Thoughts on Amps for 3's

[DavidDru]

Outstanding!

What Pre will you use with it?

I am sure the manual and schematic is over on HiFiEngine.

[owlsplace]

Thinking of getting a Crown XLS2500 to drive the AR9/Limited Model3/3a.

Would it be ok?

Or would it be a bit OTT ?

It's a class-D PA amp. Looks like they have built in xovers. I'd want to hear it first or at least know someone who has. I might be tempted to play around with some of the old Crown amps. Not sure, but I don't think the older amps had speaker protection circuits. Fried drivers are an expensive proposition so would need to add a Vellerman speaker protection circuit to the old amps.

AR did offer fuse kits during the Classic era and I did put them on my original AR-5's.

Roger

[owlsplace]

Outstanding!

What Pre will you use with it?

I am sure the manual and schematic is over on HiFiEngine.

Well, right now I'm using an SAE Mark IXb from the Classic era. I have two of them but one needs a rebuild or for parts. One is silver or Champagne finish and the other was the rare black rack mount version.

Roger

[JKent]

djcheung:

Veteran CSP member and "Restoring the AR-3a" co-author Tom Tyson, who certainly knows these speakers, is a big fan of the Crown XLS series. Here is a quote from one of his posts:

I, too, use the XLS Crown, and I did a A-B comparison awhile back between my old Adcom 555 (which was working fine, but growing long in the tooth) driving a pair of AR-10πs in my office system. I honestly could detect no difference whatsoever between these two amps on switching back and forth (with an old Switchcraft input switcher) on a variety of music. I balanced the output levels by using the input controls on the Crown, such that both amps were producing the same amount of output for a given input from my Adcom preamp. Granted, I did not play them at super-high output levels during the comparison, but on a variety of music, both amps sounded identical, across the band, on quick back and forth switching, which is exactly what I would expect from amplifiers producing very low distortion and flat bandwidth. No harshness from either amp; bass response equal in my experience; both amps exhibiting low noise. So why use the Crown over the Adcom? Reliability. If the Adcom failed for some reason—more likely due to the old age of components—the amplifier would be more likely to damage the AR speakers. Also, the Adcom protective circuits are not as advanced as with the newer amplifiers, and these older consumer amps are likely to run hotter than the newer designs.

Roger,

I sent you a 555/II Service Manual pdf. Check your email.

-Kent

[owlsplace]

djcheung:

Veteran CSP member and "Restoring the AR-3a" co-author Tom Tyson, who certainly knows these speakers, is a big fan of the Crown XLS series. Here is a quote from one of his posts:

Roger,

I sent you a 555/II Service Manual pdf. Check your email.

-Kent

Kent,

Got the manual, thanks. Interesting note from TomT. I think I'm liking the mosfet designs over the class-D amps but I'm not exactly in the loop these days

Roger

[ar_pro]

It looks like SAE is making a comeback, Roger.

One horsepower per channel!

[owlsplace]

It looks like SAE is making a comeback, Roger.

One horsepower per channel!

Impressive, but I probably won't live long enough to hear one of those on a regular basis

The S/N ration is over-the-top. Speaking of age and TomT not hearing any difference with a class D amp, I was visiting a physicist friend's house a while back and he was playing downloaded music on his system. So I said you are loosing something there over the CD version and he responded, you and I can't hear the difference. How true. I have a Galway disc burned in memory from the 80s and when I play it these days it doesn't match my memory of it. There was a decade there where I didn't listen to any recorded music so the transition was abrupt rather than gradual. Maybe that's why I still enjoy the Classic AR sound

Roger

[owlsplace]

Roger,

Please let us know your listening impressions.

IMHO with an amp that age it's a good idea to have a qualified tech check it out. As I mentioned, my guy found 3 bad caps and set the bias so it was money well spent for 1 hour's labor and 3 inexpensive parts.

Enjoy!

-Kent

Stay tuned. the Adcom GFA555II is scheduled for delivery tomorrow, woo hoo I'm sure my neighbors will be entertained.

Will see if it can handle my ADS L980, AR-5, AR-6 towers ... maybe not all at once though.

If you do the math, an AR-5 and an AR-6 together make an AR-11 If I get on the ball and do over my other AR-5 set I can make an AR-10 or AR-16 or by adding the 5s and subtracting the 6 I can have an AR-4.

The paint fumes must have gone to my head today.

Roger

[DavidDru]

Adcom GPA-5500 now in the house! Local CList listing I could no longer ignore with all this talk about how good an option the Adcoms are.

The Dynaco St400 will likely be sold . Maybe not

The guy I purchased it from had it paired with another in a monoblock set-up with some Martin Logans until he got a VTA tube amp that took it's place. He said the tube amp took everything to another level for him. So there's that.

[owlsplace]

Adcom GPA-5500 now in the house! Local CList listing I could no longer ignore with all this talk about how good an option the Adcoms are.

The Dynaco St400 will likely be sold . Maybe not

The guy I purchased it from had it paired with another in a monoblock set-up with some Martin Logans until he got a VTA tube amp that took it's place. He said the tube amp took everything to another level for him. So there's that.

Nice, David ... expecting a full report. I may have to drive up for a listen

http://adcom.com/index.php?page=shop.product_details&flypage=flypage.tpl&product_id=72&category_id=28&vmcchk=1&option=com_virtuemart&Itemid=122

Roger

[DavidDru]

Nice, David ... expecting a full report. I may have to drive up for a listen

http://adcom.com/index.php?page=shop.product_details&flypage=flypage.tpl&product_id=72&category_id=28&vmcchk=1&option=com_virtuemart&Itemid=122

Roger

Actually I was thinking, you turns yours up and I will turn mine up and see if we can hear each other?!

Just set mine up. SOunds nice with my small but powerfull Epos ES11's I had already attached to the pre.

[owlsplace]

Actually I was thinking, you turns yours up and I will turn mine up and see if we can hear each other?!

Just set mine up. SOunds nice with my small but powerfull Epos ES11's I had already attached to the pre.

Ha, ha, may have to get some roof-mounted Klipschorn speakers for that! I'm not familiar with the Epos but they seem to get rave reviews. Glad to see you are enjoying it

Roger

[JKent]

Not sure what the difference is between the original Adcom 555 and the Model II is. Was it a major design change or just mod/tweeks?

I know this is late, but here's something on that subject. So no major change, just mods/tweaks.

[owlsplace]

I know this is late, but here's something on that subject. So no major change, just mods/tweaks.

I can vouch for those improvements.

Spent an hour cleaning the new/old amp inside and out. This amp had some visible rust on the case and looks like it has put in some serious pro time somewhere. Don't like all the chemicals but it was a balmy day outside, sunny around 70.

DC offset was a wee high on one channel but had it back together before I measured it so will have to get back into it later. It will need recapping anyway if I keep it.

Well, as for first impressions of the ADCOM GFA-555II. It is a major change to what I'm used to lately. Definitely handles low impedance loads. It is currently driving three pairs of speakers without complaint, that is AR-6, AR-5, and ADS L-980 (AR=3 stand-ins). I was able to get it to distort before my ears said enough. Not quite used to clinically clean bass -- it punches rather than rumbles. It almost sounds thin on the low end in a way. Drums sounds are tight and controlled and the woofers well damped. The upper registers are well defined (at least the ones I can still hear) with a much improved sound stage, more open but a hair on the edgy side. Definitely not a warm sounding amp by any means but very clean sounding.

Jazz firing on all six speakers sounds great. Moody Blues, Live at Red Rock, oh yeah! Church organ with ease. Will try Mahler's Symphony of a Thousand tomorrow.

Jury is still out but over all it is hard not to like it. Any amp that can drive three sets of speakers without any impedance matching devices in between is always of interest.

Will bypass my ancient pre and put in some more listening time tomorrow. Not interested in going into cascade gear replacement mode any time soon

Need to move on to building bookshelves for all these bookshelf speakers and maybe a few books ...

Roger

[stupidhead]

great thread! I have read and re-read a few times which inspired me to contact someone I had bought some items from a while back. He had a set of Adcom 555s (GFA, GFP and GFT) which he offered and I then declined. I have reached back out to him and have been negotiating on the set. My AR 3s are not even cracked open yet for rehab, but this just feels like an opportunity I should not pass up. I intend to work on my 5s first before the 3s.

I have the 2325 and was planning on using it for the 3s, but all indications are that the 555 would be far superior.

I posed the "value" question here http://www.audiokarma.org/forums/showthread.php?t=646593 and have gotten some useful insights, but as is usual a good bit of off track discussion.

Roger, really looking forward to hearing specific thoughts on the 555 with the 5s exclusively.

[owlsplace]

I know this is late, but here's something on that subject. So no major change, just mods/tweaks.

Also added was full output fusing:

great thread! I have read and re-read a few times which inspired me to contact someone I had bought some items from a while back. He had a set of Adcom 555s (GFA, GFP and GFT) which he offered and I then declined. I have reached back out to him and have been negotiating on the set. My AR 3s are not even cracked open yet for rehab, but this just feels like an opportunity I should not pass up. I intend to work on my 5s first before the 3s.

I have the 2325 and was planning on using it for the 3s, but all indications are that the 555 would be far superior.

I posed the "value" question here http://www.audiokarma.org/forums/showthread.php?t=646593 and have gotten some useful insights, but as is usual a good bit of off track discussion.

Roger, really looking forward to hearing specific thoughts on the 555 with the 5s exclusively.

AK is down at the moment. Will do on the 5s since I seem to have a sentimental attachment to them. Interestingly, they are rated as having the same sensitivity as the 6s but you would not guess that by doing an A/B between the two. The 5s are more articulate but need some power to breathe properly in my opinion as I would imagine the 3s do also. I can see someone running the 6s on a low power amp with nary a complaint

Roger

[DavidDru]

great thread! I have read and re-read a few times which inspired me to contact someone I had bought some items from a while back. He had a set of Adcom 555s (GFA, GFP and GFT) which he offered and I then declined. I have reached back out to him and have been negotiating on the set. My AR 3s are not even cracked open yet for rehab, but this just feels like an opportunity I should not pass up. I intend to work on my 5s first before the 3s.

I have the 2325 and was planning on using it for the 3s, but all indications are that the 555 would be far superior.

I posed the "value" question here http://www.audiokarma.org/forums/showthread.php?t=646593 and have gotten some useful insights, but as is usual a good bit of off track discussion.

Roger, really looking forward to hearing specific thoughts on the 555 with the 5s exclusively.

Go for it! Just for fun reference, looking for a new preamp to go with the 5500 I just bid yesterday afternoon on a set of GFA535, GFP565, GFT555II, and GCD575. Didn't win it with my bid of 293.51. It went for 298.51 so apparently one other was going higher. the smaller amp would have ben a nice throw in as many feel the 535 for it's lower power is even better than it's higher power siblings. Hell of a price, even with the $82 shipping. Of course I wanted the set for the GFP565 which was one of the better Adcom pre's and worth that much or more typically by itself. If you can get those 3 for a good number, you should have a great set-up. Especially if local and no shipping.

With my 3's not yet re-commissioned and one of my 2ax's choked out with a bad pot I can't provide any feedback yet on my impressions of the 5500 with AR's. I can say it definitely provides an up grade in SQ compared to my ST400. I am not necessarily stepping up in power as the 400 was already providing the 200x2. With that Roger, I probably wont see the dramatic difference like you did in your description of rumble vs punch etc on challenging music passages. I have not had time or the privacy yet to really do a bunch of testing.

Thus far I have used it with the smaller but outstanding Epos ES11's and Polk monitor 10's and I am hearing greater detail than before. Overall I think I can see why people like the MOSFET. Smooth and warm while powerful in presentation. I can only imagine what the 5800/5802 would be like. Mr. Pass new his stuff.

Right now I am still looking into a new pre to go with it. Not sure my PAT5 is at it's level?

[ar_pro]

Roger -

I had forgotten about the fusing on the 555 II, but it was easy to do - I never blew a single fuse on either amp when driving the AR-9.

stupidhead -

Adcom electronics from that era played perfectly with each other, with a very clean presentation and very low noise.

You can't really call it a "house sound", but more of a characteristic - 30 years later, and all-Adcom system can still sound great.

David -

A notable difference between your Dyna PAT-5 and the "II" series of Adcom preamps is background noise, with the latter being virtually dead-quiet.

Again, I'd like to encourage anyone who gets the chance to try out the Adcom SLC-505 "passive preamplifier", or what they called their "Straight Line Controller".

It's an amazing piece of equipment that can reveal the slightest details of a good recording - especially when matched with a 555 II amplifier.

They are very affordable (several recently sold on eBay for well below $100), and provide a peek at what some folks with ultra-high-end equipment can occasionally experience with their megabuck systems.

[DavidDru]

Again, I'd like to encourage anyone who gets the chance to try out the Adcom SLC-505 "passive preamplifier", or what they called their "Straight Line Controller".

It's an amazing piece of equipment that can reveal the slightest details of a good recording - especially when matched with a 555 II amplifier.

They are very affordable (several recently sold on eBay for well below $100), and provide a peek at what some folks with ultra-high-end equipment can occasionally experience with their megabuck systems.

for $100, what does it not do?

[ar_pro]

There's no active stage, David - it will provide input switching, and volume & balance, but no signal boost or tone controls (and no phono preamp).

It's as quiet & transparent as the source that's connected to it, and it's well-matched with the Adcom amplifiers, which don't need a ton of voltage for full output.

Some people are uncomfortable listening with the volume control at the 3 o'clock position, and some guys miss the added "oomph" that an active preamp offers, so it's not for everyone; but still a definite bargain to experiment with.

If a system doesn't need the additional gain provided by an active preamp, or if revealing inner details and presentation in a recording are more important than "punch", a passive preamp is a very attractive option; its attributes are what guys spending zillions on high-end preamps are trying to find.

DB Systems and Mod Squad used to offer passive-preamps as well - I once owned an extremely well-built model from Mod Squad that had esoteric RCA jacks and a very high-quality Japanese volume control, and it performed no better than the little Adcom.

I've attached photos of the Mod Squad passive - they sell for about $450 on eBay.

Definitely a looker!

[DavidDru]

Interesting. And then you can just add a sep phono preamp say from emotiva. Got it. There is one on Ebay now starting at $100 so maybe I will watch it and if it stays down there, go for it. I can get the GFP565 for $250 so might pull the trigger on that.

I barely get past 9:30 currently on my volume control with the PAT5 so yes it would feel awkward. Hell even having to dial up to 11:00 or so on my PAS2 with the ST70 feels crazy.

I also happen to have a Citation I here that is in pieces that some day would be great to have available

[ar_pro]

Sure - you could feed any of the inputs with your choice of phono preamp.

One could also connect an equalizer through the tape loop if desired - this would offer a certain amount of signal boost, as well as tone control, and could be easily switched out of the circuit with the push of a button.

The Citation 1 is a very cool piece - if I recall correctly, it offered a ton of adjustments for LP playback, including phase!

[owlsplace]

Ha, ha, may have to get some roof-mounted Klipschorn speakers for that! I'm not familiar with the Epos but they seem to get rave reviews. Glad to see you are enjoying it

Roger

David,

I think I found the proper unit to beam music over to you : https://www.passdiy.com/project/speakers/the-kleinhorn-part-2

Back to the topic at hand. I don't think the Adcom GFA-555 series is the best amp to showcase the AR-3 lineage's abilities. Is it a good amp for the price? Yes. Is it a good amp at any price? Probably. Would I refuse one if it turned up on my doorstep? No. Would I mod one? Love to.

If you like free chair massages with your organ music I'd pass. If you want to keep your neighbors from beating down your doors yet still like to hear music played at realistic performance levels with full dynamic range I'd get one.

It has some known limitations and here is one set of mods to overcome them: http://www.adpslab.com/en/audio/upgrades/10-adcom-gfa-555-mkii

Here is Ken Rockwell's opinion with some graphs to back them up: http://www.kenrockwell.com/audio/adcom/gfa-555-ii.htm

Here are some owner reviews that run the full gamut: http://www.audioreview.com/cat/amplification/amplifiers/adcom/gfa-555mkii/prd_115536_1583crx.aspx#reviews

I ran the amp today straight from the Denon CD player without my old SAE preamp in the loop starting with a couple of Telarc discs, Mahler's 8th and an organ disc recorded at St John's. Then put on John Barry's Moviola disc. The upper registers are much cleaner without the pre, bass is still thinnish and overall sound is on the cool side. Played Mahler on AR-5's, organ on the ADS-L980's and Barry on both. Like the latter better with the 5's angled out. And then three sets of speakers at lower levels, all angled in different directions ... with my eyes closed it feels like I'm swimming in a pool of sound waves -- nice.

Most people who have been around for awhile know it isn't power per se that burns up speakers normally, but amps driven to into clipping. With inefficient speaker designs it is easier to run amps to clipping levels before sound levels became unbearable hence the reason for the muscle amps with greater headroom. I don't really know where it is at in today's music world but popular music tends to have a compressed dynamic range to start with. Frankly I'm a bit surprised that people are still listening to stereo after all these years with its limited ability to project an accurate soundstage.

Actually I may have to hunt up another one of these amps so I can run them bridged and maybe recapping and trying some of the mods, so little time ...

Or it may be better to just order one of David's later model mosfet-based 5500 models. Chime in David ... I've been writing this post for a couple hours while drinking wine and listening to music so maybe you already have

Roger

[owlsplace]

....

Thus far I have used it with the smaller but outstanding Epos ES11's and Polk monitor 10's and I am hearing greater detail than before. Overall I think I can see why people like the MOSFET. Smooth and warm while powerful in presentation. I can only imagine what the 5800/5802 would be like. Mr. Pass new his stuff.

...

Thought you would say that

Roger -

I had forgotten about the fusing on the 555 II, but it was easy to do - I never blew a single fuse on either amp when driving the AR-9.

...

Actually, I think I read somewhere today that they are inside the case on the earlier model.

Interesting. And then you can just add a sep phono preamp say from emotiva. Got it. There is one on Ebay now starting at $100 so maybe I will watch it and if it stays down there, go for it. I can get the GFP565 for $250 so might pull the trigger on that....

Not sure what the difference is but there is a system on CL locally that has a GFP600 which the guy doesn't mind splitting up. I wouldn't mind the cd player. The other parts are a GFA600 HT amp and a line conditioner.

Roger

[DavidDru]

The Kleinhorn. I'm on it.

Good lord!

Roger I wish I was sipping on a red in my lounge right now! The weekend is actually not the best time for me to really spend time with my gear because I am spending time with the family instead. Plus it was really nice outside. I ran the 5500 throughout the day but mostly in the background for something to listen to while doing other stuff. I did sneak into my listening room a couple times when I heard something nice being played on whatever Tidal or Spotify playlist I had going.

Here is what the seller had to say about it for reference as he has a bunch of experience with various amps.

"as for the 5500 it has been a favorite of mine, used it to run my Martin Logan CLS and Polk 2.3TL. I moved from the 5500 to a ARC VT100 tube amp, also had the 555, Dynaco 410 and Hafler DH-500, prefered the 5500 to the all of those excellent amps. This 5500 is a 2003 model, never had issue, hate to part with it but have been selling off my collection as I am approaching retirement need to downsize."

He said he notices the lower power of the VT100 he is using now but is okay with that for the overall improved SQ he gets with it.

BTW, my goal is to eventually find another 5500 and go with the two. my Preamp purchase needs to take that into consideration. I did take my ST400 to my tech on Friday for him to run through and when I get it back it should be a good candidate for comparisons before selling.