Amp Comparison 25th April 2006
The idea for the day was that we gather at Steve Shiels’ place and see how my single-ended EL34 amp with 6SN7 pre-amp, Simon Chambers’ WE91 300B mono-blocks  and Steve’s latest creation pictured above; a power amp based on the PT15 triode compared to each other when played through Steve’s Lowthers. It wasn’t a competition, just an interesting experiment
 
Ed (alias Vitalstates) who is a semi-professional musician also came along to lend his expertise on the way live bands sound and to provide another perspective on what was going on with the amps.
 
The photos are below.
he would have an absolutely unstoppable winner on his hands. Yes it really was that good!
Steve has a few ideas in his head to get the imaging sorted out, hopefully in time for Eggfest 3. Guys you’re in for a treat if he gets this fettled I can tell you.
 
Conclusions
This was a fascinating and enjoyable day. All the amps we tested sounded great but in very different ways. My set-up was the most detailed and delicate of the combos we listened to. It had a depth of imaging that the others did not have.
However when it came to weight, dynamics,power and sheer emotion - especially with solo voice and acoustic guitar recordings, Simon’s WE 300B mono-blocks were brilliant.
 
Steve’s PT15 breadboard was something else altogether. It kicked ass like no valve amp I have ever heard. The infamous prodigy track Steve is so fond of was dissected with the precision of a surgeon’s scalpel and the distortion on Keith Flint’s voice was revealed as a proper deliberate studio effect, not amplifier clipping. The bass was tight, clean and fast. if ultimately lacking the nth degree of depth. Thrilling was an understatement!
 
At five I packed my gear into the back of the car and headed home with a pair of Mullard EL34s and a vintage Mullard ECC32. The lack of welly my amp exhibited compared to the other two was a concern.
 
After getting in from work on Monday I fitted a pair of 100uF Black gates to the unbypassed cathode resistors of the first stage and fitted my newly acquired ECC32 in place of the first 6SN7. That was more like it! Good imaging excellent detail, sweetness and plenty of poke now.
 
These types of informal comparisons are great. I would not have noticed the areas my amps were falling down on had we not had the get-together. It was an extremely enjoyable and educational day. Ed was invaluable as an independent arbiter and was able to sort out Steve’s Lowthers so that they interacted better with his room. Simon’s doubts about how the 401 would stack up were blown away by the ruthlessly revealing Lowthers. He’s extremely enthusiastic about making it even better now he has heard it working well in that company. One of Steve’s comments was particularly telling. He said that the presentations provided by the amps were all different, but during the whole session we never once talked in terms of bass treble or midrange. It was all about music, musicians, studios, arrangements, imaging and the way instruments were being played. Simon and I had to agree. That’s good valve audio for you.
 
The Shadow.
OK let’s start with some valves.
 
Steve brought in a selection of 6SN7s from his extensive valve collection to try out in my pre-amp. There’s also a NOS Mullard ECC32 at the extreme right. Note also
the valve data manual just to check. Steve didn’t want any damage to either my amps or his valuable tubes.
My single ended EL34 power amp, fed by the 6SN7 pre according to Ed is producing some fine sounds via Steve’s Lowthers.
It’s nice to have an independent person think your gear sounds good.
It went loud but to me there was a sense of weight missing after hearing Steve’s latest PT 15 amp.
Next up was Simon Chambers’ WE 300B amp.
Pictured here is one of his mono-blocks.
Ed was expecting better imaging than mine due to the seperate construction and he was not to be disappointed.
Valve lineup is Sylvania 6SJ7 pentode driver, Chelmer 300B and Mullard GZ33 rectifier valve.
 
The 300B mono-blocks are being driven by my preamp. They had not been used for a week and took about half an hour to come on song. Playing David Gray’s version of “Say Hello and Wave Goodbye” Ed commented that he had never heard Gray sound so angry or his guitar be so incisive. It was a superb rendition by any standards.
 
Simon and I were pretty pleased at this point with the sound of our amps through Steve’s speakers. Different presentations. Mine majored on delicacy and detail but Simon’s had a lot more sheer stomp  Then Steve decided to (literally) blow the dust off his one watter. It kicked a lot more butt than its meagre power would suggest.
Here we see a fine collection of PX25s of various vintages and  base pin configurations. God only knows what this little lot is worth!
 
 
 
Simon then brought out his Garrard 401 on a simple plywood plinth. He had fitted the Ekos arm/Dynavector combination from his LP12. Now this was a bit special even in rough prototype form.
 
I have never heard a Garrard 401 before and was very impressed indeed.
Steve’s Lowthers revealed not a hint of rumble.
 
Phono stages were swapped to Simon’s step up less WAD in order to accommodate the high output Dynavector.
Playing Jack Johnson on vinyl we were greeted with a very lifelike rendition and according to Ed we had the best imaging yet. Steve was well pleased with the improvements Ed had wrought through careful repositioning of his Lowthers.
 
To finish off a most enjoyable afternoon Steve put in his PT15 power amp. these showed the Lowthers who was boss!
Stunning dynamics and serious welly issued forth from this breadboarded prototype.
Ed was convinced that if Steve could get the imaging of mine and Simon’s amps combined with the stomp of this PT15
Here we see my pre/power amp plus my phono stage with MC step ups. Steve’s oracle is playing some Art Pepper.
What you cannot see is that Mullard EL34s and a Mullard ECC32 have been introduced to the power amp. The improvement was not subtle. There seemed to be a reduction in gain though