infullview
Super Member
Do you have any info on what amps (I assume these are AB) use these more sophisticated temperature compensations?
Class A Watts ?
- Thread starter luxmaster
- Start date
mad shadows
Super Member
Chill a bit, it's only hifi.. I'm talking in relative terms. What sounds good or not is highly personal and system dependent.
Blue Shadow
Waiting for Vintage Gear from this century
Lots of these brands we don't read about on AK
You are talking newer units but this thread is all encompassing. The newer stuff just seems to get ignored because of a lack of interest and a firm knowledge that a mid-range receiver from entry level brand from a good stereo store back in the day is the best piece of equipment ever built and there is no way to improve it. This brings the ridicule and penny pinching because too many folks feel it is their responsibility to tell others how they should spend their money. Because we know that Boulder amps need decent speaker wire, not that 16 Ga from Home Depot or the extension cords some loved in the past.
It's a big world, maybe we could have a nice forum in Audio Forums about Separate Components, Amps and Preamps to have these discussions but the Yamaha CR-3020 guy will bomb in and disrupt the discussion (I think he has left the building, though). There are lots of great amps from the past and present that are totally unknown on AK. Heck many of the high quality brands made today are unknowns. The Aficionado site has a long list of brand name forums that are never seen here except on occasions like this where we are discussing something that is found in the regular gear at times but more common on the higher end stuff.
Oh well, it is what it is and in a few more years maybe some of that high end gear will be old enough to reach down low enough to be within my budget.
Unfortunately there doesn't seem to be an acceptance of these units. We have one thread, a sticky in General, "Classic High End Gear" where folks hit and run and then there is the High End Separates from Years Past forum hidden in System Building section instead of right out there in front of God and everyone in the Audio Forums section. This one gets some discussion but not much.
You are talking newer units but this thread is all encompassing. The newer stuff just seems to get ignored because of a lack of interest and a firm knowledge that a mid-range receiver from entry level brand from a good stereo store back in the day is the best piece of equipment ever built and there is no way to improve it. This brings the ridicule and penny pinching because too many folks feel it is their responsibility to tell others how they should spend their money. Because we know that Boulder amps need decent speaker wire, not that 16 Ga from Home Depot or the extension cords some loved in the past.
It's a big world, maybe we could have a nice forum in Audio Forums about Separate Components, Amps and Preamps to have these discussions but the Yamaha CR-3020 guy will bomb in and disrupt the discussion (I think he has left the building, though). There are lots of great amps from the past and present that are totally unknown on AK. Heck many of the high quality brands made today are unknowns. The Aficionado site has a long list of brand name forums that are never seen here except on occasions like this where we are discussing something that is found in the regular gear at times but more common on the higher end stuff.
Oh well, it is what it is and in a few more years maybe some of that high end gear will be old enough to reach down low enough to be within my budget.
I frequent AudioShark for my HE needs. Here for more fun.
fill35u
Super Member
Obviously it's in relative terms, you are comparing two things.
So are you admitting that your stance of Class A amps having, in general, larger power supplies is just your opinion?
Whether your opinion is right or wrong, it must have some basis. I'd just like to know *why* you think that's the case. Maybe we could all learn something?
Of course, although research has shown quite a consensus on some simple aspects of what people prefer.
But the size of an amp's power supply, what class it operates in, and how many of which types of amps have been available are *facts*, not personal or system dependent. And if you are going to present new facts to the discussion, you should be prepared to back them up. "Extraordinary claims demand extraordinary evidence."
There an entire chapter on thermal stability in Douglas Self's Power amplifier book which goes into the subject in great detail.
Also, section 4 of this PDF from Elliot Sound goes into some detail. Btw, he calls the Sziklai pair a complementary pair.
http://materias.fi.uba.ar/6610/Apuntes/Compound vs Darlington.pdf
I can't name specific brands of amplifiers that use Sziklai output stages.
infullview
Super Member
OK thanks for the reference. I'll have a look around on the web to see if I find out more.
quiet
Addicted Member
That would be nice. But I'm not holding my breath for a $50k unit to drop to $5k.
whoaru99
Epic Member
Blue Shadow
Waiting for Vintage Gear from this century
I ain't got 5k to spend on gear. I'm looking for garage sale, it's to heavy, please help me get it out of here pricing.
I'm really happy with my new Luxman. I did better than the $4500 list price tho
That is true, but in truth the F5 will drive about double it's bias at 0Hz DC. Mine is probably what you'd call an F5 Turbo V1. Usually an F5T is built as a V2 or V3.
Pretty much everything in the Pass XA line along with the F2(J), F4, F5, F6, F7, and M2.
Crack open almost any class A amp. They do have enormous power supplies. They need to be enormous because they're expected to deliver a steady supply of current upwards of a number of amps, whereas a class AB amp only needs to make what the amplifier outputs plus a small surplus lost to hear. A class A amp turns most of it's power into heat, not power on the posts.
Specs for the Pass Labs XA30.8 state "Power Output /ch (8 ohm) - 30"
https://www.passlabs.com/amplifier/xa30.8
Specs for the Pass Labs XA100.8 state "Power Output /ch (8 ohm) - 100"
https://www.passlabs.com/amplifier/xa100.8
Specs for the Pass Labs XA160.8 state "Power Output / ch (8 ohm) - 160"
https://www.passlabs.com/amplifier/xa160.8
Looks to me like Nelson Pass rates his amps by their output power. And why wouldn't he?
DaveVoorhis
Addicted Member
What does "drive about double [its] bias" mean?
Not necessarily. Preamplifiers are often Class A and don't necessarily have enormous power supplies, because they're not trying to swing high current into low impedance with an inherently inefficient circuit.
Blue Shadow
Waiting for Vintage Gear from this century
In terms of an amp, you must be loaded being able to get that fancy lighted glass cabinet and all for the amp that is in dire need of an expensive recap. If done by the manufacturer, they know their clientele can afford big money refreshes as they bought the amp, what another 25% of cost to rebuilt to like new with unlabeled parts. Or you could wing it without the schematic, they are not provided, and stuff it with caps that are special order, minimum 20 and sell for a c-note a pop. Find some friends to share that bill as you will only need about 4 of the big ones and a couple few of the high voltage smaller? ones that are half a c-note but available.
Well we can dream of these, I guess.
twitch54
Super Member
Specs for the Pass Labs XA30.8 state "Power Output /ch (8 ohm) - 30"
https://www.passlabs.com/amplifier/xa30.8
Specs for the Pass Labs XA100.8 state "Power Output /ch (8 ohm) - 100"
https://www.passlabs.com/amplifier/xa100.8
Specs for the Pass Labs XA160.8 state "Power Output / ch (8 ohm) - 160"
https://www.passlabs.com/amplifier/xa160.8
Looks to me like Nelson Pass rates his amps by their output power. And why wouldn't he?
yep, looks that way to me as well, not sure what 'RL' is talking about ??
quiet
Addicted Member
I think I see the problem. So I'll just stick my best old receiver in the fancy glass case and call it good.
Only the best ones.
Power supply chassis of Pass Labs Xs Pre with over 100k uF of C:
Power supply chassis of Audio Research REF10 with over 7k uF of C - running 285V rails!
DaveVoorhis
Addicted Member
Big caps in a preamp mean very small hum, particularly with low level inputs.
The REF10 runs 285 volt rails because it uses tubes, which -- depending on the type of tube -- in typical tube amplifier circuits runs anywhere from several hundred (typical) to several thousand (power amplifier) volts on the tube plates.
This is an internal view of a fairly typical solid-state Class A preamplifier:
The largest power-supply component is the (rather unusual) power transformer on the right, but it's minuscule compared to the welding transformer needed in any beefy Class A amplifier to get reasonable current into the speakers past all the inefficient heatsink warming.
