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In Reply to: RE: Tympani IVs in a 12x 22 x9 room posted by BDP24 on May 15, 2017 at 17:13:22
Either you have had some bad luck or I, some good luck. I have two of the original Adcom GFA-555s, and neither has even been recapped but both are in service today. I've used them to drive top/bottoms when bi-amping, and as bridged 'mono blocks' to drive Tympani 1Cs, IV-As and MMGs.
Admittedly long ago I showed some poor judgement and set one afire while playing the canons on a Telarc 1812 LP too loud. (CD weren't even around at that time.) It happened while I was driving Tympani 1Cs and Adcom was kind enough to replace it at no charge with yet another original GFA-555.
Follow Ups:
I don't know if your experience with 555's is more typical than mine, Norman, or visa versa. What I do know is that the 555 was a lot of amplifier for not a lot of money, a clear best buy. Anthony Cordesman's Stereophile review of it was, as usual for him, a bit over-enthusiastic (he was always trying to "scoop" all the other hi-end reviewers), as Stereophile owners/editors Gordon Holt and Larry Archibald stated in their follow-up comments.The amp was designed by Nelson Pass, but built to a price point. I don't know what causes some power supply capacitors to dry out (as mine had, I being the at least second owner) and others not to, but before hooking up a 555 to a valued set of speakers and turning it on, have it checked out on a test bench.
I bought one 555 to use for the bass columns of my Infinity RS-1b's, and a PS Audio 200C for the m/t panels, a good combination. As a 200C can be had for around the same price as a 555, I would much prefer the 200C. I actually still have mine, the 555's long gone.
Edits: 05/17/17 05/17/17
'If it ain't broke, don't fix it.' I myself have been on the "test bench" and most likely will continue to be there again in the near future (if I allow myself to be placed there), but my 2 Adcom 555s, NOT.
Ha! True, for one already having and using a 555 or two, no need to bench test. I was talking to anyone considering getting a 555.
The speakers have been purchased. A pair of Wyred4Sound mAmp monoblocks are now available at the same price point as the Crown Macrotech Reference. These would allow for vertical bi-amping of the Tympani IVs (not IVas). Wyred4Sound is well reviewed with Magnepans, but I wonder if there is any issue with mixing older and newer technology. Please comment.
Edits: 05/17/17
In a word, no problem mixing a class D and AB amp. Especially not a problem on the tympani where slight time domain variations between the amps can be easily compensated with tiny changes to relative distances between the drivers..
I had no problem obtaining coherent performance and great imaging using a blend of class AB, tubes and class D amplification in triamping and biamping my Tympani IV and with its modified Neo8 mids..
I am leaning towards the Wyred4Sound mAmps with the Tympani IVs, in a vertical bi-amp arrangement. I'll hang on to the Adcom and MMGs for a while until I get used to the Tympani Sound.
Very highly regarded little amps at their price point. Very convenient form factor.
Satie,Two Wyred$Sound mAmps or one Crown Macrotech Reference for the same cost?
Edits: 05/18/17
I would take the Crown Macro Ref. since it can do over 1KW into 4 ohms and has a deep bass that is very impressive. It is fairly easy to get around its thin high end signature with a tube preamp. And it drives anything while the mAmp is going to have problems below 3 ohms and has only 1/3rd the power.
It will be useful to have the extra power.
Thank you. I was leaning toward the Wyred4Sound as newer pieces, but the dealer was being difficult, so I will pursue the Crown.
The other thing that you would care about in owning a vintage amp is that there is a pro audio repair shop that can rebuild/service a Crown amp in practically every town.
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