SE 1.5W OTL

[Andrewbee]

Hi Bas

How does it compare with say an EL84 single ended amp?

No comparison, I love the EL84 in any shape or form but the OTL slays it. IMHO (self protection from those who protest such a statement)

Reinhard, pretty much told the story (especially the bass!- tuneful with lots of slam), add to that great clarity and a neutral character and you have a winner.
It sounds even better after its been on for about 8 - 10 hours!
I would like to see a higher power version, ~ 20W.

Andrew

 

[Fuling]

Oh, I didn´t know that the 6C19 can pass 1A peaks!
According to the curves I´ve seen it should be more like 150mA or so, but at a closer look the first curve is -5V instead of 0V as one would expect.

 

[Fuling]

A little inspirational reading about SE otl´s:

http://www.eng.umu.se/personal/morgan/Valvular Pages/pages/otl_page.htm

 

[reinhard]

SE

http://www.eng.umu.se/personal/morgan/Valvular Pages/pages/otl_page.htm

 

[reinhard]

SE OTL

Hi Bas

look at the link, one Pl 519 = 1 Watt
two Pl 519 = 4 Watt

and so on.

Reinhard

 

[Fuling]

Reinhard:
I understand why you don´t want to share the schematic, but some hints about the voltages and currents in the output stage would be very helpful

 

[reinhard]

As I told you the cathode follower is working on an inductor.
Each C19 has an additional cathode resistor of 5 Ohmsfor better
current sharing. The plates are sitting at nearly 100 Volts and the grids are at -12 Volts (Three teminal reg)

Don´t know the bias current but I thnk it is near 400 ma to get
1.5 Watt at 8 Ohms.

Reinhard

 

[reinhard]

Hello Minhaj,

your e-mail does not work.

Reinhard

 

[Fuling]

Thanks Reinhard!

Those numbers indicates that my own ideas are not that far off

 

[audio3chung]

Dear All,
Howabout the circuit in this:-
http://www.jogis-roehrenbude.de/Verstaerker/6C19/6C19.htm
Does ant of you tried the OTL one ?
CHOW

 

[reinhard]

6C19

Hello,

that Jogi circuit is not OTL.

we are speaking SE OTL here.

Reinhard

 

[Fuling]

The article in the link says "Kopfhöhrerverstärker" which I guess means Headphone amp.

 

[reinhard]

Kopfhörerverstärker

Yes,

Kopf Hörer Verstärker = Head Phone Amp

Reinhard

 

[Fuling]

Not suitable for driving 8 ohm speakers, then.

 

[reinhard]

Yes, think 32 Ohms minimum

Reinhard

 

[Fuling]

Should work with 8 output tubes or so per channel, but SE OTL feels more attractive.

 

[audio3chung]

Hi, happy Lunar New Year!
The 1.5W SE OTL from BR use 1 6H30 and 4 6C19 per channel as i know;
is it 4 x 6c19 build up two pairs of SRPP which can drive 8 ohms load. If not, can anyone tell me how the SE OTL manage to drive a 8 Ohms speaker.

Thanks a lot.

CHOW

 

[reinhard]

NO SRPP

No, not SRPP, have described the outputstage above. Read the thread carefully.

An SRPP is more push pull than single ended.

Reinhard

 

[guglielmope]

Hello,
I'm very interested in se OTL.
What about KTR circuit?(about " super Totem circuit" I saw in LED magazine.They use as preamplifier, the output impedence is about 5 times lewer than SRPP.
In the next days I'll scan the circuits and I can mail if you are interested.
Another thing :Morgan Lundberg , the audio friend with the link of 519 OTL is very friendly and I think that can help us.
Sorry for my poor english.
Ciao
Guglielmo

 

[reinhard]

Hello,

what is LED Magazine?

Yes I´m interested, mail to

in.audio@gmx.de

What is a super totem and why is the impedance 5 * lower?


Reinhard