Tube DIY Asylum

Do It Yourself (DIY) paradise for tube and SET project builders.

Return to Tube DIY Asylum

Message Sort: Post Order or Asylum Reverse Threaded

damn 40 years of collecting

72.130.117.241
Posted on July 29, 2015 at 15:50:54
unclestu
Dealer

Posts: 5851
Joined: April 13, 2010
 So I buy this Dyna A-410 output: NIB, potted leads unterminated. It take me decades to find another matching half, although this one is already built up. Now to only find that damned NIB transformer !!!!

 

Hide full thread outline!
    ...
still looking for Acrosound 290 series... 12k for 807 Triode-nT, posted on July 29, 2015 at 16:49:13
Cleantimestream
Audiophile

Posts: 7551
Location: Kentucky
Joined: June 30, 2005
 !
The Mind has No Firewall~ U.S. Army War College.

 

RE: still looking for Acrosound 290 series... 12k for 807 Triode-nT, posted on July 29, 2015 at 17:08:55
unclestu
Dealer

Posts: 5851
Joined: April 13, 2010
 frustrating ain't it? I got a Altec 340 and a 350 thinking they were the same: no dice... still looking of a single to make up a pair but the prices are simply getting too high....

 

Freed QGA-42...:), posted on July 30, 2015 at 05:28:18
PakProtector
Audiophile

Posts: 12365
Joined: May 14, 2002
 I got my first one of these from a collector who gave up on finding another. Guess I will have to wreck it and wind two in order to get a pair...:) Or maybe it will go like my S-258-Q useage; I found a second and left the new winding and modification alone...
cheers,
Douglas

Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.

 

RE: still looking for Acrosound 290 series... 12k for 807 Triode-nT, posted on July 30, 2015 at 13:13:52
mqracing
Manufacturer

Posts: 4323
Joined: June 29, 2000
 Even more frustrating--- though many people are not aware of this--- is that finding the second unit to have a matched pair--- may not actually be a matched pair in the details....

over the course of several years a particular output transformer may have undergone one or several changes in design or in the materials used to build the transformer... the change may have been minor or (in some cases) significant.

If you can match date codes and get close... the closer you can get the better the chances of the two being close to each other in design and materials.

MSL



Builder of MagneQuest & Peerless transformers since 1989

 

RE: damn 40 years of collecting, posted on July 30, 2015 at 13:19:43
mqracing
Manufacturer

Posts: 4323
Joined: June 29, 2000
 All three transformers mentioned in this thread are obscure (physically scarce). All are very good designs.

I have a pair of NOS Acrosound TO-250's that one of these days I'm going to put up on the bay.

the QGA series by Freed are sleepers in the marketplace. They are a top shelf design built in the British tradition (coil design wise).

Another sleeper in a series are the Triad HSM series of outputs. These are as close as possible to the design precepts of Herbert Keroes of Acrosound fame. The Triad outputs are much easier to find the the Freeds or the early Acrosound designs.

All good stuff... enjoy... and good luck in finding these rare birds.

MSL




Builder of MagneQuest & Peerless transformers since 1989

 

I have a pair of Acrosound TO300s,..., posted on July 31, 2015 at 06:53:25
Lew
Audiophile

Posts: 10912
Location: Bethesda, Maryland
Joined: December 11, 2000
 which I used to build a pair of 807 amplifiers. Just two OP tubes per channel. What's the difference between the TO300 and the TO290? The TO300 does offer optional UL hook-up.

 

300 primary impedance is 6600, posted on July 31, 2015 at 07:57:46
Cleantimestream
Audiophile

Posts: 7551
Location: Kentucky
Joined: June 30, 2005
 far too low for my liking in a triode wired 807.
The Mind has No Firewall~ U.S. Army War College.

 

RE: I have a pair of Acrosound TO300s,..., posted on July 31, 2015 at 10:24:20
Lew
Audiophile

Posts: 10912
Location: Bethesda, Maryland
Joined: December 11, 2000
 I built the amplifiers back during the early years of my DIY experience. I followed a schematic. They are in fact wired in Ultralinear mode, FWIW. I don't know whether or not that would ameliorate the perceived impedance mismatch, because I cannot offhand recall the Rp of an 807 or how UL mode affects impedance matching, except that it almost certainly does. I'm strictly an OTL guy, usually.

 

OY VEY !!!!!!!!!!!!!, posted on July 31, 2015 at 10:44:45
unclestu
Dealer

Posts: 5851
Joined: April 13, 2010
 Not what an anal retentive OCD wants to hear, although I know deep down inside its true. All I need do is to look at my Dyna Iron over the years, power transformer and even outputs show slight differences.

I know Mike Sanders, of Quicksilver, designs his own transformers. When I asked (politely) who his winder is, he back tracked completely. He told me the most difficult thing was to find a custom winder who will NOT deviate from the specs, which included thing like the thickness of the paper and insulation and such. And he did not want to reveal the information least he gets overloaded.....

Most winders will go "good enough" or "close enough" and leave you wondering why things are the way they are....Mike is very picky in that regards. Then again, I know of few designers who actually design their own iron, I used to wonder why his iron used basically the same sized lams.....and very large secondary windings

 

Nice to know, posted on July 31, 2015 at 10:46:03
unclestu
Dealer

Posts: 5851
Joined: April 13, 2010
 Thanks for the comments


 

Page processed in 0.019 seconds.

[ Top Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2024, Audio Asylum, all rights reserved ]
[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]