Audio Asylum Thread Printer

Get a view of an entire thread on one page

FAQ / News / Events

Tube DIY Asylum

RE: Modification of a Heath W5-M - Help and advice

52.119.121.37

6bq5

In Reply to: RE: Modification of a Heath W5-M - Help and advice posted by Frank Gelbert on December 28, 2023 at 05:03:55

The art of an output transformer is the multifaceted knitting of circuit, output tubes, power, frequency response and linearity.

This is not a trivial task, nor one that leads to a 'universal' device

The operating parameters of a KT-66 / 6L6 are different enough from an EL-34/KT-77 that a new transformer (or different, at least) is truly in order.

Yes, the Peerless 16548 transformer is wonderful. And it may well represent a great value. That does not change the fact that it is a bad match for the circuit & tubes you are suggesting.

If you want an EL-34/KT-77, start with a Dynaco ST-70 and see what changes you make to the circuit do to the sound.

Good transformers are expensive,
and the reason that old Heath, McIntosh, Marantz, Leak, Quad, Pilot, H.H.Scott, Fisher, Siemens, and the like command high prices, is that they are Great. VAC, Music Reference, MFA, Hadley, Sonic Frontiers also make great output transformers, and You too can wind your own.

For me, using the W5-M to support 4 EL-34s is kind of like putting a 5 Liter V8 engine in a 1950 Citroen 2CV and NOT changing the transmission!
It might run for a bit,
Happy Listening

Follow Ups:

RE: Modification of a Heath W5-M - Help and advice - Frank Gelbert 09:40:56 12/28/23 (1)
O, I think I was not clear enough. We want to build up an amp with one pair of El34, perhaps EL 37 with a higher plate voltage. The impedance of the 16548 fits very well for this. Also the leakeage inductance between the two primarys is low enough for pentode mode. Weknow the limitation of the mass of the iron. This would be no problem for us. Max power output is not the goal. We are looking for this authorative sound of a well designed pentode stage. The 16548 would fit this.
The only problem is the unknown strength of the insulation.
Thank you very much for your remarks. It is good for us to reconsider every part of the design.
By the way, do you know the sound of an Eico Hf81? This sound is roughly what we want. With lower distortions and more power.
Frank
- RE: Modification of a Heath W5-M - Help and advice - 6bq5 09:47:52 12/28/23 (0)
  I would echo Triode Kingdom's comment on the application of higher voltages and power through the Peerless transformer.
  these units had a simple varnish and paper in-between windings.
  Not the polymer coatings of today's wire or robust fishpaper.
  
  I have heard a few Eico units, but could not recall the specifics-
  
  Happy Listening

Post a Followup:

FAQ

Post a Message!

Forgot Password?

Moniker (Username):
Password (Optional):
	Remember my Moniker & Password (What's this?) Eat Me
E-Mail (Optional):
Subject:

Message:	(Posts are subject to Content Rules)

Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:	Automagically notify you when someone responds.

To view your new posting or follow-up, click on the RELOAD or REFRESH button on your browser.

This post is made possible by the generous support of people like you and our sponsors: