I, like most DIY audio members, like to hear good sounds and that usually means modding equipment to our liking. Everyone has different Idea as to what is "Great Sound". That I believe is our personnel choice. I have modded a Marantz 67SE, Aracam Alpha 5, Nakamichi Player 4, and a Magnavox CDB-630. Some to Destruction, by my own doings. I decided to choose my next victim, and after reading "Reviews" picked an Adcom GCD-700. Of course, price was an issue, but it was universally praised as an excellent sounding unit. It was also touted as a "quality unit". Bought one that had some tracking issues, Taking a chance(seller completely honest, not a factor in my discovery). What I found was quite a shock! I received the unit and immediately took off the cover to dig into the laser unit(maybe adjustment). The box indicated that it was built in Japan, but immediately it was obvious to an experience DIY it was made in China. Sure enough, the name plate confirmed it. Many of the large caps had spewed out on the horrible constructed circuit board. Parts were not only of inferior quality, but not place in alignment, and had unequal length leads. Some parts where against the board others with half inch lead lengths. The player had 2, I repeat, two regulators. It had been repaired in the past, one capacitor of much greater quality. I recognized this unit. I pulled out my unmodified, working, Denon DCM-260, exactly the same mechanism, frame chassis, and even the power transformer. I was SHOCK to see a $200 unit with the same basic chassis as a $1000(?) unit. The denon parts where laid out even, aligned, with normal positioning found on most units. None of the parts had failed yet. Both units are from the mid 90's. How did this unit get such rave reviews? Does this prove that quality(including parts) don't make the difference between MID FI and HI FI. I didn't even find a medium review anywhere on the Adcom. Just as a side note, all the Philips chip/mech units are still working some 26 years old, all my Sony units have failed at least once.
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LOL - proof (as if it were needed) that the reviewers either talk through an orifice not located in the region of their face AND/OR that they are as suseptible as anyone to a flashy exterior and a marketing spin.
Audiophools the world over should consider this in the context of cables, "audio quality" capacitors or semi-conductors etc etc.
The electronics in the ADCOM appear to be completely different from the Denon, this could explain sonic differences.
I'm not too surprised they're both using the same transport, maybe ADCOM didn't want to spend the $$$ in developing their own transport.
except for two powersupply-caps that were located very close to the small heatsinks used by the powersupply-regulators.
Roughly estimated working-temperature would be 50-60 degrees Celsius.
They showed no visual signs of failure, but looking at the powerlines on a scope showed a lot of hf-crap so i replaced them.
Voila, the hf-crap was gone,and sound-quality notably improved.
Since it sounds fine to my ears and appears to be well engineered, i've done no modifications to it.
Maybe i'll fit those regulators with larger heatsinks to avoid premature failure of the caps in the future
.
Regards,
Klaas
I'm not too surprised they're both using the same transport, maybe ADCOM didn't want to spend the $$$ in developing their own transport.
In a Denon DCD-1560 i bought ~2 years ago, all caps were fine,
except for two powersupply-caps that were located very close to the small heatsinks used by the powersupply-regulators.
Roughly estimated working-temperature would be 50-60 degrees Celsius.
They showed no visual signs of failure, but looking at the powerlines on a scope showed a lot of hf-crap so i replaced them.
Voila, the hf-crap was gone,and sound-quality notably improved.
Since it sounds fine to my ears and appears to be well engineered, i've done no modifications to it.
Maybe i'll fit those regulators with larger heatsinks to avoid premature failure of the caps in the future
.Regards,
Klaas
Yes, it sounds tempting to swap the NE5532's for something better.
Opinions on the merits of swapping opamps in existing equipment seem to differ though.
Another option for a future upgrade would be adding an external DAC,
the Denon transport surely looks like it's built to last.
Best regards,
Klaas
Opinions on the merits of swapping opamps in existing equipment seem to differ though.
Another option for a future upgrade would be adding an external DAC,
the Denon transport surely looks like it's built to last.
Best regards,
Klaas
Well, swapping the opamps will convince you within seconds of the opposite. Opinions of others won't do you any good, it is your ears that will decide.
Even better and cheaper (which might appeal to you because you are Dutch too
) would be a new internal DAC. No need for SPDIF and less jitter.
Just throw in:
- an ES9023 with 2 x power supplies 3.3 V and proper decoupling. One 3.3 V reg for the chip, the other one for the 50 MHz XO.
- a low jitter clock for the mainboard of the player
- remove the muting transistors if it has those (I forgot). Only relevant if you reuse the original output RCA's.
It would be best to design a small drop-in PCB with the chip and regs on it. Make that 2 x ADP151 and feed those with the players 5 V, preferably a clean 5 V. No need for an output stage so you won't need new opamps at all. Total cost : less than 25 Euro excluding a low jitter clock. Personally I would replace all caps because of their age. They sure won't be in optimal shape after all those years. Also the heatsinks should be added ! There is no excuse making the same mistake as the manufacturer did for a second time.
Marvellous sound quality can be done cheap too nowadays as DAC chips don't cost as much as the older ones. They are way better than most older chips too.
Even better and cheaper (which might appeal to you because you are Dutch too
) would be a new internal DAC. No need for SPDIF and less jitter. Just throw in:
- an ES9023 with 2 x power supplies 3.3 V and proper decoupling. One 3.3 V reg for the chip, the other one for the 50 MHz XO.
- a low jitter clock for the mainboard of the player
- remove the muting transistors if it has those (I forgot). Only relevant if you reuse the original output RCA's.
It would be best to design a small drop-in PCB with the chip and regs on it. Make that 2 x ADP151 and feed those with the players 5 V, preferably a clean 5 V. No need for an output stage so you won't need new opamps at all. Total cost : less than 25 Euro excluding a low jitter clock. Personally I would replace all caps because of their age. They sure won't be in optimal shape after all those years. Also the heatsinks should be added ! There is no excuse making the same mistake as the manufacturer did for a second time.
Marvellous sound quality can be done cheap too nowadays as DAC chips don't cost as much as the older ones. They are way better than most older chips too.
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Thanks for replying Jean-Paul
The main reason i've been weary of modding the Denon is that
i really hate to do a hack job, that will make the internals look like a bowl of spaghetti.
Replacing the NE5532's with sockets to make swapping opamps easy without risking ruining the pcb sounds easy enough.
Do you have any suggestions for suitable replacements ?
Same thing for replacing the caps and removing the muting-transistors
-I do have a service-manual for the Denon.
The other mods you propose sound really interesting but are really something i need to look into,
since my knowledge of digital audio technology is almost non-existent.
Best regards,
Klaas
The main reason i've been weary of modding the Denon is that
i really hate to do a hack job, that will make the internals look like a bowl of spaghetti.
Replacing the NE5532's with sockets to make swapping opamps easy without risking ruining the pcb sounds easy enough.
Do you have any suggestions for suitable replacements ?
Same thing for replacing the caps and removing the muting-transistors
-I do have a service-manual for the Denon.
The other mods you propose sound really interesting but are really something i need to look into,
since my knowledge of digital audio technology is almost non-existent.
Best regards,
Klaas
Thanks for the suggestions, guys.
I'll give it a try
I think improvement on the powersupply could also have significant benefits.
Not so easy to implement though.
Best regards,
Klaas
I'll give it a try
It's surely the easiest thing to modify.
I think improvement on the powersupply could also have significant benefits.
Not so easy to implement though.
Best regards,
Klaas
Why change opamps if the DAC chip is outdated ?! If you work tidy it will function good, sound good end look good (if you replace the DAC for a small 3 x 4 cm PCB that is). Only you are responsible that it may look like spaghetti so if you don't like that please build it nice and tidy. Even the LM4562 won't make a mediocre PCM17XX DAC chip sing ! Sure it will sound better with better opamps but it will never be better than what the DAC chip can deliver.
I like electronics to look good to but is sound quality not the most important feature ?
I tried ES9022 recently and I am very impressed what it can do without any output stage at all. Please mind that it only costs less than 4 Euro.
Regarding caps: you can't go wrong with panasonic FC/FM. Old news.
I like electronics to look good to but is sound quality not the most important feature ?
I tried ES9022 recently and I am very impressed what it can do without any output stage at all. Please mind that it only costs less than 4 Euro.
Regarding caps: you can't go wrong with panasonic FC/FM. Old news.
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ESS is making 9023 chip now - I don't know if 9022 is available - but it has apparently been replaced.
There is a thread about the ES9023 here: http://www.diyaudio.com/forums/digi...9023-sabre-premier-dac-integrated-op-amp.html
' Outdated ' ... which dac is that btw ?
Is there one ?
' Look good ' ... what difference does that make ?
Check the Lampizator site for the worst visual appeal in wiring and spaghetti garbage then challenge the author on how it looks .... erm ..don't !!!
that crap doesn't just look bad, replacing good ceramic and film decoupling caps in digital and clock high speed circuits with teetering lopsided inductive air sculptures? really? this makes an improvement? and he has a whole league of followers who now think that is an acceptable way to do things and that ripping anything related to engineering out in favour of these monstrosities is the way to go?
Agree entirely !
I just would not want to be on the wrong end of his vitreol
Looks and sound quality - completely irrelevant
This thread is about a multi changer and op amp swapping - then it extends to ' just drop in this and that ' high end smart **** stuff
The player is simply not worthy of the rest of the mods we could advise.
Just let the guy swap op amps and enjoy himself for pete's sake.
I did once upon a time and it was fun
LM 49710's rock..... drop them in kvholio and see for yourself !!
I just would not want to be on the wrong end of his vitreol
Looks and sound quality - completely irrelevant
This thread is about a multi changer
and op amp swapping - then it extends to ' just drop in this and that ' high end smart **** stuffThe player is simply not worthy of the rest of the mods we could advise.
Just let the guy swap op amps and enjoy himself for pete's sake.
I did once upon a time and it was fun
LM 49710's rock..... drop them in kvholio and see for yourself !!
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