15yrs old Conrad kit: good enough trying?

[hiwiho]

Hey all,

it's beginning winter time and thus a good opportunity to warm up one's apartement with the soldering iron... It's not that I would really need another amp (I have an Onkyo 9711 for dedicated and a Sony TA-F210 for computer-based listening), but I have both an old external drive housing big enough and this old manual from an amplifier kit that Conrad Electronic sold 15yrs ago lying around (No.196274).

It's based on a couple of 2SK133/2J48 that would have to be replaced by either 2SK1058/2SJ162 or IRF530/IRF540, but anyway, is this circuit worth diying??? Most effort would be to layout the pcb which is not given in the manual.

The whole kit is rated 75(55)watts/4(8)ohms at +/- 44volts - a nice size for a spare amp and not needing that big hsink.

Yes, you will ask why I won't make a gainclone - but how many am I supposed to make during the long winter

Note: First thing to be changed would be the nf coupling 1uF cap to some non-electrolyte type

Matthias

[hiwiho]

Manuals first page. Maybe someone remembers it.

[richie00boy]

It's basically the industry standard Hitachi MOSFET amp circuit. Performance is perfectly acceptable, but there are quite a few upgrades that can be done. You wouldn't be able to use IRF devices unless you added a Vbe multiplier instead of just the pot for bias.

[jaycee]

Yeah, it looks practically identical to the Maplin MOSFET Amplifier kit they used to produce up until early 2000 when they discontinued most of their kits.

[richie00boy]

I was going to say that If you want a play with IRF devices, have a look at IR App Note 948.

PS You look like Jerry Springer

[hiwiho]

Hmm, well I'm no expert in construction electronics so I guess the hint concerning IRF was rather helpfull. I somewhere found them as replacement for the original trannies. I would get the first replacements I wrote easily just a few bus stops away at segor electronics so I would go with them anyway then.

Who is Jerry Springer?? But please note the Calexico poster up left. Some of the finest tunes around!!!

m atthias

[zinsula]

Must be this, eh?

Power Amp Schematic

Ciao, Tino

[hiwiho]

Ok, I checked out Jerry. He is some 30years older than I am but has less grey hair than I have now or a better makeup!

Thanks for mentioning the application note. I found it quite fast and will work through it in a couple of days!

Must be this, eh?

Yeep, this looks pretty much the same. I think I will give that thing a try after the first snow has arrived.

Thanks all for your assistance!!

matthias