I have an Adcom CD player. GCD 750. Approximately 12 years old.
Took it into shop for failure of drawer to open.
According to the manual, it has 20 Bit processing, dual Burr Brown.
Is it wise to get it repaired and keep it?
Modify it?
What modifications could be done to improve it?
Or consider a more modern 24 bit player?
Thanks in advance.
Took it into shop for failure of drawer to open.
According to the manual, it has 20 Bit processing, dual Burr Brown.
Is it wise to get it repaired and keep it?
Modify it?
What modifications could be done to improve it?
Or consider a more modern 24 bit player?
Thanks in advance.
I have owned an Adcom GDA-700 DAC for some number of years. I do not know whether the GCD-750 player contains essentially the same DAC circuits, but if it does, I can tell you that The GDA-700 contains an excellent digital sub-system. It features an UltraAnalog digital input reciever, the famous Pacific Microsonics PMD-100 (HDCD decoding) digital filter, and a pair of Burr-Brown PCM1702 20-bit R-2R DAC chips (which are brothers to the 24-bit PCM1704). I feel that the potential sound quality of the digital sub-system is let down some by a rather pedestrian power supply and analog sub-system design. The power supply is comprised of LM317 type 3-terminal regulators while the I/V and analog outputs both are monolithic op-amp based. Perhaps, no sins here, but no particular virtues either.
I would characterize the base sound as being decent typical CD playback, but nothing to get excited about. I made one modification that did improve the sound some. I swapped the stock (NJMs, as I recall) op-amps in the I/V converter stage with AD829 devices which I happened to have on hand. While the sound did improve, it still sounded like, well, CD. While a bit of op-amp 'rolling' did make a positive difference, I do not consider the scale of modification from which the unit truly would benefit to be practical. My GDA 700 now gathers dust. The sound is decidedly inferior to that produced by my home brew DAC projects. So, depending on your finances, I suspect that you would be better off obtaining some different model player. Be certain to sufficiently audition any prospective player before buying.
I would characterize the base sound as being decent typical CD playback, but nothing to get excited about. I made one modification that did improve the sound some. I swapped the stock (NJMs, as I recall) op-amps in the I/V converter stage with AD829 devices which I happened to have on hand. While the sound did improve, it still sounded like, well, CD. While a bit of op-amp 'rolling' did make a positive difference, I do not consider the scale of modification from which the unit truly would benefit to be practical. My GDA 700 now gathers dust. The sound is decidedly inferior to that produced by my home brew DAC projects. So, depending on your finances, I suspect that you would be better off obtaining some different model player. Be certain to sufficiently audition any prospective player before buying.
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thanks
Thanks for all the info.
From your description, it sounds like my Adcom GCD 750 was pretty good for it's time. My guess is that even if I do alot of upgrading and modifications it will still be an obsolete, by today's standards, cd player.
What would you recomend as a realy good player without modifications?
Also, is it better to go with a separate transport and DA convertor?
Again, thank you for your help.
Thanks for all the info.
From your description, it sounds like my Adcom GCD 750 was pretty good for it's time. My guess is that even if I do alot of upgrading and modifications it will still be an obsolete, by today's standards, cd player.
What would you recomend as a realy good player without modifications?
Also, is it better to go with a separate transport and DA convertor?
Again, thank you for your help.
Your decision is complicated by the fact that you apparently don't have the option of using your GCD-750 as a transport, unless you spend part of your budget to have it repaired. Otherwise, you would need to either buy another disc player, or both another player (for use as a transport) and a DAC. There are certainly more DAC choices available than there are disc player choices. However, I won't attempt to recommed any specific models as that would be a very personal assessment based on your system, room, and ears.
Here is the link to a site with a list of DACs, catagorized by their price. I suggest identifying those models falling within your budget that are available in your area and seeking them out for audition. An integrated disc player is more convienent, and should be more cost effective, and I suggest similarly seeking ot those models within your budget for an audition. Yes, this will be a bit of a hassle, but it's the only way I know to minimize audiophile equipment selection regret.
http://www.alldacinfo.com/?page_id=242
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Thanks
Thanks Ken for all of your input. I appreciate it.
Yes, I do have a budget that I hope to use to upgrade my entire system.
If the Adcom GCD 750 comes out of the shop soon, then I'm considering using it as just a cd transport and having it feed a D/A converter. This would allow me to step up from 20 Bits to 24 Bits.
If the cost is too high to repair, then I have been looking at the "Emotiva" ERC-2 CD player which sells for about $400.
I'd welcome your opinion!
My pre amp is also an Adcom which I use only in the passive mode. It does make a difference with it's amplification stage switched out.
My active crossover is a pair of Marchand XM-6's connected in parallel ,which permits me to use them as a 3 way xover for my tri amped loudspeakers. I can vary the xover points which I see on the LEDs and I can set the gain to all 3 amps.
The eventual goal is to somehow have a 4 way active or digital crossover to add a fourth amp with 15" sub woofers.
Again, I thank you for your very helpful opinions and feel free to comment more !
Thanks Ken for all of your input. I appreciate it.
Yes, I do have a budget that I hope to use to upgrade my entire system.
If the Adcom GCD 750 comes out of the shop soon, then I'm considering using it as just a cd transport and having it feed a D/A converter. This would allow me to step up from 20 Bits to 24 Bits.
If the cost is too high to repair, then I have been looking at the "Emotiva" ERC-2 CD player which sells for about $400.
I'd welcome your opinion!
My pre amp is also an Adcom which I use only in the passive mode. It does make a difference with it's amplification stage switched out.
My active crossover is a pair of Marchand XM-6's connected in parallel ,which permits me to use them as a 3 way xover for my tri amped loudspeakers. I can vary the xover points which I see on the LEDs and I can set the gain to all 3 amps.
The eventual goal is to somehow have a 4 way active or digital crossover to add a fourth amp with 15" sub woofers.
Again, I thank you for your very helpful opinions and feel free to comment more !
Hi, speedy,
I avoid giving specific equipment recommendations for the following two reasons. I've not heard anywhere near the majority of equipment options, and even if I had, I do not possess another persons's system, room, or ears. Having said that, It does sound to me like you are on the right track.
Another option for a new disc transport you might consider is the Tascam CD200 at about $300 or less, which features a Teac drive optimized for audio playback. With either the Tascam or the Emotiva you would have at least $600 out of a $1k budget left to spend on a DAC. I suggest checking out the Simaudio Moon 100D DAC in that price range. However, as I siad, the options are plentiful for DACs, perhaps, too plentiful. Also, at a $1k budget, you may want to audition the one box Marantz SA8004 disc player, especially, if you foresee acquiring any SACDs.
Please understand, I'm not recommending that you purchase any of these choices, indeed, I've not auditioned them myself. I'm merely suggesting that they are likely worth your effort to seek out for audition based upon their pedigree and industry reputation, and at your budget. What I do recommend is that you long audition any component before committing to keep it. A purchase is fine, so long as you have the option to return it for a full refund after a sufficiently long in-home audition period. Doing otherwise can lead to costly heartbeak in my experience, even with generally well regarded name components.
Product: CD-200 | TASCAM
http://www.uhfmag.com/Tech/Moon-100D.pdf
sa8004
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Mike,
The following hyperlink may also be of some interest to you.
2013 TAS Editors' Choice Awards: DACs Under $1000 | The Absolute Sound
The following hyperlink may also be of some interest to you.
2013 TAS Editors' Choice Awards: DACs Under $1000 | The Absolute Sound
Thanks again
Hi Ken and thanks again for responding and for providing the information.
I've just gotten my Adcom GCD 750 back from the shop.
It works fine and only cost me $75 in parts and labor.
What would the advantages be of using it as a transport and adding an outboard DAC? An outboard DAC would provide 24 Bits as opposed to the GCD 750's 20 Bits. Would I hear a difference and why?
Again, thank you for your advice.
Hi Ken and thanks again for responding and for providing the information.
I've just gotten my Adcom GCD 750 back from the shop.
It works fine and only cost me $75 in parts and labor.
What would the advantages be of using it as a transport and adding an outboard DAC? An outboard DAC would provide 24 Bits as opposed to the GCD 750's 20 Bits. Would I hear a difference and why?
Again, thank you for your advice.
I feel pretty certain that you would not hear a difference between otherwise identical 20-bit and 24-bit converters. For one thing, the effective resolution of audio application digital to analog converters rarely exceeds about 19-bits. Any more bits are mostly marketing selling points. In fact, many feel that the pinnacle of converter chip design was the 16-bit TDA1541.
In my experience, most of the audible difference between DAC designs is due to the digital filter implementation (or, lack thereof), and the post conversion analog circuits. Additional key factors are jitter suppression, and supply voltage regulation implementation. Some others also feel that converter type (sigma-delta vs. full resolution multibit) plays an consistently audible role as well.
So, where does that leave you? My advice is to ignore checking for any particular laundry list of technical features, other than for media and component interface compatibility. Such a list will not tell you how a given component would sound to your ears. Instead, determine which DAC choices are within your budget are available locally for audition - ideally, in your own home if possible. Resist the temptation to buy any component based on my opinion, or that of a magazine reviewer, or of anyone else. Take the time to educate your ears by carefully auditioning what's available to you, then make your choice. Whatever you choose, it won't be your last such choice, so, have fun.
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I have the Marantz CD6004 which you can get shipped for $499. It does sound very nice and it contains a port where you can run an iPod or iPhone through it's DAC while recharging. I highly recommend getting a good power cord which improves dynamic punch. I still marvel at how natural and effortless it sounds and it remains one of the leading contenders at it's price range.
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