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Yet another Heath W5M rebuild

Man am I glad I found this thread! I have a W5M inbound from Ebay as I type this. I can't wait to roll up my sleeves and find that soldering iron...super excited and thank you so much for this thread. What great work you've done...quite an inspiration for sure!

-Steve Murphy
Chico, CA
 
A schematic (and crossing fingers - a part list) would be killer. About the only tube amp experience I have is keeping my 1968 Fender Super Reverb alive and minimizing the smoke that sometimes rises from the cabinet during my prolonged guitar solos...sonic bliss I might say at that. Not to say I haven't built a zillion guitar pedals and moded amps (fully understanding and respecting the high voltages involved in my endevours)

I'm also wondering about different versions that Heathkit has put out for the W5M. The manual I downloaded might be an earlier version as some of the older component values I have seen in this thread are different from the Heathkit parts list. I haven't laid eyes upon my 'inbound' W5M amp yet, but I do know it has the larger 16458 Peerless OPT so I am assuming its a later model or possibly reburbished - we'll have to see. I have to admit that I'm not understanding alot of the mods and improvements you are making to this circuit...for me this is going to be a learning experience and a 'monkey see, monkey do' affair at best...but I do think I have been bitten by the 'amp building bug' to say the least.

I think it might be a good idea (and this is your fault for totally inspiring me) to completely gut this bad boy and make a build similar to yours. If I decide on this route I might want to wait until I procure another W5M so I can double build and match resistor values and such (is this a good avenue to pursue or am I over thinking here? I do want 2 monoblocs eventually to drive my dream system.

Not to hijack this thread, but I think I would like to homebrew a stereo tube preamp for these beasts eventually...any suggestions on kits or circuits I might want to look at that would complement 2 W5Ms?

Thanks again for all your hard work...I hope your shoulder is healing well and happy holidays buddy!

-Steve
 
As requested by Tom_R, here is a picture of the 2.2K resistor that is connnected to both cathodes of the driver 6CG7 tubes.
 

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You betcha! The lower the resistance/impedance on a grounding buss the better and it doesn't cost very much at all.
 
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I made short ground busses for a couple amps I did, but just between the filter caps. I used 12, since thats what I had on hand. 14 would be a lot easier to work with, but the idea was to get the power supply ripple off the chassis as much as possible. The amps are quiet, so I guess it worked.
 
Since your amps are quiet, I'd say it worked!

At this point in time, both of the W5Ms are about 98% done. I can't wait to hear them on my modded KHorns!
 
Tom, here's two pics of the old 300 ohm pots I promised to send you. Sorry for the delay as i explained in the PM I sent to you.

They will go out in the mail tomorrow!
 

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SteveMurphy;8387625 Not to hijack this thread said:
FWIW, the best pre that I've used with my W-5's is a Van Alstine Super PAS 3. Some of the best sound I've experienced with the many amps/preamp combinations that I've tried. Natural and powerful.
Click to expand...
 
Man, the answer to the question it depends: on your entire system, size of the room, etc.
 
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This has been an amazing thread for me, thanks so much. Lots of good information, education and style to learn here!
 
Thank you Sir. I'll post pictures of the finished product and schematic just as soon as I can. It's my pleasure to share any knowledge and/or skills I might have.
 
ab0ez said:
Tom, here's two pics of the old 300 ohm pots I promised to send you. Sorry for the delay as i explained in the PM I sent to you.

They will go out in the mail tomorrow!
Click to expand...

Thank you very much Jim, much appreciated!

I think it's safe to say we all appreciate the guidance unselfishly put forth by knowledgeable members of AK so that us with desire can rebuild/mod these great pcs of gear from times gone by.
 
Hi Jim,

I have just finished reading through this whole thread taking notes. I am just about to start a W-5M Rebuild and am planning on using your wonderful work as a guide. I have a few quick questions.

1. What are the advantages of the change to 6CG7? I was planning on keeping the 12AU7 configuration but am considering changing so that it is easier to follow your pictures. If I stick with 12AU7 will I be able to avoid those changes or does the change follow through the entire amp circuit?

2. Can I get away with a different type of cap for the first filter section besides PIO?

3. What kind of wire did you use for your connections other than the heater wires which you identified as silver plated stranded Teflon?

Up to this point I have just worked on basic solid state repairs and passive crossover rebuilds. Diving into this build is a big step but your work and attention to detail has given me the confidence to really go all out on this set of amps :)
 

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1) The 6CG7 is a more linear tube vs the 12AU7. The only thing you need to change is the filament wiring, regardless of any other changes, such as different plate & cathode resistors, etc.

2) You can use other than an oil filled (the big one in my post is a an oil filled cap, not a PIO cap). The main thing is make sure its a 4uF (or close) and rated at least for 600V.

3) All of the wire I use in my builds are Teflon insulated silver stranded wire.

Please feel free to ask me any other questions!

Jim, AB0EZ
 
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Thank you for the reply Jim.

I have decided to go with the 6CG7. I picked up a couple 6CG7 test tubes and some rectifiers from a local 2 channel shop. One of my amps had a set of Mullard KT66 so I'm all set for test tubes. I will buy some matched sets once the amps are finished and tested.

I am moving along pretty quickly on my rebuild. I have both of my chassis stripped and a buddy is blasting them for me tomorrow morning. I have all new hardware coming from fastenal and I also have tube sockets, jacks, and switches on the way. I am stuck on caps and resistors. I have notes on most of what I need from going through the thread but still need some values on some of the power supply filter caps and some of the resistor values and wattage ratings that you changed. Do you have a modified parts list yet for this build?

A few more questions:

1. On your RCA jacks it looks like you ran a pretty thick wire to the center connection. Did you use 14GA copper wire here with heat shrink?

2. What gauge wire do you recommend for the heaters and for misc hookup?

3. Do you have any preferred vendors for caps and resistors? I will probably be getting the snap in Nippon Chemicon caps on eBay but am looking to consolidate as many parts into one order as possible.


Thank you so much for your help. I really appreciate it.

Ben
 
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