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Does Adcom make good Amps ?

Old Adcom amps do not have speaker protection. Many are pushing 20 years or more now so they are definitely a risk to expensive and rare drivers. This is not to say the 555 and other models are bad sounding amps, I've owned two 555's and liked them. However, this risk reward is not there. They don't sound different from other high power ss amps. In fairness to the 555, the latest SE version has speaker protection so they have addressed this issue.
 
I got a 545-2 in a trade, intentional choice out of the series, it looked like the best averaged "Goldilocks" design and build of the series.
I use it in a system primarily for background that is really a much better setup. I'd considered replacing it with a more highly regarded amp but cannot really justify the change as that system doesn't get critical listening these days, and the Adcom is more than adequate.
 
@SoCal Sam
I think the main thing that some of the posters are trying to get across is that there's a whack of great amps that have the same unprotected circuit. Pass, Levinson, and Krell, just to name a few. They all actually mention it, and warn the buyers of the, DC servo only, protection in their amps circuitry. Adcom has the same (great sounding) open circuitry, and is no different than any of them. They will all amplify DC current, and are all a threat to your speakers if your tube preamp's coupling caps fail, or something in the amplifier fails. So, it's not a likely issue for any of them, if one keeps one's tube preamp caps in good repair.

Dave
 
david1111 said:
@SoCal Sam
I think the main thing that some of the posters are trying to get across is that there's a whack of great amps that have the same unprotected circuit. Pass, Levinson, and Krell, just to name a few. They all actually mention it, and warn the buyers of the, DC servo only, protection in their amps circuitry. Adcom has the same (great sounding) open circuitry, and is no different than any of them. They will all amplify DC current, and are all a threat to your speakers if your tube preamp's coupling caps fail, or something in the amplifier fails. So, it's not a likely issue for any of them, if one keeps one's tube preamp caps in good repair.

Dave
Click to expand...
Amps with output transformers or output DC blocking caps won't pass offset to the load.
 
Hey Pio ... I'm interested in buying, at some point, the amps I mentioned, so I downloaded the Owners Manuals and read them a while back. They all seemed to be concerned with DC current amplification, and the affect on one's speakers. You know way more about the circuitry than I do, so what are they talking about? I'd like to think that there's no real issue regarding a DC surge from somewhere.

Dave
 
Any amp that isn't DC coupled at the input is relatively safe and immune to input offset, amps DC coupled input to output not. For instance, the original Adcoms are DC coupled input to output and will amplify input offset, the mark 2 series have an input DC blocking cap and cannot. Other amps should be specified as to whether DC coupled input or not, or optional.
 
I've read more than enough posts of 555's taking out rare and expensive drivers to not ignore the threat they pose. There is a relay kit that can be retrofitted to 555's. It's worth the effort.

To be fair to Adcom, any amp with no speaker protection poses the same potential threat.
 
Even Upscale Audio sold someone a PrimaLuna Dialogue preamp, and it blew up the guys speakers. They got it back and
checked it out, and something had failed inside he pre. I think Kevin paid for the guys speaker repair.
I suppose there's a chance that an internal failure could happen to a Pass or Levinson, but a $15k amp probably has higher quality
parts, and a failure is rare.

Dave
 
david1111 said:
...
I suppose there's a chance that an internal failure could happen to a Pass or Levinson, but a $15k amp probably has higher quality
parts, and a failure is rare.

Dave
Click to expand...
giphy.gif
 
david1111 said:
Even Upscale Audio sold someone a PrimaLuna Dialogue preamp, and it blew up the guys speakers. They got it back and
checked it out, and something had failed inside he pre. I think Kevin paid for the guys speaker repair.
I suppose there's a chance that an internal failure could happen to a Pass or Levinson, but a $15k amp probably has higher quality
parts, and a failure is rare.

Dave
Click to expand...
Probably about the same as a Mk-2 Adcom.
 
Fusing your speakers will protect them just fine if you have an old Adcom that blows a transistor and goes rail DC. A normal crossover with a cap on a tweet or midrange will be immune. Only the woofer is normally at risk.
 
Sounds like a good idea. Can it be installed inside the cabinet, on the small gauge wire from the crossover to the woofer? I have Kef R107s.
It shouldn't degrade the signal/sound? Thanks.
Y'know, in general, I always find the interior wires to be a little amusing. People spend $5k on speaker cables from the amp to the rear connections; and from there on, it's just tiny gauge wires with crimped on, push-on connectors. Is that weird, or is it just me?

Dave
 
Pio1980 said:
Amps with output transformers or output DC blocking caps won't pass offset to the load.
Click to expand...
No modern solid state maps are cap coupled at the outputs, and AFAIK, McIntosh is the only manufacturer using output transformers in non-tube gear.
 
david1111 said:
Sounds like a good idea. Can it be installed inside the cabinet, on the small gauge wire from the crossover to the woofer? I have Kef R107s.
It shouldn't degrade the signal/sound? Thanks.
Y'know, in general, I always find the interior wires to be a little amusing. People spend $5k on speaker cables from the amp to the rear connections; and from there on, it's just tiny gauge wires with crimped on, push-on connectors. Is that weird, or is it just me?

Dave
Click to expand...
IMO, the retrofit relay kit is a better option than an inline fuse. They are available on the 'bay for less than $20, and a trained monkey could install it.
 
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