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Adcom opinions?

N

N8Nagel

Addicted Member
Today I just picked up some Adcom stuff

GFA 555ii
GFP 555ii
GFA 5800

coincidentally, I also already have a GCD 700 CD carousel so that's kind of cool. All I know is "something" in the stack is broken but I got it for a "get it out of my house" price. I have a feeling unless all three pieces are broken I'll be going back to the seller and offering more money because they're in really good cosmetic shape and she also joined our local audiophile FB group, so I want her to feel welcome and not taken advantage of. ANYWAY.

Last time I was near any Adcom equipment except for the CD carousel I was still in college and it was just my semi crazy housemate's stereo, I really hadn't caught the bug yet, my little HK 330c was enough for me (although I didn't realize at the time what a little gem it was.) What's the general consensus of the above? I don't have anything close to the rated power of either of those amps, closest thing I have is a pair of HK775 monos (130WPC) but would these hold their own sonically? I know the original GFA555 was a Nelson Pass design but does the 555ii hold up as well? Pre good, or is my Luxman TP-117 better? How about the 5800? I don't really care about finding the matching tuner, if I end up doing an Adcom stack I will probably use a Sangean HDT-1x, as I have two of them working.

Any opinions welcome. I don't know what to do with the stuff, I was actually hoping the owner would let me come over and troubleshoot as it was her dad's stereo but she said she had another setup and just wanted the space. I wasn't looking for any more gear, but I don't have a single "big power" system. So here we are...
 
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You got a great deal I feel and some of Adcom's best.

I use Adcom amps for my home theater. I use a 5803 three channel up front and a 5300 for the rears.

Check fuses , might be as simple than that if they dont work.

Athanasios
 
It will be easy enough to determine which of those pieces isn’t working, and you are to be commended for making sure that she’s treated fairly. Goodonya.
:thumbsup:
 
Don't let the HK go, of the bunch, it's a keeper. Although there are upgrade boards for Adcom that might alleviate some of the old Adcom sonic proclivities. Hope you scored well.
 
hopeless said:
Don't let the HK go, of the bunch, it's a keeper. Although there are upgrade boards for Adcom that might alleviate some of the old Adcom sonic proclivities. Hope you scored well.
Click to expand...

were you referring to the 330c or the 775s? The former went to another member a few years ago when I somehow done blew it up after Deoxiting it, but I do have a 330B so it is not so sad. I was running the 775s for a while with my Luxman TP-117 and that was a great sounding system.

In a more general sense, should I be hoping that the GFA 555ii or 5800 is working? I've been reading up and it seems like there's no real consensus which is "better" although I remember hearing that the 555 could take out speakers if it died. Is that just the Mk1 version and not the 555ii? I think the previous owner's dad must have been biamping a pair of Cornwalls with these amps which sounds insane yet cool to me. I didn't buy the Cornwalls because I knew I could not offer what they were worth.

What about the GFP 555ii? Is that worth keeping, or should I stick with my Luxman? Or sell it and try to get a 565?

any opinions appreciated.
 
Of all the preamps you mentioned the GFP565 would probably be the best. It has a really great phono section and was liked by Stereophile back in the day.

The GFP555II was a lower level preamp than the 565 and not up to the latter's performance.

Stereophile reviewed the original GFA555 and critiqued the later 555II as more refined with tighter bass.

I own a GFA555II and a GFA555SE, the SE is really a different animal in performance, much more refined in all aspects of it's performance and a very listenable amplifier...not like say my Mc240, but very, very close to my ModWright KWA-100SE...

The GFA555 of any iteration can pass enough current to launch woofer cones if you screw around with stuff in the system while the amp is powered up...been there, ouch, done that. Just make sure to power it down before messing with cables or components that could then end up sending a huge spike through the system, I have the dead drivers to prove it!

Good luck and have fun

/
 
N8Nagel said:
were you referring to the 330c or the 775s? The former went to another member a few years ago when I somehow done blew it up after Deoxiting it, but I do have a 330B so it is not so sad. I was running the 775s for a while with my Luxman TP-117 and that was a great sounding system.

In a more general sense, should I be hoping that the GFA 555ii or 5800 is working? I've been reading up and it seems like there's no real consensus which is "better" although I remember hearing that the 555 could take out speakers if it died. Is that just the Mk1 version and not the 555ii? I think the previous owner's dad must have been biamping a pair of Cornwalls with these amps which sounds insane yet cool to me. I didn't buy the Cornwalls because I knew I could not offer what they were worth.

What about the GFP 555ii? Is that worth keeping, or should I stick with my Luxman? Or sell it and try to get a 565?

any opinions appreciated.
Click to expand...
You will have to figure out what you like. I wouldn't let the 775s go too far.
I've not tried the 555 pre, but you will just have to play with it. The overall Adcom sound is one I never really warmed up to. That's my ears. Owned a GTP600 and 545II amp, moving from an h/k 330C. I enjoyed the bass and the dynamics, but the sound was a bit wearing. Went back to h/k with their tuner/pre and one, then two PA2200 amps. Was very happy for a long time. Then the upgrade bug struck. I made a couple of missteps, but typically I was able to scratch off or lessen the annoyance du jour.
Don't live on my experiences, go out and get your own. Your tastes will change over time. Each step is important in getting your sound.
 
A common problem with the GFA-555 II is the transistors used in the Voltage Amplification Stage. This would be transistors Q107, 108, 157 & 158. These trannies are run at the top of their rated voltage limits and fail often. They should be upgraded with higher rated voltage transistors with heat sinks attached. Another problem area is the transistors used for the Instantaneous Distortion Alert LEDs. These tend to fail and turn ON the warning LEDs. I forget the part numbers.
 
so I've finally got to testing this stuff. I got knocked flat on my ass by something; I was dragging all day Friday and in bed most of the weekend. Oddly I didn't have a temperature, but I definitely was nonfunctional and now I've got a nasty cough but am feeling better. So I took the day off work today on the theory that I probably needed a slow day to ease back into work so I don't stay sick for too long, and finally got around to testing.

GFP 555ii works fine.
GFA 555ii - would light my DBT for longer than I was comfortable with, but it did dim eventually. No significant DC offset so I hooked it up. Initially had some serious hum and distortion, but I took it off the DBT and it's playing fine now plugged into the wall. Hooked up my tester Sony DVD player and it's been playing some Mozart through some little Canton mini speakers for about half an hour now.
GFA 5800 - one speaker fuse holder was popped out. Fuse was fine, I put it back in and put that one on my DBT. It never goes dim. I think bulb is 60W (writing is worn off) and I don't have a 100W bulb. DC offset measures at about 300mV on both sides.

Question: is this a beefy enough amp that a 60W bulb really isn't enough to evaluate its condition? Or do I assume that this piece is in fact faulty and I should take it to the amp doctor before hooking any speakers up to it? Is the 300mV cause for concern or does this one give floaty readings like an old cap coupled Sansui if there is no load on it?
 
Service manual says this thing draws 250VA at IDLE so I don't have a 250W bulb... I just crossed fingers and plugged in. Holy carp, it works. So, I messaged the seller and let her know what I found and we'll see what happens next.
 
Just thought, if I can figure a way to keep at least the GFA5800, will that be sufficient to drive electrostatics? Just thinking out loud here. I have never considered them before because I never had sufficient amplification. I've been told that they like lots of headroom but then again, when Magnolia was still a going concern near me, they had a pair of Martin Logans as their demo fed by a McIntosh MC275...
 
I never really understood the function of a DBT on solid-state equipment. :dunno:

Glad it's all working for you,
 
Well, I did message the seller and told her that I didn't know what issues she was experiencing but that everything was working fine for me and I had tested the preamp thoroughly as well. Surprisingly she replied that I should just keep the gear despite my trying to be honest about its value (I probably threw what some would consider a lowball number out there, but I really did try to get in the ballpark about what would be a good price for a local sale.) I did throw out an are you sure but haven't heard back and it's been over a week. So, it looks like I have an Adcom system. What do I do with it now? My "good" speakers are Rectilinear IIIs. Would that be a good match? Would the 5800 have enough beans that I could consider looking at electrostatic or planars?
 
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