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Heathkit W5M questions

I have never seen where an amp is better with smaller iron,
Exception would be speciality Expensive SET x-formers. 45, 300b's ect
 
Kevdog said:
Maybe the character lies in the smaller transformer/different tubes!?
Click to expand...

The output transformers have a good deal to do with it. Also the circuit design, a standard Williamson but with a good deal of extra tuning and using 12AU7s instead of 6SN7s. That accounts for part of the laid-back character of the amps. But I have tossed a pair of 16309s onto my Williamson experimenter amps, and there's no question that they retain the smooth, mellow sound that makes the W5 rather distinctive.
 
Nyjblbob said:
I have never seen where an amp is better with smaller iron,
Exception would be speciality Expensive SET x-formers. 45, 300b's ect
Click to expand...

There's no lack of bass response from the 16309s. The nickel striping increases the primary inductance and thereby compensates for the small size. Maqnequest used to charge a significant premium for their nickel-striped SET transformers. Here's a 10K square wave and FR plot from my experiment, granted at only 1 watt:

CFA57DB4-2BDD-4790-8215-4540FDD024C2.jpeg

05BFBB69-C210-4A58-A98D-E51AE80BF99A.jpeg
 
Sounds like it might just be a worthwhile experiment from what you’re saying since these are sorted and all original.
What price tag is normal for these?
 
I have a pair of these in storage, for over 20 years. So watching with interest. No idea which I have, or if they even match. It's been that long.
<edit> - checked, they are both 16309, silver units marked with a Peerless sticker in the side. Also have the 4 original Genelex KT-66, so definitely will get these dusted off and back making music soon.
The John Atwood tests for the 16309 show they put out "25W @ 34 Hz with no visible waveform distortion".
John added that for the "Full Power F min measurement" - "DC balance affects this value greatly."
 
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Kevdog said:
Sounds like it might just be a worthwhile experiment from what you’re saying since these are sorted and all original.
What price tag is normal for these?
Click to expand...

We can't discuss value on the regular forums. I suggest you do a search on popular auction sites. There are usually a few W5s for sale.
 
I rebuilt a pair some years ago from scratch. At the end, it is a very nice sounding amplifier.

Powerful enough, very detailed, very good overall.

Regarding reliability of the OT, this is not a design problem of the amplifier but a component choice.
The coupling caps was rated 400VDC when it needs to be 600VDC.
As a result, the coupling caps were damaged over time, start to leak DC downstream, upsetting the power tubes, resulting in meltdown and OT damage.
With properly rated coupling caps, the OT is not more or less abused than in any other amplifier.

The PT is another story.
Yes they blow up, for no reason. I blew one (open primary) while listening to it. No pop, no ding, no crack. A silent death.
That's the nature of the beast and you have to be ready for that, as some point.
 
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