replacing a processor [Archive] - Audio & Video Forums


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03-04-2007, 04:25 AM
Hello all. I am new, have been reading for a few hours, now maybe you can help.

I have a Adcom GSA 700 that needs repaired for the third time. I want to replace it so I can at least have dolby digital 5.1
I have Acurus preamp, Acurus Amp (2channel) for Definitive technology mains.
The system was originally for music. I added the Adcom surround processor for home theater. It has built in amps for the rear and center. Adcom suggests I trade it in for their new reciever ($2,000).I don't have that kind of money anymore, I got married.:confused5:

What can I replace this with to get my home theater back up and running that wont leave me broke? Should I be looking at recievers so I can power my rears and center or find another processor with built in amps thats more up to date?

I would like to buy used/refurbished, anything to save me money while still keeping as clean as possable.

Any links or suggestions on how to find a solution would be much appreciated. (models/numbers)


03-04-2007, 05:00 AM
Definitive Tech speakers average around 89 or 90dB sensitivity so they are not as difficult to drive as some speakers so you may be able to get away with a stand alone receiver and still get pretty good results.

I'm a Denon man now a days but Yamaha, Harman Kardon, and Onkyo are all very good receivers, as well, and for half or even a quarter less than a new Adcom.

Now I would not put them up there with Adcom but if you are having that much trouble, performace may not be your only priority at this point in time.:idea:

And if getting married puts a damper on your party, wait till you have kids:incazzato:

Good Luck and keep us posted. I would like to hear how it all turns out.

03-04-2007, 11:42 AM
Thanks for the reply!

I was told that the GSA 700 was obsolete, it only has pro logic. This is told to me by the Adcom sales rep trying to get me to buy a $2000.00 reciever.
Am I that obsolete with pro logic.
As I said this system was mainly for reproducing music. I am no where near up to speed on the latest home theater changes.
If I bought a cheaper reciever, not cheap- cheaper, maybe a decent used one, and used it for it's newer surround and to power only the center and rears, keeping the Acurus's for the def. tech's would I be compromising anything? Trust me, I don't want the confusion of a reciever. my system is simple right now, turn on POWER and listen, no treble, bass, theater 1,2,5,9,,, Keep it simple ( and powerful!!!)
I don't want to throw a monkey wrench into my system, I just want to watch movies and have no idea how "obsolete" pro logic is. Adcom makes the GDD 1 to add to the GSA 700 which decodes the digital surrounds, I can't find it, yet. Maybe it's "obsolete" now too.

Frustrating, I mean we all know that every year makes the last year "obsolete". I have had the same amps, speakers, cables for ?? 8 years?? or more. I still love them, thats why I spent so much on them. This home theater is not my "forte". I need you all to tell me, not a Adcom sales rep, How obsolete am I ???
What would you all do?

03-04-2007, 12:22 PM
I think most would agree that Dolby Digital is a minimum for todays home theater experience. I think some people do not place enough importance on the center channel. It delivers a much greater percentage of the audio information than the rest of the speakers and because it is placed further from the side walls, is the least affected by room interactions ( should also be at ear level with the left and right speaker). Some try to use a pro logic system to simulate a center channel but it is very ineffective in a home theater environement where there is more than one listener. Once you move from the prime seating position or even tilt your head, the sound stage falls apart and its effectiveness is lost.

I think I understood you to say the Adcom you want to replace was a preamp. Most decent Dolby Digital receivers have a pre out so they can act just like a preamp. You can still use your existing dedicated amplifiers without losing any of the power. Actually, if this is the case, you are in good shape as separates allow you to upgrade the DSP (digital signal processor\preamp) without having to replace the dedicated amplifiers.

I guess the crux of the matter is if you are going to lose any audio performance? It all depends on your room setup, your hearing acuity, and how in tune you are with your system but I would have to say that 99.9% of the population would never hear the difference with todays digital and competitive technology.

03-04-2007, 01:29 PM
The Adcom GSA 700 that I'm having problems with is a preamp/surround processor with 3 built in amps. a 100w for the center and two 50w for the rears. It has pro logic, concert hall, night club then has 5 channel(all on) and two channel (just the mains). It also supports dolby digital by adding the Adcom GDD1 decoder.
Pro logic worked well, but now the center channel doesn't come on when I select it. I don't know if this is a componant problem or that the dvd's don't support pro logic, causing the center channel to not register. It always worked before.
If I choose to use a reciever I would still need to have power for the center and rear's. That is what was nice about the GSA 700, it converted my two channel system to a five channel without having to buy more amps. But that was then.

So your saying Digital is far better than pro logic, just as I was told by Adcom. Now I can either fix the GSA 700, not knowing how much that will cost and buy the GDD1 for I'm guessing $300.00 or less to decode the digital. Let's say thats $500.00 total to go that route. Can I find a reciever used/refurb/new for that much? Where? What kind? I've never bought one.I really don't want a reciever loaded with a bunch of stuff to make the system complicated.
Where can I look for the Adcom GDD 1, I tried ebay, any other places?

03-04-2007, 01:57 PM
You could find a receiver for that price but something tells me that anything you buy that is a receiver would be an all or nothing proposition. Either it acts solely as a preamp with no power or it must power all the speakers in AV mode. I am not 100% positive on this but a call or email to the AV receiver mfgs being considered could give you a definitive answer. And, as always, you might get an answer here from someone far more knowledgable than me on this particular subject.

03-04-2007, 03:09 PM
a simple receiver to do 5.1 is the NAD T743 (

also check out Pioneer Elite, Marantz and Integra (high end onkyo)...

03-06-2007, 10:08 AM
Boy, your post is bringing back a lot of painful memories. I remember switching from 2ch separates to a 5.1 mc set-up...


Before you take a peak at the back panel of a modern AVR or Pre-pro...drink. A lot. Trust me, you'll thank me ;).

First, the difference between Pro Logic (DPL) and Dolby Digital (DD) is HUGE. The former is a program that decodes 2 channel information and spreads it around to 5 channels as it sees fit. The latter takes discrete information and places it exactly where the sound engineer intended it to be. Big difference. Today, you need a minimum of DD and will soon need DD Plus and DTS HD, which are the new lossless formats being promoted with the new 1080p video formats (BluRay, HD-DVD). Confused yet? It gets better...

There are a couple of ways you can configure your rig. The easiest way would be to get a good AVR, (Cambridge Audio, NAD, Rotel) and use it to power your cc and surrounds. Hook your Acurus up to the preouts and use it to power your mains for two channel music while the AVR acts as a pre-pro. Sell your pre-amp and buy more tunes.

Now, if you prize music over movies and want to keep your Acurus preamp in the mix, then I'd get a lower priced AVR (Denon, Marantz, Pioneer) to act as a pre-pro and power your cc and surrounds. There is a way to plug your Acurus equipment (pre and amp) into your system using the tape loop so that you can listen to your 2ch music without worry about signal degredation from the AVR, but I can't remember off the top of my head. The goal is to listen to 2 ch music without any processing from the AVR. Honestly, most AVR's have a Pure Direct function these days whereas they act as a passive preamp anyway, so I don't know how important it is to you to still use your Acurus, although it is likely of higher quality than most mass market AVR's.

Hope this helps.

03-06-2007, 01:13 PM
so am I understanding that if I upgrade to digital I will still be obsolete? That by the end of the year I will have to do this again?
Or will Dolby Digital be in the loop for quite some time still. I am sure I will be happy with DD for a long while (compared to pro logic) just as long as the DVD's will keep supporting DD for even longer!!

03-06-2007, 03:36 PM
Yes and no. Dolby Digital will be around for a long time to come, just like Dolby Pro Logic has and still is on older programs and DVDs. The new formats are pretty much only included on HD DVDs an BlueRay. When will these become dominant like DD? Who can say but it is probably safe to say the time line will probably be similar to the transformation from DPL to DD.

This is why, in the long run, a preamp that is separate from the amplifiers is a good investment long term. I have not thoroughly researched which preamps now support the HD formats but you may be able to find a few but your selection will be limited until HD audio gains more ground.

Your equipment failure could not have been less timely as this transition period is just now becoming problematic. Some mfgs may be able to provide a modular upgrade solution but this is the exception, rather than the rule. I do not remember who makes this last pathway possible but I do remember reading something about it a few months ago.

I will do some digging if this last option interests you.

New HD Audio formats (

03-06-2007, 06:42 PM
You're not going to get any preamp / processor and 3 channels of quality amplication for much less than the Adcom unit would cost you.

Not sure if I'd fix the old unit and add the Dolby Digital processor or not... With multiple reliability problems... Adding another component... Depends on how much you like it I guess... and if you're willing to pay if it needs repair again...

Aside from repairing your old Adcom, I agree that a quality receiver is probably your best bet on a budget. Make sure you get one with preamp outs for the main 2 channels. Not all receivers have them. Most of the better ones do. You will be able to use your outboard amp for the main two channels. It will take some strain off of the power supply in the receiver and improve power and sound quality to the remaining channels powered by the receiver.

I'm using a Harmon Kardon HT receiver with an outboard amp for the 2 main channels and I'm pretty satisfied. All of the brands already suggested here are good. Most receivers really aren't much more complicated than need be to properly calibrate home theater. Any outboard equipment will tend to have the same settings / adjustments. Keeping everything in one box, controlled by one remote keeps the system a little simpler IMHO. If you listen to several the brands listed here, you could probably find something to your liking.