sub system is not set to
Hi-pass, it is set to full range, as I don't need any more headroom out of the amp itself, and I prefer the interaction of the lower frequencies in the main
speaker cabinet most of the time.  For Jazz players, I reconfigure to hi-pass for a very clean sound.  If you
CLICK HERE you will see the amp with the
front panel on.  This is one of my "rock" amps, one the "kids" (under 40) borrow.
 Tube compliment:  Three 12AX7WA's, two 12AX7LP's, and four
Svetlana (from Rivera) 6L6's.
 November 02, Svetlana 6L6 quartet, 5 Groove Tubes SAG selected 12AX7R3 (even more quiet than

Rivera Rack System - This is a Rivera TBR1M and a Rivera TBR5.  The upper amp is 120 watts stereo at 60 watts per side using four Svetlana
EL-34's.  Speaker compliment is four Rivera 2x12 wide dispersion sound array cabinets with Celestions.  This amp typically benches over 75 watts per
side.  Off this amp (TBR-1M) is a Rivera TBR-5.  This is a 320 watt tube amp at 160 watts per side as rated.  It also benches more.  This amp uses
USA GE 6550A's .... an octet (8) of them.  It's speaker compliment is four Rivera 4x12 cabinets.  This amp can fill the Hollywood Bowl without any form
of sound reinforcement.  On the first page of my website, at the bottom, one of my sons is playing through the top half of this rig.  In that picture, the
top (TBR-1M) was set to low power and triode mode ( 8 watts per side, stereo ) and run into a Rivera CS-210 open back stereo / mono cabinet.  This
amp is probably my "largest" amp, and I see the need for nothing larger.

Phil Jones Bass - Briefcase - 28 pounds of compact pure technology.  The amp can run off AC, car adaptor, 12V car battery or an optional 12
volt 7.2AH internal battery.  Great EQ, built in compressor / limiter, 110 watts, XLR out.  A great portable bass amp but ALSO a great jazz guitar
player's rig.  Before you move away from something like a classic PolyTone check out this amp.  Great cleans and active and passive inputs too!

Fargen Blackbird - This is an amp that is in the tone arena of a Fender Blackface Deluxe.  It has 2 6V6GT output tubes.  I have a lot to say about
these amps in my "world's great amps" section.   Currently running 3 different 12AX7's and one JJ 12AT7/ECC82 which was trace matched to be
balanced for the phase inverter.   Fina tubes are being chosen at this time.  Some photos of this amp are at the bottom of the page the link here will
take you to.  There are inside photos on the first page of this website.

Marshall JTM-45s This amp is one of the blues and rock standards.  I have a few of these.  The earliest is a 1966 that was purchased in 1966 (I
was in the 11th grade) from Ace Music in Santa Monica CA. new for $325.00 which was tot total cost including tax for the JTM-45 head and Marshall
4x12 cabinet in a half stack configuration.  
 Current config as of 6/4/02 for testing is a GT SAG-MHG kit with two  ECC83's (rating from
116-130), a SAG-AX7-MPI,  and a set of GT-6L6C (Chinese power tubes) with a #6 rating for testing.
(As of 7/02, the output set is now
KT-66HP's with a #6 rating).
 As of AUG 02. the KT-66HP's were replaced with #4 rating for studio use.  V1 is an ECC83 with a SAG rating of 95 and
V2 is an ECC83 with a rating of 85 and 40ms longer rise time to a level of 70% of output voltage to increase front end rise time to limit pick attack
amplification and smooth character as a client using this for a recording was seeking the same sound of an SG and Firebird from EC's Bluesbreaker
recording on a particular song.
November 02; GT KT-66HP's in a #6 rating.  ID set at 60%.  V1 and V2 GT SAG ECC83S's with ratings of
100/108 and 92/95 respectively.  V3 is a GT SAG ECC83S MPI.  Rise time of V1 was replaced with a 45% rise time, 5% longer than the last
tube for a bit more compression and less sharp click when a light pick ( Fender 351 thin celluloid) is used.
 I have had this amp since the
11th grade (1966), and I guess it's tone and sound made too much of an impact on my limited style to change all that often at this time :)  
May 2004 -
#7 GT-KT66HPs set at 70% ID.  V1-V2 ECC83S SAG selected.  V3 ECC83S SAG MPI.  Cabinets used now alternate between a Dr. Z Z-Best
Ported 2x12 (V30 and H30) and a Rivera ported CS-410 4x10 cabinet.   

Groove Tubes Soul-O 45 amp.  Current tube compliment:   12AX7MPI (phase inverter), (7025's in V1 and V2), a 12AT7 (effects loop), and
a 12AU7 for the reverb driver.  The output section is most commonly used with GT-6L6GE's, E34LS, KT-66HP's, 6L6S, and as of 7/11/02
with 6550's
for a project.  This is the amp that is used with pedals as the front end was tailored for pedal use and does not get overloaded as just
about every other amp out there in the universe.  A guitar pickup is a high impedance low level device, while a pedal is a low impedance high output
level device that just turns the front end of amps with a higher gain structure into mush.  It may sound normal to you rather than like mush, but try
your pedals and effects on a Soul-O 45 amp and you will see what I mean.   This amp is by blues amp when I need a bit more than the Deluxe
Reverb, or my rhythm amp or 12 string amp.
 Aug 02 - Output GT-6550C #5, V1 = GT-12AX7A NOS, V2 = GT 12AX7A NOS, V5 = SAG-AX7-MPI.  
Nov 02; Output set now KT-88SV's for a project (Jazz).  Later this month, a change back to 6550C's is planned.   Dec 02 - 6550C's again.
January 03 - currently on loan to Danny Jacob (Leann Rimes) with ECC83's in V1/V2 and E34L-S GT's in the output.
 March 03 - V1
Mullard 12AX7/ECC83 SAG traced.  Output tubes are NOS 6L6WGB biased at 35 mA.  
 As of 4/4-5/2 2003 this amp has gone through
extensive modifications.  This is now a prototype of a Fender meets Marshall sort of amp.  The lower gain front end has been modified
and now has much higher gain.  The B+ is 517v and the amp puts out about 60+ watts off two good 6L6 tubes.  It now has a VFE and
some other features.  If you are in Los Angeles and want to play it, to see how things are progressing, give me a call.  This amp is not
for sale, and the other prototypes are spoken for.  In all there will be ten of these built, and then the prints will be destroyed.  This
amp has a cathode follower tone circuit (Fender Bassman / Marshall Plexi) with one extra gain stage.  It is also a very quiet amp in the
area of background noise.  It surpasses anything else I own in the "neck squeeze test".  
4/04 tube changes; V1 / V2 GT-12AX7M SAG
rated at 1.4/1.4 and 1.2/1.2 respectively.  Bias is set at 75% ID based on B+ on GT-6CA7GE duet calculating them as a 25 watt tube.

Fender Pro Reverb with stock Fender tubes with the exception of V1 being a GT-12AX7R2 with a rating of 92/100, and V2 a GT-12AX7R3 with
a rating of 100/85.  The phase inverter still stock
, as tests are being done with this amp and a Rickenbacker 360-12.  The NORMAL channel of
this amp is used by myself for clean sounds.  The overdrive channel is not used by me ever.  This amp is used for clean 60's rhythm (San Francisco
Acid Rock ... from my childhood), where the single 12" speaker had a bit more clarity than the twin 12's of a Twin Reverb.
 (As of 7/02, 7025's are in
V1 ( at 92/100) and V2 ( at 75/92)  ( dropped front end gain for more clean on the clean channel, as the high gain channel was also too
gainy and not as usable).  The phase inverter was changed from the stock 12AX7 to a SAG-AT7-MPI which gave much more control
over the output section.  The output tubes are now 6L6GE's in a #5 rating.)  
 August 02 - V1 = GT12AX7A (SAG 87/92), V2 = GT12AY7 (to
drop the gain channel as the stock Fender 12AX7 has so much gain that it's articulation is lost and it's range of use on vol/gain were very limited.  V4
(the phase inverter is this somewhat unconventional layout = is a an AT7 now, rather than the factory supplied 12AX7 ( in this case a SAG-AT7-MPI
from my department at Groove Tubes ).
 March 03 - mods for Ludovic Pierson - V2 SAG 12AX7R3 80/85.

Fender Tone-Master   This is a stage amp and some have said it is as loud as a jet engine.   When many folks think "Fender" they think of the
black face amps that are generally thought of as clean amps.  The purpose of this amp is rock.  Two switchable channels and some great features by
Bruce Zinky including a very unique output section that can run at three different wattages.  There are two transformer buffered effects loops, one for
each channel.  The clean side is glorious.  The gain side is all that one could expect from an amp more from the Marshall camp than the Fender
camp.  The front end is much more Marshall than Fender so even on the clean side the amp is not as clean as say a Twin Reverb or a Showman but
with 100+ watts on tap there is more clean headroom available than anybody could generally ask for.  These were spectacular amps and when
Fender brought them out they even did so in the best of the Fender tolex colors in their history from my point of view:  Cream tolex, oxblood grill cloth,
white knobs on the dark brown panel.  This amp is played through the stock Tone-Master 2x12 closed back cabinet at 16 ohms.  The output tubes
are GT-6L6GEs in a #7 rating biased at 34mA.  The three preamp tubes are SAG selected sets that use two short plate 12AX7 tubes and the phase
inverter is a matched phase inverter picked off a long plate 12AX7 type tube.

Groove Tubes Soul-O 75.  The tube compliment of the amp is: V1 = GT12AX7R3 at 116/115,  V2 and V3 are GT-ECC83S, one at 112/110 and
the other at 103/100. (the gain of this amp exceeds the current Marshalls or Bogners as an example. It's gain can pass the levels of a Soldono SLO
100 with less background noise).  The phase inverter, V4, is a GT 12AX7R2 long plate. Its SAG rating is 112/112 and is an MPI (matched phase
inverter).   V5 (effects loop send and return), is a GT12AX7R3 with a SAG rating of 107/110, and a very quiet tube.  The output set are GT-KT88SV's
that are a specific design to Groove Tubes. These are #7's.  The output of this amplifier is in excess of 95 watts. This amp may be re biased to use
any 6L6, 5881, KT66, KT77, 6CA7, EL-34, E34L, E34LS, 6550 or KT88 output tube. The output transformer is of a custom design to allow various
output tubes. The B+ voltage of this amp is about 525 volts.   This amp can run in class A/B, or two different class A configurations. Most amps with a
"Class A" switch, due nothing more than turn off the screen voltage, thus turning a Pentode configuration into a triode configuration. This amplifier
has two class A settings; one which will use the Fender pre 1954 class A circuit topology. The second class A setting uses a cathode bias circuit
topology such as the Vox AC-30 or Matchless. Think of this as a Matchless C-85 on steroids.  There are two channels, clean and scream. These can
also be combined. There is a foot switch that selects the channels, and can also turn on and off the parallel effects loop.

THD Univalve with various tubes and speaker cabinets.  My basic setup is using open back 1x12 cabinets with various Celestion speakers when
using EL-34 / EL-84 tubes, or a Jensen P12R when using 6L6 or 6V6 tubes.  It is currently configured with a NOS Telefunken short plate ( 1.3mA /
1.0mA  1760 / 1420TC )  in V1.  In V2 there is a hand selected ( and not too typical of an example ) NOS Philips EGC JAN 12AT7WC  (  13.1mA /
17.0mA  6700 / 7350 TC ).  In the power tube position there is a Groove Tubes 6L6GE NVM tube as the power tube that rates at 78.3 mA, about 8%
stronger than the typical 6L6 tube.   For the British hi-gain sound I use a JJ ECC83 in V1 (1.3ma / 1.2mA, picked for its curve characteristics), in V2
another JJ ECC83, picked for less gain and a nicer rise time on the curve tracer, at (1.0ma/0.8 mA) and an Electro Harmonix EL-34, as I don't need
the power of a E34LS or EL-34L.
 As of July 02, a Mazda 6V6GT is the output tube for a blues project, with an NOS 12AX7 in V1 and 12AT7
in V2
.  August 02 RCA 6V6 NOS Black Plate.  November 02, Fivre NOS 6V6, JAN 03, Mazda CB 6V6, V1=12AY7, V2=RCA 12AX7. This amp is
used quite often  as a preamp with a Fender BF Twin or teh Pro Reverb.  
As of July 2003, V1 is a GE 5 star 5751, V2 is a Tung Sol 12AX7,
and the power tube is a GE 6L6 or a Tung Sol 5881.  This amp is currently used stand alone for a recording project with a ported 1x12
K&K Audio cabinet with a Celestion G70-12M speaker.

THD Flexi 50 - This amp was purchased in November of 2004.  There is more detail on this amp in a review I wrote on Harmony Central which I also
copied  and included in the THD area of this website
HERE.  The reason for the acquisition of this amp was due to be impressed by a few of these
that had crossed my path.  I wanted a mid power amp that could cover many tonal requirements and this amp did the job better than most of the other
amps I had seen.  This is sold as a "single channel" amp but with it's footswitchable boost and input gain with it's own unique voicing and tone controls
for the boost channel I see no reason why this is not thought of as a channel switching amp.  The transformer isolated line out is perfect for the
largest venues to augment a mic'd cab.  THD may have the best line out in the business, bar none.  The front end of this amp is articulate and
defined at any setting, the tone stack is one of the most impressive I have ever used and the amp has a very extensive feature set that is described
elsewhere.   The amp was delivered with a fine set of NOS 1990's 12AX7C tubes and the great Ruby EL-34B-STR.  I have amps that cover the EL-34
tones and this amp covered them just as nicely, or more so but I was looking for more of a darker tone set and this amp gave me ability to have
whatever I wanted for the most part. The tube set was changed to 3 GT-12AX7M tubes, V3 being an SAG-AX7-MPI built off a 12AX7M.  The output set
is an EL37 Black Plate duet biased as per THD instructions. The name "Flexi" should mean "flexible" when you think of this amp.  The Flexi 50 would
be great for folks wanting to experiment with tube changes or have some of the foot switching features.  The effects loop works very well.  It is a great
amp that is very versatile for a very nice price that is something of a bargain these days.  In May the output tubes were changed to GT-E34LS.   The
clean headroom of this amp in any setting with any tubes is quite a bit lower than other 50 watt grid biased amps that I have in my inventory.  This is a
rock amp for the most part and lives in a particular tonal envelope that feel nice to players of Marshall era amps of the JCM 800 and 900 era.  More
info at THD by

Mesa Boogie Blue Angel -  Mesa Boogie Mk. 1 with GT-6L6S tubes  -   Mesa Boogie Formula preamp

A Carvin Quad X preamp - Carvin DCM-1000 SS amp - loved by rhythm, steel, and jazz folks

Banks of Groove Tubes speaker emulators

Hughes and Kettner Red Box, Blues Master, and Creme Machine preamps.

Various effects for the use of others, and various speaker cabinets.

For pictures many amps, guitars (though not even close to all of them ... these are the ones I play most often), and more
detailed descriptions and information