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Heathkit W5M questions

K

Kevdog

Active Member
Looking to purchase some Heathkit w5m Mono blocks and have a couple questions I haven’t been able to find anywhere. There looks to be an adjustable pot near the 12au7 tubes that says Bass-bal adjust. Can you tell me what this balances?? Is it only a bass gain adjust? It’s not a general gain I take it?

The other question may sound silly, but this can be used with any modern Preamp I take it? I have a Mapletree Audio tube preamp or vintage McIntosh MX110Z I could mate with them.
Many thanks and these seem like wonderful little amps. It is completely stock btw.
-Kevin
 
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Kevdog said:
Looking to purchase some Heathkit w5m Mono blocks and have a couple questions I haven’t been able to find anywhere. There looks to be an adjustable pot near the 12au7 tubes that says Bass-bal adjust. Can you tell me what this balances?? Is it only a bass gain adjust? It’s not a general gain I take it?

The other question may sound silly, but this can be used with any modern Preamp I take it? I have a Mapletree Audio tube preamp or vintage McIntosh MX110Z I could mate with them.
Many thanks and these seem like wonderful little amps. They are completely stock btw.
-Kevin
Click to expand...
 
Kevdog said:
Looking to purchase some Heathkit w5m Mono blocks and have a couple questions I haven’t been able to find anywhere. There looks to be an adjustable pot near the 12au7 tubes that says Bass-bal adjust. Can you tell me what this balances?? Is it only a bass gain adjust? It’s not a general gain I take it?

The other question may sound silly, but this can be used with any modern Preamp I take it? I have a Mapletree Audio tube preamp or vintage McIntosh MX110Z I could mate with them.
Many thanks and these seem like wonderful little amps. It is completely stock btw.
-Kevin
Click to expand...
@Dswankey answered part of your question and provided you links to the manual.
As far as using the maple tree preamp i would say give it a try you wont hurt anything .As far as the mx 110 goes that should do.
 
If you didn't already purchase them, I would say Don't
Not that they are that bad, clean, quiet detailed,
Just Not that good either. I had the bigger 458 x-formers.
Cool looking Yea for sure.Kinda Bass shy
They just don't do anything special. I think a Modded Dyna 70 beats them
and a Fisher X-KX 200-202.Handily beats them. everywhere!
any decent Preamp will work with them
 
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Kevdog said:
Looking to purchase some Heathkit w5m Mono blocks and have a couple questions I haven’t been able to find anywhere. There looks to be an adjustable pot near the 12au7 tubes that says Bass-bal adjust. Can you tell me what this balances?? Is it only a bass gain adjust? It’s not a general gain I take it?

The other question may sound silly, but this can be used with any modern Preamp I take it? I have a Mapletree Audio tube preamp or vintage McIntosh MX110Z I could mate with them.
Many thanks and these seem like wonderful little amps. It is completely stock btw.
-Kevin
Click to expand...

The W5 is a basic Williamson-style amplifier that uses self, or cathode, bias for the tubes. The "bass-balance control" simply balances the current draw of the output tubes to provide the best bass response from the output transformer. Unbalanced output tubes tend to weaken bass response and increase distortion in a push-pull amplifer due to the unbalanced current on the output transformer primary.

I disagree with some who say these amps aren't special. But there are several issues that need to be addressed when considering a purchase. The W5 came with two different output transformers--a smaller Peerless 16309 which was prone to failure, and a larger replacement Peerless 16458 which was more robust. The original power supply and coupling capacitors were under-spec'd with regard to voltage tolerances and should be replaced with higher-rated components.

If they are completely stock and still in working condition, that says a lot for them, but for continued service they should be upgraded with more modern components--caps, resistors, etc.--to sound their best and avoid failure.

The preamps you list will not be a problem. The amps like a fair amount of gain and have a high input impedance which most preamps can drive easily.
 
zackthedog said:
The W5 is a basic Williamson-style amplifier that uses self, or cathode, bias for the tubes. The "bass-balance control" simply balances the current draw of the output tubes to provide the best bass response from the output transformer. Unbalanced output tubes tend to weaken bass response and increase distortion in a push-pull amplifer due to the unbalanced current on the output transformer primary.

I disagree with some who say these amps aren't special. But there are several issues that need to be addressed when considering a purchase. The W5 came with two different output transformers--a smaller Peerless 16309 which was prone to failure, and a larger replacement Peerless 16458 which was more robust. The original power supply and coupling capacitors were under-spec'd with regard to voltage tolerances and should be replaced with higher-rated components.

If they are completely stock and still in working condition, that says a lot for them, but for continued service they should be upgraded with more modern components--caps, resistors, etc.--to sound their best and avoid failure.

The preamps you list will not be a problem. The amps like a fair amount of gain and have a high input impedance which most preamps can drive easily.
Click to expand...
Thanks Zack! They have been upgraded with total cap replacement and higher values. Still original tube types, will have to ask about which transformers (is there a way to tell??). i have Mac gear and specifically MC30 amps. Are these Heathkits class A? Also, how do they compare to say a MC30. Is it even a fair fight?? If I tied them in with the 30’s to help run highs or lows might that be an advantage over my current setup of simply 30’s running everything? They are both 6L6 OT.
i have options if I had them, but I do want to make sure they’rea very good sounding amp first and foremost.
 
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Perhaps do a search on here for various postings. I seem to recall someone comparing W5's to MC30's that they owned already, so perhaps impartial.
 
stanko said:
Perhaps do a search on here for various postings. I seem to recall someone comparing W5's to MC30's that they owned already, so perhaps impartial.
Click to expand...

Yep…. found nothing directly comparing them. I understand comparisons are tough. What shape something is in (updated or not), mods, tubes rolled all make such differences in tube gear. Tubes alone can take something from lifeless to lifelike. It sounds to me that this is a candidate (canvas) that has some potential if the proper specs are there and the right tubes are rolled. I guess that’s what I’d like to know if nothing else. I understand it’s fragility. Most old stuff has that built in also.
Need to decide before long to bite on it.
 
I put a pair on ebay many years ago, the guy that got them ending up buying 12 or 14 of them from me with the smaller, 16309 transformers. Drove from Michigan to pick them up. Wrote me a check, then a couple weeks later I get another check. Seems he figured wrong and owed me some money. Someone posted pics of frequency response of the larger transformers, 16458's. The response is flat as if drawn with a ruler. If I get some time sitting here with my wife, I'll see if I can search out some of these posts. Maybe they were under different headings, but I know I read about someone comparing W5's to mac 30's.
 
Kevdog said:
Thanks Zack! They have been upgraded with total cap replacement and higher values. Still original tube types, will have to ask about which transformers (is there a way to tell??). i have Mac gear and specifically MC30 amps. Are these Heathkits class A? Also, how do they compare to say a MC30. Is it even a fair fight?? If I tied them in with the 30’s to help run highs or lows might that be an advantage over my current setup of simply 30’s running everything? They are both 6L6 OT.
i have options if I had them, but I do want to make sure they’rea very good sounding amp first and foremost.
Click to expand...

The Macs and the W5s are very different animals. Every Mac I've heard has a hefty, sturdy sound due to the unity-coupling design. The W5's have a much lighter footprint but a very natural tone due to the Williamson topology and the Peerless outputs. They are largely Class A, I believe. If I were bi-amping I would use these for the mids and highs. If you can't see the transformer numbers, the original 16309 is shorter than the KT66 output tubes, whereas the later 16458 is taller than the tubes. The 16309 had nickel striping in the lams to increase the low frequency response relative to the transformer's size. It also gave them a very sweet sound in the highs. I have not heard the 16458s, but you can't go wrong with Peerless outputs.

If they've been reworked they should be fine.
 
zackthedog said:
The Macs and the W5s are very different animals. Every Mac I've heard has a hefty, sturdy sound due to the unity-coupling design. The W5's have a much lighter footprint but a very natural tone due to the Williamson topology and the Peerless outputs. They are largely Class A, I believe. If I were bi-amping I would use these for the mids and highs. If you can't see the transformer numbers, the original 16309 is shorter than the KT66 output tubes, whereas the later 16458 is taller than the tubes. The 16309 had nickel striping in the lams to increase the low frequency response relative to the transformer's size. It also gave them a very sweet sound in the highs. I have not heard the 16458s, but you can't go wrong with Peerless outputs.

If they've been reworked they should be fine.
Click to expand...
zackthedog said:
The Macs and the W5s are very different animals. Every Mac I've heard has a hefty, sturdy sound due to the unity-coupling design. The W5's have a much lighter footprint but a very natural tone due to the Williamson topology and the Peerless outputs. They are largely Class A, I believe. If I were bi-amping I would use these for the mids and highs. If you can't see the transformer numbers, the original 16309 is shorter than the KT66 output tubes, whereas the later 16458 is taller than the tubes. The 16309 had nickel striping in the lams to increase the low frequency response relative to the transformer's size. It also gave them a very sweet sound in the highs. I have not heard the 16458s, but you can't go wrong with Peerless outputs.

If they've been reworked they should be fine.
Click to expand...
zackthedog said:
The Macs and the W5s are very different animals. Every Mac I've heard has a hefty, sturdy sound due to the unity-coupling design. The W5's have a much lighter footprint but a very natural tone due to the Williamson topology and the Peerless outputs. They are largely Class A, I believe. If I were bi-amping I would use these for the mids and highs. If you can't see the transformer numbers, the original 16309 is shorter than the KT66 output tubes, whereas the later 16458 is taller than the tubes. The 16309 had nickel striping in the lams to increase the low frequency response relative to the transformer's size. It also gave them a very sweet sound in the highs. I have not heard the 16458s, but you can't go wrong with Peerless outputs.

If they've been reworked they should be fine.
Click to expand...
zackthedog said:
The Macs and the W5s are very different animals. Every Mac I've heard has a hefty, sturdy sound due to the unity-coupling design. The W5's have a much lighter footprint but a very natural tone due to the Williamson topology and the Peerless outputs. They are largely Class A, I believe. If I were bi-amping I would use these for the mids and highs. If you can't see the transformer numbers, the original 16309 is shorter than the KT66 output tubes, whereas the later 16458 is taller than the tubes. The 16309 had nickel striping in the lams to increase the low frequency response relative to the transformer's size. It also gave them a very sweet sound in the highs. I have not heard the 16458s, but you can't go wrong with Peerless outputs.

If they've been reworked they should be fine.
Click to expand...
Many thanks on this information! I would say the OT are Definitely taller than the output tubes! What you say about the lightness compared to Mac gear is fine by me. Detailed and true sounding, along with linearity are my key areas of preference. Pics below are difficult to see, but another pic I’ve seen of them shows the OT is definitely taller.
 

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The transformers that show in the picture are the power and choke. Outputs on the other side can't be seen.
Edit: sorry, I didn't cue in on your comment of having seen another picture. Good luck with them.
John
 
nerdorama said:
The transformers that show in the picture are the power and choke. Outputs on the other side can't be seen.
Edit: sorry, I didn't cue in on your comment of having seen another picture. Good luck with them.
John
Click to expand...
Is that The “silver can” transformer? There are three. Two on the right, one on the left. The two smaller ones are both shorter than the OT and nearly the same height with each other.
 
I had my pair of W5's for 2 years. early 90's. Both were Professionally restored by Ed Duda, Engineer/Inventor.
best of everything., tung Sol 6L6's and 5881's were used. they were beautiful.
I wound up using them in a Biamped system, Mids and Highs only.
on Horns . Quiet and detailed yea, but without much Character to keep them.
I doubt they came close to 30 Watts especially at the low end.
 
Kevdog said:
Is that The “silver can” transformer? There are three. Two on the right, one on the left. The two smaller ones are both shorter than the OT and nearly the same height with each other.
Click to expand...

yes, it's a silver-ish can. The power supply transformer and choke are black.
 
Nyjblbob said:
I had my pair of W5's for 2 years. early 90's. Both were Professionally restored by Ed Duda, Engineer/Inventor.
best of everything., tung Sol 6L6's and 5881's were used. they were beautiful.
I wound up using them in a Biamped system, Mids and Highs only.
on Horns . Quiet and detailed yea, but without much Character to keep them.
I doubt they came close to 30 Watts especially at the low end.
Click to expand...
Maybe the character lies in the smaller transformer/different tubes!?
 
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