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How to build quick and cheap table for my amplifier

Discussion in 'd.i.y.' started by ToTo Man, May 16, 2019.

  1. ToTo Man

    ToTo Man the band not the dog

    That's a very creative idea actually, I'll give it some thought. I could even swap the DAC (2nd shelf) with the headphone amp (1st shelf), that way I could elevate the sub shelf to give even more clearance from the fan.
     
  2. allthingsanalog

    allthingsanalog pfm Member

    Into this thread late (as always), I have the A-S3000 amplifier also and they do run warm, no doubt about it. As Richard says, with full ventilation, around the mid 30's, mine is about 36c.

    My first amp was faulty and that reached 60c on the top plate!!!!! My replacement is fine however and after 19 months there's been no issues. Even running hard it doesn't really get hotter so it's temperature stable, not an amp to leave on 24/7 especially as they use Nichicon FW 85c caps but I'm sure it's fine and normal.
     
    ToTo Man likes this.
  3. ToTo Man

    ToTo Man the band not the dog

    Thanks for replying to my PM, Andrew, much appreciated, I'm just about to drop you a reply.

    I don't have a lot of experience with different amplifier designs as I've mainly grown up with vintage Class AB receivers. My A-S3000 doesn't run much hotter than my CR-1000, CR-2020 or SX-1250, for example. The warmest running solid-state amplifier I owned was a Quad 909. Sadly I didn't have a laser thermometer then so wasn't able to measure it, but to the touch it was warmer than the top of my racked Yamaha, so I'm guessing at least high 40's C, yet the Quad was sitting on the floor in free space on a granite chopping board. Not as hot to the touch as the valve amps I've owned but certainly warmer than I'd expect it to be. I wonder why they didn't vent the top?

    As a child I recall my dad's Technics V-707DC integrated ran pretty warm, so I guess I grew up thinking this was normal for all amps!
     
    allthingsanalog likes this.
  4. Tony L

    Tony L Administrator

    That really surprises me about the Quad. I’ve no experience with the 606 onwards, but the 405 and 306, also current dumpers, should only get hot if working very hard. The idling temp should just be ‘slightly warm’ as I understand it. Is there perhaps some DC offset somewhere upstream or something like that, i.e. the amp is spending all its time trying to push the cone out or in?
     
  5. allthingsanalog

    allthingsanalog pfm Member

    If you look inside the A-S3000 you will notice the massive heatsinks go almost all the way from the top to the bottom so they clearly realised the heat that would be generated. Someone reviewed one of their other amps, the 2100 I think and they measured that even when idling it used around 70w of electricity and hour so if you think of a 60w lightbulb for example and how much heat is generated it probably explains why they run warm and also while even running them hard they don't get much warmer, in a domestic environment anyway.

    Another thing of course, while we all want our kit to last for decades, the manufactures give for example a 5 year warranty on these so they probably think if it lasts at least that then it's job done. Another good friend of mine pointed out that in reality we often change our kit long before it wears out. I know in the past I've had kit where I wanted it to last forever and then changed it shortly afterwards!! Although if look at some of the other famous Yamaha amps from yesteryear they are only really now needing a recap after 25 years or so.

    Having said all that I would certainly buy another Yamaha amp in the future, no question. This amp gives me everything I want and more, I've owned more big name brands than I can think of and they've all had their quirks and faults.

    Impresses me every time I look at the internals! A re-cappers nightmare though I would think, like most Jap amps!

    [​IMG]

    [​IMG]
     
    ToTo Man likes this.
  6. a.palfreyman

    a.palfreyman pfm Member

    If you have sufficient head-room (by switching round) just put a fan-sized hole and sub-shelf in for simplicity. Only think about a fan if really required.
     
  7. allthingsanalog

    allthingsanalog pfm Member

    I've always wondered about the benefits of an additional fan? If when setting the bias current and then you blow air on the circuity after adjusting it the bias current drops like a stone on the meter measurement so would that actually affect the sound?
     
    ToTo Man likes this.
  8. ToTo Man

    ToTo Man the band not the dog

    I'd think it unlikely given it was only a few years old, but perhaps the 909 I had needed a service? There was no abnormal DC offset from it when in use, just a brief increase for a few seconds when powered down. I've since sold the 909 so can't investigate further.
     
  9. ToTo Man

    ToTo Man the band not the dog

    The A-S3000 will almost certainly be my end-game amp..... until I win the lottery and can afford the C-5000 / M-5000 combo! ;)
     
    allthingsanalog likes this.
  10. ToTo Man

    ToTo Man the band not the dog

    For @allthingsanalog and anyone else interested, I've just measured my A-S3000's idling power consumption. There's a switch-on surge of 280W which drops two or three seconds later to 46W and then gradually climbs over the next 10 minutes or so to around 68W-70W, then finally settles at around 72W-73W after about an hour. My voltage measures 240 Vrms at the moment which should equate to a current draw of approx 0.3A, but according to my meter the current draw is 0.4A which would imply the amplifier is actually drawing 100W. When I press the 'Watts' button on the meter the reading changes from 70W to 100W. The symbols on the display are too bloody small for me to read in artificial light so I'm not sure what each refers to, but I'm assuming the lower value is the true power draw and the higher value is the VA reading?
     
    Last edited: May 21, 2019
    allthingsanalog likes this.
  11. allthingsanalog

    allthingsanalog pfm Member

    This is very interesting indeed. Would explain the heat when idling. A 60w lightbulb gives a significant amount of heat!

    Thanks for that. Also explains why amps sound better once warmed up as the circuit stabilises.
     
  12. ToTo Man

    ToTo Man the band not the dog

  13. ToTo Man

    ToTo Man the band not the dog

    @Arkless Electronics and/or any other fishes with knowledge of such stuff:

    With regards to the above review in post #52, I note the comment about Electrostatic speakers being incompatible with the A-S3000 due to its floating balanced design. Can you confirm if this is true and possibly explain the reason/s for it?

    I was not aware of this, but I've never actually tried my ESL 63s on my A-S3000 (I bought a 909 specifically to run my ESLs), so if it is true then it's a stroke of good fortune that I resisted the temptation to try the ESLs on the Yamaha!

    Are there any other precautions I should take with a floating balanced design? e.g. can DC offset at the speaker terminals still be measured in the usual way with a multimeter's VmA and COM inputs without frying anything?
     
  14. Sunflower Sutra

    Sunflower Sutra Active Member

    The reason it shouldn’t be connected to an Electrostatic is because the negative speaker terminal is not set at ground potential due to it being balanced.

    Have you thought of wall mounting the tv?
     
    ToTo Man likes this.
  15. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    It would usually imply that it is a bridged amplifier in which case both the + & - speaker terminals in effect connect to a separate amplifier and both are outputs. It doesn't necessarily mean it's incompatible with electrostatics as it all depends on how the ESL's are wired internally. I have heard of people using bridged amps with ESL63's but not sure if they had to do a quick mod to the grounding inside them.

    You can still do measurements with a battery powered multimeter but as a generalisation don't connect the outputs to anything mains powered or to any sort of speaker switching box etc.

    FWIW some bridged amps actually have say 40V DC present on both red and black terminals! As both are the same (40V in this example) no current flows through the speaker but, as you can imagine, the consequences of grounding either red or black speaker terminals on the amp would be severe...
     
    ToTo Man likes this.
  16. martin clark

    martin clark pinko bodger

    Quad ESLs - certainly 63s and 988/989s and later - are not grounded to mains earth; in fact the IEC mains input is two-pin only (no earth pin in the scoket); and of course the HV generator/ internal clamp& monitoring circuit, and speaker inputs are all transformer-isolated.
     
    ToTo Man likes this.

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