Major upgrade (Adcom CD player)

[Knuckledragger]

The Adcom GCD-750 CD player I won off eBay just arrived. FedEx tormented me by delivering it two days late. I've just finished wiring it into my sound system, which was a right royal PITA. The GCD had to sit on the bottom of my rack, with my receiver on top of it, and my Edirol DAC and Gilmore Lite on top of that. The wiring was especially difficult. The signal goes USB -> Edirol DAC -(digital)-> Adcom -> GLite -> receiver -> speakers. Factor in power, and that's a lots of cables for a relatively simple setup. For some reason, the speakers aren't working right now, but my 650s work fine, and I'm done futzing with it for the moment.

The first track I listened to was "L.S.G." by "L.S.G." vintage 1993 German hard trance by Oliver Lieb, my favorite producer of all time. I'm barely into the "honeymoon phase" of listening, so it will be quite some time before I can make an objective opinion. What I can say is that this represents my first "real" DAC. It listed for $1,500 when new, and the conventional wisdom is that it's a $1000 DAC with a $500 transport and $2 display attached to it. This theory is supported by the fact that Adcom saw fit to include a digital input on it.

I had for some time been considering the purchase of an Apogee miniDAC or something similar. After reading up on the GDC-750 at significant length, I came to the conclusion that it offered similar sound quality to the Apogee, with the addition of a CD transport. When I saw the chance to get one for $400 (1/3 the cost of an Apogee), I sprung for it without thinking twice. Already my ears are thanking me.

Who needs tax returns anyway?

Thus continues the upgraditist. Because of Head-Fi:
Fall '04: Purchased HD-650s, without ever having heard a set.
Spring '05: Replaced te 650's stock cables with Moon Audio Blue Dragon MK IIs.
Fall '05: Bought Gilmore Lite & Dedicated Power Supply on eBay (from a head-fier, actually).
Spring '06: Adcom GCD-750 to function as a DAC and occasional CD transport.
Next: Power conditioning! I've already good feelers out on several different units. From there ....who knows? The Adcom has balanced outputs, and I hear that 650s take on a whole new life in the balanced dimension...

 

[kentamcolin]

Congrats! At $400 that was a STEEL. I had a GCD-750 for about two years and found it to be a wonderful sounding player. If I saw one for $400, I'd buy another.

 

[rocktboy]

congrats!

yup adcom stuff is very nearly untouchable in terms of price/performance, excluding some chinese gear.

they havent' changed their flagship 2 channel lineup since the mid 90's. And there is no need, just like Grado headphones.

Their GFP 750 preamp is stereophile class A that sells for less than the sales tax of most other preamps in class A. Their top of the line GFA 5802 amp was designed by John Curl, who now designs Parasound JC-1 monoblocks for $6k a pair. GFA 5802 can be picked up for <$1k!!!
GCD 750 is part of the flagship lineup. It's hard to find a $400 cd player that can compete with GCD 750

 

[fewtch]

How's the older GCD-575?

 

[Knuckledragger]

Note quite a week with the GCD-750, and maybe 300 tracks played, and I'm just now beginning to get a feel for it. What struck me first is how different deep bass sounds. I noticed that bass response went up (or more to the point, went deeper) significantly when I got my first outboard DAC (a decidedly prosumer Edirol UA-5) vs my craptastic soundcard. I'm struggling with the vocabulary to describe what the Adcom's DACs do differently, but I can say this much: basslines that I formerly thought of as "dirty" and "grimy" now sound much cleaner to me. This isn't entirely a good thing, as I listen to a lot of trip hop and the like, where big, ugly basslines are often an intended and desirable quantity. A great example is Waldeck's "Floater," which has a nasty bassline that dominates the whole song in a similar fashion to a heavy metal guitar riff. I've heard this track countless times on many different sound systems (I've played out as a DJ for years). With the Adcom, the bass isn't quite as big and ugly, and is in fact a bit better behaved, allowing the female vocal lead a lot more breathing room. This makes for a more balanced sound, but it doesn't rock as hard. The issue certainly isn't lack of bass. I'm now listening to the "Dubblestandart" mix of the Waldeck track, which has a clean, but massive dub bassline, and I can feel my brain being squeezed by the standing waves.

I should add that I had to switch ICs when I set up the Adcom. My old Kimber HC-1 (shielded version of a PBJ) half-meters were not long enough, so I had to dig out my Kimber Tonik 1Ms. I never A/B'd these two cables, but I can't imagine there's a massive difference between them.

I've got a lot more listening to do before I can really dig into the sound that the GCD-750 offers. I've noticed that both it and the Gilmore Lite are really sensitive to power conditions (I can hear it when my housemate turns on the TV), and it's clear that my next purchase is going to be some type of power conditioning. More reports (and pictures), to follow...

 

[Drag0n]

About the only thing that may compete with that Adcom CD player,might be a California Audio Labs(CAL) Icon Mark 2 with Power-Boss Upgrade,sometimes seen on EBAY $400-500us or so. I still see reviewers using that to review equipment.

 

[Knuckledragger]

Also availible in not so wee and freakin' huge if you're so inclined. The Flickr page has notes on the different components. I feel kind of bad sticking the GLite's DPS off to the side like that, but there's no more room for it anywhere else.

I'm still exploring the bass response of the Adcom. Another example of a track that previously had as massive bassline is "We Reject the Now" by Yagya, availible on the excellent Flow.ers compilation (free to download if you so desire). With my old DAC (the Edirol UA-5), the bass to this track was skull-crushing and visceral. With the GDC-750's DACs, it's still quite strong, and a possibly even a bit deeper, but it's not as up front and present. The chilling arctic pads that make up the main element of the track are even more spacious and frozen that before, and I suspect that the sound overall is more balanced, but I do wish the bassline was a bit more assertive. So far all the listening I've done to the Adcom has been with my 650s/Blue Dragons. I'm going to have to dig out my HD-280s, KSC-75s and (shudder) MDR-V700DJs to see what they say about it. I might even hook up the HD-590s, but if I'm already concerned about lack of bass presence, then they are hardly going to help the situation...

 

[robert]

i'm still using my GDA-600 coaxed from a Yamaha player. it resolves well enough to show (hear?) me the difference between distortion and grunge of my SR-325 and transparency of my K501. considering the Rotel 1072...

 

[Knuckledragger]

A minor update here. One quirk of the 750 is that its outputs are insanely hot. With my old DAC, I would often turn my GLite's volume 3/4 of the way up. With the Adcom, 1/4 up is too loud.

The class A output stage does not mess around.

The extremely high output had made me realize a flaw in my crusty old Technics receiver that otherwise went unnoticed: at very low levels, its volume pot is exceedinly uneven. In the first 1/8th or so of its rotation, the left channel is favored hugely, meaning I have to turn the balance knob fully half a turn to counteract it. This is enough of a PITA that I'm using the analog outputs from my old DAC (now feeding SPDIF to the Adcom) with the reciever. The Technics isn't sufficiently high fidelity for the difference sound quality to be that evident, and it beats having to contually adjust the balance knob with the volume.

It's poor functioning gives me one more reason to move toward my ultimate goal of going all balanced.

The idea is Adcom -[balanced outs]-> Balanced headphone amp (most likely a Headroom) -> Adcom 750 Preamp -> a pair of Genelec powered monitors. Of course, this will cost a small fortune, but it's good to have dreams, no matter how poorly founded in reality they are.

 

[ezkcdude]

Quote:

Originally Posted by Knuckledragger A minor update here. One quirk of the 750 is that its outputs are insanely hot. With my old DAC, I would often turn my GLite's volume 3/4 of the way up. With the Adcom, 1/4 up is too loud. The class A output stage does not mess around. The extremely high output had made me realize a flaw in my crusty old Technics receiver that otherwise went unnoticed: at very low levels, its volume pot is exceedinly uneven. In the first 1/8th or so of its rotation, the left channel is favored hugely, meaning I have to turn the balance knob fully half a turn to counteract it. This is enough of a PITA that I'm using the analog outputs from my old DAC (now feeding SPDIF to the Adcom) with the reciever. The Technics isn't sufficiently high fidelity for the difference sound quality to be that evident, and it beats having to contually adjust the balance knob with the volume. It's poor functioning gives me one more reason to move toward my ultimate goal of going all balanced. The idea is Adcom -[balanced outs]-> Balanced headphone amp (most likely a Headroom) -> Adcom 750 Preamp -> a pair of Genelec powered monitors. Of course, this will cost a small fortune, but it's good to have dreams, no matter how poorly founded in reality they are.

Maybe you could use some passive attenuators. I don't even use a preamp, since I got my SqueezeBox.

 

[Knuckledragger]

Quote:

Originally Posted by ezkcdude Maybe you could use some passive attenuators. I don't even use a preamp, since I got my SqueezeBox.

I think at this point, I'll probably put money toward a new reciever vs. trying to kludge any more life out of this one.

Yesterday was a pretty extended day of listening for me. Probably 10 or more hours in total, almost all of it was Adcom -> Glite -> 650s. After a couple of hours, I noticed that thing started to sound really good. Sounds were jumping out at me, my 650s were starting to remind me of my 590s (this is a good thing,

I listen to my 590s when my 650s aren't lively enough).
I found myself listening to tracks I normally skip, and appreciating them quite a bit more than I had previously. I know the GCD-750 has a class A analog output stage, and it will sound its best when it reaches operating temperature (as will the Glite). I'm wondering... how long is the warm up time on something like this? It's pretty cold in here (and in fact it's snowing outside

), but I should suspect that most modern solid state gear should be at operating temp in 20 minutes or less.

Today hasn't been quite such a marathon, but I've had my rig on for a good 4 or 5 hours, and I'm again noticing an improvement in sound. Especially in the bass department (the one area where the Adcom has thusfar not impressed me). I've just finished listening to a couple of UK dub compilations, and the bass was downright visceral. The soundstage also seems to have opened up quite a bit. It feels like my Senns have gotten a foot or so deeper in the last hour. In a few minutes, I'm going to load up my standard test tracks for soundstage (by Global Communication and Biosphere) and see just how far things go back. Even with a low end DAC and a Yamaha receiver's headphone output GC's "Epsilon Stage" in an ...expansive track.

I'm also going to revisit the some of the massive bassline tracks I mentioned earlier (Yagya's "We Reject the Now" and Waldeck's "Floater") so see if they will display any of the visceral grit I've been missing.

I've done no major changes to the setup other than to plug the Adcom and the GLite into a Furman power conditioner, a PL-8 Mark I left over from one of my mobile sound rigs. The PL8 is pro grade surge supressor and RF and EMI noise filter. Its impact on sound should be minimal at best. I'm curious if the changes I'm hearing are the the results of my gear warming up ...or my ears getting used to the new sound.

 

[elrod-tom]

At $400, it's a steal even if you use it just as a transport. Nice buy...

I owned several GCD-575's over the years, and it's also built like a tank...but nothing compared to the construction of th GCD-750. I almost bought one a few years ago, but elected instead to go universal. Sigh....

I wasn't aware (must have forgotten) that the GCD-750 has balanced outs. That makes it a particularly good buy at $400!! Nice buy!!

 

[Knuckledragger]

Recently, I've had a bit of a nutty idea. I haven't read the entire thing, but I have browsed Alwayswantmore's 650/Blue Dragon thread. I am toying with the idea of trying soemthing similar. As I mentioned previously, the analog outputs of the GCD-750 are forcefully hot. The RCA outs are, at any rate. I have not properly tested the balanced XLR outs yet. I have the capacity to do this (using a 16 channel production console), but it will be a right royal PITA to do so. The Adcom is at the bottom of a very tightly packed rack of gear, and the 16 channel mixer is a gargantuan Allen & Heath from the late 80s. Fortunately, I have more XLR cables than I know what to do with.

What I'm missing is an easy way to attenuate the volume. The Adcom doesn't have a an output volume control on the front panel, and I don't have the remote for it. So I have a few questions:
Is this madness? The Wadia 830 and Adcom 750 are very different beasts. What works with one might not work with the other. I'm not even sure that the Adcom can attenuate its output volume.
Any advice on where to get a remote for the GCD-750? This is assuming that the remote does in fact have variable outputs. Are Adcom CD player remote codes generic? Will the remote from another model work with the 750?
Lastly, what about passive attenuators? I suspect a pair of balanced attenuators of sufficient quality are going to cost me about half the price of a balanced headphone amp.

I suppose my first step is to find a PDF of the GCD-750's manual.

 

[Alwayswantmore]

Quote:

Originally Posted by Knuckledragger I'm not even sure that the Adcom can attenuate its output volume. Any advice on where to get a remote for the GCD-750? This is assuming that the remote does in fact have variable outputs. Are Adcom CD player remote codes generic? Will the remote from another model work with the 750? Lastly, what about passive attenuators? I suspect a pair of balanced attenuators of sufficient quality are going to cost me about half the price of a balanced headphone amp. I suppose my first step is to find a PDF of the GCD-750's manual.

I am not an expert, but will add what I can...

For starters: Congrats. It looks like a good find. Here is a link to the owners manual http://www.adcom.com/pdfs/gcd_750manual.pdf

The voltage out for balanced is 6 volts (higher than I use with my Wadia 830). The impeadiance for balanced is 50 ohms. Based on feedback I got when researching this topic, some headphone amps are in this range. So that leaves attenutation, which the manual does not address. Word to the wise -- 6 volts would probably be enought to blow 650s, so you will need attenutation.

Good luck.

 

[Knuckledragger]

Thanks for the info, Alwayswantmore.

Even if it wandered pretty far astray from its original topic, I've been enjoying the K1000 vs. balanced 650s thread you started. I think a full understanding of what "balanced" means is key to persuit in this particular area.

For the moment, I've backpedalled away from plugging my 650s straight into the back of my Adcom, with or without attenuation. This is for a couple reasons, not the least of which is that I just bought a Monster Power Conditioner.

It's a HTS-5100 Mk II. Currently it's eating up a huge amount of real estate on top of my desk, because there's no room for it audio rack for it. It's pretty clear at this point I'm going to have to rearrange the entire setup, from the ground up. I also think I need to *ahem* add some structural support to this desk if this madness contines much further.

I've drawn some inspiration from Jahn's "Tower of Power" arrangement. I'm going to have the power conditioner on the bottom, then the Adcom CD player, and the receiver on top. The GLite and its DPS could sit on the desk beside the bigger components.

I've come up with a tentative upgrade path, money, logistics and sanity allowing: Next is a balanced headphone amp, followed by a balanced preamp, and finally my speakers will be replaced by a pair of powered studio monitors (I'm looking at Genelecs.) This of course will take years to fully materialize.

I've been listening to my rig as fed by the Adcom for about 24 hours now, and I've definitely noticed some differences. It'll be a while before I've catalogged them sufficiently to make an articulate post on the subject, however.