Sugden A21SE

[Dobs]

Hi,

Is someone can tell me what the two adjustment pots (one on each amplifier section (left/right)) are intended for?

Thanks

 

[Mooly]

Why ? Is this the new A21 SE (Current version).

 

[Dobs]

Yes the current A21SE

 

[AndrewT]

don't touch them.
Ask JES for a schematic.

 

[Mooly]

Is there a specific fault with it or are you just curious to know ?

 

[Bonsai]

Sugdens are really crap amps.

 

[AndrewT]

Sugdens are really crap amps.

Can you use another descriptor, so that we can see what your opinion is?

 

[Dobs]

I suspect an adjustment to be needed on those 1k pot, because one side of the amplifier run hotter then the other. And there is a ceramic resistor close to the pot is running very hot, over 200 celsius unlike the other side wich is running at 170.

If i can find the value they should be set so i can see if they need to be adjusted or not would be great.

Thanks again

 

[AndrewT]

ask JES

 

[Mooly]

Perhaps it sets the quiescent current. Or perhaps not. It all depends on how experienced you are. The hotter one could be the correct one. They do run very very hot.
It's up to you !!! Would you know how to measure the quiescent current, or the output DC offset voltage so you could readjust it back again.
Just don't want you to damage it that's all. It may all be normal and within spec anyway.

 

[Mooly]

Sugdens are really crap amps.

Hi Bonsai,
Could you be more specific please Sugdens are really Cool ? maybe.

 

[Mooly]

Dobs,
Whats the value of this ceramic resistor and what is the voltage across it compared to the other channel. Lets try and put some numbers in.

 

[thejohn]

er 200 celcius is a touch hot! surely 200 fahrenheit (~93 C)?

 

[Dobs]

I have made a search in the members list and there is a Jes but he never posted a message, is the Jes your talking about?

 

[Dobs]

Sorry it's not celsius but Farenheit, someone changed the setting of my temp tool to farenheit.

 

[Mooly]

JES = J.E.Sugden Any more thoughts on what to do ?
How experienced are you with electronics etc.

 

[Geoff]

http://www.sugdenaudio.com/index.htm

 

[Dobs]

Dobs,
Whats the value of this ceramic resistor and what is the voltage across it compared to the other channel. Lets try and put some numbers in.

1ohm 5% and 48v ac pass across both

 

[Dobs]

JES = J.E.Sugden Any more thoughts on what to do ?
How experienced are you with electronics etc.

You think they will answer that kind of question!?

I think more i will get something like.. Send it to our authorized dealer for a service check-up.

I sent two modification suggestion i made on my A21SE to JES, one minor and one i consider major and i got funny answer... So i dont expect anything positive from them since.

 

[Dobs]

I took the voltage in dc end to end and there is a difference between them, i used the pot and this changed the value, so for now i have adjusted both to the same value (1v dc) and both run at the same temperature.

I think i just need the value Sugden use to compare.