Audiolab 8000a Transformer

[digiman]

Hi all,

I've just bought an audiolab mk2 8000a and love the sound. However the transformer had to be replaced because it made a pretty loud hum. The shop I bought it from were very helpful and offered to replace it for free.

Since getting the amp back i've noticed it is a little louder, and maybe more aggressive. I'm trying to figure out whether i'm just imagining things or whether the new transformer isn't quite right and has worsened the sound.. even though it still sounds very good.

I checked the transformer and it is a Nuvotem 7529-P1S2. Does anyone know if this the correct transformer for this amp, specifically the mk2 version (serial B)?

Any advice would be much appreciated!

Thanks,

Tim

 

[Th3 uN1Qu3]

If the transformer was humming it could have simply been tightened up a bit, or dipped in some varnish. Anyway, a mains transformer cannot have any effect on the sound in a solid state amplifier. Things are different with tube gear, but on transistors, i repeat, no.

It is possible that the new transformer is more powerful thus it is able to cope better under high load conditions, thus the volume goes a little louder. But good power supply stability is always welcome. Edit: The only info i could find is here: http://www.diyaudio.com/forums/solid-state/92331-audiolab-8000a-transformer-replacement-2.html and it seems that your transformer could very well be identical to the old one, so you could be just imagining.

 

[jaycee]

It might be that you have a DC offset on your mains supply causing the hum. The only way to find out would be to try a line conditioner

 

[danspy]

Different sound with Transformers is definitely Possible, i don,t no why but i had a similar experience.

 

[digiman]

Thanks for your help.

So from looking at the thread about replacing the 8000a tranformer. I might have a mk3 transformer in a mk2 model. Does anyone know if this would be a problem?

Thanks for your help

tim

 

[digiman]

bump

any thoughts anyone?

thanks

 

[anatech]

Hi Tim,

I might have a mk3 transformer in a mk2 model. Does anyone know if this would be a problem?

We would have to know what the voltages were for each transformer, and a schematic wouldn't hurt either. Some voltage changes can affect the sound of the circuit, depending on how sensitive it is to mains voltage changes. A reduction in voltage would normally cause a more aggressive sound. Is it possible the store reduced the bias current?

As for a change in gain, that is set by the feedback network. So a transformer change can not change that. I would be suspicious that there was a bias change if you could confirm if the heat sinks were running at a different temperature now.

-Chris

 

[audiolabtower]

was the B series rated at 60Watts? The original 8000A was rated at 50W and during the lifetime this was changed to 60W - maybe the transformer had a couple more volts added to it? (but within the safe operating area of the other components).