300B PP NottFest Meetup

[Tony Moore]

Hi All,

I'd just like to be the first to thank Richard for hosting a very interesting and fruitful day at his home in Nottingham! I gained a great deal from the day and enjoyed meeting up with all present.

I'm not great with HiFi reviews so I'll leave that to others who are so much better than myself but just to say that it was a very interesting day based around the comparison of four WAD 300B-PP amps, each with it's owner's preferences of components and hence presentation.

In addition we also compared CD sources (including my own CDpro2M based CDP), Squeezebox/MF DAC and Richard's very nice Pioneer spinner. I for one certainly came away with food for thought (and a certain deafness following that Hendrix track! )

Once again, thanks Richard for your hospitality and I hope we'll see you at EggFest or WobblerFest?

Best wishes,
Tony

[Greg.]

To put this in perspective, this is a continuance from the '300B ringing' thread.

I'd like to add my thanks to what Tony has posted. Richard was a marvellous host looking after us all well for many hours in his lovely house and fixing up a first class pub lunch in the interval.

I understand, travelling from Bristol, that I was a little late at 10 o'clock. Some of the guys arrived at 8.15

The whole day was really useful and great fun. We (something went on before, as apparently I was late ) started sampling passive pre amps in Richards system being his Pioneer CD player (he'll have to fill in the detail, but be sure it is seriously tweaked) into his original tweaked WAD 300B PP fitted with standard EH 300B valves into his lovely (I think 1980's HFN 9TL?) TL speakers. Sorry, I'm not completely sure of their identity and pedigree. We listened in a big listening room with a relatively high ceiling (big for me, anyway). The sound was very smooth, detailed and expansive albeit very directional. Bass certainly got fat if you moved outside of a few feet within the optimum listening position.

We compared passives using the cheap ebay available ladder switches that use Dale resistors, a shunt switched attenuator I constructed with an Elma switch and Welwyn R55Y/C precision resistors and a Pseudo shunt Alps Blue wired with standard Maplin resistors for input (see FAQ) . Fitting with my own experience, the Pseudo shunt won. This has got to be one of the most cost effective mods you can do to any volume control.

We then tried my tweaked WAD PSU/PRE II that is converted to cathode follower design as per the FAQ albeit mine is hard wired and uses boutique components. The sound was slightly frequency limited in comparison with the best passive and much smoother with less cutting edge. This was with Richard's own 300B PP which he has tuned to suit his system and taste. I actually liked the sound and preferred it over the passive option but recognised it was not so revealing or cutting edge with his power amp. The whole thing is subjective taking into account the sound of my own power amp as detailed below, which for me reveals why it works in my system, but not necessarily in Richard's.

We then did some 300B valve swapping. EH 300B gold grid certainly showed they had a smoother, more extended and revealing quality over the standard EH which in comparison were grainy. CVC's were tired with plenty of use and were expectantly bloated but still had something to offer. TJ meshplates were then tried and they had excellent sound although I was surprised that they did not in Richard's system shine over the EH golds as they had when we listened a while ago to these at my session (previously reported). For the rest of the day we stuck with the EH golds.

We then tried different 300B amps and this was very interesting. Four amps of the same design, but all tweaked differently to meet the listening needs of the owner, and would you believe it, they all sounded completely different! Neal's was the sweetest and politest sounding (we think down to him having a potential divider on the input the rest of us don't use, but that's not confirmed and Neal is exploring this). Richard's which is converted to resistor only cathode bias on the input that had a very transparent and distanced 3D sound stage compared to mine with battery bias which was a very upfront and IMHO (in your face) most detailed of the sounds. We then listened to Steve's amp which (I think I am right in saying) has no electrolytic caps in it anywhere and is all completely very stuffed in with polyprops. Last time I heard this amp it was a bit muddled but I now understand that at the time it had few hours on it. This time it was a completely different beast and sounded lovely. Somewhere in between my 'in your face' presentation and Richard's more set back imaging. I was well impressed, especially as I've seen inside this chassis and you simply would not believe how Steve has crammed it all in.

(continued below)......give me more room please, Peter!

[Greg.]

Four amps of the same family all sounding very different. It was evident that the owners of each preferred the respective sound of their own product, and surely that's how it should be. I loved the atmosphere at the time of comparison. A simple recognition that all were different yet also acknowledged that each amp was right for it's individual owner without even a hint of challenge or criticism about the different sound.

We also tried Tony's lovely CD Pro2M player and accompanying DAC. Now this is not you basic CD Pro2M kit and is heavily developed, but I have to say (as a vinyl lover) this player really rocked. I'm now very seriously interested in going for buy and build around this module based kit.



There is no real conclusion to all this. Everything we listened to was excellent. It was the differences that counted and these fitted in with the individual’s personal taste. I've done these things before and often it is easy to dismiss something as sounding ****. Certainly not on this occasion. Everything was good, but different, and the particular beauty in the difference was certainly in the eye/ear of the owner/beholder.


I've probably missed some stuff out and hope others can fill in. One of the best boys days out I've had. Very many thanks to Richard again, especially as he provided excellent accommodation my daughter Bekki to do her own thing whilst we all exploited our own interest. Good one mate!


Best wishes,


Greg

Great write up Greg. That's all very useful to me.

[Tony Moore]

Hi All,

Thanks for the great write-up Greg! That was an accurate summary of the day and I don't know what went on earlier either as I only arrived a few minutes before you.

I would also like to mention that for me I was also very interested in Neals psu/reclocked SqueezeBox modifications and I intend to pursue that avenue using my TDA1541 based DAC. It will be interesting for me to compare a Tent clock/Tent Link modded SqueezeBox 3 against the CDPro2M transport using the same DAC and see if I can tell the difference.

All in all, that was a great day out and I think everyone came away with at least some further ideas to pursue.

Thanks again Richard,
Tony

[leo:)]

I'm a bit late posting but would like to say thank you to Richard for a great day and to the rest of the guys for giving me the chance to have a listen to some very nice sounding kit!
It was also nice to meet up with you guys, great company

Me and Andy was the first to arrive we had a chat, a few drinks and mainly listened to Richards system so you didn't miss a lot regarding comparisons.

I'd totally agree with Gregs write up too
I was very surprised with the shunt modded pot, it easily beat the vishay dale attenuator I use so this will be the next thing I try at home.

All four amps did sound excellent, although they presented the music differently I liked them all, I guess thats what makes this hobby so addictive, we get to tune things to our own tastes

I'll never forget that Jimi Hendrix track, apart from Neal we was all foot tapping along, great stuff!

Cheers,

Leo

[Richard]

Many thanks to all who came; Steve, Greg, Neal, Andy, Leo and Tony, I really enjoyed it and hope you all did too. Everyone showed great commitment, had brought loads of kit with them, and 3 guys made overnight stays to be here, much appreciated

Following the February Bristol Show was a discussion about the the merits of pre-amps and synergy and during the summer this developed to include power amps. The idea now then was to compare pre-amps (various), power amps (all 300bpp), some 300b tube rolling and CD players/dacs/Squeeze box.

The system of room, speakers, positioning, cables and interconnects remained fixed. Speakers were modded Pro9TL transmission lines. Room is 22ft x 17ft x 9ft with concrete floor and brick walls, full carpet, 3 piece suite, bookcase and tables around the sides (not heavy nor minimalist). Speakers are 3ft off the front wall and the main seating 6ft from the back wall. We used the same interconnects for all gear for consistency. Music was Rebecca Pigeon and Sarah McLaughlin for the girls with Cat Stevens' morning has broken and Hendrix for the boys. Greg's bass(?) and Peter Green made a guest appearance when needed. I'll try and go through the day in chronological order. This will be a personal view as these visiting components are being tried within a system which has been balanced to suit me

Format of the day ended up as,

1) Pre-amp comparison
2) 300B tube rolling
Lunch
3) CD players, Squeeze box, dacs.
4) Power amp comparison

No-one missed anything at the beginning other than the first round of tea and coffee! Leo had brought along an eBay stepped attenuator. He'd not tried the shunt pot mod and I'd not heard that attenuator so we had a listen whilst we were waiting for the others. It turned out Greg had the same attenuator in his comparison box alongside his self-built one so we all covered that ground again together.

1) Pres were

20K Alps Blue shunting 18K metalfilm series R
eBay stepped attenuator
Greg's own stepped attenuator (Holcos?)
Steve Bench transformer attenuator
Cathode Follower pre with shunt type Alps vol control

The 20K Alps was already in so the eBay attenuator and Greg's own were put against it. The eBay one was the least refined, detailed but a little thin and metallic sounding. Greg's was much better but I felt the Alps shunt still won out with no downsides. The transformer pre was of real interest as I'd never heard one. Smooth and creamy on the voice tracks but it also felt somehow "dense" with the music compressed into centre stage. I really wasn't sure what was going on and Neal, who'd heard a similar pre before, suggested putting on some dynamic stuff. Greg obliged with (bass music Greg?) and Peter Green. This confirmed the unease as a loss of dynamics and soundstage and a generally compressed and slow feeling. Sounds awful when read like this but heard in isolation this would have been a very smooth, sweet, creamy pre which left you with a feeling of "almost there". I can imagine on small scale music in the right system it could be very convincing. The cathode follower pre sounded like the Alps shunt (which I think was used for its vol control) but more controlled/restrained. Switching back to the passive version, I felt the soundstage expanded and the air returned. Pre choice was agreed as being between these two and we continued using the passive 20K Alps.

2) Tube rolling had us listening to

EH standard grids
EH Gold grids
TJ Meshplates
CVC (Valve Art?) black plates

Very easy to hear the differences. The EH were similar tonally but the Gold grids were so much better, most notably in the mid range and control of sibilance. The standard ones were good to my ears, better than the CVCs, but rough compared with the Gold grids. The CVCs were not so good(!). They weren't knackered, they test perfectly and sound powerful, but simply don't have the air and detail of the others. I had a new set of Valve Arts and they sounded the same. On their own they would sound fine but not in this company. I've left the meshplates till last as these are in a class of their own. Definitely ones to get a listen to imo. They didn't work here as I felt they had too littlle bass and lacked a feeling of power or scale compared with the others. However they had superb mid tone with great detail and a delightfully sweet and airy treble. I can imagine they might be an se lovers dream. So from here we listened with the same set of Gold grids in all amps.

[Richard]

Lunch was

Cow Pie
Big Gammon
Modest Bangers and Mash
Veggie Burger
Chicken Tika

Got to give the honours to the Cow Pie, Desperate Dan would have been a happy man

3) CD players, Squeeze box and dacs were

Modded Pioneer PD91
Tony's Pro2 Hawk Custom
Neal's laptop with Squeezebox (rebuilt custom?) and MF A3 dac
Andy's TD??? passive output (more details Leo/Andy?)

We heard the first 3 as stand-alone units then compared the dac of the Pioneer with the A3 and later with Andy's dac. These were all quite easy A/B comparisons, done in pairs mostly, as 2 could be connected to the pre and selected easily. Cables were the same for all.

The Pioneer had been used up to this point and was generally working well with everything tried so far.

We were all holding our breath for a listen to Tony's player and weren't disappointed. Very transparent and a little brighter than the Pioneer would be my inadequate summary. It doesn't give a clue as to the detail, scale and power that meets your ears. I'd need more listening to persuade me whether to change the treble level of my system to accomodate it, I think, but it's a very classy and beautifully built player. I hope Tony will expand as I know he views it as "work in progress" and was in two minds about some changes before bringing it here. During this we got to discussing phase which led to a listen to Hendrix Electric Ladyland first track. After many comments about drugs(!) I suggested a listen to the track "come on" which brought a big grin to Steve's face We returned to Tony's player and that track later with the power amps.

Squeeze box was new ground for me. Thank you so much Neal for bringing it, many of us would never get an opportunity for such a comparison of this new technology anywhere else but one of these meets. Steve also uses one at home so I was in no doubt this was a "must have" listen.

(For newcomers like me this is a system where CD digital info (or from vinyl or other source) is loaded onto a computer. In the case of CD it can be error checked when loaded. It's then converted with a loss-less compression system called Flac. The Squeeze box acts as controller and has a dac built in. It also has a digital output so an external dac can be used for better quality. Thus, in theory, we have digital info loaded onto a hard-drive and stored in loss-less compression. This is read from the harddrive, de-compressed and dac'd to analogue. Convenience for the computer-literate is an obvious benefit. It also removes optical reading of the info from the replay chain. Downsides must be needing a computer and any real-world losses of reading, compressing and de-compressing the info before it's converted by the dac.)

What does it sound like? Sweet, smooth and spacious. I'd like more time with it but it's certainly very good. I quizzed Neal about how it compared at home with his Naim CD5/Flatcap. He said he preferred it and having heard his Naim here last time I can understand as they are both good but quite different.

The Squeeze box setup sounded different to the Pioneer, so to see if this was due to the dac, we next tried the MF A3 dac alone against the one in the Pioneer, each fed alternately from the Pioneer transport. Nothing in it. That surprised me as I've heard a complete A3 player here only a few weeks ago and there was a definite difference. Conclusion has to be that the stand-alone MF dac is better than the integrated one or the Pioneer transport was better than the MF one. Whatever, as these dacs were similar then the digital front ends must have been accounting for the differences between Squeeze box and Pioneer CD player.

I'll include Andy's stand-alone dac now, although only Steve, Leo and myself heard it right at the end. I felt awful that we'd completely missed this as it sat un-assuming in the corner of the room. Hopefully Andy or Leo will tell us more about it. Hooking it onto the digital out of the Pioneer, again we were able to simply switch A/B from Pioneer dac to Andy's. Nothing in it again like the MF! Really, this wasn't a case of not being able to hear differences but one of there not being anything much different to hear. To put this in perspective I've done this with other dacs such as Da Capo and it's easy to hear. Down the scale, complete players such as 6000Ki really don't get a look-in at this level. So either the system isn't revealing much past this level or the modded Pioneer, MF A3 stand-alone and Andy's custom are all pretty much identical. Tony's player was different but we couldn't/didn't separate the dac off for a listen. This was a short listen and living with them may show differences but they will be small.

[Richard]

4) Power amps were all original WAD 300bpp

mine with unbypassed first stage cathode R
Neal's with battery bias
Greg's with battery bias
Steve's with battery bias

So far we'd been listening to mine using the 20K passive pre and Gold Grids.

We switched to Neal's first. Woah! super sweet and relaxed sound. Neal pronounced himself pleased and, having heard his other amps, I felt it agreed with them tonally. Neal suggested this was perhaps why he didn't like the unbypassed cathode resistor when he tried it, finding the sound too far back. I did find my 300bpp had a similar sound when I bought it from him and one change I made, removing a carbon resistor divider on the input, made more of a change than I could account for so maybe part of the sound lies with that.

Greg's was next up and, no doubt about it, this was one forward-sounding amp! It really did project the soundstage to near-field with loads of detail, completely the opposite of Neal's.

Steve's is full of polyprop caps in place of electros and he's noticed it still running in. Presentation fell somewhere between mine and Greg's with loads of detail. Overall there was a much bigger sound difference in these power amps than the CD players. Whilst Steve's amp was connected he asked to hear the Hendrix track again. With the Pioneer it sounded terrific (as had Tony's player with my amp earlier on). Trying Tony's player now with Steve's amp did tip the sound over just a little to the bright side and I felt it lost some tone from the guitar. So synergy was playing its part. The great thing with diy is that any of the amps could have been tweaked to suit any of the players we used.

It's taken so long to write this up as we covered so much ground. All the gear was excellent with the only real quality judgment to be made in the pre-amp section where the passive Alps shunt was a clear winner. Everywhere else there were differences but sound preference would play a bigger part.

Thanks again All for a great day and I hope we do it again

Rich

[leo:)]

Excellent write up Richard!

Just a few details about the dac, it was just something simple we knocked up.
CS8412 reciever, Asynchronous reclocker on the i2S lines, single TDA1543 with passive I/V, we crammed as much as we could in that little box its not bad for a little squirt

I think Gregs cd was Oriental bass, Renaud Garcia-Fons, I'd never heard it before to be honest but thought it made a great test track

Forgot to mention about lunch, good choice of place Rich, I enjoyed my Veggie burger I could not believe the size of those cow pies, the guys who ordered the bangers and mash looked a little gutted