My Victory Sheriff 44 came with PM pre-amp valves, and TAD EL34’s.
It was a rotten, hi-mid heavy mess. Serious lack of gain. Lifeless. Everything a struggle.
The bass and lo-mids were indistinguishable from each other, and post-EQ could not successfully define those areas.
The top-end was horrible, and the amp was unusable.
It then sat for 2 years whilst I explored modelling alternatives, and a Budda SD45, which immediately caught fire.
I was trying to replace a modified Pro Amplifiers V65, which had stopped working - my amp of some 15 years.
Cathode bias was out of the picture. The SD45 saw to that. But, on paper, and having studied the Sheriff’s circuit diagram - it seemed worth digging out.
I decided to source vintage Mullards.
Only interested in used valves that had better than book spec, with full test results.
Early on, it appeared that the short-plate type 161 ECC83 from Blackburn was my main contender.
Mullard XF2 EL34’s were expensive. But I bought a pair. Unfortunately they rattled, so were returned.
I went with used Original Svetlana winged-C EL34’s and biased them up correctly.
In my search for type 161’s, the following criteria had to be met, although all of them tested above book figures.
V1 - This was to be the quietest valve, with the highest anode current on both triodes. Still with good transconductance.
V2 - The cathode follower runs at unity gain, so current should be good, but transconductance should be the highest possible. Bear in mind it compresses only half the waveform.
V3 - Loop return and Impedance matcher. This just requires a good all-round valve.
V4 - Splitter. Good current needed. Transconductance should be high too. Both triodes must have identical test figures.
That was I think common sense, and at this time, there were still great examples on eBay UK, on average £50 each.
The whole premise, apart from anything else, was to achieve linearity across the complete frequency band.
The amp needed distinct, controllable bass. Lo-mids should be separate and also distinct. The overpowering, gnarly hi-mids had to go, and the top-end needed to be smoother, with a nice roll-off.
I serviced the amp fully, fitted the correct valves in their allotted positions, and biased the Svetlana’s to the recommended figure.
The transformation was off the charts.
I use a Palmer PDI-03, and a Joe Meek VC6Q, for recording.
The deep switch could now be switched from deep to flat.
With amp’s bass on 4, there was the perfect bottom-end.
I use middle on full, and the lo-mids were nicely distinct. Raising bass now did not affect lo-mids!
The hi-mid bias was gone. Instead, the entire mid-range was beautifully full and with seductive complexity.
The top-end was utterly sweet.
I could take your head off with harmonics and pick-slides, so treble and presence was reduced to virtually zero on this amp.
It became quickly apparent that the amp had a negative feedback sweet-spot. Master was happiest around 7 or so.
So, first try was really promising.
The Palmer was set flat.
To give more V1 level and gain, I begrudgingly added a Koko Boost to the high input. This gave +6dB of level, and an extra 6dB of mids in a modestly wide Q. Slightly wider, and set lower than an EMG SPC, or Clapton TBX.
This again transformed the amp up another level.
My highest gain was set with the guitar on 7 or 8 to weight the input, and the amp was then given an extensive testing.
First impressions were that the amp was now responding to the guitar’s input properly. All 3 single-coil EMG’s of different types, were now so distinct in their sound, and there was nothing else there. The amp was utterly silent, even with input gain on 10, where it stayed.
I use a big isolated UPS on my recording amps, and all cables are balanced. But it was the Mullards that were responsible for the noticeable lack of hum, hiss, and microphonics.
I gave the used Svetlana’s a week to develop, but to be honest, they didn’t need it, and were wonderful within minutes.
Not the massive bottom-end of NOS GE’s for sure. But still very, very good, and tight. Top-end was delightful, once the treble and presence controls were minimised. Mid-range was staggeringly clear and concise - becoming more complex as you added more content harmonically. Double-stops and triads rang clear, with huge density. The note-separation on full chords was unbelievable. An open E - you could still hear all 6 strings ringing - 30 seconds after hitting them!
The amp had simply lost all its earlier bad points, and was a lovely sounding, stable platform.
Playing with guitar-level, I could roll off to 3 or 4, and clean up nicely for any distorted rhythm work.
I did have the option to turn off the mids on the Koko Boost, if I wished to be cleaner, with the guitar on 2.
I also have channel one on the Sheriff, if I want to get really clean.
For my ultimate lead sound with this amp, I decided to add 6dB of mids at 1Khz on the VC6Q, and a smidge of bass boost/treble cut - probably 0.5dB.
Yep, that was it.
The amp is now impeccable, and a dependable recording platform.
Aside from zero noise issues and added frequency-distinction - the amp is now absolutely linear in its ‘processing’ of all frequencies. This means I’m really hearing the guitar, and what it is putting out. Overall gain is set by the Koko’s level, and guitar-volume.
Touch-sensitivity is incredibly good, and the amp is both efficient and responsive to anything I give it.
Summing up, I would say the amp has design faults. Certainly in it’s EQ section, and lack of V1 gain.
Victory relied on ‘shredders’ using cathode bias, and being wowed by the ugly, up-front hi-mid cacophony.
Ok for 15 minutes in a music shop, surrounded by gear.
But get it home, and it’s a dead duck - with only the Chinese bargain-bin valves to give it any kind of life.
My journey with Mullards began with my Pro-Amplifiers V65, converted to adjustable-bias with Svetlana’s.
But for the Sheriff, I’m glad I took the time to get the circuit-diagram, research valve-amp tech fully, and buy valves using a careful selection process. The used valves were £400 in total, but the amp would have been sold without them.
I then bought a Victory Baron 10W combo, and kitted that with 161’s, a 5751WC reverb valve, and XF2 and EL84 Blackburn Mullards. This amp is equally responsive and linear - through a Celestion Cream Alnico. Although I do use a Joe Meek VC6 and VC5 on the loop. It’s my upstairs practice amp.
The sound is more direct from the 1x12”, but this helps me focus. The Sheriff downstairs goes straight to the Mac from the VC6Q, and is more ‘processed’, as I add effects on the computer, and listen on my monitors.
So I can get parts right upstairs, then do a ‘performance’ in my whole mix.
This wouldn’t be at all possible without the linearity of the Mullards.
At this time, it is becoming increasingly difficult to find used 161’s way over book spec. EBay is full of some very poor, clapped-out valves, at scandalous prices.
I am happier to now source from the USA, and the private market is still quite buoyant, with good prices.
The good thing is that my Mullards will last a very long time indeed. In fact they will probably see me out.
And quite simply - no modern production valve comes close to that level of expertise and manufacturing.
The audiophile world has a couple of good valve-makers, but none will match the ruggedness and longevity of Blackburn 161’s - or the consistent quality, from a factory that produced millions every year.
Yes, there are Chinese, Russian, Slovakian valves in everything new you buy. Often re-badged to look fancier. But honestly, they are bargain bin junk, designed just to get the amp in the shop, and making a noise.
I recently branched out somewhat. I rebuilt a Seymour Duncan 100W Convertible Head.
Original valves are Groove Tube.
I kept the EL34’s, which work well.
With stock modules, I went with Mullard 161’s, using the same constraints for individual specs.
But this time, on the blue ‘presence’ channel, I used two GT12ax7M Mullard copies (Chinese!).
This gave a distinctly Joe Walsh/Carvin flavour to the blue channel, which is interesting. Hi-mids aren’t too much.
The red channel however with the 161’s - Now this is a real amp. EQ it anywhere and it sounds great.
Approximating my usual lead gain could be done easily without a Koko Boost, and the instant mid-range complexity is simply staggering. This is a well implemented amp. On paper it has faults, but in operation - it’s the missing link between the 60’s and what we have now. Even your average Pitbull fanboy would love it, for its density and downright guitaristic nature.
So now, the Convertible sits alongside my Sheriff for recording. The Sheriff is clinical and linear. The Convertible is simply exciting and makes me want to play.
In my view, I don’t think anyone has made an amp that sounds as good as the Convertible. It has no limits, no sweet-spot, everything is so good. Roadworthy it is not, unfortunately. 13 valves make a rebuild expensive. But mine is here to stay.
Mullards are not ‘dull’, they are simply linear - crying out for a well-designed amp to exploit their sonic excellence.
Lots there, and thanks for reading.
But the above is but just a few years of my long journey, and I hope keen readers will take some pointers and inspiration from that.
Lastly. Take time to go out in the woods, and just sit there and listen.
Nothing has EQ on it, yet the panorama is full of life and vibrant sounds.
After an hour, begin to imagine your ideal lead-tone. One that might belong in this soundscape.
I’ll bet that it won’t be flubby bass, no lo-mids, raspy hi-mids, with screeching treble.
So why the hell go home to Chinese valves with exactly those attributes ‘eh?

