Actually, I HAVE used some of your ideas. Back when you were preaching about those huge 500 ma Signal Industrial Control Transformers and low henry, low dcr Triad and Stancor chokes.
I built a PP 6B4G amp which you gave me some advice on during construction. Later, after I mentioned that the chokes buzzed, you told me that those chokes should only be used for SE builds. Go figure.
Then I built a SET using the same PS ideas. There is choke buzz in that one too. This despite the fact that their rating was well above the current drawn in either one of those circuits.
Quite some time later you admitted that neither you nor your guru, Dennis, had ever actually used these chokes in anything you had built.
So, thank you, Reverend Jeff.
I'm not particularly tech saavy and certainly not an EE. I am quite willing to experiment and try new ideas. I have not tried the amps mentioned with more traditional PS so I can't say which would be better and, other than the choke buzz, they sound great. But I have learned, through my experience, that your ideas should be taken with a huge dash of salt . . . and that I don't care for salt in my pudding.
Your endless promotion of Dennis' $14,000 amps also gets old fast. These are DIY forums. If I were inclined to spend that much on audio gear I'd hop in my Lear Jet and fly on out there instead of restoring vintage gear and building stuff with scrounged, junkbox, parts.[/QUOTE]
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OK FlaCharlie, I better understand you now .
Lets talk technical . You should have had this conversation with me a dozen years ago, privately, instead of harboring feelings of ill will !!
As I was reading your complaints about buzzing chokes, I was thinking to myself " This guy had to be using those cheapie Triad C-40 Xs",..... and sure enough, you were.
The C-40X cost about $10.00 and the Stancor C-2708, built more substantially, was about $24.00 as I recall, just guessing, it was a dozen years ago. Both chokes are rated 320 mHY at 10 Ohms at 600 mA. Most DIYers I know of, due to human nature, will use the cheapest part they can, especially if both show the same spec. This is human nature.
Similarly, you elected to use a cake pan instead of a custom steel chassis of 14 gauge, as I do in my builds. The cake pan was your choice to live with.
( I, as a human being and a DIYer, did the same thing Fla Charlie with DC LINK film caps, several years ago, that you did with chokes.
When it came to using DC LINK caps, which Dennis suggested to me several years ago, I bought the VISHAY DC LINKS, because they were about 60% the price of a similarly speced WIMA DC LINK. )
BUT - back to the chokes. Listen up Fla Charlie, we found out, from A.A. people who bought and tried the C-40Xs, that they buzzed. Just like you, NO one then ever told me HOW they were using them, technically ( VAC input, total current draw, etc ). Dennis, and I however ONLY used the Stancors, and we never had a hint of a problem. I did suggest the C-40X, on A.A. back then, without trying them. My my... bad.
But think for a moment or two.... HOW you used your inexpensive buzzing C-40X !!
As you say, you are not an EE. The circuit we used the C-2708s in was a monoblock 2A3 amp. The 2A3 stage was drawing 42 mA. and the front end was drawing about 11 mA. So, FlaCharlie, the TOTAL current draw was conservative, 53 mA. ..... for an entire mono amp.
Your Push-Pull 6B4G amp may have used as much as 60 mA. for each 6B4G, so right there was 120 mA. - to the Finals alone . So, to the Finals, you possibly were using 2.26 times the current, that we were using in an entire monoblock 2A3 amp,.... 53 mA. You have to design the filter for its intended purpose, it is not " cut and paste ".
Your post is like you complaining to me, and me finding out - a dozen years later, that a 100 MPH rated Michelin tire didn't run well for you, operating it at a steady 226 MPH !!!
Given the same operating environment as we were using, 53 mA. of total draw, it may be possible that a C-40X will, or won't buzz where a C-2708 won't. As I honestly told you, then and now, Dennis and I never thought to use the less expensive C-40X. The C-2708, with improved leads SOUNDS good to us.
Back to caps. Jeff bought a whole slew of VISHAY DC LINKs, several years ago. Last year, I spoke to Dennis, and asked him if he ever A-Bed a VISHAY DC Link, against the 4 Pin WIMAs DC LINKs he likes. He said "Yes - and the VISHAYs sounds like any cheap cap sounds, when compared to a WIMA 4 Pin". So, I have about 16 VISHAYS collecting dust on my shelf.
Back to the SET amp you mentioned. I suspect you re-used the C-40Xs there. I bet it was a stereo SET amp you built, which , like the P-P amp, would have twice the current load on the ( mis-designed for it's purpose ) B+ Filter. Tell us if it was a stereo SET, or a Monoblock please, FlaChalie, and - do you recall the total current.?
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Good news, UPDATING from a decade or so past, to 2018 friends.
Stancor likely went out of business, or, stopped production of the C-2708. For several years now, eBay auctions was a source, if none were stockpiled. In the last several years, I have become more and more sensitive to the amount of total DCR in L1+ L2. With the C-2708s, it was 10 Ohms + 10 Ohms - or 20 Ohms, total. I had custom-built Ls at 8 ohms each, over the last 9 years, and I thought that 8 Ohms plus 8 Ohms, or 16 Ohms total, was quite a bit more fun to hear, than 20 Ohms total . Cool.
In 2017, I built a SET with two Hammond 159ZAs ( 6 Ohms DCR each, 1 A. rated, 300 mHY rated, at full load, about 400 mY at little load ). Well, guess what, two of these 159ZAs, as L1/C1/L2/C2 just "killed" my 9 Ohm Ls ( 18 Ohms was bested, sonically to my ears, by the new 12 Ohms, of total DCR ).
I think Dennis has had custom-made ultra chokes from Magnequest, expensive boogers, done all first class, that were lower in DCR than my 6 Ohm 159ZAs I
The potentially good news for DIYers is, Hammond makes a 7.85 Ohm 159ZB . I will be testing these, over the rest of the year,. It is smaller and less weight than the 6 Ohm Hammond Ls. This 7.85 Ohm 159ZB is rated at 600 mA. and 320 mHY at that load ( guessing 390 mHY at light load) , which " looks" to be a replacement, and improvement, over the NLA Stancor 10 Ohm C-2708.
Inexpensive..... $12.52 each. Same mounting holes as a C-2708, but it LOOKS to be made better, and will total 15.7 Ohms in DCR, instead of 20 Ohms. All these chokes get lead-rewired, to optimize dynamic performance in real-life terms. The lower DCR and improved lead wire is audible, in our implementations. Chokes, are DRIVEN elements, and are critical to overall timing and amplifier performance.
FlaChalie, if he defines his circuit to me, could possibly FIX his PP 6B4G amp, and his SET amp, and have under 16 Ohms DCR in either amp, with these new Hammond Ls thoughtfully employed. How about a L1/C1/L2/C2 for each channel in his stereo SET amp ?? 159ZBs are tiny, inexpensive and light. I hope this helps some of you. I love it !!
Have fun, I certainly still do !!
Dowto1000
