Any thoughts on this Amp?

[ShinOBIWAN]

I've bought the following bits in kit form for assembly at home, these were all recommended as a compatible kit ie. it all works together.

The link to the amp is HERE

It uses Sanken SA1294 with SC3263 and is rated at around 2 x 140w into 8ohm

And here's a picture of the finished article.


For the power supply I went with this one HERE. Which is decribed as power supply for amplifiers - 2x56Vmax at 14A and 2x30V 200mA

Picture of completed PCB:




And the Input/Output stage is this one HERE

Picture of completed PCB:



Right my questions are twofold.

Firstly I would like to hear people opinions of the above and even better would be people with first hand experience. I have been told by a friend that it should be competent but will not offer a great performance.
You can also probably tell that this is my first step into DIY amplification but not electronics in general. I have about a year of basic theory behind me and a good soldering iron with the skill to use it well.

Secondly aside from people opinions on the performance I would like to know how the seperate components are likely to connect together. Luckily the pictures are rather large so identifying connectors shouldn't be a problem to someone familar with amp topology.
One thing that has me confused is the fact the amp looks to be dual voltage (2x56Vmax at 14A and 2x30V 200mA). I understand that you'd connect the 56V line to the amp but whats the 30V for?
Also confused as to why I'm going to need to use two toroidal's rated at 2x18v(8.3A 300VA) or at least thats what was recommended to me. Looking at the amp specs, it require 2x40-55V DC and these transformers don't seem to offer that sort of juice.

Cheers,
Ant

[Nelson Pass]

I think it would be a big help if you could get hold of
some documentation - it's a little tough figuring it
out from the photos.

[ShinOBIWAN]

Originally posted by Nelson Pass
I think it would be a big help if you could get hold of
some documentation - it's a little tough figuring it
out from the photos.

Any thoughts as to a rough idea on performance or the toroidal transformer query?

[BrianDonegan]

Found this:

http://www.bmm-electronics.com/Produ...roduct_ID=1171

[ShinOBIWAN]

Originally posted by WorkingAtHome
Found this:

http://www.bmm-electronics.com/Produ...roduct_ID=1171

Thanks but I already linked that page at the top of my original post.

[hienrich]

shin:

do you have schemes for this amp.

it's better to understand if there are schematic diagrams for this.

schematics tells partly of its performance.

regards

hienrich

email: hienrichb@yahoo.com

[ShinOBIWAN]

Originally posted by hienrich
shin:

do you have schemes for this amp.

it's better to understand if there are schematic diagrams for this.

schematics tells partly of its performance.

regards

hienrich

email: hienrichb@yahoo.com

Hi

Won't actually get a copy of the schematic until the parts arrive unfortunately.

The Sanken SA1294 and SC3263 seem highly regarded transistors though.

I suppose the proof will be in the listening, I will of course post back here with my thought's these have been built.

[djk]

Close counts for horseshoes and handgrenades.

I see no bias tracking on the heatsink.

Handgrenade?

[Alme]

Maybe there's no need for temperature bias adjusting
Anyway they use sil-pad insulation, those pink pads under sankens, which adds over 1K/W thermal resistance to each package, so there's no major concern to put temperature bias sensor on heatsink unless it's glued directly to bjt case.

Shin, looks like you will need to connect all your 18V windings of both transformers in series to get required +/-50V. Do they have separated 18V windings or 36V split with central tap? First case is better.