I was able to get the adjustments dead on, 0.400 volts across all 4 tubes. Its just that I've been churning it over in my head that maybe I got something wrong and that is causing the power transformer to run hot.
I had the amp turned on for a couple hours last night and I couldn't put my fingers on the transformer for more than a few seconds because it was so warm. It is also physically vibrating and the hum from the transformer is audible from a couple feet away.
I had the amp turned on for a couple hours last night and I couldn't put my fingers on the transformer for more than a few seconds because it was so warm. It is also physically vibrating and the hum from the transformer is audible from a couple feet away.
Mine got hot - uncomfortably so - which is why I bought a Toroidy replacement which is over-spec'd. Runs cooler (and a computer fan running on very low voltage also helps massively!)
The noise is not usual. A very faint hum / buzz in a quiet room when up close, not from 2 feet. Again, the toroidal Tx got rid of that in my case.
Somewhere in this thread (or perhaps elsewhere) there was a discussion on the power TX and someone identified theirs had a fault / defect. Tightening the screws was suggested, but in the end I think a replacement was needed.
T
Does this issue remain if the PT is running at idle, i.e. after you have disconnected all secondaries? If so, it is a syptom of a PT being knitted to the edge by the manufacurer (too low turns count per Volt).
Best regards!
I notice in your underside shot that the copper traces of the power input module are very close to the aluminium top plate. Or is it a view issue and you do have enough space there ?
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Mine gets to 70°C which is really too hot for my taste, this is why I will replace it. I did need to tighten the screws after its trip, didn't help either. Edcor is not up to my taste. Long wait times, ugly blue. Toroidy is nearer, faster and nicer look if you get the potted versions. I don't imply that Edcor does bad stuff, I probably had bad luck with that one, but the shipping to Switzerland is simply to expensive to continue working with them. The OPTs are ok, I will keep them on that 1st build. Simply replace the PT and move on.
I dunno... I have a Hammond that has been running at 95C for years... I have transformers that run at 60c without load, too. 70c doesn't seem overly hot to me but then again I tend not to touch it while it's hot anyway 
Agreed though, Toroidy seem to make nice coils, that's for sure. Shipping to you should be much less than shipping to me, too.
Agreed though, Toroidy seem to make nice coils, that's for sure. Shipping to you should be much less than shipping to me, too.
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I built this amp about 9 years ago. It is still running with the same set of tubes. I haven't run it daily lately because it's become a little noisy and I feel I have to check the components.
The power transformer does run hot, hotter when idle.
I think I have to replace the tubes to get rid of the noise it's making, or it could be the mains that is doing that.
I do not get any hum on mine, even with the hot PT.
This is a great amp, I still love it.
The power transformer does run hot, hotter when idle.
I think I have to replace the tubes to get rid of the noise it's making, or it could be the mains that is doing that.
I do not get any hum on mine, even with the hot PT.
This is a great amp, I still love it.
Yes, that points exactly to what I meant above: Too little turns per volt
.Best regards!
With the tubes unplugged check the PT primary current. Wait for a while, check the temperature. Might be a shorted turn inside.
With the tubes back in check the PT primary current again. Be sure the meter is true RMS responding, it is the RMS current that cooks transformers, not the average. To large 1st caps after the rectifier can put the PT in dangerous territory while under load.
I got sent home from work early today because of the virus crap, they didn't want me hanging around the office anymore.
The good thing is I got to come home and listen to music as loud as I want with no one in the house! I followed the little tip about tightening the screws on the transformer and tweaked them a little tighter, actually seems to have cut down the buzzing a lot.
I've had the amp running for about 6 hours so far, and yeah the PT is hot but it sounds great and appears to be working perfectly fine. So I'm thinking who cares if it's hot? I'm gonna ship it and if it breaks it breaks, but it probably won't
The good thing is I got to come home and listen to music as loud as I want with no one in the house! I followed the little tip about tightening the screws on the transformer and tweaked them a little tighter, actually seems to have cut down the buzzing a lot.
I've had the amp running for about 6 hours so far, and yeah the PT is hot but it sounds great and appears to be working perfectly fine. So I'm thinking who cares if it's hot? I'm gonna ship it and if it breaks it breaks, but it probably won't
For the sake of liability & insurance would it pass a UL inspection?
OK if for yourself but be careful what you put your name on.
If your stuff causes injury or fire its not a good day!
Many underemployed lawyers are always looking for an opportunity.
Apparently anything can pass UL inspection...
https://www.alibaba.com/product-det...4857.normalList.73.7ac44a38T5t4ZP&bypass=true
https://www.alibaba.com/product-det...4857.normalList.73.7ac44a38T5t4ZP&bypass=true
Until it doesn't. We (the companies I worked for) brought in loads of test equipment over many years from the US, Germany, Korea & others for sale & trade shows. And often had to submit samples on the spot for inspection. Then a temporary permit might get issued.
I recall one in particular, the inspector asked for a match or cigarette lighter. He tried to set on fire the plastic case of the interface for a bar code reader on our sample. It didn't burn, we got the OK. And the sticker.
Another case involved a fraudster with a degree mill pedigree. He had a piece of our TE on loan for demo. He put a bogus CSA sticker on some work he had performed for his customer. For that he spent two months in jail. We had to get our demo out before the bank closed him down. Then he resurfaced under a different name.
If your intention is to have someone else use your masterpiece, be careful. A simple mistake can quickly become serious money.
True. Safety is paramount of course!
"No user serviceable parts inside" and all the other legal stuff they write in the back of the user manual nobody reads usually gets by most of it, at least if it's the customers own stupidity.
It's like safety class in auto shop. It was common sense to us back then. Basically "Don't put your hand in the vise and close it". Now you really have to spell it out for people because as you said, no shortage of lawyer scum. Or "Common sense isn't that common anymore".
"No user serviceable parts inside" and all the other legal stuff they write in the back of the user manual nobody reads usually gets by most of it, at least if it's the customers own stupidity.
It's like safety class in auto shop. It was common sense to us back then. Basically "Don't put your hand in the vise and close it". Now you really have to spell it out for people because as you said, no shortage of lawyer scum. Or "Common sense isn't that common anymore".
Adding a filament transformed to the DCPP
Hello all..
As with many of you, I have built and love the Engineer's Amp. However, like others have noted, I am "concerned" over the PT heat build up. I've read through this post, but have not seen a definitive cause or solution laid out.
Unless I missed it and apologies are in order.
The filament demand seems to be right at the Edcor's rated output, so I'm assuming this is a good place to start.
I am considering the addition of a Hammond 166S6 transformer to the build. The unit is 6.3ct @10 amps, and small enough to fit in the chassis (I think 4x2.5x2.5 ish ).
So ...disconnect the Edcor filament winding (brown/brown/white+brown) and wire in the 166S6 to the same PCB inputs. I know there is an offset voltage and increased AC wiring won't help....but I think it would fly.
Thought I would reach out for any input of cautions.
I also can't help but wonder if converting to DC filaments would gain anything. I seem to be happy with how quiet the amp is now... May just be adding complexity for no gain. I did see mention of this in the post but no result that I am aware of.
Thank You for any guidance...
Hello all..
As with many of you, I have built and love the Engineer's Amp. However, like others have noted, I am "concerned" over the PT heat build up. I've read through this post, but have not seen a definitive cause or solution laid out.
Unless I missed it and apologies are in order.
The filament demand seems to be right at the Edcor's rated output, so I'm assuming this is a good place to start.
I am considering the addition of a Hammond 166S6 transformer to the build. The unit is 6.3ct @10 amps, and small enough to fit in the chassis (I think 4x2.5x2.5 ish ).
So ...disconnect the Edcor filament winding (brown/brown/white+brown) and wire in the 166S6 to the same PCB inputs. I know there is an offset voltage and increased AC wiring won't help....but I think it would fly.
Thought I would reach out for any input of cautions.
I also can't help but wonder if converting to DC filaments would gain anything. I seem to be happy with how quiet the amp is now... May just be adding complexity for no gain. I did see mention of this in the post but no result that I am aware of.
Thank You for any guidance...
I would be wary of adding the Hammond. You could get mechanical hum from the transformer. This has been an issue for me with many of the Hummand, woops!, I mean Hammond transformers that I have used. Often it is louder than the electronic hum coming out of the speaker. A small quiet fan may be another solution.
I would be wary of adding the Hammond. You could get mechanical hum from the transformer. This has been an issue for me with many of the Hummand, woops!, I mean Hammond transformers that I have used. Often it is louder than the electronic hum coming out of the speaker. A small quiet fan may be another solution.
Sometimes in the summer months I use a computer fan running at 6 volts to cool the amp a bit. Unless the PT is smoking hot, I would just run it as is.
Of course there's nothing wrong with experimenting with your amp.
jeff