Hi !
I will use ECC88 for that purpose,because the EL156 only needs less than 10Vpp in grid for full power,it is a very special valve,i think!And i like very much the sound of ECC88! I have to check the price for sowter transfos for this,i heard they have very good quality,but i am not a rich guy ,so if not sowter,maybe Hammond!
Silvino
Yes, DIY may be fun, however with this one I'm after the sound quality and cost of this amp, more than the fun of building it.
I wonder if Ultra-Linear will have the same magic sound quality as triode. As I wrote, I'm not into a race after max power.
Once the amp will be running, I'll report the good, the bad and the ugly about it.
Yes, it's the perpetual debate between sound quality and cost. Since this one will probably be my last amp, if it will sound good, I intend to go for the best I can afford.
10Vpp is very impressive! Be interested to see your design, I have loads of ECC88s here 😉
Hi Joshua!
From my telefunken Datasheet they say,for SE class A Pentode ,
Ua 450V
Ug2 280V
Rk 90 Ohm
Ia 112 ma
Ig2 17 ma
Ra 3,8K
Pout 25W
Ug eff 9,2V~
So, for full output (in pentode mode),it needs 9,2V eff in the input! Or Not?
But for triode mode i dont know if it is much different.
Regards
I can only guess roughly from the triode strapped anode curves.
Anyhow, for the time being I dropped this project in favor of another one.
Anyhow, for the time being I dropped this project in favor of another one.
Hi Joshua,
I just bought a special publication from Elektor "Röhren 6"
which happens to contain an article about a single ended
EL156 power amp. Triode and pentode mode is switchable, the
(measured) power at 5% THD is 12.5 W in triode and 20W in pentode
mode. They use one ECC99 (dual triode) per channel to drive the EL156.
I just bought a special publication from Elektor "Röhren 6"
which happens to contain an article about a single ended
EL156 power amp. Triode and pentode mode is switchable, the
(measured) power at 5% THD is 12.5 W in triode and 20W in pentode
mode. They use one ECC99 (dual triode) per channel to drive the EL156.
Hi Joshua,
if you are still interested, I was able to drop down the distortion and make mine sing and punch. Pretty cheap mods also. However, no good results with the EL156, I am using 6550's. I am designing another SET amp around the EL156 in a 2 stage. I will build it later as I am having lots of fun with the present one.
I made a pair of (Shuguang) EL156 SEUL amplifiers driven by the EF86. Tube rectified, Hammond iron, Russian Teflon couplers, etc etc. Nothing special, but I still consider it my best DIY amplifier ever.
Having said that, they now runs real Tungsol 6550s and have found a place with a friend of mine. They sound even better with the vintage output tubes and GEC CV4085s for the input tube. A nice low powered amplifier which is perfect for his small room. I would have kept the amplifiers, but I went on to the power hungry planar speaker world.
Having said that, they now runs real Tungsol 6550s and have found a place with a friend of mine. They sound even better with the vintage output tubes and GEC CV4085s for the input tube. A nice low powered amplifier which is perfect for his small room. I would have kept the amplifiers, but I went on to the power hungry planar speaker world.
http://oldradio.qrz.ru/tubes/foreign/02/EL156.gif
Extrapolating from the above (in SE triode mode with an EL156) should yield 15W audio output:
Ua = 500V
Zout = 2.8Kohms
P(out) = 15W
Ia = ?
500V x .090A = 45W (Pd looks about right)
Find a good drivestage, and it should reach ~15W. 15W is sufficient to drive most speakers, and 15W are a lot of nice SE triode watts. (Average listening level is 10-12W.)
The PP triode config in the data sheet looks like best. 30W audio output - about 6 watts better than most KT88s in PP triode - unless the specs are way off.
Extrapolating from the above (in SE triode mode with an EL156) should yield 15W audio output:
Ua = 500V
Zout = 2.8Kohms
P(out) = 15W
Ia = ?
500V x .090A = 45W (Pd looks about right)
Find a good drivestage, and it should reach ~15W. 15W is sufficient to drive most speakers, and 15W are a lot of nice SE triode watts. (Average listening level is 10-12W.)
The PP triode config in the data sheet looks like best. 30W audio output - about 6 watts better than most KT88s in PP triode - unless the specs are way off.
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