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Posted

Hmm... reminds me I still need to try to deal with the dang buzz on the power transformer. Filling the obvious gap in the lams with some superglue didn't seem to do the trick. :/

Posted

Could the problem be with the shield or something, instead of just the lams? I've been letting it run today and after the buzzing started, barely even touching it at all on the one corner would make it stop, and after pressing firmly around on the foil, it's stopped (at least for now).

Posted (edited)

OMG, Marc! That's fantastic!! :D

P.S. Umm ... who's the audience behind some of those pics? Looks like some of the folk on top of my daughter's piano ... or maybe it's someone I saw in Clash of the Titans? ;)

Edited by TomB
Posted (edited)

Just to keep everyone in the loop, we are waiting on a vendor. But, I think we are getting close ...

Great, really looking forward to building this :)

luvdunhill I really dig the venting!

I have a local powdercoater here that colors whatever items I've left with him on the side when he has a "real order" to take care of. He usually charges ~$40 an item or around $100 for a small box of stuff. I just had him handle an old Dynaco PAS2 that I'm rebuilding.

Edited by HiGHFLYiN9
  • 3 weeks later...
Posted

Hmm... reminds me I still need to try to deal with the dang buzz on the power transformer. Filling the obvious gap in the lams with some superglue didn't seem to do the trick. :/

Buzzing transformers are caused by incorrect manufacture in the first place. The only way to shut one up is to decouple it from the chassis big time. Assuming for the moment that it is a toroid, first take it out. Then make a vey thick layer of RTV - maybe 3/8" or so - and gently seat the transformer onto it. Make sure it does not squeeze out. When that has set somewhat, make a similar layer on the top and set the clamping washer on it. Put the bolt through to keep it lined up. When everything has set, nip the bolt up. The transformer is now vibration isolated from the chassis via two thick resilient layers.

A similar thing can also be done with EI core transformers of course, but it would need some extra thought about how to deal with the bolt fixings. Using rubber grommets instead might work fine and is quick to try out.

Precautions - try to chose an RTV that will cope with a transformer temperature of 60C.

Posted

Buzzing transformers are caused by incorrect manufacture in the first place. The only way to shut one up is to decouple it from the chassis big time. Assuming for the moment that it is a toroid, first take it out. Then make a vey thick layer of RTV - maybe 3/8" or so - and gently seat the transformer onto it. Make sure it does not squeeze out. When that has set somewhat, make a similar layer on the top and set the clamping washer on it. Put the bolt through to keep it lined up. When everything has set, nip the bolt up. The transformer is now vibration isolated from the chassis via two thick resilient layers.

A similar thing can also be done with EI core transformers of course, but it would need some extra thought about how to deal with the bolt fixings. Using rubber grommets instead might work fine and is quick to try out.

Precautions - try to chose an RTV that will cope with a transformer temperature of 60C.

A quick glance at the first page would show there's no toroidal transformers in this amp :P, but an interesting solution nonetheless. I actually did track down the problem though, there was another gap in the lams that you could only tell it was there by looking at a specific angle; sealing it up took care of the problem nicely.

Very nice to be able to listen to this amp regularly now. Now I have no excuse not to get off my butt and finish the chassis.

Posted
I actually did track down the problem though, there was another gap in the lams that you could only tell it was there by looking at a specific angle; sealing it up took care of the problem nicely.

Good to hear you solved this. And, good to know that we need to check each of these transformers individually before sending them out.

Posted

How are you guys coming along on the production version Doug?

I was just over at my brother's briefly yesterday, and he is still enjoying his immensely. Thanks for letting me in on the proto phase!

Posted

How are you guys coming along on the production version Doug?

I was just over at my brother's briefly yesterday, and he is still enjoying his immensely. Thanks for letting me in on the proto phase!

Basically, the only step left is telling the case manufacturer to go ahead and start. That should happen this week ... I think.

  • 3 weeks later...
  • 5 weeks later...
Posted

No, not dead, just delayed. We have, in hand, what we hope to be the final revision of the PCB -- it is now 14" long. We are waiting on a prototype of the final case, which we thought would have arrived already. Probably in the next week -- other cases ordered at the same time from the same vendor are in transit, so this one can't be far behind.

There were only two of the final prototype boards made. Tom is building one, but if anyone (HiGHFLYiN9) wants to do the other, I also have a set of the transformers and a blank 14" case. Whomever wants it can have it for cost.

Posted

I'd love to build another proto. Drop me a pm with total cost.

Thanks -

No, not dead, just delayed. We have, in hand, what we hope to be the final revision of the PCB -- it is now 14" long. We are waiting on a prototype of the final case, which we thought would have arrived already. Probably in the next week -- other cases ordered at the same time from the same vendor are in transit, so this one can't be far behind.

There were only two of the final prototype boards made. Tom is building one, but if anyone (HiGHFLYiN9) wants to do the other, I also have a set of the transformers and a blank 14" case. Whomever wants it can have it for cost.

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