Russ White said:
When you've been building them as long as I have, you get a little set in your ways...😉
safetyman, you are doing fine...please continue.
Right
tomatos, tomahtos, potatos, potahtos
I have the deepest respect for Mauro and this amp he has shared with us. Let us not get too hung up on what we call it. The name won't change the sound one bit.
edit: duh! spelling
Right
tomatos, tomahtos, potatos, potahtos
I have the deepest respect for Mauro and this amp he has shared with us. Let us not get too hung up on what we call it. The name won't change the sound one bit.
edit: duh! spelling
schematic
sorry guys...
this topic is really long and i cannot find where final evolution of mauro's design is. i think it is called RevC.
can someone point me to this schematic?
thanx
sorry guys...
this topic is really long and i cannot find where final evolution of mauro's design is. i think it is called RevC.
can someone point me to this schematic?
thanx
Giorgiano,
I've attached the schematic of the Rev C mono boards as supplied with the current Twisted Pear Audio Kit,
The schematic is for one channel. The power supply schematic is the same as the one for the RevA.
There is also a later version of Rev C, but it is not available in kit form. A schematic is available for it also.
Audie.
I've attached the schematic of the Rev C mono boards as supplied with the current Twisted Pear Audio Kit,
The schematic is for one channel. The power supply schematic is the same as the one for the RevA.
There is also a later version of Rev C, but it is not available in kit form. A schematic is available for it also.
Audie.
georgiano,
Sorry, but for some reason I couldn't get the file attachment to work.
I have to go off line now-it's well past bedtime.
You can get a schematic by sending an an email to: questions@twistedpearaudio.com .
Audie.
Sorry, but for some reason I couldn't get the file attachment to work.
I have to go off line now-it's well past bedtime.
You can get a schematic by sending an an email to: questions@twistedpearaudio.com .
Audie.
carlosfm said:
Master Carlos 😉 How do I measure the primary of the EI trans? It's supposed to be for 240-110-0 and the secondaries are 24-0-24. When I solder my mains to the primaries, and measure with a MM, they show 240V in and 25.8V out. Is that the right way to confirm?
Ed, thank you for your kind words, but I'll respect Russ and won't post any further questions concerning chip amps in this thread.
Hi folks,
Could anyone please spare me opening up my Mauro (where's that scalpel 😀 ) erm, yeah... Could anyone please tell me the lead spacing of C9 on the TP boards?
Cheers & thanks
Kendal
Could anyone please spare me opening up my Mauro (where's that scalpel 😀 ) erm, yeah... Could anyone please tell me the lead spacing of C9 on the TP boards?
Cheers & thanks
Kendal
safetyman said:
Safetyman, I didn't explain myself well.
Measure your mains voltage, and measure AC on the secondaries too.
So, you measure 240V in (primary) and 25.8V on the secondaries.
If the trafo gets warmer than normal with a light load (comparing to your other, weaker trafo), this may indicate that the primary of this trafo is not really 240V, it's less, like 220~230V. That's the reason why you have 25.8V on the secondaries instead of ~24V. It's not a small difference.
And yes, in these conditions it gets warm.
Carlos is correct. It could also be a very inefficient transformer, with unbalanced windings. This can lead to small oscillations that generate heat. In more extreme cases, it can hum audibly.
carlosfm said:
Thanks a lot guys. Carlos, I think you explained it perfectly. It's my inability to comprehend. Still crawling. 😀 OK!!! I am going to pull out my 400VAC EI trans and give it a shot. I had that wound to 22-0-22, so hopefully, it would be okay. The other strange thing is that the electrical supply to my house is so unstable that it fluctuates pretty badly. I use a regulator, that I have to change the settings ever so often, from 240V to 260V.
must contact the electricity board to get them to have a look at it.Brian, initially it had hum, but it went away after I changed to a tiny cable for the common 0, and routed it from underneath the board.
Thanks a lot for all the help. All this is in preparation to continue my newfound DIY spirit. Next project will hopefully be the My Ref C and Carlos's snubbers. 😀
Just to share something with all of you. My little kid saw Daddy doing all this and he just completed his first electronic project. This is the great stuff that this forum is all about. Now, we have 2 kids in the house, learning how to crawl together. 😀
OK.....I had changed out the 250VAC trafo to a 400VAC (22-0-22) trafo. Measured 239VAC in the primaries, and it's showing 22.9VAC in the secondaries. Is that ok? The trafo runs very warm too. Is this still an indication of an inefficient trafo with unbalanced windings? Or this is acceptable?
I am trying out the best trafo that I can use for the My_Ref C. Please advise, or whichever you think is best. No torroids though. Very difficult to get here and even available are ver expensive. Thanks.
I am trying out the best trafo that I can use for the My_Ref C. Please advise, or whichever you think is best. No torroids though. Very difficult to get here and even available are ver expensive. Thanks.
safetyman said:
I wonder if something is oscillating or ringing.
- would not expect trannies to run hot.
I have moved the transformer about 2 feet away from the amp and there is no humming now, but the trans still runs hot. Do you guys think it is till safe to use the trans?
Do you guys think it is till safe to use the trans?
What is the rating of your primary (voltage) and then what is the actual voltage of your mains. i Had this wil E/I cores. were the primary were wound for 220V and the Mains were 230 , then you will find that it runs hot. or the other problem might be that you have very bad laminations if you are running E/I cores,
Bad Lams is my bet. Try Transformer from another manufacturer if you want to get rid of the heat, but i doubt you will have a safety issue
rudi said:
rudi, my EI transformer was custom wound to 400VAC, primaries 240-260-0 and the secondaries are 22-0-22. The supply from my mains fluctuate from anywhere like 220 to 250AC. At times the supply has exceeded this and gone to 259VAC. And this mystifies me. Why would the mains coming in fluctuate so frequently and drastically?
My plans are to build TP's Kookaburra, My_Ref C and your X-calibre. Now I want to ensure that my 3 transformers are up to this 3 projects. I'll list out the EI transformers that I have:
1) 100VAC; Primaries 240-110-0 and secondaries 24-0-24 (runs cool or warm to the touch)
2) 250VAC; Primaries 240-110-0 and secondaries 24-0-24 (runs very warm to hot) When secondaries are 240VAC, primaries show about 25.9VAC
3) 400VAC; Primaries 260-240-0 and secondaries are 22-0-22 (runs warm to very hot after extended play) When secondaries are 240VAC, primaries show about 22.9VAC
When you say the laminations, do you mean the lacquer that they are dipped in? I was told a good transformer will smell for a few days when you initially use it. Is this true?
I may be willing to get another transformer custom wound and pay a bit more for better quality but before I do that, I need specifications and what I should insist the supplier to follow.
Suggestions please.......