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In Reply to: RE: Its hard to ignore...... posted by gusser on March 18, 2012 at 19:05:25
Though my last post may have seemed to be totally aimed at gusser and a couple others, part of it also applies to the admittedly overzealous Jeff too. As he said, he likes to stir the pot. I wouldn't let him manipulate you like that. Customers try to do that to me at work all the time. I don't allow myself to get involved in their personal issues or games.
My ears are super sensitive to any brightness/harshness in the upper midrange and high frequencies, but I love to hear the subtle details within a recording. I'd like to hear Jeff's PS in a well designed amplifier to see if its my cup of tea or not. I'm looking for something that is realistic, musical, and listenable for long periods of time. I plan on trying to build an amp with a low DCR PS soon. If it doesn't work for me and is not to my liking and if it can't be remedied to sound right, then that will be the end of it. I'm willing to give it a shot.
I'd like to see you two narrow down your differences by determining if Jeff's ideas work, hands on. Then, if they work, determine where they work, where they don't, what's good, & what's not so good. Like I said, maybe its just a matter of what you like to hear in music reproduction.
I'd like to see it handled on a 'professional' level as you both profess to be, then maybe Jeff's and/or your conclusions can be presented in an credible manner. I tend to believe things presented to me in a professional/logical manner, rather than following whoever shouts the loudest in an argument. I'm fairly new at all this electrical stuff and all I want is help in learning about how it works and how I can make it do what I want it to.
Larry
Follow Ups:
Jeff is not a professional when it comes to electronics. Where do you get that idea?You just said you are new to electronics. So what qualifies you to make judgements as to others competence in the field?
It's not just the power supply stuff. And for the last time nobody ever said low DCR was not a good thing. The LSES is what is in question.
Forget the power supply. What about these ideas of needing 12ga wire in a 12AX7 plate circuit? How about this hacking up parts to replace wiring provided by a reputable manufacture? What of claiming different parts of music go through different resistors when paralleled? This are just some of the off the wall theories Jeff tries to cram down our throats.
When challenged with the lack of any credible published data to substantiate these claims, we get the EEs are closed minded rag.
Don't you think it's kind of silly for someone with no formal engineering background to make such claims against those who are professionals?
Edits: 03/18/12
Gusser,What in the world are you talking about??
You say this:
"What of claiming different parts of music go through different resistors when paralleled?"
Show us WHERE I said or claimed that. (Word search is your friend.) You totally misquoted me, that is not even remotely correct.
I do not want any such inaccurate statements posted from a "professional" like you.
Jeff Medwin
Edits: 03/19/12
Posted by drlowmu (M) on February 3, 2012 at 11:10:37
In Reply to: Best Damn cathode Cap posted by Neff on February 2, 2012 at 20:48:42:
Dennis Fraker explained this on this Forum, a few years ago, and has it PERFECTLY executed in his Serious Stereo 2A3 DC amps.
1) Never one cap, because the music will tune to that value.
2) Never a electrolytic.
3) Multiple value film caps rule !! Very often five or more in one Rk location.
4) Even though a cap can measure wide band, in cathode bypass duty, different value caps play the speaker in a NARROW band.
5) Put your main film cap value in place. Listen to that. Then, over time, you bypass that cap with lower value caps, determining the values, and the makes of film caps by ear. The process may take you up to a year of break in and listening time, to find the optimum values and types. If your system is mediocre, you may never find it.
6) If and when you optimize it, the results sound wonderful.
No free lunch, you have your work cut out for you, so, open up your wallet and pull out five C-Notes to start. You are in the audio big leagues now Neff, no more cheapo kiddie stuff.
Jeff Medwin
One bypass cap value will do depth. Another cap value will do juiciness on the soprano's lips, and another cap value will do extreme air. Your job is to BY EAR, find the values and the best types.
And it is very audible on high efficiency speakers. Rk bypassing, almost everyone screws it up. Others have attempted it, and sorta half a**ed it, but ONLY Dennis Fraker, in 1989, had it down to a "tee". I hear it in all his amps when I listen at RMAF, assuming his digital source is clean, which is not always the case.
I'll stand 100% by that early post.
If you think about it, you may deduce why this is so Gusser. Listening to it is the way it is done, not with osillyscopes can one get it, nor with spectrum analyzers.
A film cap may measure flat, with simplified sinusoidal sources, but not play back flat under dynamic / music conditions. Different values, and different manufacturers caps, play back different parts of the audio spectrum, as heard at the speaker voice coil.
Nasty to contemplate isn't it !! That is OK, Dennis did the heavy lifting with this. ONLY Dennis did this correct in my experience. Kudos to him, that is just ONE reason why he gets my support.
Jeff Medwin
this whole idea about multiple bypass capacitors and what they do has a very low transfer efficiency into my belief system.
Hi Lew,
It would be readily audible on high efficiency speakers, when doing all film bypassing.
From what I understand, it takes a minimum of five different values to get it REALLY optimized, which so far, only Dennis Fraker, in 1989 no less, knew how to do. Also amazing to me was his development of LSES or a modern power supply WAY back then, also found in the original 1989 Serious Stereo 2A3 amp.
Myself and a few other amateurs are working on learning this bypassing topic in 2012. It takes good LISTENING on a GOOD high efficiency audio system, and a big pocket-book to do right.
Read the article on the two stage DC SE stereo amp by the two Italian audiophiles in Sound Practices, about 1994 as I recall, re: Rk bypassing. They used three caps on each Rk, a film-only main cap, bypassed with a .22 PIO, bypassed with a .01 uF Silver Mica, three in parallel, LONG time ago. Its there, in print Lew.
I write this to you as "my" side of the topic. Do and think as you would like to, I have no big problem with you doing that.
Jeff Medwin
I have no doubt that Dennis may have found a potion of 5 different capacitors that made HIM happy, listening to his chosen sources and driving his particular set of speakers using his amplifiers. In fact, I stand in awe of his patience and perseverance. But I think you over-state the significance. There is no general conclusion to be drawn from this story. It's just an interesting anecdote. It's not solid data, even in this touchy feely subjective audio universe.
Every time you add a capacitor, you have to take the bad with the good. You cannot say you are using capacitor X because it does a great job on female vocals and capacitor Y because it does a great job on male vocals, and, by gum, when you parallel them both, you get an amplifier that sounds fabulous on male and female vocals. That might happen, but it's a happy accident. It is equally likely that you will get an amplifier that sounds like shit on vocals.
Have you ever used multiple value DynamiCaps? They can parallel without a lot of the conventional problems you experienced and allude to in your post, according to Dennis.
Jeff Medwin
Jeff, I like reading your posts.
I do have to ask, what happened to Dennis F in 1989? Did he get hit by lightening or run over by a farm implement? There seems to have been an epiphany in that year for Mr F. with all things solved at once. You have mentioned a few things that Dennis realized / discovered at that time.
As I understand it, here is my take :
Dennis told me he used to just modify amps, McIntosh 60s, MI-200s, and he had a pretty good reputation then with AudioMart people.
Some person gave Dennis $40,000 to develop a SE amp, and over two years, he came up with the Serious Stereo 2A3, his first-ever total amp design and build. He made four monoblocks, which I can see have hardly changed at all since then.
Film caps would go out of production, and wiring choices got better (Siltech), but Dennis thoughtfully engineered it from the start, optimized the design, so he has only made minor changes over the years.
The basis for the LSES supply came about as he and Dr. Charles Halijak, E.E. PhD. did amplifier mods. These two audiophiles used to get winders to copy the Citation 2 choke, and noticing that smaller chokes worked better, Dennis simply greatly refined the concept.
He is an unusual bird. Always honest. It is a fact he has spent several fortunes owning Hi Fi equipment. Never married, he has owned two good movie theatres, and a movie theatre service company. Besides being trained as a technician (electronics) in the Coast Guard, and working in mines, Dennis worked for Montana Power and many in-the-field / head electrical engineer positions, plus oil refineries with his Dad. Hey, that was Montana, go where the work is.
Jeff
.
Larry,
The power supply is just part of an amplifier, and the entire design and its lay out has to be conceptualized, optimized and built as one total piece. No bread boards. Just define the speaker load, design the amp, and build it in a chassis.
This is exactly what I am now doing in my 6AQ5 DC SE amp - whose photos I put up this week.
So, you don't like a crummy top end, nor do I.
What sort of speaker load do you need to power? What is its efficiency?
If its a high efficiency speaker, you are "golden" because I can email you good information on how to build a simple two stage DC SE amplifier.
Jeff Medwin
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