Looking for circuit of SE amp. for Eimac 100TH

[head1962]

box is on its way too. lasercut and bend today. paint job this weekend..
made some little boards for the FET interstage too.

 

[brommermartin]

Very nice project
What kind of output transformer have you used ?

 

[jpak]

Very nice, have you done distortion measurements? It's interesting seeing Eimac tubes operated at such low plate voltage.

 

[rcavictim]

Hi Eimac

check out this link: www.triodefestival.net/uploads/.../michimori%20(PPTminimizer).ppt
this is a cool way to drive the A2 tubes, if you don't like to use a FET.

best regards
Karsten

Unfortunately, this link doesn't appear to work. Anyone know a working path to this info?

 

[MelB]

Yes would be nice to get some distortion numbers or maybe a few square waves.

Cool looking tube can't wait to see your finished amps!!!

 

[H.Michi]

Unfortunately, this link doesn't appear to work. Anyone know a working path to this info?

Hi rcavictim, attached is a renewal version of 100th SE amp.

Renewed 100TH SE Amp 2010

Hiro

 

[rcavictim]

Hi rcavictim, attached is a renewal version of 100th SE amp.

Renewed 100TH SE Amp 2010

Hiro

Thanks buddy. Nice project.

 

[H.Michi]

Thanks rcavictim,

I like a temple bell type tantalum plate valves such as 100TH, 8025A and 808 which sounds are good in bass, though soft and smooth.
Also looking for the reddish valve during operation is a pleasure for me.

Hiro

 

[brommermartin]

Hiro,

Is it possible to use a 6080 instead of the 5998A

 

[head1962]

Very nice project
What kind of output transformer have you used ?

I use RITTER 3k 20W. they're 5 times intertwined and can handle a bit more than 20W and support 215mA. I've used a lot of the Ritter transformers, a real nice product.

 

[head1962]

Very nice, have you done distortion measurements? It's interesting seeing Eimac tubes operated at such low plate voltage.

I can make some screen shots of a 1kHz sine and square wave this weekend at different levels.

 

[H.Michi]

brommermartin,

I have not tried 6080.
But you need a higher swing voltage for 6080, as an amplification factor of 6080 is only 2, compared with 5 of 5998A.
Also it`s gm is half of 5998A.

 

[brommermartin]

Thanks for you quick reply
I ask this because in Europe this tube is hard to find.

 

[head1962]

Very nice, have you done distortion measurements? It's interesting seeing Eimac tubes operated at such low plate voltage.

here are some screen shots of my scope.
in order 1W 5W 10W 15W 20W, sine and than square. my function generator (old) makes a little peak at the up flange of the square. I think it looks pretty descent. I also melted the clip of my probe
I measured on a 5ohm load on the 4ohm transformer output.
The sines are very precise, if I invert one channel and add the other, the line is pretty much flat.
I don't have a real distortion meter.
The little FET interstage boards should be arriving next week. Eurocircuits is pretty fast!!

And if anyone likes to see other measurments, I'll be happy to do them.

 

[jpak]

Excellent, thanks!

 

[Technical]

What frequency are your scope pictures at?

here are some screen shots of my scope.
in order 1W 5W 10W 15W 20W, sine and than square. my function generator (old) makes a little peak at the up flange of the square. I think it looks pretty descent. I also melted the clip of my probe
I measured on a 5ohm load on the 4ohm transformer output.
The sines are very precise, if I invert one channel and add the other, the line is pretty much flat.
I don't have a real distortion meter.
The little FET interstage boards should be arriving next week. Eurocircuits is pretty fast!!

And if anyone likes to see other measurments, I'll be happy to do them.

 

[head1962]

100TH scope pics

scope pics at 1kHz

 

[brommermartin]

Are the amps already assenbled ?
I am collecting parts and will contact Ritter for some output transformers .
Did you use the "hifi "or the "highend" serie transformers ?

Grtz...

 

[head1962]

Are the amps already assenbled ?
I am collecting parts and will contact Ritter for some output transformers .
Did you use the "hifi "or the "highend" serie transformers ?

Grtz...

The RTS020.30 can handle ca. 200mA, DC, in both versions "/S" or "/H".
Also the RTS025.30 can handle upto 200mA DC, if you want more (but you don't) you need to move to the bigger core trannies EI105. The Studio Quality in EI96 version has a too high interlacing (7 or 8),l the wires get thinner and can't handle the current.

 

[jps1964]

Hello,

what is the value for C11 (C14) in the schematics?

Regards