No more Peter Dahl parts sez Harbach

[KM1H]

The question with Hammond is where are they going to get the C Core knowledge from?
Building E-I Dahls should be fine but C Cores are a different animal and from what Ive read Magcap, who has built them long prior to doing them for Harbach, had a quality problem with audible hum.

Carl

[W2ZE]

Hammond manufacturing is a very large facility in Guelph making small filament transformers to large power transformers for power generating plants. They employ over 500 people and are an ISO 9001 certified company. I think they can figure it out.

Mike

[Opcom]

A ham told me during the Exchange that Magnaquest copied the Peerless iron from the altec 1570B for their PP output iron, and I went looking there. A crazy person invented the prices on the 'large' push pull iron, which is not so large.. I have no doubt the units sound fine, but wow! My ear nor wallet is made of such gold!

I trust 'em but the cost is more than I wish to pay. I'd get more value from Lundahl for the 100W stuff if I were going to pay like that. Hammond is for me!

Help me understand better - what's the 2 or 3 biggest differences difference between:

1250VCT to 63V @ 1KVA @ 60Hz power transformer
and
3100 Ohm to 8 Ohm @ 500VA @ 30Hz audio transformer?

both about 19:1 turns..
I see thinner laminations on the audio one.
same magnetism energy in the iron.. 500VA@30Hz or 1KVA@60Hz.
The better audio XFMRs may have the windings split up in sections.
  (is there really a sound difference or is this for the "golden ear" customer who hears a pin drop in a machine room?)

I'd agree Hammond can make what is asked for. The only question mark is price, and if they will truly get all the old Dahl paperwork.

like I been begging for, a BTA-1 mod trans with a speaker winding.

http://qrz.com/db/K5LRX and scroll down.. so pretty.

[WD5JKO]

like I been begging for, a BTA-1 mod trans with a speaker winding.

http://qrz.com/db/K5LRX and scroll down.. so pretty.

Pat,

   Maybe the secondary of the BTA-1 is wound over the primary? If so, it might be possible to take apart  the transformer, remove the secondary (while counting the turns), and then lay in low impedance speaker winding(s).

  Go a step further, and use a core you have as the basis of a new transformer. Patrick Turner has the best step by step I've ever seen on how to roll your own:

http://www.turneraudio.com.au/output-trans-pp-calc-1.html

Jim
WD5JKO

[WZ5Q]

Patrick Turner has the best step by step I've ever seen on how to roll your own:

http://www.turneraudio.com.au/output-trans-pp-calc-1.html

Jim
WD5JKO

Mr. Turner has always kept me in awe, and I just love his persona.

I had thought about pursuing "rolling my own" hi-fi audio transformers, but after researching/dabbling in it for a while, my personal conclusion was that it is a very time consuming, extremely math intensive, and a VERY specialized undertaking. IMO, the high end audio transformers being made today are well worth the money they ask.

It seems that the transformers missing from today's selections are the inter-stage matching iron like they made in yesteryear, i.e. the UTC LS series. I believe Lundahl & Sowter are the only manufacturers making anything close, albeit in small wattage ratings and limited impedance selections. Nothing in the Modulator Driver category unfortunately.

Once I get "caught up" in honey-dews, and other projects, I just might take the final step over into this specialized field and commit. It is very intriguing field to say the least.

Take Care,

[Opcom]

I'm not up to the risk of hand-winding a hi-fi transformer. rectangular bobbin, HV insulation, neatness requirements so it will actually fit together, and a couple thousand turns counted precisely. Any goof and the time and possibly the materials are wasted.

[W3RSW]

I keep opening this thread to see if, I guess by magic, someone will make the great announcement that Dahl's drawings and info have been bought and the great works will go on.

Oh well..., think I'll fire up the 32v on 40 this am.  I'm remiss in real hamming.

[KM1H]

I guess you missed post 20-25 of this thread.

Prior to that I posted a seperate thread announcing it but it seems to have disappeared.

[W3RSW]

I sure did.  Second thing to go I guess
Thanks for the gentle nudge.

Is that Nooge or nuhg?   Heh, heh.