custom reverb combo

vintage Traynor guitar amplifier rescued and re-introduced….


when i was growing up in southern Ontario, Canada and getting into playing amplified music, there was a brand of gear – Traynor – that was manufactured out of  Toronto’s Yorkville Sound, headed up by a technician/musician named Pete Traynor.

as i remember, this gear was plentiful but considered average, functional, dependable – it would get the job done but nothing fancy. It was everywhere – speakers, PA components and lots of amps for guitars and basses. If you needed to outfit your band and not spend a fortune, this was the stuff you used.

what i didn’t know at the time (or wasn’t really concerned with) was that from the mid-60’s to early 70’s this workshop was churning out some of the most reliable, hand-wired units found anywhere,  made with top quality components and were destined to last for decades.

it is interesting to see that there is still a healthy inventory of this gear still in circulation in southern Ontario, where you can find original YGM’s (Guitar-Mate combo’s) and (less so) YBA’s (Bassmaster heads) and YSR’s (Custom Reverb heads) offered for sale for less $ than the current (2019) re-issues of YGM and YBA from the Traynor brand.

The re-issues are admirable, hand-wired tributes, but i don’t think they can come close to the original units outfitted with enormous over-sized Hammond power transformers, Mallory capacitors, ‘mustard’ caps, Mullard tubes and other vintage-era components. The originals were built to last, and they have.

Traynor YSR-1 Custom Reverb Combo

i cannot recall how, or when i first acquired the Traynor head, but it was rediscovered (sept 2014) in the attic after idling there for 20 yrs or so. I had thoughts on scavenging some tube components for another amp i was working on at the time, and i kinda knew i had an old tube amp of some kind in the attic.

but when i brought it out and opened it up (what?!), i decided to see if this Traynor could be useable. Connected to an old speaker cab, and a mismatch of old power tubes, it powered on and was fully functional. Only a little noise from dusty pots that hadn’t been rotated for 20 yrs. As soon as i dialed in the tremolo, i was hooked.

i had discovered a hand-wired beauty – all tube, reverb and tremolo,  and containing heavy-duty , high quality vintage components, circa 1971. And , via Pete Traynor’s  Yorkville Sound workshop in Toronto, a local and Canadian made gem.

i wasn’t really aware of what i had found. As soon as i opened it up and had a look, i started the research that would pull me into the history of these amplifiers, as well as the construction and design of the components that it contained.

mine was missing the front logo, and had all the knobs replaced at some time, but looked very much like this one.

earlier versions (1968 ish) of this amp had 2 pilot lights, on/off & on/standby, and reverb transformer  – mine was a later version (1971) with single pilot, without the reverb choke design, but still the squared outline around the 2 channel inputs on the front plate. Later versions used an oval outline.

i had some experience with soldering and wiring guitars and cables, etc, but was just starting to learn about the functions and components of a tube amp. I enlisted the help of a good friend, Dave Fougere, a brilliant musician/technician , who would give me an overview of the wiring and where to start with bringing this amp up to date.

i read countless pages on the internet regarding every aspect of this family of Toronto-based sound equipment, but particularly about Traynor’s  Custom Reverb YSR-1 and Bassmaster YBA amps, (closely related) and would not have been able to do very much myself , without this wealth of available information. It seemed this era of Traynor amps was very highly regarded for quality of construction and unique voices – there is lots of conversation on the web from techs getting inside of these. A testament to their usability and staying-power.

so i decided to not only bring the amp safely up to date, but to modify the interior and exterior to suit myself. As a result it has lost it’s ‘original vintage’ state, but i believe i have kept it’s voice true to it’s origins. Obviously i have made major modifications to its shape and format, but i have left the circuit pretty much intact with only minor (and reversible) modifications.

head to combo

what i really wanted was a combo amp, chassis and speaker contained in one box.

i also really wanted a combo that was relatively low-powered, along the lines of a Fender 22W Deluxe Reverb. However, this amp was going to be a different beast. This circuit was rated at 45W and everything i read about it declared that it was loud. So i tailored my modifications to try to tame that, to try to make the result end up at the lower end of the power/volume scale. The wiring circuit in this amp is inherited from Traynor’s YBA Bassmaster amps, which was in turn derived largely from the 1950‘s Fender Bassman circuit . An admirable lineage.

the YSR-1 is a marvel of sensible design. the interior chassis has a support ledge on each side that fits into grooves cut into the sides of the cabinet, so removing is easy – 4 screws undo from the top and the chassis slides out. the reverb tank is built into the bottom of the cabinet and is accessible from a panel located on the outside bottom.

so, i knocked apart the head cabinet but  kept the top and bottom panels. 

made 2 longer sides and re-attached the top and bottom, now in a cabinet that could also accommodate a speaker.

i kept the top panel, as i liked the handle and the vintage tolex , and kept the bottom panel , as it neatly houses the spring reverb tank.

i used the front speaker baffle from an older amp, so i could install 12” speaker, and kept the back open. Later i installed a partial panel to make the back semi-open.

i love the combo format and the pairing of the amp with a single Celestion G12M Creamback  65W 12″ speaker gets me the sound and volume options i was looking for – but it is a heavy beast to carry.

circuit updates and modifications

volume controls

this amplifier has 2 pairs of input jacks on the front panel – a pair (hi and low) for channel 1 and a pair for channel 2. Channel 2 has an added capacitor for brighter tone. Each channel has an independent volume control, similar to old Marshall ‘plexi’ amps. There is no master volume, nor ‘gain’ control. These two channels are wired in a way that they can be combined , to be active at the same time. The easiest way to combine is to use a short ‘jumper’ cable that connects the two channels together.

i changed the vol pots to 1M values, from the original 4M – which makes the volume much more gradual and useful throughout the sweep. i liked the result but wanted more options.

both vol pots were changed to 1M push-pull pots – vol 1 has a ‘bright’ cap engaged with the push-pull and vol 2 has a ‘channel defeat’ when engaged.

if you are plugged into channel 1 , channel 2 can be ‘defeated’ with the push-pull which removes this path entirely. the quality and clarity change of the channel 1 signal is quite noticeable. channel 1 engaged with the ‘bright’ cap adds a bit of high end with a guitar that may need it.

i had another option in mind with this setup – i wanted to able to ‘footswitch’ channel 2 on and off, so i wired the channel 2 ‘defeat’ to the ‘reverb footswitch’ jack on the rear panel

– a customized footswitch plugged into the 2 footwitch jacks can now toggle the tremolo and channel 2 on/off.

i have removed the foot-switchable reverb function, but gained the much more useable channel 2 on/off toggle.



master volume

another major addition i added was a Post-PI master volume circuit (PPIMV or Post Phase-Inverter Master Volume) which, by way of a dual-ganged pot, gradually grounds out the analog signal travelling to the output tubes. Pot is mounted on the rear panel in spot left by the (removed) ground switch.


i don’t use this control very much, but is useful for slightly notching down the volume and still retaining the tone.

when the pot is at zero, the circuit is effectively taken out of the signal path.





i based my wiring on the schematic below




other wiring changes

i was advised to change all the electrolytic capacitors as they are components that could deteriorate and dry out with time, causing some noise issues with the circuit.

the amp wasn’t excessively noisy, the caps including the big cans were probably still ok after 40+ years, but i went ahead and changed them anyway.

the original Mallory filter caps were 450V 40/40 – i left the Mallory’s in place but re-routed and rewired a pair of JJ 32/32 mounted inside the chassis.

also replaced all electrolytic caps on the eyelet board, the blue-coloured ones, with fresh ones.

now there are zero noise issues with the amp and it’s good for another 40+ years…

tone caps

there were a couple of cracked caps in the tone wiring, so i replaced two but left all values the same.

the tone circuit in this amp takes some getting used to – i am not tech enough to understand completely, but it is very much linked to the overall volume……

also changed the feedback resistor (R51) from 100K to 47K



power cord

one of the very first changes i made to the amp was switching the 2-prong power cord to a grounded 3-prong cord, and removed the associated ‘death-cap’ resistor. safety first….


tube resistors

the original design had only one common  screen resistor wired to both power tubes (R34 on schematic).

i replaced the 470R with two 1k-5W units, one to each power tube. These will help with the longevity and health/safety of the power tubes.

these are the two green resistors at the end of the eyelet board.

bias control

the amp had a fixed bias circuit, but i wanted to try different tube types, so i added a variable bias control – operated from the exterior by a small pot (at left in picture above)

i have biased and tried EL34’s, 6CA7’s and even 6V6 in this amp, but in the end i prefer the big-bottle 6CA7 , which is the spec’d tube for this amp.


the schematic calls for 6CA7  power tubes , so that is what i use. EL34 will work (with re-bias) and i have tried, but i prefer the sound of 6CA7 – they have a more raw and immediate sound compared to the smoother crunch of the EL34.

The 6CA7/EL34 are, in some manufacturers catalogue, one and the same – however i have used the big-bottle 6CA7 by Electro-Harmonix and find a quite different sound than the Tung-Sol EL34.

I seem to go back and forth with these 2 types …..

the amp head still had all original preamp tubes – 12AX7 /7025 with ‘Phillips’ branding which were actually Mullard (UK)

i have used the original vintage Phillips (Mullard) 12AX7 in 2 preamp slots (V1 and V2), and use other brand 12AX7 in rest (reverb, tremolo) and currently using 5715 in phase-inverter spot, slight less gain, more headroom.

i have tried some other lower-powered variants (12AU7, 12AT7) , which can tame reverb or tremolo intensity, and can reduce power-output via phase-inverter, but i have gone back to original lineup of 12AX7 and  5751 in PI slot.

in the end….

i love to play this amp. The presence and clarity, dynamic touch and  punch are completely useable through the whole volume sweep. Jumping the 2 front panel channels together opens it right up and gives it a vintage snap that can be dialed up or down, for a hugely versatile range.

I imagine the tone gets somewhere between old Fender combo’s  and Marshall vintage , but it is it’s own sound.

i soon as i did the basic mods (3 prong power, filter caps), i started using it and completed the rest of the circuit modifications and cabinet alterations during the course of the next year.

i went through a lot of trial and error and self-schooling, picked up a lot of knowledge and feel pretty good about how this turned out.

with the amp in this format and playing through only a single 12 inch speaker, i have found my goal of low (to high) powered guitar amp, useable in any situation.

the amp is very friendly with my small pedal-board that includes a overdrive/boost unit, and with this, it hits the front-end a little harder and i can get a louder volume on clean playing with guitar volume rolled back. With additional overdrives, the hit gets harder and the amp loves it.

playing the amp at lower volume settings provides a so-sweet, resonant, dynamic sound and the tube tremolo is quite addictive. It’s got that tone of old R&B, CCR. I play pretty clean and like a good crunch with it and this amp constantly makes me smile.

i am done with the tweaking, but there are some upgrades i have considered – perhaps a new cabinet made from more resonant material , such as pine and/or birch. It would lose the vintage tolex as it would have to be re-covered with new material.  the Celestion Creamback sounds wonderful, but Celestion also has some nice Alnico speakers…..

I have not a lot of experience playing through different amps – some time spent on playing and tweaking my buddy’s 100W Fender Twin started me off on my tube-amp path that led to the revival of this Traynor classic.


ontario, canada



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pictured here with my 2006 Fender American Deluxe Telecaster, which i love equally as much…