DCAudioDIY.com

A couple of years ago, I posted an ad on Audiogon asking if someone in the D.C. Metro area who owned Magnepan Tympani IVa loudspeakers would allow me to audition them as I was considering purchasing a pair, but had never heard that particular iteration. Fortunately for me, Stuart responded to that ad and invited me to his home for a meet up with a few members of this group. For that simple act of generosity, I want to say Thank You. Since that first listening session, I have met several members of this club to whom I also owe a sincere Thank You. Folks who have invited me into their homes, shared their knowledge, and most importantly are becoming friends.

I have been lucky to spend quite a lot of time at Charlie P's house enjoying his fabulous, carefully put together system. Charlie builds some great sounding gear. Better than most anything I've heard available commercially. His system reveals differences (for better or worse) when swapping equipment, or accessories. It's all most any of us could want for in audio. And yet today, it was taken to another level. One that I have never experienced before, and am thankful to have been a part of. A small group of us got to listen to a pair of amps built and brought over by Dave Berning. They are custom 845/211 amps. Combined with the rest of Charlie's gear, it was simply a perfect listening experience. For me, there was absolutely nothing to be critical of. Every piece of music, regardless of type, sounded effortless, natural, and emotional. Thank You Dave and Charlie. It was stellar.

Jim

As Jim points out, it's wonderful that people like Charlie and Dave are so knowledgeable, and free with that knowledge! Also in this group of reliable sources are (at least) our moderator Roscoe Primrose, David McGown, Stuart Polansky, Joel Merritt, and others whose names unfortunately escape my holey memory at this time.

In the past, I have posted thoughts and/or questions with the assurance that people will offer their thoughts and experience on the topic, thus saving us time, money for parts, and opening the windows to clear out the smoke. Then they invite us over or come to our houses and offer reviews and encouragement on our results. Regardless of what I build, I know that the results will sound better than what I would have built before meeting these people - maybe not as good as their products, but better than my old efforts.

Thanks to them, and to everyone willing to read, respond, and/or submit items to our bulletin board - this is one thing that makes our Club worthwhile!

_________________
- Guy

I was among the lucky group who heard the Berning amps with a pair of 845s in each mono block at Charlie's house. Listening to Charlie's system, with either of his DIY amps, is such a pleasure and it makes you appreciate how much effort Charlie has put into fine tuning every aspect of his system. Every parameter of his system is in the WOW category, sound stage enormous, transparent loaded with detail, effortless, never gets confused with complex music- each note delineated and clear. The preamp and amps I have brought to audition left with their tail between their legs, not good enough to challenge Charlie's gear. After each of the sessions with equipment comparisons, I have just wanted to continue listening to music, both mine and new horizons Charlie has exposed me to. His system makes you want to listen to music more than anything else, your brain is confident the gear is not a limiting factor, and it is busy following melodies, identifying instruments, and plain enjoying the music. I was unprepared for the level of improvement David's 845 amps brought to Charlie's system, an order of magnitude better. Stunning level of detail retrieval without loss of tone or image solidity. The stage improved in all dimensions and we gained an octave on the bottom. The music was just live sounding, solo piano/orchestra/pop/rock, all were presented effortlessly and conveying the emotions of the musicians. I didn't want the session to end. Thanks to David Berning and Charlie for inviting me, it was special.
Kemper

Kudos to Dave Berning and thanks to Jim and Kemper for the nice comments about my system.

I've had my current set of Nestorovic speakers for about 12 years. They do many things amazingly well and make the differences in source equipment easy to hear. The one thing that they haven't done is give a full size presentation. It's like the orchestra is a scale model. Maybe 1/3 or 1/2 size. Astounding detail but miniaturized. Then along come Dave's amps. Suddenly everything is full sized - I didn't know the speakers could do that. It was like you could walk out amongst the musicians and shake their hands, "thanks guys for such a great performance". After a performance of Mahler by Janet Baker with Bernstein conducting I had tears in my eyes. As close to the real thing as I've ever heard. To bad those amps are beyond my financial ability.

But hey, that's what DIY is all about right? I'll have to get started on my 845 PP amps. They are already in the planning stage.

As an aside Grover once told me that the finest amp he ever heard was a PP 845 made by his friend Bruce Wenger. Maybe there is something to this PP idea??

Charlie

Charlie:

While building your amp I would stick close to David. He is one of the most knowledgable people I know. He definitely understands the benefits of design choices at each stage of the process including the need for a good power supply to free you from mains power problems and the advantages of going transformerless. He is also one of the most open minded persons I know and always willing to listen and learn.

Tom

Tom,

Thanks for the thought, but don't worry, I know how to design a power supply. Since I'm not limited by commercial constraints I can overbuild to my hearts content. Fortunately I have a collection of old military surplus power transformers, a pair of which will do for 845s. Having said that though, even with filters on the input and careful layout including grounds I can hear the difference when I put a power conditioner in front of anything that I have built and also with pieces of commercial gear. It is subtle but there. Clearer backgrounds, better delineation of musical lines, a more holistic tonal quality. The kind of stuff that Kemper was talking about in my system before we put Dave's amps in. We ran the 845s with the power conditioner as well by the way. Would have made an interesting comparison to try with and without but we were to busy listening to music and I didn't even think about it. This may be one of the things that made such a difference in the amps between Dave's system and mine. To be honest I wasn't very impressed with the 845 amps when we heard them in Dave's system. It was only Jim's urging that got me interested in trying them out here. The resolving power (or in Allen Wright's immortal term "downward dynamic resolution" ) of a system makes a difference.

I would like advice from Dave about running the filaments on RF if I can do it without polluting the neighborhood airwaves.

Charlie

Thanks for the nice comments, guys, and thanks, Charlie, for hosting the get together. Charlie, your system is a great resource. My system sucks, by comparison. I am so busy designing and building amps that I spend 90 % of my time listening to the radio and use my main system relatively little. Therefore, I have put relatively little effort into doing the refinements that make a great system great. It is not surprising that when I had the group over to hear the 211/845 amps initially, that the sound left the group less than excited. Everything in an audio system has to be good if the system is going to deliver, and Charlie's system is quite refined in this regard. Thanks also to Jim for prodding everybody to get together to make this listening session happen.

David

I have a perverse desire to know just exactly what common factor existed in every one of Charlie's amplifiers that facilitated the "miniaturization" of the soundstage through the Nestrovonics. There have been a number of amps in the system, and as Roscoe might say, "None of them sucked." They were all competent performers, some better than others.

The reason I'm asking the question this way, is that I think it may be easier to solve this puzzle, than to understand precisely how David's amps do it better..... As an amp builder, am I stuck with a limited performance envelope if I stick to conventional topologies? I'm assuming the 211/845 amp was some variant of David's ZOTL technology....is that right?

I've been thinking about this one. I'm not sure if it's just a power issue - the amps that have been in the system are under 50 watts where Dave's will put out up to 120 - or something else. My first experiment therefore (since it will be easy) is to make a parallel PP EL34 or KT88 amp to see if that does the same thing for the sound stage. If that doesn't do it, it may be because the 845s are run class A or maybe they are just a more linear output tube. I was looking at the curves of a triode connected EL34 this AM thinking of it as a driver and it leaves a lot to be desired (this from an EL34 devoted type person), so maybe the 845 is just more linear. Maybe it's the magic of getting rid of the output transformer....... which reminds me. I did hear this once before, probably close to 20 years ago with a OTL amp, a Futterman if I remember correctly. Not enough power to live with in my system but it does give one pause.............

Dave, were you serious about making those output modules?

Charlie

Charlie,

If he is, you gotta help a brother out building a set.