Sugden A28 II schématic ?

[v6us]

Hello,

I search the Sugden A28 II schematic for repair this one.

Thanks.

Hervé.

 

[destroyer X]

Here you may have the one you want

Ill y a beaucoup de esquematique.

http://www.audiomisc.co.uk/JES/Si402/Si402.html

à bientôt

Carlos

 

[v6us]

Hello destroyer X,

Thanks you for this very interessant links. But there is no A28 II schematic.

Hervé.

 

[destroyer X]

I am sorry Hervê... into my imagination you would find it there

Sorry for that.

au revoìr.

Carlos

 

[Zen Mod]

what's difference between A25 and A28 ?

I have schematic of A25 , from some frenchy forum ; it's in fact , plain OP based preamp , and output amp literally replicated from Hitachi CookBook for mosfet amps , all away from 2SK135/2SJ50 era .

 

[v6us]

The A25 used AOP and the A28 II only discret component.

 

[Zen Mod]

A25 output

that's all I have ;
I can't remember where I got it , except that is form some french forum

 

[v6us]

Hello,

I have resolved my problem. It's was just two soldering dry out on the balance potentiometer.

thank you very much for your responses.

hervé.

 

[Willitwork]

Ah, the A28II! Always worth fixing if you ask me. I have owned many integrated amps over the years including a few that cost quite a bit more than the A28II but I have yet to find one I enjoy more. Listening to it right now as a matter of fact, 23 years of ownership and still no fatigue on my part 🙂

 

[quantran]

Hi all

I 've just got an A28II. There is a minor problem that the bias current of the R chanel is higher than the left chanel. I measured the voltage across the power resistor near the output transistors and adjust the pot to reduce the bias current of right channel to be equal left channel but not sure if this is correct setting. The heat sink is only slighly warm, clearly not much in class A.

Can anyone help me with this? I would appreciate if any of you can email me the schematic (quan_ta at yahoo dot com).

thanks

 

[samgoro]

Hi all,

I have a Sunden A28 serie1 with the vertical heater on his back side ; No sound from the left speaker , The relay contacts are good , the socket Jack was cleaning too , the faults still percist...:/
Is it possible to find the full electrik diagram and some asset codes from A 28? I need it because some composants of the power amplier need be change .
Thanks foward for your help

 

[east electronics]

Just repaired one of those and realized that all its life was playing mono due to a wrong connection of the pre-main switch ...English quality of make ...unreal ...

 

[rwk]

Hello.
I have the power section of the a28ii and the full schematic of the
A28B, the input sections are identical if I recall correctly.
(Please check) links below.

These things run hot as hell, perfect for the winter season !
Nice sounding amps but I had some oscillation problems and they have a lot
of cross-talk between the inputs (if you have a source running you can hear it on
another selected source...)

http://capsaicine.ch/sch/a28ii-power-circuit.pdf
http://capsaicine.ch/sch/smA28B.pdf

 

[AndrewT]

Just repaired one of those and realized that all its life was playing mono due to a wrong connection of the pre-main switch ...English quality of make ...unreal ...

That Sugden probably still has the Builder's signed sticker inside, where they sign off on the build after testing.

A mis-wired input is more probably a modification done by some technician after the unit left the factory.

 

[east electronics]

No Andrew there was a trace on the PCB to cut which they missed ...

 

[electrochap]

Hey there, I'm fixing a A28B and am looking to replace LN2G Diode... Haven't found any corresponding diode anywhere. It is lit (red) on the other channel and has 1.8V accross it. Is it just to show channel is up? Mine was short and this side has very low output... Can I just live without it? Haven't try powering the channel without it yet.

Anyone can tell me what diode to replace this LN2G ?
THanks!

 

[Cal Weldon]

Thread reopened by request.