Guitar Tube Amp Schematics

Here you'll find a modest collection of some interesting (bass)guitar tube amplifier schematics.

Ampeg
Elk
Fender
Gibson
HiWatt
Laney
London City
Marshall
Mesa Boogie
Music Man
Orange
Selmer
Simms Watts
Sound City
Traynor
Vox

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Gemini

G-12 Amp schematic (Joe Piazza)

G-15 Amp schematic (Joe Piazza)

GS-15-R Amp schematic (Joe Piazza)

GV-22 Amp schematic (Joe Piazza)

PortaFlex

B-12-N Amp schematic (1962) (Joe Piazza)

B-12-NC Amp schematic (1964) (Joe Piazza)

B-12-NF Amp schematic (1968) (Joe Piazza)

B-12-XT Amp schematic (1967) (Ampeg)

SB-12 Amp schematic with 6L6GC's (Joe Piazza)

SB-12 Amp schematic with 7868's (Joe Piazza)

B-15-N Amp schematic (1962) (Joe Piazza)

B-15-N Amp schematic (1968) (Joe Piazza)

B-15-NC Amp schematic (1964) (Joe Piazza)

B-15-NF Amp schematic (1968) (Joe Piazza)

B-15-S Amp schematic (1971) (Ampeg)

B-18-N Amp schematic (1967) (Joe Piazza)

B-18-X Amp schematic (1967) (Ampeg)

B-25 Amp schematic (1968) (Joe Piazza)

Super Valve Technology

SVT Pre amp schematic (1972) (Joe Piazza)

SVT Power amp schematic with 6550's (Ampeg)

SVT Power amp schematic with 6550's (1970) (Joe Piazza)

SVT Power amp schematic with 6146's (1969) (Joe Piazza)

V Serie

V-2 Amp schematic (1971) (Ampeg)

V-2 Pre amp schematic (1971) (Joe Piazza)

V-2 Power amp schematic (1971) (Joe Piazza)

V-3 Amp schematic (1970) (Ampeg)

V-3 Pre amp schematic (1970) (Joe Piazza)

V-3 Power amp schematic (1970) (Joe Piazza)

V-4/VT-22 Amp schematic (1970) (Ampeg)

V-4/VT-22 Amp schematic (1974) (Magnavox)

V-4 Pre amp schematic (1970) (Joe Piazza)

V-4 Power amp schematic (1971) (Joe Piazza)

V-4B Amp schematic (1971) (Ampeg)

V-4B Pre amp schematic (1971) (Joe Piazza)

V-4B Power amp schematic (1971) (Joe Piazza)

V-7 Power amp schematic (Joe Piazza)

V-9 Pre amp schematic (Ampeg)

V-9 Power amp schematic (Ampeg)

V-9 Pre amp schematic (1975) (Joe Piazza)

V-9 Power amp schematic (1975) (Joe Piazza)

VT-22/V-4 Amp schematic (1970) (Ampeg)

VT-22/V-4 Amp schematic (1974) (Magnavox)

VT-40 Amp schematic (1971) (Ampeg)

VT-40 Pre amp schematic (1971) (Joe Piazza)

VT-40 Power amp schematic (1971) (Joe Piazza)

Most of the above listed Ampeg schematics originated from Joe Piazza's Backstage.

Also worth checking out is the Blue Muse Unofficial Ampeg Page.

For Ampeg parts see the FlipTops site.

For more Ampeg V4 information see the Ampeg V4 pages.

If you want to see what Ampeg is up to nowadays, you might want to check out the Ampeg site.

Elk was a Japanese manufacturer (Miyuki Ind. Co.) who started out in 1953 making amplifiers inspired by the Fender amplifiers of the day. The original brand name was Echo. In the early 60's Miyuki started making pro quality guitars under the brand name of Elk and changed the brand name of the amplifiers to Elk as well. The brand probably stopped in the early 1980's.

Miyuki also used the Luxor and Royal brand names for their amps in Europe.

In 1969 there was a big fire in the factory, burning many amps and guitars. Quite a shock for the people who worked there.

It seems that the later Elk amps had solid state preamps and tube power amps.

Japanese Elk partial magazine article. It looks like some sort of timeline stating which models were introduced in which years.

Can anyone translate this to english?

ES-30, Stageman 30

This 15W combo was fitted with a 12" AlNiCo speaker.

Stageman 30, schematic.

EL-30, Custom Amp 30

Photograph of an Elk Custom Amp 30 top.

EL-50, Custom Amp 50

Photograph of an Elk Custom Amp 50 top.

EB-213, Custom Amp 60, 60W top.

This top was often seen residing on a 3x12" speaker cabinet. It was fitted with 2x 6CA7 (EL34), 4x 12AX7 (ECC83), 1x 6AQ8 (ECC85) and 1x 5AR4 (GZ34).

Photograph of an Elk Custom Amp 60 top.

EB-213S, Custom Amp 75

This top has a 2,7Ω output, so I think it was meant to reside on the 3x12" Elk speaker cabinet.

Photograph of an Elk Custom Amp 75 top. Thanx to Dick Sikkema.

EL-150L, Custom 150L

No info on this amp yet.

EL-150S, Custom 150S

No info on this amp yet.

EB-103, Pro-Sonic, 2x12" combo

The power amp section is fitted with 2x EL84's so it's probably a 15W or 20W amp.

EB-105, Guitar Man, 45W 4x10" combo

This 4x10" combo uses the same amp chassis as the EB-202 Twin Amp. It was fitted with 2x 6CA7 (EL34), 4x 12AX7 (ECC83), 1x 6AQ8 (ECC85) and 1x 5AR4 (GZ34).

EB-202, Twin Amp 45

This amp was fitted with two EL34's and has a 4Ω output to match its 2x12" 4Ω cabinet. It was fitted with 2x 6CA7 (EL34), 4x 12AX7 (ECC83), 1x 6AQ8 (ECC85) and 1x 5AR4 (GZ34).

EB-202S, Twin Amp 50

This amp was fitted with four ECC83/12AX7's, an ECC85/6AQ5, two EL34's and a GZ34/5AR4 rectifier tube and has a 4Ω output. Apparently this used to be the Twin Amp 45 but I guess Twin Amp 50 sold better.

Twin Amp 50 schematic. (Thanx to H. Wessels, PA2HWG).

Photograph of an Elk Twin Amp 50 top.

Twin Amp 60

Photograph of an Elk Twin Amp 60 top.

VK-50, Viking 50

Photograph of an Elk Viking 50 top. (Thanx to Mark).

VK-60, Viking 60

The VK-60 cabinet for this top is a 2x12" 4Ω cabinet.

Photograph of an Elk VK-60 cabinet. (Thanx to Dick Sikkema).

VK-100, Viking 100

Photograph of an Elk Viking 100 top on its cabinet.

VK-100S, Viking 100S

Photograph of an Elk Viking 100s top on its cabinet.

VKB-100, Viking Bass 100

VKB-100, Viking Bass 100, schematic. (Thanx to Joe "Fire" Dudzik).

Photograph of an Elk Viking Bass 100 top. (Thanx to Rikkert Gordijn).

VKB-135, Viking Bass 135

No info on this amp yet.

Obviously information on the Echo & Elk brands and the amps is scarce. If you have any material you would like to share, it would be most welcome ofcourse!

Champ

Champ Amp, 5C1 schematic, (Fender Musical Instruments)

Champ Amp, 5C1 layout, (Fender Musical Instruments)

Bassman

Bassman Tweed 5F6-A Amp schematic, (Fender)

Bassman Tweed 5F6-A Amp layout, (Fender)

Bassman 100 Amp schematic, (CBS)

Bassman 135 Amp schematic, (CBS)

See the excellent Fender Amp Guide for lots and lots of information (including schematics) on almost all vintage Fender tube guitar amps.

See Viva Analog's Fender Amps Page for a lot of technical information on modding Fender amps.

See Fender's own Schematics Page for the modern Fender amp schematics.

If you want to see what Fender is up to nowadays, you might want to check out the official Fender site.

GA-1RT Maestro Reverb-Echo, 8W 1x8" Combo

With reverb-echo.

Schematic with 1x 12AX7, 1x 6BM8 & 1x 5Y3GT, (Gibson)

GA-1RVT Maestro Reverb-Echo, 8W 1x8" Combo

With reverb-echo and tremolo.

GA-2RVT Maestro Deluxe Reverb-Echo, 16W 1x12" Combo

With reverb and tremolo.

Schematic with 4x 6EU7, 1x 12AU7A, 2x 6V6GT & 1x 5Y3GT, (Gibson)

GA-3RV Reverb III

All transistor pre-amp with reverb and tremolo.

Schematic, (Gibson)

GA-4RE Reverb Echo

Pre-amp.

Schematic with 2x 6EU7 & 1x 12AU7, (Gibson)

GA-5 Les Paul Junior, 5W 1x10" Combo

The Gibson amplifier model GA-5 has had many incarnations. The first model GA-5 Les Paul was introduced in 1954. The circuit of this amp is an almost identical copy of the Fender Champ (5C1 circuit). It was fitted with a Jensen 10" field coil speaker. It had a "TV" style cabinet.

Schematic with 1x 6SJ7, 1x 6V6 & 1x 5Y3, (Gibson)

Schematic with 1x 6SJ7, 1x 6V6 & 1x 5Y3, (Joe Piazza)

Fender Champ Amp, 5C1 schematic, (Fender Musical Instruments)

GA-5 Skylark, 5W 1x8" Combo

GA-5T Skylark Tremolo, 5W 1x8" Combo with Tremolo

The GA-5 Les Paul was renamed to Skylark in 1957. This Skylark lasted till 1961. The 10" speaker was changed to an Jensen 8" 'special design' speaker. The input circuitry was changed too. In 1962 the Skylark underwent a major redesign.

Schematic (1957) with 1x 12AX7, 1x 6V6 & 1x 5Y3, (Joe Piazza)

Check out John King's GA-5 page if you're looking for more info on the GA-5 amps.

GA-6

This amp is very similar to the Fender Tweed Deluxe (5C3).

GA-6 Lancer, 14W 2x12" Combo

This amp replaced the BR-6. The circuit is identical to that of the GA-14.

Schematic with 2x 12AX7, 2x 6V6 & 1x 5Y3

GA-7 Les Paul TV, 4W 1x10" Combo

Introduced in 1955/56. It used the same circuit as the GA-5 Les Paul Junior amp.

GA-8 Gibsonette, 9W 1x10" Combo

Photograph of 1952 Gibsonette.

GA-8 Discoverer, 9W 1x10" Combo

There were at least two different models GA-8 Discoverer.

GA-8T Discoverer Tremolo, 9W 1x10" Combo

The first GA-8T was in production from 1954 upto 1961. It was covered with tweed, and used a 12AX7, two 6BM8 triode/pentode tubes and a 5Y3 rectifier. The second GA-8T was part of the Crest Line range of amps and was in production from 1962 upto 1966 and used two 6EU7's, two 6BQ5 pentodes and a 6CA4 rectifier. This was the same amp as the Epiphone EA-35T Devon.

Schematic of the first GA-8T with 1x 12AX7, 2x 6BM8 & 1x 5Y3.

Photograph of 1962 GA-8T Discoverer Tremelo.

GA-9, 10W 1x10" Combo

This amp replaced the BR-9. It used a 6SJ6 pentode on the input, two parralled 6V6 tubes as a single ended power amp and 5Y3GT rectifier.

GA-14 Titan, 14W 1x10" Combo

The circuit of this amp is identical to that of the GA-6 Lancer and the Epiphone EA-30 Triumph amp.

GA-15 Maestro, 14W Amp

This amp was introduced in 1955.

Schematic

GA-15RV Maestro, 14W 1x12" Combo

GA-15RVT Explorer

With reverb and tremolo. This is the same amp as the Epiphone EA-32RVT.

Schematic

GA-16T Maestro Viscount, 14W 1x10" Combo

Schematic

GA-17RVT Scout

Schematic

GA-18T Explorer, 15W 1x12" Combo

With tremolo.

GA-19RVT Falcon

Schematic

GA-20 Crest, 14W 1x12" Combo

This amp was introduced in 1950. This amp is almost identical to the Epiphone EA-25 Century amp.

Schematic

GA-20T Ranger, 16W 1x12" Combo

This amp was introduced in 1956. With tremolo. This amp is almost identical to the Epiphone EA-25T Century amp.

GA-20RVT MinuteMan

With reverb and tremolo.

Schematic

GA-25, 15W 1x12" & 1x8" Combo

This amp was introduced in 1947.

Schematic (1961) (Gibson)

GA-25RVT Hawk, Combo

Schematic (1963)

GA-30 Invader, 14W 1x12" & 1x8" Combo

This amp was introduced in 1948.

Schematic with 2x 6SJ7, 1x 6SC7, 2x 6V6 & 1x 5Y3

GA-30RV Invader, 14W 1x12" & 1x8" Combo

This amp was fitted with a P12R and a C8S speaker. It had a reverb. It used 3x 6EU7, 1x 12AU7, 2x 6V6 and 1x 5Y3 tubes.

GA-30RVT Invader, 25W 1x12" & 1x10" Combo

With reverb and tremolo.

GA-30B

Schematic

GA-35RVT Lancer

With reverb & tremolo.

Schematic

GA-40 Les Paul, 14W 1x12" Combo

This amp was introduced in 1952. With tremolo. The speaker is a 12" Jensen Concert.

GA-40T Les Paul, 25W 1x12" Combo

This amp was introduced in 1955. With variable tremolo.

GA-45RV Maestro, 16W 4x8" Combo

This amp was introduced in 1955. With reverb.

Schematic with 3x 6EU7, 1x 12AU7A, 2x 6V6GT & 1x 5Y3GT (courtesy of Keith Robb)

Photograph (courtesy of Keith Robb)

GA-45RVT Saturn?

With reverb and tremolo.

GA-45T Maestro, 16W 4x8" Combo

This amp was introduced in 1955. With tremolo. It is essentially a GA-40 with a bass & treble tone control and a different speaker configuration.

GA-46T Super Maestro, 60W 2x12" Combo

With tremolo.

GA-50, 1x12" & 1x8" Combo

This amp was introduced in 1948.

GA-50T, 1x12" & 1x8" Combo

With Tremolo. This amp was introduced in 1948.

GA-55, 18W 2x12" Combo

This amp was introduced in 1954.

Schematic with 2x 12AY7, 1x 6SC7, 2x 6L6GA & 1x 5V4G

GA-55V, 18W 2x12" Combo

With vibrato. This amp was introduced in 1954.

GA-55RVT Ranger, 50W 4x10" Combo

With reverb and tremolo.

GA-60 Hercules, 25W 1x12" Combo

GA-70 Country Western, 25W 1x15" Combo

This amp was introduced in 1955/56. It was fitted with a Heavy Duty Jensen 15" Concert speaker with an Alnico V magnet.

GA-75 Recording, 25W 1x15" Combo

This amp was introduced in 1950.

Schematic with 2x 6EU7, 1x 6C4, 1x 6FQ7 & 2x 6L6GC

GA-77 Vanguard, 25W 1x15" Combo

With high gain channel.

Schematic

GA-77RV Vanguard, 25W 1x15" Combo

With reverb and high gain channel.

GA-78RV Maestro 30, 2x15W 2x10" Combo

With reverb.

GA-79RV Stereo-Reverb, 2x15W 2x10" Combo

With reverb and high gain channel.

GA-79RVT Stereo-Reverb, 2x15W 2x10" Combo

With reverb, tremolo and high gain channel.

GA-80 Vari-Tone, 25W 2x15" Combo

With improved tremolo and 6 preset tone control switches.

GA-83S Stereo-Vib, 2x18W 1x12" & 4x8" Combo

With stereo vibrato.

GA-85, 25W 1x12" Combo

GA-86 Ensemble, 25W head with 1x12" Cabinet

With removable control panel.

GA-87 Maestro Stereo, 2x18W 2x12" Combo

Stereo accordion amp with reverb.

GA-88S Stereo Twin, 2x18W 2x12"Combo

GA-90, 25W Combo

This amp was introduced in 1953.

GA-100 Bass, 35W Head with 1x12" Cabinet

The control panel is seperated from the speaker cabinet. This is the same amp as the Epiphone EA-70 Bass amp.

GA-200 Rhythm King, 60W 2x12" Combo

Two channel high fidelity sound with built in compression circuit to prevent overloading.

GA-Super 400, 60W 2x12" Combo

Three channel high fidelity sound with built in compression circuit to prevent overloading.

Check out Björn Anger's The Gibson Amp Project site with lots of information on a lot of old Gibson tube guitar amps.

Check out John King's GA-5 page if you're looking for more info on the GA-5 amps.

If you want to see what Gibson is up to nowadays, you might want to check out the Gibson site.

DR103, 100W

Pre amp schematic

Power amp schematic

PSU schematic

DR112, 100W

Pre amp schematic

Power amp schematic

PSU schematic

DR201, 200W

Pre amp schematic

Power amp schematic

PSU schematic

DR203, 200W

Pre amp schematic

Power amp schematic

PSU schematic

DR405, 400W

Pre amp schematic

PSU schematic

Power amp schematic

DR504, 50W

Pre amp schematic

Power amp schematic

PSU schematic

L50R

Pre amp schematic

L100R

Pre amp schematic

SA112, 50W

Power amp schematic

PSU schematic

SA115, 50W

Power amp schematic

PSU schematic

SA212, 50W

Power amp schematic

PSU schematic

STA100, 100W

Pre amp schematic

Power amp schematic

PSU schematic

STA200, 200W

Pre amp schematic

Power amp schematic

PSU schematic

STA250, 200W

Power amp schematic

STA400, 400W

Power amp schematic

PSU schematic

Check out the HiWatt Story for more information on the HiWatt tube guitar amps.

HiWatt UK is worth checking out too.

See the Shinrock Transformers HiWatt DR103 page for a DR103 restoration project, with lots of pictures.

See Mark Huss's HiWatt page for a lot more technical infromation.

GC30V

Amp schematic, 2279 (1994) (Laney)

LC50 Combo

Amp schematic, (Obsolete Electronics)

Klipp 100

Amp schematic, (Obsolete Electronics)

Super Group 100 Mk1 (1969)

Schematically this amp is very similar to the Marshall Super Lead 1959 amp.

Pre amp schematic, (Thanx to Ico van Diemen)

Power amp schematic, (Thanx to Ico van Diemen)

PSU schematic, (Thanx to Ico van Diemen)

Thanks to and with permission of Joe of Obsolete Electronics for some of these Laney schematics.

If you want to see what Laney is up to nowadays, you might want to check out the Laney UK site.

The London City brand was created in the late 1960's by the Dutch Sound Experience (DSE) when a music shop in Amsterdam wanted a cheaper alternative for the expensive Marshall amps of that time. The London City 100W heads were schematically very close to the Marshall model 1992 Super Bass amps, but they were built using cheaper parts. Especially the transformers weren't very robust.

At first the amps were grey. Amps from this time were the DEA50's and DEA100's. Later, probably in 1971 or 1972, the switch was made to the very characteristic green/cyan colored amps. Examples of these amps are the DEA70 MkV and the DEA130 MkV. Even later in the early 1980's, shortly before the demise of London City, the amps were made in black.

A competing music store also wanted to sell these London City amps. These amps were branded as Power City. They were identical to the London City amps though. The Power City amps were produced in grey longer than the London City amps.

These amps were hand built on an aluminium U shaped chassis, terminated with two blocks of wood at both ends of the chassis. As costs had to be kept low, build quality was mediocre. If, for example, the 22nF capacitors were out of stock then 27nF caps would be used instead, no questions asked. You'll find many schematic details differing from one amp to the next due to this "policy".

These amps do have the potential to sound very good though. After a retube, recap, fitting the screen grid resistors on the tube sockets and changing the power amp section to Marshall specs, and some other tweaks, these amps really do rock! Move over Jimi... ;o)

I've recently had a Castle top in the shop. This amp too originated from the London City stable. The build quality and the transformers were better, and instead of 4 inputs and two channels this amp has two inputs and one channel with an extra distortion control. It also sported an extra 4 ohm output and a P.A. line level output. The cabinet was black and the chassis was painted black and had a turquoise colored imprint.

The London City 4x12" cabinets were fitted with the Celestion G12H30 bass speakers. The 2x15" Super Bass cabinets were fitted with RCF speakers.

DSE London City info.

DSE 1978 price list in Dutch guilders.

DSE brochure, part 1.

DSE brochure, part 2.

Logo's

4 different London City logo's. The first logo is from the grey period, the second logo is from the green/cyan period, the third logo was never used and the fourth logo is from the black period.

DEA70 MkV Super Amplifier

Amp schematic (courtesy of Ilppo Nousiainen)

DEA100 Super Amplifier

Amp schematic (with some obvious errors!)

Thanks to Nico van Gijn for most of this info and the pictures!

The Marshall section has grown so large that it now is a seperate page to keep matters manageable. Go to the Marshall Page.

There are no Mesa Boogie schematics here, but have a look at Maarten van Helden's Mesa Boogie Page.

Music Man

GB-2, 150W

2275, 2475 chassis schematic, 8001 (Music Man, 1980)

GP-3, 65W & 100W

Schematic (Music Man)

GP-3A, 65W & 100W

Schematic, 6001 (Music Man, 1980)

RD-50A,

Schematic, 5004 (Music Man, 1980)

If you want to see what (Ernie Balls) Music Man is up to nowadays, you might want to check out the Music Man site.

Check out pacAir's Music Man site.

Check out the Music Man Amps Discussion Forum.

Graphic 120

Mk2 Amp schematic (Orange)

Mk2 Amp schematic (Orange, 1972)

Mk2 Amp schematic (Musonic, 1974)

Do check out Geert Jacobs Orange Amps Field Guide with lots of links, pictures and other info concerning the Orange amps.

If you want to see what (the newly revived) Orange is up to nowadays, you might want to check out the Orange Amps site.

You might also want to check out the Mat Amp site. Mat Amp (Mat Mathias) was the original manufacturer of the Orange amps.