Below I will have continually updated vacuum tube data sheets listed and guitar amplifier prints. There are also links to some websites with prints on the first page of this website. In the area of guitar amp schematics on the front page are also links to speaker manufacturers where there are detailed specs on many speakers.
5751 – 5751WA – 6550 – 6550A – 6550 C Svetlana – RCA 6BQ5 / EL84 – Svetlana 6L6GC – Tung Sol 6L6WGB – 6V6GT – 6V6GTA – 7025 #2 – 7025 – 7189A – 7408 – B339 – E83CC – ECC803S – ECC803S #2 – ECC83 – Svetlana EL-34 – EL-37 – EL-84 – GE 6L6GC – KT-66 – KT-77 – KT-88 – KT-88 #2 – KT-88SC – KT-88S 50 watt – RCA 6V6GTA – Amperex 5AR4 – GE 5AR4 / GZ34 – GE 12AX7 – GE 7025 – RCA 7025 – Telefunken EL34 – Mullard EL34 – Philips EL34 – GT E34LS – GE 12AU7 – GE-12AY7 – GE 5814 – GE 6072 – 12AY7 – GE 6201 – 12AT7 – GE 6L6 – JJ 6L6S – JJ 6V6S – JJ 7027 – JJ 7591 – JJ E34L – JJ KT-88 – Marconi 12AU7 – Mazda EF86 – Mullard EL-37 – Philips 12AT7 – Philips 12AU7 ECC82 – Philips 6201 – Philips 6BM8 ECL82 – Philips – Mullard – Amperex EF86 – Philips 2 – 12AT7 – Philips EF86 – RCA 12AY7 – RCA 6679 12AT7 – RCA 6L6 – RFT 12AT7 ECC81 – RFT 12AU7 – Sylvania 5814 – Sylvania 5963 – Sylvania 6L6 – Sylvania 5932 – Sylvania 6L6 different version – Telefunken 6267 EF806S – Telefunken ECC801S – Tung Sol 5881 – Tung Sol 12AT7 – GT Exclusive E34LS 30 watt EL34 – GT Exclusive KT66HP – GT Exclusive KT88SV (vintage) 42 watt KT88 – Telefunken E88CC / 6922 – Tung Sol 5881 – RCA 12AZ7 – GE 5751 – 7868 RCA – 7189 Sylvania – Philips GZ34/5AR4 – Tung Sol KT120 – Tung Sol 12AX7 – Philips ECC83/12AC7 – RCA Tube Manual
It is important to keep in mind that all tubes of the “same type” may not share characteristics. As a few examples, the 6L6 tube types can range from the mid 20 watts to 30 watts of max dissipation. The EL-34 is generally a 25-watt tube while the E34LS is a 30 watter. The KT66 is thought of as a 25-watt tube but also carried a 30 watt “maximum” rating on some sheets. The 6550s ran from 35 or so watts to 42 or so. The KT88 is stronger than a 6550 and ran from the 32 or so watt versions to 50 watts with the KT88S and 42+ watts with the KT88SV. Refer to the datasheets above for exact figures.
The 12AX7, 7025 and ECC83 carry the same specifications but may sound very different, especially in the first gain stage of your amp. Swapping different tubes of the same type is a fast and easy way to get different tone or response from your amp. V1 or V2 in some amps such as the Vibrato channel in Fender black face and silver face amps (the first gain stage) has more impact than the changing of any other tube for the most part. 12AT7, 12AY7, 5751, etc., will all react differently depending on brand, construction (due to changes in materials and construction), etc.
List of GT tubes
As a bit of side info – Some people think that Groove Tubes “re-brands” other factories tubes. They do sell a number of tubes from other factories that go through GT’s own selection and testing process in some cases but they also have a number of tubes specific to GT which are of their own design and done on their own tooling – exclusive to GT. Some of these are:
- GT-E34LS (the only 30 watt EL-34 tube with additional plate mass and is NOT the same as the JJ E34L. If you look at the JJ and GT side by side at the plates you will see a physical difference.
- GT-KT88SV – also an exclusive tube off GT and Penta tooling out of the JJ factory from a long standing relationship with JJ and formerly Tesla.
- GT-6CA7GE – the reproduction of the General Electric 6CA7 which is an electrical replacement for the EL-34 tube but has a harder vacuum and an active beam forming element not found in an EL-34.
- GT-6L6GE – the reproduction of the General Electric 6L6GE clear top using the original micas and materials. This tube is stock issue in Fender’s custom shop series amplifiers.
- GT-KT66HP – a proprietary KT66 which can handle over 525 volts on the plates.
- 12AX7M – a reproduction of the Mullard 12AX7.
Actual test results on current production tubes
One reason I will be doing this, is that all current tube makers show the specs for their tubes by just copying the specs of the past that are the standards. Unfortunately … everybody falls way short of the standards and the range of specs in any given run is +/- 50% typically, and typically on the minus side. There is very little consistency today.
I am in the process of building datasheets for all the GT proprietary tubes and I am working with Aspen to get him to allow me to publish ACTUAL data and curves, not just replicate spec. I want to do this on EVERYBODY’S current production tubes and publish this. Doing things this way will there be a bit better chance of keeping the tube makers honest and have them improve or utilize better QA processes. I spent almost ten years at United Technologies doing QA so it is a bit hard to let go of some of those
methods. That is one reason the GT-12AX7M has gone through at least ten design and tooling changes, and many material changes. I get samples, I find problems, I shut down production if I can.
If, as an example, the GT 12AX7M has specs that are not as good as they should be, they will be published just like everybody else’s as an example. The same set of standards will apply to everybody. Hopefully some day we can once again have tubes that are the same in their specs and the only decision for the player will be to pick what tonal characteristics they prefer. Right now most people cannot even compare two tubes tonally as they generally differ way too much to make it an accurate comparison.
Guitar Amplifier Prints and JCM 2000 bias instructions plus some manuals
Fender 65 Deluxe Reverb Reissue – Fender 65 Super Reverb Reissue – Fender 65 Twin Reverb Reissue – Fender Blues Deluxe – Fender Blues Junior – Fender Hot Rod DeVille – Marshall Model 1959 100 watt – Marshall JCM 2000 Bias Instructions – Marshall JTM-30 page 1 – Marshall JTM Valve Combo and JTM 600 manual – Marshall JTM30 page 2 – Mesa Boogie Mk 1 – Mesa Mk1b – Mesa Mk 2 – Sunn 100S – Sunn 200S – Sunn 200S #2 – Sunn 200S power section – Sunn 220S – Mesa Boogie 290 – Vox AC-50 – Ampeg B12 and B15 – Gretsch 6162 – Gibson Guitar Serial Numbers – Guytron GT-100 owner’s manual – Fender Prosonic – Fender Dual Professional – Fender Tonemaster – Fender Vibrosonic – Fender Vibro-King – Fender Cyber-Twin – Magnatone 260A – Magnatone 450A –Magnatone 460 – Magnatone 480 – Ampeg SVT Preamp – Ampeg SVT Power Section 6550 – Ampeg SVT Power Section 6146b – Ampeg VT-22 – Ampeg VT-40 – Matchless Chieftan – Matchless DC-30 – Matchless Hurricane – Matchless Lightning – Matchless Lightning 15 – Matchless Spitfire – Matchless Tornado – Matchless Vibrobox – Groove Tubes STP (G)
Preamp Tube Actual Specs
Preamp Tube Actual Curves
Output Tube Actual Specs
Output Tube Actual Curves