Thanks guys! It's still good fun to see the finished board, after so many hours looking at it on the computer screen 
Ray
Ray
Got the machine working. Pretty happy so far!
Results still need to be interpreted, but a first listen gave:
+ clearer (even my girlfriend noticed, and that says a lot)
+ bass less boomy
- placement of voices and instruments became worse
LM337 = -11.9V (almost perfect)
LM317 = +12.7V
Would there be any effects from this?
I also measured the entry voltages going into the new regulators. According to the SM, should be +/- 20V.
Vin(LM337) = -17.8V (ok)
Vin(LM317) = 21.3V (ok)
Anyway, pretty proud of my first tweak (leave aside removing the muting stage)!
Results still need to be interpreted, but a first listen gave:
+ clearer (even my girlfriend noticed, and that says a lot)
+ bass less boomy
- placement of voices and instruments became worse
LM337 = -11.9V (almost perfect)
LM317 = +12.7V
Would there be any effects from this?
I also measured the entry voltages going into the new regulators. According to the SM, should be +/- 20V.
Vin(LM337) = -17.8V (ok)
Vin(LM317) = 21.3V (ok)
Anyway, pretty proud of my first tweak (leave aside removing the muting stage)!
Muting and output caps removed, lm317 and lm337 in place. Still waiting for LM4562 to arrive...
But for now, I think you could describe it as more delicate.
Highs and mids are clearer, bass is less 'present'. Not sure how much I like it yet, it is not so warm anymore. I probably need to some to adjust to it as well ;-)
-Would there be any effect from the caps on the regulators to break-in over time?
-Is there an effect from the 'not exactly +/- 12V' output of the regs?
But for now, I think you could describe it as more delicate.
Highs and mids are clearer, bass is less 'present'. Not sure how much I like it yet, it is not so warm anymore. I probably need to some to adjust to it as well ;-)
-Would there be any effect from the caps on the regulators to break-in over time?
-Is there an effect from the 'not exactly +/- 12V' output of the regs?
Did you mod the psu caps.... what about the rectifier diodes ?
Bigger psu caps might give you the correction in tone.
Bigger psu caps might give you the correction in tone.
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Steve
Ian,
many thanks for your help with the clock install. What an effect! It has given my player life! There's an extra layer of detail now that I couldn't hear before.
Op amps next and then I'll need to work out how to bypass the hdam.
Other advice welcome.
Steve
Ian,
many thanks for your help with the clock install. What an effect! It has given my player life! There's an extra layer of detail now that I couldn't hear before.
Op amps next and then I'll need to work out how to bypass the hdam.
Other advice welcome.
Steve
Its good to be the one now giving advice and not taking it! 😱
Make sure you sort the decoupling caps C611-C614 when you do the opamps. As BG's are pretty hard to come by now, I'd go for Rubycon ZA at about 220uF there. While youre at it, i'd also replace the other 4 around the DAC (CD04,07,15 & 16) with the same value.
Bypassing the HDAM's is very straight forward. 1st you can remove the voltage supply to them (meaning the +/-12v supply will now only service the opamps) by removing 4 resistors inbetween the HDAMS (just in front of the 4 caps) R651-R654.
You should also remove and replace with wire links R613-R616 which are the supply rails to the opamps. The resistors were there to help stop interference from other circuits on the rail. As the HDAMs are now isolated (when you removed R651-R654) they will now hinder the performance of the uprated opamps.
The audio out from the opamps can be picked up by removing U210(L) and U212?(R). Pick up the audio from the holes closest the opamp.
If you are retaining the muting circuit, you can link direct to the place where you removed the output caps (as per pick). If you have already bypassed the muting, connect the wire direct to the phono's.
Another pic attached- Red=remove, Blue=Upgrade & Green=Wire link
*save the picture and view it with paint or similar, you can blow it up and see the detail better!
Ian
Make sure you sort the decoupling caps C611-C614 when you do the opamps. As BG's are pretty hard to come by now, I'd go for Rubycon ZA at about 220uF there. While youre at it, i'd also replace the other 4 around the DAC (CD04,07,15 & 16) with the same value.
Bypassing the HDAM's is very straight forward. 1st you can remove the voltage supply to them (meaning the +/-12v supply will now only service the opamps) by removing 4 resistors inbetween the HDAMS (just in front of the 4 caps) R651-R654.
You should also remove and replace with wire links R613-R616 which are the supply rails to the opamps. The resistors were there to help stop interference from other circuits on the rail. As the HDAMs are now isolated (when you removed R651-R654) they will now hinder the performance of the uprated opamps.
The audio out from the opamps can be picked up by removing U210(L) and U212?(R). Pick up the audio from the holes closest the opamp.
If you are retaining the muting circuit, you can link direct to the place where you removed the output caps (as per pick). If you have already bypassed the muting, connect the wire direct to the phono's.
Another pic attached- Red=remove, Blue=Upgrade & Green=Wire link
*save the picture and view it with paint or similar, you can blow it up and see the detail better!
Ian
Attachments
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Don't forget to insert a 47ohm resistor in series with the output, most opamps don't like the capacitive load of the interconnect! Take a look at some datasheets and look for overshoot pictures with 100pF load 
Ray
Ray
Nice technical input as I was ready to go direct MKP to RCAs on the CD951... Metallic or carbon? Another part in the audio path 😉region from a saturated condition.
"CAPACITIVE LOAD DRIVE
The AD8510/AD8512/AD8513 are unconditionally stable at all
gains in inverting and noninverting configurations. Each device
is capable of driving a capacitive load of up to 1000 pF without
oscillation in unity gain using the worst-case configuration.
However, as with most amplifiers, driving larger capacitive
loads in a unity gain configuration may cause excessive
overshoot and ringing, or even oscillation.
A simple snubber network significantly reduces the amount of overshoot and
ringing. The advantage of this configuration is that the output
swing of the amplifier is not reduced, because RS is outside the
feedback loop."
The best way Ray?
If any of you wanna help that'll be lovely!
http://www.diyaudio.com/forums/digi...7-tda1547-vs-tda1541a-r1-vs-sm5872-story.html
Matthieu
"CAPACITIVE LOAD DRIVE
The AD8510/AD8512/AD8513 are unconditionally stable at all
gains in inverting and noninverting configurations. Each device
is capable of driving a capacitive load of up to 1000 pF without
oscillation in unity gain using the worst-case configuration.
However, as with most amplifiers, driving larger capacitive
loads in a unity gain configuration may cause excessive
overshoot and ringing, or even oscillation.
A simple snubber network significantly reduces the amount of overshoot and
ringing. The advantage of this configuration is that the output
swing of the amplifier is not reduced, because RS is outside the
feedback loop."
The best way Ray?
If any of you wanna help that'll be lovely!
http://www.diyaudio.com/forums/digi...7-tda1547-vs-tda1541a-r1-vs-sm5872-story.html
Matthieu
If you reed a bit further in the datasheet (AD8510), some values for the snubber network are given. It depends on the capacitance of the interlink and input capacity of the next stage. But 500pF is a lot, I don't think any interlink has that much capacity. My Nordost has only 8.9pF/feet (which is quite low). A series resistor also reduces ringing, I never tried a snubber, maybe that works even better. I'd say try it, and see how it sounds 🙂
Ray
Ray
Ray, you mean resistor between output of the opamp and RCA or between ground and RCA?
Was about to replace the standard opamps in my cd63se today for a lm4562. Thought it was a matter of plugging it in and bypassing HDAM. Now it seems a bit more to it...
Was about to replace the standard opamps in my cd63se today for a lm4562. Thought it was a matter of plugging it in and bypassing HDAM. Now it seems a bit more to it...
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I mean between the opamp and the output sockets, about 47 ohm is often used. Although it is not a bad idea to insert a resistor between the output and ground too, to prevent an open output in case the player is not connected to anything. These are already present in the player, R655 and R656, 10k. I usually raise them to 100k.
Ray
Ray
Hi Ray
I need to place a dos in a DENON DCD3300....
It is an old player built like a tank and surelly worth the work.
My first issue is related with some errors I am getting while trying to read discs... it does not read them all and most of the times, when reading, it produces a scratching noise (directly related with the CD spin speed).
Can you please tell me if I should replace the lens and if after that I could install the dos ?
Ricardo
PS: Sorry for the off topic
I need to place a dos in a DENON DCD3300....
It is an old player built like a tank and surelly worth the work.
My first issue is related with some errors I am getting while trying to read discs... it does not read them all and most of the times, when reading, it produces a scratching noise (directly related with the CD spin speed).
Can you please tell me if I should replace the lens and if after that I could install the dos ?
Ricardo
PS: Sorry for the off topic
DENON DCD3300, PCM56 dac Ricardo. Very nice indeed!
I expect you'll need more gain from the dos, unless it has higher output than the TDA1541. You may also be better with a transistor version as opposed to fet as they're reputed to be better for current/voltage conversion, although I didn't try this.
Lee.
Lee.
I expect you'll need more gain from the dos, unless it has higher output than the TDA1541. You may also be better with a transistor version as opposed to fet as they're reputed to be better for current/voltage conversion, although I didn't try this.
Lee.
Lee.
Yes a DOS is probably not what you need. It's for balanced voltage output DACs.
This DAC has unbalanced current output and an internal I/V op-amp for unbalanced voltage output too.
The player may of course have two per channel for differential signals, I don't know.
If you use the internal I/V op-amps for v-out, and there are two per channel giving balanced voltage, you can use the DOS. (You could use it for unbalanced too but there wouldn't be much point.)
Maximum performance would be to use the current outputs and a discrete I/V stage.
But remember the DOS does not perform I/V conversion.
This DAC has unbalanced current output and an internal I/V op-amp for unbalanced voltage output too.
The player may of course have two per channel for differential signals, I don't know.
If you use the internal I/V op-amps for v-out, and there are two per channel giving balanced voltage, you can use the DOS. (You could use it for unbalanced too but there wouldn't be much point.)
Maximum performance would be to use the current outputs and a discrete I/V stage.
But remember the DOS does not perform I/V conversion.
How can I determine if it has two opamps per channel ? (I can see 3 x NE5532P on each channel and it has balanced outputs)
Ray, I connected everything. I now have one of the original 100ohm resistors between the the hdam-bypass and the RCA's. Volume is pretty low now, for my understanding, what are the other side-effects from having this 100ohm instead of your recommended 47ohm?
(didn't have a 47ohm here, just a 40 or 100)
(didn't have a 47ohm here, just a 40 or 100)
Hi lee
I agree that it looks quite cool but I am having trouble with the lazer... can you help me find a replacement ?
Lee,
I would be very happy if you can tell me how you spiced your TDA1547 😉
How do you know if it's balanced or not? I think it is as it looks symetrical...
Right now I plan on using an extrenal single opamps like top Analog Device or National Semi to do the work of the internal ones and the DOS it.
Again, I'm begging all you even if have different points of view (that makes us more rich!) on my http://www.diyaudio.com/forums/digi...7-tda1547-vs-tda1541a-r1-vs-sm5872-story.html ! Promise I won't do (too soon...) commercial break for my church again 😀
Ricardo why not a new thread! That may be exciting =)
I would be very happy if you can tell me how you spiced your TDA1547 😉
How do you know if it's balanced or not? I think it is as it looks symetrical...
Right now I plan on using an extrenal single opamps like top Analog Device or National Semi to do the work of the internal ones and the DOS it.
Again, I'm begging all you even if have different points of view (that makes us more rich!) on my http://www.diyaudio.com/forums/digi...7-tda1547-vs-tda1541a-r1-vs-sm5872-story.html ! Promise I won't do (too soon...) commercial break for my church again 😀
Ricardo why not a new thread! That may be exciting =)
