Studiomaster 2000E power amp performance concerns

[pinyoro]

Hi all,

I recently purchased a second hand Studiomaster 2000E power amp rated at 500W:8ohms, 800W:4ohms and 1000W:2ohms RMS per channel

After opening the top cover to have a visual inspection I noticed that the heat sinks appear to be too light, or thin for the quoted powers. Does anyone have experience with these amps as I'm concerned that it may overheat when drived hard into low impedances.

Are there any known problems with these amps? The Smoothing caps seemed to be pretty small too.

Many thanks,

Mike

[h_a]

First of all, I do not know this particular amp.

Generally one sees regularly tiny heatsinks and smoothing capacities in commercial gear, simply due to 2 reasons: 1st of all most customers simply overestimate the needed power by far.

It is an interesting exercise for everybody into audio to measure the power while listening to music (for better accuracy use a 100 Hz sine) - I guess a lot of people would be stunned.*

2nd: since heatsinks and caps are besides the necessarily large toroid the most expensive components the manufacturers can save, especially due to point 1, quite some money.

Short high power peaks in music are usually not a problem for these 'budget' amps, but never do sine-wave testing at full load.

Have fun, Hannes

*(By the way, in this regard I also very much like John Linsley Hoods articles, he clearly writes that he found 3 W to be sufficient for him, even at higher listening levels...if just everybody would read this!)

[destroyer X]

The bigger the area, the bigger the heat transference, bigger the capacity to manage power.

The thickness, in my experience, just creates a delay into this heat transference, increases the mechanical resistance into the heatsink, make it more heavy and more expensive..but not better than one using very thin (1 milimeter thickness) fins.

Convection current, the natural motion of hot air, that goes up sucking air from below...the heated air that goes up carry the heat from the heatsink blades, so...they are cooled this way.

Need holes under and space over to obtain the needed convection natural air current... the enclosure needs space below (stand posts, feet, support, rubber blocks) and cannot be covered into the top..if covered will need some open holes or gaps to air flow.

This movement is the same you have into the nature...hot sun overheat ground, lakes, rivers and ocean.... watter evaporates and goes up.... when do that sucks air from the surrounding because the low pressure generated when hot air goes up and this generates the wind into the nature.

In my life experience, each 200 square centimeters surface (10 by 10 centimeters aluminium fin) will work fine with a 10 watts amplifiers.... so... 2 blades of this size (400 square centimeters) will hold 20 watts and this way things goes increasing.

My measurement was learned doing... seems the amplifier is producing 10 watts RMS, continuously, sinusoidal 1Khz tone, non distorted, and producing around 15 watts of heat... the metal fin, aluminium thin metal blade (2 milimeters), will hold the job...if not covered up or down..and into the correct position of placement avoid to obstruct on of the sizes that must work together the other aluminium face.

Huge heat sinks are pretty, better because they can be part of the entire mechanical body, the chassis, resistant to be bent or damaged easy, but the thickness will just create a delay.

You start to operate your amplifier and seconds latter the heat start to appear distributed into the fins...just that...absorbs some peaks of power only.

I am sorry to explain thing in such a detailed way.... i know strangers have good culture and good schools and knows those things...but here, down in Brasil, things are not this way...my own people use to read this forum, some of them can read in english and others use google translator, and many of them have not those informations....i use to be detailed because of that.... do not know your culture, your know how, your scientific knowledge, so...i am sorry if this bothers you.... is made with double intention, to clarify to you and to explain this to my own personnel, my own country citizens.

I do not thing strangers are stupid...the opposite, i can see enormous superiority related school and professional skills...but this does not happens here, i use to try to help my people to remove the feet from deep lame of ignorance.

regards,

Carlos

[John Audio]

This amplifier (from memory) - has 2 cooling fans, with proportional control of their speed.

It is not an expensive amplifier - so clearly component economies have had to be made. Remember that aluminium heat sinks are very expensive, but fans are really quite cheap!

They do perform quite well - but in the event of an amplifier fault, are difficult to repair - with a lot of transistors to replace!

JG

[Greg Erskine]

Originally posted by h_a
It is an interesting exercise for everybody into audio to measure the power while listening to music (for better accuracy use a 100 Hz sine) - I guess a lot of people would be stunned.*

Funny you should mention that. I've been playing with a power analyser / datalogger today, monitoring the power consumed by my amplifier, an AKSA 55 N+

Here's what I found:

Idle: 13 to 14 watts
Normal background listening level: 13 to 16 watts
Critical listening level: 14 to 30 watts
Max volume: Approaching 200 watts

The analyser is connectd to the mains cable so it is measuring the total power consumption of my amplifier, both channels, including power lost by the transformer and the generation of heat. It was interesting to actually see the different power consumption for different types for music and the reasonable increase in power consumption for heavy bass passages.

So you could get away with much smaller heatsinks if you do not use the your amps at the levels approaching the maximum rating.

regards

[h_a]

Hi Greg, you would be even more surprised if you measured the audio power only...only little left after stripping all the generated heat from the total power consumption

Have fun, Hannes

[pinyoro]

Hi Carlos,

I am truly thankful for your detailed explanation as you described it so well. Many thanks for sharing knowledge with me.

Regards,

Mike

Originally posted by destroyer X


The bigger the area, the bigger the heat transference, bigger the capacity to manage power.

The thickness, in my experience, just creates a delay into this heat transference, increases the mechanical resistance into the heatsink, make it more heavy and more expensive..but not better than one using very thin (1 milimeter thickness) fins.

Convection current, the natural motion of hot air, that goes up sucking air from below...the heated air that goes up carry the heat from the heatsink blades, so...they are cooled this way.

Need holes under and space over to obtain the needed convection natural air current... the enclosure needs space below (stand posts, feet, support, rubber blocks) and cannot be covered into the top..if covered will need some open holes or gaps to air flow.

This movement is the same you have into the nature...hot sun overheat ground, lakes, rivers and ocean.... watter evaporates and goes up.... when do that sucks air from the surrounding because the low pressure generated when hot air goes up and this generates the wind into the nature.

In my life experience, each 200 square centimeters surface (10 by 10 centimeters aluminium fin) will work fine with a 10 watts amplifiers.... so... 2 blades of this size (400 square centimeters) will hold 20 watts and this way things goes increasing.

My measurement was learned doing... seems the amplifier is producing 10 watts RMS, continuously, sinusoidal 1Khz tone, non distorted, and producing around 15 watts of heat... the metal fin, aluminium thin metal blade (2 milimeters), will hold the job...if not covered up or down..and into the correct position of placement avoid to obstruct on of the sizes that must work together the other aluminium face.

Huge heat sinks are pretty, better because they can be part of the entire mechanical body, the chassis, resistant to be bent or damaged easy, but the thickness will just create a delay.

You start to operate your amplifier and seconds latter the heat start to appear distributed into the fins...just that...absorbs some peaks of power only.

I am sorry to explain thing in such a detailed way.... i know strangers have good culture and good schools and knows those things...but here, down in Brasil, things are not this way...my own people use to read this forum, some of them can read in english and others use google translator, and many of them have not those informations....i use to be detailed because of that.... do not know your culture, your know how, your scientific knowledge, so...i am sorry if this bothers you.... is made with double intention, to clarify to you and to explain this to my own personnel, my own country citizens.

I do not thing strangers are stupid...the opposite, i can see enormous superiority related school and professional skills...but this does not happens here, i use to try to help my people to remove the feet from deep lame of ignorance.

regards,

Carlos

[pinyoro]

Thank you all for taking time to answer my questions. I think I'm more confident to use this amp in a correct application, like Mid and Tops on a P.A/Disco system. Maybe someone could advise whether it could be used to drive bass bins in a system using an active crossover.

Thanks,

Mike

[kevvywevvywoo]

The 2000E is a class H amp so the heatsinks are smaller than usual. The variable speed fans are very efficient and speed up as the heatsinks get hotter, these were a very popular amp in nightclubs and bars and can take quite a pounding....I wouldnt worry.

[ceharden]

Having worked on a 2000E recently the one thing I would say is that the smoothing caps originally fitted are complete rubbish. If they haven't been replaced, do so because they will fail, leaving you with no power supply smoothing and a very wierdly behaving amplifier.

They're not the heaviest-duty amplifier out there but they should cope with most usage fine.