I am sick of failing amplifiers

[Republicoftexas69]

Agree its gone way pass class D

Heard the GAN fet amp on many occasions and thought them good not surprised you find them better than your high distortion low powered toob amps ..!

I also do believe when your audio intelligence and exposure grows a bit more you will feel differently ..!

I enjoy them both and may just look at a toob pre for my PA-10's.

 

[Geardaddy]

I enjoy them both and may just look at a toob pre for my PA-10's.

Historically, whenever I use solid state it was always with a tubed pre. that always sounded best.

 

[gryphongryph]

Solid state Sugden or Bladelius, amps that last a long time and trouble free.

 

[Bjorn]

Solid state Sugden or Bladelius, amps that last a long time and trouble free.

Not Sugden. We have seen a good number issues in Norway with those. Get super hot, which is never a good thing for an amplifier.

 

[gryphongryph]

That’s the first I heard of that, Sugden are made for running hot, but they need to be placed where there is good ventilation.

 

[Kingrex]

I hear the new First Watt 5 runs hot too.

 

[Cellcbern]

Pathos TT runs super hot but I've never had any type of failure or technical issue through more than a decade of use and two upgrades. A few years back, on the advice of the late Jim Thalman who did my upgrades, I added cooling fans on top of the heat sinks (see photo) which are on whenever the amp is on. They just sit on top and pull air from below the amp, through its interior, and up through its "chimney" heat sinks. They are quiet enough not to be audible during playback, and operate off of either AC or a usb connection. Here's a link to the fans I'm using: https://acinfinity.com/quiet-usb-fans/

 

[DasguteOhr]

Runs super hot SAC- the amplifer 400watt class A at 0.5 ohm heatsinks 75-80 degrees.

 

[microstrip]

Runs super hot SAC- the amplifer 400watt class A at 0.5 ohm heatsinks 75-80 degrees. View attachment 146892

Unless we have a picture of the inside showing type of components used in amplifier it is hard to comment. The more frequent problem with hot electronics is electrolytic capacitor life - it decreases to half for each 10ºC increase and is usually stated at 25ºC. However if the manufacturer uses the much more expensive capacitors specified for operation at such high temperatures it is not a problem anymore.

BTW, I think EC rules do not allow audio equipment having unprotected zones at such high temperatures - there is a risk of dangerous burns in these heatsinks!

 

[LL21]

Our infrared thermometer typically measures the Robert Kodas around 38C - 42C at most of the innerworks. It has its own quiet fans underneath, and we set up our own pair of cooling fans on top which are super-silent to draw that hot air up and out of the top of the units as well. So that is why the temperature is 38C - 42C..normally without our additional fans, it would probably be around 48C - 50C. The Robert Koda is designed to operate up to 60C (internally out of hand-reach) before red lights start to warn and then a bit higher and it goes into protection mode.

 

[microstrip]

I highly recommend Noctua silent fans - they are noiseless and last forever in silent condition. I found some silent fans become noisy after a couple of years. An important aspect is using large fans - small fans must turn much faster at higher air speed and are intrinsically noisier. I have got several of their 120 mm silent ones : https://noctua.at/en/products/fan

 

[LL21]

I highly recommend Noctua silent fans - they are noiseless and last forever in silent condition. I found some silent fans become noisy after a couple of years. An important aspect is using large fans - small fans must turn much faster at higher air speed and are intrinsically noisier. I have got several of their 120 mm silent ones : https://noctua.at/en/products/fan

Those are the exact ones Robert Koch uses in his amps, and by coincidence the ones we use on top as well...their ultra silent. We have the ultra-quiet 140mm above which work extraordinarily well.

 

[DasguteOhr]

The power supply and capacitors are located in the bottom, it is not hot the 40 degrees. The housing have ventilation effect is like a chimney at the top, all the hot air comes out hot enough just to keep a cup of coffee warm over hours. The amplifiers are on slate bases. In the sun you can see how the metalhousing has discolored.
Change most capacitors to 105°C types


If you can touch the heatsinks for longer than 3 seconds, it won't be 60 degrees. I promise you won't touch the Sac Amp for 1 second. I was in a hi-fi shop once and touched it by accident. Never again.

 

[microstrip]

Those are the exact ones Robert Koch uses in his amps, and by coincidence the ones we use on top as well...their ultra silent. We have the ultra-quiet 140mm above which work extraordinarily well.

Nice to know - I found them by chance many years ago when assembling an ultra silent desktop computer. When I owned the Audio Research REF 150 it was the obvious replacement. The good news is that now we can get them easily from Amazon.de.

 

[microstrip]

The power supply and capacitors are located in the bottom, it is not hot the 40 degrees. The housing have ventilation effect is like a chimney at the top, all the hot air comes out hot enough just to keep a cup of coffee warm over hours. The amplifiers are on slate bases. In the sun you can see how the metalhousing has discolored.View attachment 146905View attachment 146906
Change most capacitors to 105°C types
View attachment 146907

If you can touch the heatsinks for longer than 3 seconds, it won't be 60 degrees. I promise you won't touch the Sac Amp for 1 second. I was in a hi-fi shop once and touched it by accident. Never again.

Can we guess they had to replace all the electrolytic capacitors? Looking at those shows that they seem to be inadequate to this task - IMO they should be rated to 105ºC for such high temperature operation.

When were they manufactured? The PCBs look vintage - it remembers me of the Stan Curtis Class A amplifier I built with a friend in the late 80's. https://hifisonix.com/wp-content/uploads/2018/02/Stan-Curtis-60W-Amplifier-1.pdf

 

[Kingrex]

I have been running my Audion for a while now. Then I put my Blade KT88 back in. The Audion 845 is surprisingly good. I like that rich SET sound. The 845 doesn't have quite the same crack on a snare as the KT88. But the fullness is pleasing.
Still pisses me off the one 845 amp is microphonic. Why a tech walks away half way done saying its good enough. F-er. I want the 845 done. So that I don't have a lingering doubt around it.

 

[Folsom]

I highly recommend Noctua silent fans - they are noiseless and last forever in silent condition. I found some silent fans become noisy after a couple of years. An important aspect is using large fans - small fans must turn much faster at higher air speed and are intrinsically noisier. I have got several of their 120 mm silent ones : https://noctua.at/en/products/fan

Be Quiet's 4 model has surpassed Noctua by a fair bit recently. But yes, PC fans are pushing the best air flow results for noise levels. I recently put a 200mm Noctua in my mom's TV/internet buffet/furniture thing because the modem would get too hot and kill the internet. It's big enough you can hear it if you know to listen for it, and get close enough. But it is also quieter than everything else in the house so only during the total dead of the night would you ever be aware of it. 140mm are probably the sweet spot for size, 120mm runner up. Some people like to turn down faster models over using the "quietest" variation.

 

[Kingrex]

If I get a Inverter, I will work one of these fans onto the chasis to keep the small factory fans from kicking on.

 

[DasguteOhr]

Can we guess they had to replace all the electrolytic capacitors? Looking at those shows that they seem to be inadequate to this task - IMO they should be rated to 105ºC for such high temperature operation.

When were they manufactured? The PCBs look vintage - it remembers me of the Stan Curtis Class A amplifier I built with a friend in the late 80's. https://hifisonix.com/wp-content/uploads/2018/02/Stan-Curtis-60W-Amplifier-1.pdf

I don't know at 1987 are 105°types already existed, some had esr over 100ohms i change all after 38 years. protection works fine at 0.44 ohms the relay switches off the output until then full class A power. sounds amazing good after refresh. with a high damping factor over 15000 in the bass normaly sounds this dry this amp not. Love this oven

 

[microstrip]

Be Quiet's 4 model has surpassed Noctua by a fair bit recently.(...)

Thanks. Can you point a link to a 120mm Be Quiet model that is more silent than the equivalent Noctua - e.g. https://noctua.at/en/products/fan/nf-a12x25-5v-pwm?