Hi and sorry to bring back this old 3D. A friend has a not working Delta 290.
If i understand well at least to locate in which section the problem is he should set the internal selector switch to EXT INPUT position to enable the power amp input (the pre outs being permanently active i read on the user manual).
Am i right ? Am i also right that the power section is the nicer part in this amp ? Let's hope that the problem is in the preamp section then.
Thanks and regards, gino
If i understand well at least to locate in which section the problem is he should set the internal selector switch to EXT INPUT position to enable the power amp input (the pre outs being permanently active i read on the user manual).
Am i right ? Am i also right that the power section is the nicer part in this amp ? Let's hope that the problem is in the preamp section then.
Thanks and regards, gino
yesss..pre section is the weakest area sonically. Using that slider switch turns off the pre amp section and.. Everything.. other than the Power and speaker switches.
What does the orange/green LED above the power switch behave like?
If it doesn't turn green after 10 ~ 15 seconds then there are Power amp issues...
Commonly the Diodes fail when aged
What does the orange/green LED above the power switch behave like?
If it doesn't turn green after 10 ~ 15 seconds then there are Power amp issues...
Commonly the Diodes fail when aged
Hi and thank you so much for your very helpful reply
The amp is now at a friend house ... tomorrow we will open it.
From the user manual i understand that the pre outs are always active with the slider in both positions. Instead the main ins only in one position.
But we will have to open it and see. I cannot do it until tomorrow.
Thanks again and i will let you know asap.
Which diodes are you referring at ? the ones in the rectifier bridge ?
I was thinking some relais maybe ?
But tomorrow i will have it on my desk and i could check.
From the picture in the web the toroid looks quite substantial ... good !
I do not like very much the mosfet output ... usually gives a soft sound.
Anyway i will report on the findings.
Thank you very much indeed, for now.
Kindest regards, gino
Hi again .. so i checked
Unfortunately it stays amber ...
So the issue is with the power section ?
The toroid is quite big indeed, but diodes and also power resistors are very small at the point to seem undersized.
is there a way to assess where the problem is safely ?
It is a pity because the transformer is quite a beast
Thank you very much indeed, gino
Unfortunately it stays amber ...
So the issue is with the power section ?
There are some aspects that leave me perplexed
The toroid is quite big indeed, but diodes and also power resistors are very small at the point to seem undersized.
is there a way to assess where the problem is safely ?
It is a pity because the transformer is quite a beast
Thank you very much indeed, gino
Hi the more i look at this amp the more it looks to me like a
After a very big and beautiful transformer everything around the output stage is very tiny and low power from diodes to power resistors.
Is this normal ? I have had some Rotels and by comparison the transformers were smaller but everything else seemed better sized.
Anyone aware of this design philosophy ... a little against Ohm's law ?
Transformer aside ... very very beautiful indeed. What a waste ...
An externally hosted image should be here but it was not working when we last tested it.
After a very big and beautiful transformer everything around the output stage is very tiny and low power from diodes to power resistors.
Is this normal ? I have had some Rotels and by comparison the transformers were smaller but everything else seemed better sized.
Anyone aware of this design philosophy ... a little against Ohm's law ?
Transformer aside ... very very beautiful indeed. What a waste ...
Dunno everything seems the size it needed to be at the time it was designed.
Current Electronic components are often surface mounts.
Technology keeps moving on.
Old amps have Huge parts Big Transistors and Massive capacitors. OLD tech in a word.
Old cell phones were the size of a briefcase Does that make those "better"
Did you really think you could open the Amp and see an obviously broken axle ?
Take it to a competent shop, pay for a diagnosis, then decide if you want to pay for the needed repairs.
You live in Stavanger? Why don't you buy Electrocompaniet ??? and be done with Audio purchases.. for Years/decades Save up if Needs be.
Current Electronic components are often surface mounts.
Technology keeps moving on.
Old amps have Huge parts Big Transistors and Massive capacitors. OLD tech in a word.
Old cell phones were the size of a briefcase Does that make those "better"
Did you really think you could open the Amp and see an obviously broken axle ?
Take it to a competent shop, pay for a diagnosis, then decide if you want to pay for the needed repairs.
You live in Stavanger? Why don't you buy Electrocompaniet ??? and be done with Audio purchases.. for Years/decades Save up if Needs be.
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i get back this thread live,
the best recap for this amp is reservoir 10k mf with BHC/kendeil or any other 105C caps, don't oversize to 15k, it get it slow and muddy, then lm 3x7 output matrix with 4 x 10mf tants Mil spec , the gray bipolar elna 4 x 10uf signal caps with Muse or Kaisei , the 2x 100 mf with KZ , and of course the Tl072 with dual difet 627 and 2 other BB 2134 to replace the tone controle NE 55xx on each side !
after all this it bring this amp back some nice music, i personally like mosfet amp over Bjt , the trans is about 400va and Ps section is well build!
the best recap for this amp is reservoir 10k mf with BHC/kendeil or any other 105C caps, don't oversize to 15k, it get it slow and muddy, then lm 3x7 output matrix with 4 x 10mf tants Mil spec , the gray bipolar elna 4 x 10uf signal caps with Muse or Kaisei , the 2x 100 mf with KZ , and of course the Tl072 with dual difet 627 and 2 other BB 2134 to replace the tone controle NE 55xx on each side !
after all this it bring this amp back some nice music, i personally like mosfet amp over Bjt , the trans is about 400va and Ps section is well build!
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Pos...Japanese are better. Even Americans.
Like a Jaguar or other British car, more reputation than performance.
Depends where you want to use your car, on the road or frequent garage trips...
Basically they were a small operation, and more hot air and 'reputation'. Parts quality and consistency was bad, and so was circuit design compared to Japanese.
Now indirectly owned by Samsung I think.
Search for 1980-1995 Japanese sets, terrific components, good quality.
Denon and Onkyo excepted.
Like a Jaguar or other British car, more reputation than performance.
Depends where you want to use your car, on the road or frequent garage trips...
Basically they were a small operation, and more hot air and 'reputation'. Parts quality and consistency was bad, and so was circuit design compared to Japanese.
Now indirectly owned by Samsung I think.
Search for 1980-1995 Japanese sets, terrific components, good quality.
Denon and Onkyo excepted.
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