Crescendo ME using 2sk135/2sj50

[bikejog]

I got some pairs of those and I'm wondering if the Crescendo ME can be easily converted to those lateral? If not, how does the original Crescendo sound? What's the power rating of the Crescendo for either version? Do I need to make any changes to either circuit to use 2 pairs of output Mosfets instead of 1?

Andy

[joensd]

Looking at the schematics of either they´re actually not that different. The newer ME-version uses more powerful devices so you can get away with one pair.
Due to the temperature coefficient of the new devices, DC-offsets and overloads a bias regulation, DC-servo and overload protection is included (ME).
It gives 90W into 8Ohms and 135W into 4Ohms. Rails are +-(45-50)V.
The original delivered about 140W into 8Ohms and the mini crescendo about 70W if I remember correctly.

Cause you already have laterals I´d go with one of older versions. You still can include DC- and overload-protection of course.

Cheers
Jens

[bikejog]

I have only one schematic on the original Crescendo. How
can I tell whether it's the mini or the full-blown version? The
rail voltage was listed for 40-50V and one pair of Hitachi
was listed on my version. Is this the mini? Is so where can
I find the full version?

Also where can I still buy the semis? Can I substitute for more
modern ones? If so what should I use? Also do I need a
DC servo? If so, how can I add one to it?
Sorry for all the questions. I guess you can tell I'm no EE.


Thanks
Andy

[joensd]

Hi Andy,
the ME versions is shown here.
If you don´t have that already you probably got the schematic of the mini version with 2SK135/2SJ50.
The latter doesn´t need the bias regulation.

I´d go with the mini as you already have the semis.
There are more interesting amplifier with 2SK135/2SJ50,
I can look them up if you want.

If you still want the ME-version, I can send you some construction notes. The 2SK1530/2SJ201 are quite easy to get by the way.

Cheers
Jens

[bikejog]

Hi Jens,
I already has the ME and the Mini schematics. I'm interested
in the big Crescendo (140w, which I don't have the schematic for).
If you can find more interesting amps using those semis, please
post them. I know there's a TA-3600 (or is it TA-4200? TA-4600?)
from Mark V on this website. I brought the Mark V kits
TA-477 and that's where all my semis are from, but I'm not
sure of the quality of the Mark V designs.

Thanks

[joensd]

I think you can basically build an amp that uses 2SK1058/2SJ162 pair too as they are also laterals but I´m not sure.

I´ve got another article from l`Audiophile magazine which is basically the same as the crescendo.
The schematics of the original crescendo you can download somewhere on the net (french article!).
If I don´t find the site I can email it to you.
It´s about 3MB.

Cheers
Jens

[joensd]

Should have looked before writing.
Here is the site you can download the schematics.
It´s on the bottom one the page where it says "exemples de realisation".
The site is maybe intersting to you anyway cause there are a lot of amps using laterals. But mostly class A designs.

Jens

[bikejog]

Thanks for the link. It was great..

Andy

[Samuel Jayaraj]

Rather than the Crescendo big brother, consider building the Playmaster Amp. Someone here can provide the link. Randy Slone's OPTIMOS amp is another alternative.

[diyman]

Andy,

You can find the English version of the original "big brother" Crescendo article at :-

http://www.pacificdecal.com/solidstate.htm

I have built it with good parts and its still very much alive and kicking. Excellent for AV and quite good for Hifi.

my 2 cts

ckt