Help - Search - Members - Calendar
Full Version: drilling a new hole between the ears
The Fée Verte Absinthe Forum - The Oldest, Largest, Most Authoritative Absinthe Forum. > The Monkey Hole > Corn Hole
dakini_painter
Started with a bunch of Violent Femmes, including Country Death Song, then Warren Zevon Lawyers, Guns and Money, Velvet Underground I'm Waiting for My Man, Steve Earle Copperhead Road (thanks WBT), Smokin' Joe Kubeck Band from Texas Cadillac, Gimme Shelter, Factory Girl, P.W.E.I. from The Cure for Sanity, Neil Young…

Yes drunken posting. Sorry.
Marc
The Stooges "I wanna be your dog", one of the best rock song ever.

Yes hangover posting. Sorry.
Le Gimp
I've gotten back into amplifier design in the past year. It started with an old acquaintance who used to run a TV repair shop gave me his old tubes. Over half of them were used and shot, however I still ended up with a couple hundred serviceable tubes. Most are not suitable for audio design, but some are.

I've wanted to design a tube amp since I left college in 81 and figure now is as good a time as ever.

I've designed a small push pull amp that will deliver 10W into 8 ohm speakers (they need to be efficient to produce much sound, but all my speakers are). It sounds surprisingly good in my opinion, and tests well for THD (less than .05% at one watt with all harmonics above 4th below -80dB) and frequency response (+/-3dB 16Hz - >32KHz).

I've only built one channel so far, and have been using it as a test bed for tweaking and trying different topologies like Tetrode, UltraLinear, and Triode mode.

Next is a line amp / phono-input amp.

It turns out that the old Russian Federation Military Complex is selling off a lot of tubes that work well for audio amps.

After selling my brewing equipment, I used the money to buy a bunch of tubes off e{vil}bay.
Kirk
I've been trying to score a revamped Dynaco st 70 for less than 300 but can't do it, I gave up on trying to get a pair of Mcintosh MC 30 amps, at 3 grand plus for a good pair it's money I can't justify. I'm using old David Hafler solid state stuff now but I'd like to hear a good tube amp.
If you want silver wire let me know, I'll draw whatever gauge you need.
Le Gimp
Thanks Kirk.

Right now I'm working mid level audiophile designs with Hammond output transformers and PIO (Paper in oil) and MKP (Polypropylene) capacitors. I haven't moved up to Teflon caps and high end transformers yet, and that is where silver wire might make a difference.

I'm looking at getting a set of James or An Tek output transformers as well to test with. I doubt I'll step up to the high end stuff for a while, if ever since I have reservations about spending $150 per output transformer with the marginal gain I'll get.

If you ever get a ST-70 and want someone to rebuild it, let me know. I'd be glad to help you out.

From what I've read the ST-70 UL transformers are what are what I considered mid grade audiophile. Good stuff and probably 99% as good as the high end stuff.

You pay a lot for that last 1%.
Kirk
Just like volume, you can turn it up half way, no problem, any more gets to be dicey and expensive.
Thanks Gimp, I know next to nothing about electronics. I have a hand wound transformer kicking around here someplace, never had the right plan or skills to use it, I'll send it to you if I can find it.
I heard the dynaco transformer was the best part of that amp so it (the transformer) got an undeserved reputation for being a good one when it was just better than the other components, which weren't so grate.
I have 3 David Hafler transformers you can have, you can have the chassis too. All 3 amps quit and I don't know a thing about working on them, I use 7 of them between the house and shops, they get a lot of abuse
so I go through about one a year. I buy them cheap off ebay and when they break I don't spend time wondering about it or working on it, I just swap it with another cheap one.
Kirk
Here's some audio porn TGO posted at the Lounge, in caser you missed it.
22 lbs of silver
I saw a pair of caps from him on ebay going for $450 each, second hand, down from $900 each. About the size of a cigarette butt with about 10 bucks worth of silver in it, prolly took 20 minutes or less to make it.
Le Gimp
Interesting site.

As an Engineer I have my doubts about a lot of audiophile snake oil out there. On the other hand, there are some things that do make a difference, but are out there in the last 1% or less AFTER a good design is completed.

I had a reputable transformer designer tell me he would be glad to take my money for a pair of custom output transformers, but I would be better served with a set of Hammond or James OPTs till I had my design perfected. Then and only then would I see the difference the custom transformers would make.

I can hear the difference between the Olson Transformers (I got off ebay) and the Hammond 1609 so my hearing isn't totally shot. Interestingly enough I have a hard time measuring the difference in the two transformers using Audio Tester Audio Tester program. Hammond has a slightly stronger base.

Kirk if you don't still have my address pm me and I'll send it.

Thanks for the offer.


Kirk
Yeah, a lot of what is on that site is pure hype, you'd think with the type of product he sells he'd leave out the snake oil. Age hardened for 10 years for example, give me a break.
Provenance
Age hardened? Sounds like my arteries.
Absomphe
Your arteries?
Le Gimp
I'm not much into solid state amps, but if I can salvage one between the three I'll get it going and send it back.

Le Gimp
And, my apology to dakini painter for hijacking the thread.

Not listening to too much music tonight. I'm smashing bottles and having a roaring good time.

I'll finish the night off with a glass of champagne, with absinthe in it of course.

DITA! And to memories of Hemingway. One of the worlds great writers.

I wish everyone a happy and prosperous new year, and many more.

early abs-cheers.gif ….



Kirk
Sent the amps out yesterday, no need to salvage one unless you feel like it. There are some good parts in there though.
dakini_painter
QUOTE
my apology to dakini painter for hijacking the thread


I think your hijacking was totally in tune with the intention of the thread.

Much more interesting to read than a listing of individual song tracks.
Bruno Rygseck
Now listening to Metropolitan Suite by Larry Fast, perfect "pre-prohibition" music for absinthe drinking (Helfrich verte). Here are some links:

North River
Steam and Steel Towers
Metropolitan Theme

This is a "lo-fi" version of our main content. To view the full version with more information, formatting and images, please click here.
Invision Power Board © 2001-2018 Invision Power Services, Inc.