Threshold-like amp that doesn't get hot?

Vistance

Super Member
Ok, so for various reasons I've come to decide I strongly wish to have a Threshold amplifier (at least one anyway). My current main system has an AVR that gets way too hot, and it makes my room miserably hot. If I leave it off, it's comfortable but with it on I need the fan on and I'm still too warm. So it's important the replacement amp runs cooler than the AVR.

So Forte is a sister company to Threshold, not quite as beefed up as a Threshold but quite similar and still well regarded. I had considered one of their amps, but the ones I found were Pure Class A amplifiers - 40-50 watts per channel. The concern I have here is Class A is generally always a "hot" amp isn't it? Would it give off so much heat so as to warm up a room literally, or is it just warm to the touch? Most amps I've had over the years never did seem to really get hot, in fact in this same room I have an older Denon AVR that never heats the room up. These Forte amps are more readily available than a Threshold, but my concern is the heat.

By "Threshold-like" I mean I don't want something that's bright (Bryston) or sterile and lifeless (Krell), something that just has a nice smooth mix of all the good stuff (I know this is subjective but I've heard this describe Threshold amps very much). Of course expressing my personal views on those brands for my own use, no intent to bash them as they're all well made gear regardless. I'm just kinda at a loss, functionally a Class A amp would be wonderful as I'm in a small room and I don't need a lot of power for my speakers. But I don't want heat.

So does this leave me with just Class A/B amps biased less towards A? Is there such a thing as a cool running Class A amp? I had considered a Sumo Andromeda III as it's a very healthy Class A/B amplifier, but that's getting into the realm of excess power I'm paying for that I don't really need. 100 watts a side would leave plenty of headroom for me. I want a high-end amplifier, relatively speaking from say Adcom, NAD, Emotiva, etc. I'm trying to take my level of listening to the next "plane" if you will, I have the money and want to give it a go.

I feel my own research now is too heavily biased on Threshold, can anyone else recommend something that would be high-end and not cook me out of my own room? I know this one's "high-end" status is questionable depending on whom you ask, but I had considered the Sunfire Load Invariant amplifier as I know it drives crazy loads and never gets hot. It's in that realm of ridiculous power though, 300 watts @ 8 ohm and doubles power up to 1 ohm. I know that's the sign of a good amp, so I'd kind of like to find a power amp that does that as well.

Anyone know of anything? New or used is fine, sub-$1k would be ideal since I probably won't be happy until I've bought a Threshold (The Threshold doesn't have to be used in this system as I have another system in a different room it can go in where heat is irrelevant, and I have a need for at least 2 high-end amps).
 
Not sure if it fits your requirements fully, but an Odyssey Stratos amp is not too bright and runs dead cool no matter what you are doing.

Stratos Stereo:
base model specifications:

$1,275 USD
2 x 150 Watts RMS @ 8 Ohms
2 Ohm load stable
Class A/AB
2 - 400,000 Hz frequency range
60,000µF memory
45 amps current delivery
<0.04% THD (not audible)
>500 continuous damping factor
Input impedance 22K ohms
DC offset <1 mV
RCA & XLR (bridged) inputs
400 VA Plitron transformer
Sanken Epitaxial Planar Transistors 2SA1216 & 2SC2922
Anti vibration dual thickness PCB
Power consumption when idle ±30Watts
4 internal fuses 250V/6.3A, 5x20mm, fast blow
Additional electrical protection fuse
54 lbs weight / 24.5 kg
Dimensions: 19 width x 18 deep x 7 height (in) /
48.3 width x 45.7 deep x 17.8 height (cm)

Stratos Stereo Plus:
improvements over base model:

$ 1,400 USD
Additional 60,000µF memory bank for 120,000µF total
55 lbs / 25 kg weight

Stratos Stereo Extreme:
improvements over Plus model:

$ 1,700 USD
Additional 60,000µF memory bank for 180,000µF total
>60 amps current delivery
Additional 400 VA Plitron transformer for 800VA total
Power consumption when idle ±35Watts
70 lbs / 32 kg weight
 
Class A amps run wide open at idle so if it is not producing heat, it is not working right. Look elsewhere if heat is a concern. You might find an early TH within your budget but you will have to get it comprehensively restored. Maybe a non-TH Pass design like the Nak PA-7 or PA-7II will fit your budget.
 
Understood about Class A, guess it's just something I'll have to live without in this room. So is there a "next best thing" to class A, or is it generally just Class AB?
 
Some of the best sounding amps in the World are Class A/B, you have many choices out there
 
Also meant to say I've thought about the Nakamichi amps, but considering their prices are still not cheap (In fact, assuming I can find an S/150 Threshold that isn't insanely overpriced I can get a Threshold for the same or even less money because of the lower power rating - 75w/channel or 90w/channel if Series II) and I've heard too many people who compared Nak's to the Thresholds and said the Thresholds sounded better I'd just assume avoid those. I personally think the PA-7 looks cool, but most that are in good shape are going for what Threshold amps are (There's a Stasis-3 on eBay for about the same price as good condition Nak's - but the Stasis-3 is overpriced based on the research I did for one with no restoration performed).

I'd actually like to find something closer to under $800. The Forte amps do kinda seem like the obvious choice, though now that I don't want the Class A version that's almost all I can find. I saw a Model 5 for about $500, doesn't seem terribly unreasonable though I have to question buying something like the Model 5 for $500 when a Sumo Andromeda III is available for $650 (Not that much more, IMO). I guess here's where I personally need more help, I don't know which is to say if the Sumo just as an example, would be so different in sound as to be better or worse - or if it offers a jump in performance over the 100 w/channel Forte Model 5.

If this makes any sense I'd almost kind of like to experiment with something different on this cheaper amp since I'll still probably go out and buy a Threshold as well. Would leave room to do an ABX comparison between them and find out if the Threshold is as good as I thought, or if whatever else I chose might be my preference. This is kind of why a reasonably respectable resale value might be good, since I might end up reselling the amp. I guess I want something that sounds good, but maybe also...fun? I'm thinking in car terms here, something that might not be the absolute best but is different in an alternate way enough that you like it and would enjoy using it.

Sorry that probably made less sense the further I went on. Specific amp suggestions are definitely welcome, I expect used considering what I'm looking for (I don't know of any high end amps that are new that you could buy for $600-800).
 
If you need high output levels (large voltage swings) and want Class A output stage bias, you'll need to get creative in what to select.

The Thresholds, as well as the Nakamichi (PA-7's) both dissipate quite a bit of heat.

Most amps have fixed rails that supply the output stage. The voltage across the output devices multiplied by the current through them will determine the dissipation (heat/power) coming off of the output devices.

So there's a couple of ways around this.
One way, is to reduce the rail voltage. If the rail voltage is fixed, you will also limit your maximum output voltage swing, or output power

Another way is to get an amp with some sort of "auto-bias" that turns the bias current down when no signal is present.

Another way is to dynamically control the rail voltage, so that it puts only a couple of volts across the output devices. That's why I mention Sunfire, because it uses this approach.

Class-D has come a long way and I've heard some very good implementations. They run cool too.
 
The Sunfire amps are interesting to me, but I don't think in the price range. I still have my eye out for one. A personal factor, I do have concerns about how serviceable they are since only Bob Carver can fix them. I've only had one amp die on me and it was a very old Sherwood, but you never know and I plan to own whatever I buy for a good while.

I don't have a need for high output levels. I play my system at moderate levels at best, and in a small room. Power usage probably rarely even approaches 1 watt. In my inexperience I just know people rave about Class A amps, but I've used nothing but Class AB amps generally and been happy with them. I think the only digital amp I have is a SMSL T-amp. It's a cool little thing, but of course not something suitable for this application (Even if I wanted to, it isn't configured right to allow it).
 
Have you looked into Audiosource amps? I've had one for about 10 years and it is unbelieveable. And inexpensive to boot. Not a budget hunk of junk, either. Designed by Carver.
Read this review on Audiogon. http://forum.audiogon.com/cgi-bin/frr.pl?ramps&1178725691&3&

I own the Model seven T. Not available anymore (maybe on ebay where I got mine)
Tri-path switching amp. They RUN COOL TO THE TOUCH AND NEVER OVERHEAT!!

Also this very short one: http://www.stereophile.com/content/audiosource-amp-seven-t-1
 
Well guys, I decided to splurge and I bought a Threshold! So this is just an eBay question, would love if someone could advise me here - I just want to double check that the seller will double box it and pack securely for shipping. They have 100% feedback and have sold lots of stereo stuff, so I'd assume they do know but should I make payment immediately or can I kind of wait for them to answer me - then pay for it? I definitely have intent to pay, just wanted to make sure they answer me before they run off and box it up and then I have no say so in how they package it.

EDIT: Nevermind, seller was super quick and answered me already! Woohoo, so excited! :D
 
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The best of luck with your move!

BTW, I'd choose to describe Bryston's sound as neutral and detailed rather than bright, but anyway those descriptions depend a lot on the speakers used (mine are, again, neutral, East-coast-sounding to be clearer).
 
Stasis 3. I wanted to get the Stasis topology, but personally do kinda have a thing for those neat LED meters - so I figured this was a suitable choice. The S/150's may be cheaper when they show up, but their blank slab faces while nice looking aren't quite as cool as the meters. I may have just started something expensive here...maybe I'll end up with a pair of Stasis 1's, and a 400a, and probably an S/150 II or S/300 II...

I mean these are some handsome looking amps I think (And the sound, can only imagine).
a.jpg


Those are the Stasis 1 amps, not my Stasis 3 of course. I couldn't spend the thousands those two amps would cost.
 
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Whoa! man you went for it! I was going to chime in saying I just picked up a s/300s2. It runs cool and sounds amazing but it looks like you made up your mind. Man those are some nice looking amplifiers. what preamp will you be using with these beast?
 
Well, the guilty party that necessitated this upgrade will likely be the preamp for awhile (Integra DTR 9.9 receiver). I nearly jumped on a DTC 9.8 for $450 since it's the processor only version of my receiver, but I was a little leery on how reliable Integra stuff is in the long run. Not super confident of my current one, but I bought it cheap so if it lasts a few years I'm cool with that.

I had a post over in the modern day hifi asking about a decent surround processor but haven't had any suggestions yet. I really just need DTS/DD decoding for 5.1. I have a 4 channel system (No center) so I'm sure I screw up all sorts of surround stuff by that but my room is so small a center channel would literally be almost touching my mains on both sides - and I only have it hooked up through a single digital coax cable so I'm not getting all the DTS-HD Master Audio and so on that requires HDMI.

Any ideas? I feel like based on what I said above, I probably wouldn't even be that bad off using an older processor - though I like my Audyssey EQ and the large amount of adjustments the more modern processors offer over the old ones. The DTC 9.8 truly would be perfect...if only I could trust it.
 
Meh, who cares about meters? If a non-meter version exists that sounds better, that's what I go for.

But then, I had both with my Mesa Baron....
 
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