If the hiss is only present when the DAC is connected, it is obviously coming from the Dac! (brilliant deduction, I know)
It could be an imbalance in the filter section or even in the amp itself.
More likely causes could be bad DAC chip, either in the dac or the output section., or poor regulators/ bypass caps around the dac.
Andy
It could be an imbalance in the filter section or even in the amp itself.
More likely causes could be bad DAC chip, either in the dac or the output section., or poor regulators/ bypass caps around the dac.
Andy
Hi
I am now tghinking about replacing the Analog 12v TX.
Can you suggest a model that fits inside the CD53 ?
I am not sure about using a 80VS or a 30VA 2x18v from farnell (9531831) / (9531742), but both seem to be too big (Diameter 96.7mm / 81.5mm).
As the difference is so small, I think I will use one 80VA in a outside box... But it would be better to do it Brent style.
Please advise.
Ricardo
I am now tghinking about replacing the Analog 12v TX.
Can you suggest a model that fits inside the CD53 ?
I am not sure about using a 80VS or a 30VA 2x18v from farnell (9531831) / (9531742), but both seem to be too big (Diameter 96.7mm / 81.5mm).
As the difference is so small, I think I will use one 80VA in a outside box... But it would be better to do it Brent style.
Please advise.
Ricardo
avr300 said:
No, it sounded fantastic with the opamps. Could they have filtered out the hiss?
The caps around the dac are Rubycon ZA and Black Gate nx & std. Regs on the dac are lm317 raygulator for dig and Brent's S-Power for analogue, fed by their own windings off a 30va tx.
I will try the output stage in my test player and report back.
Lee.
RCruz said:
Hi Andy
I measured the offset in the power amp output without the speakers connected and it is 0.13V (129mV).
As it happened before I removed the output caps, I tried the radio and even with the volume pot set to zero, there is always the same offset.
Is this normal ?
Ricardo
I fitted the board in my cd63se and it works perfectly. Does anyone have any idea what could cause this noise in the output of the dac?
Lee.
Lee.
RCruz said:
Hi Ricardo
The offset is a bit high (it should not damage anything though). If you get the same offset with or without the output caps on the CD then I would say its save to remove them. What offset do you get with the amp input open?
André
Andre Visser said:
The same.... -129mV left chanel and +129mV right chanel , with or without signal
I always felt the Meridian topology to be strange...
Just removed the output caps and there is no difference in this offset.
This made a BIG difference.
The sound is now open and with a low bass with detail.
Thank you for your help.
PS
Can you suggest a TX for the analog PSU ?
Regards
Ricardo
Hi Ricardo
I believe the 2 x 18V, 30VA with good capacitors is more than enough. Good to hear about your sound improvement.
André
I believe the 2 x 18V, 30VA with good capacitors is more than enough. Good to hear about your sound improvement.
André
Andre Visser said:
Hi André
Can you help me choose between Nuvotem 0030P1-2-018 (toroidal,estructura abierta,30VA,0-230V primario,50/60Hz,2x0-18V secundario) and Nuvotem 91231 P2S2 (toroidal,30VA 115/230V primario,50/60Hz,2x0-18V secundario).
Both are available on RS.
The difference seems to be the primary windings but what should be the best option.
I have 220V mains.
Regards
Ricardo
Hi Ricardo
As you have 220V mains the plain 230V transformer will work fine, less wires to sort out.
Regards
André
As you have 220V mains the plain 230V transformer will work fine, less wires to sort out.
Regards
André
If anyone's interested, my discrete stage is finished
The resistors are tiny smt's.
Lee.
An externally hosted image should be here but it was not working when we last tested it.
The resistors are tiny smt's.
Lee.
And the top:
Sounding very good through my test machine at the moment. I am just finishing my KI with dedicated Superclock2's for dac and servo
Lee.
An externally hosted image should be here but it was not working when we last tested it.
Sounding very good through my test machine at the moment. I am just finishing my KI with dedicated Superclock2's for dac and servo
Lee.
Thomo said:If anyone's interested, my discrete stage is finished
The resistors are tiny smt's.
Lee.
Cool! And another one playing... 😎
Nice work, Lee!
Ray
Thomo said:If anyone's interested, my discrete stage is finished
Lee.
Fantastic Lee! Sounds natural, doesn't it? Will this ultimately go in yout main / KI machine?
Simon
SimontY said:
Hell Yes! In fact I am just about to start fitting all the power supplies now.
My cd67 has been in the drying out clinic, after a vase of flowers smashed into it with the lid off. It appears rather poorly now, so I am changing to a cd63 which I was going to sell, but now I can't.
Lee.
Thomo said:
Poor things. If they don't get burned, they get flooded
That's why I don't solder at the dinner table in the living room 😀
Ray
Where are you Brent??
Just been catching up on the thread and I've noticed that one of the main contributors is conspicuous by his absence.
Is it coincidental that the absence started round about the same time as some (I consider to be unfair) criticism?
I for one hope not.
Brent has always been more than willing to help (as have Ray and others, I hasten to add!!) and has got me out of more than one self-inflicted ham-fisted sticky situation.
So what if Brent has decided to branch out and add mods to his existing company portfolio of test equipment?
He has worked damned hard at his research and put an awful lot back into this thread and I say good luck to him.
Come back mate, we miss you!!
Just been catching up on the thread and I've noticed that one of the main contributors is conspicuous by his absence.
Is it coincidental that the absence started round about the same time as some (I consider to be unfair) criticism?
I for one hope not.
Brent has always been more than willing to help (as have Ray and others, I hasten to add!!) and has got me out of more than one self-inflicted ham-fisted sticky situation.
So what if Brent has decided to branch out and add mods to his existing company portfolio of test equipment?
He has worked damned hard at his research and put an awful lot back into this thread and I say good luck to him.
Come back mate, we miss you!!
Yes, from what I have seen and read of this thread, I thought that this post was unfair and in poor taste. Brent seems to go out of his way to provide guidance and assitance... certainly not what you would expect of someone "pushing" their own products.Mags said: