SE Class A with 845or 211. Need a good circuit - diyAudio
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Old 6th January 2004, 07:38 AM   #1
diyAudio Member
 
Join Date: Feb 2002
Location: Flensburg
Default SE Class A with 845or 211. Need a good circuit

I´m planning to biuld a tube amp with the 845 or 211 tube.
I saw an article in

http://www.ptsoundlab.free.fr/sectub...mas/845/84518w

The idea was published in "La revue LED".

Has anyone experience with this kind of tube or has even built this amp?

Or is the 211 tube the better choise (e.g. J. LeBong211SE) when 8 - 10 Watt are more then enough to drive my speakers.

I want an tube amp (SE without feedback) for the mids and highs which sound very open and naturell.

Any different ideas?

regards

Günter
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Old 6th January 2004, 07:56 AM   #2
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Default Re: SE Class A with 845or 211. Need a good circuit

Konnichiwa,

Quote:
Originally posted by Selfmade
I´m planning to biuld a tube amp with the 845 or 211 tube.
I saw an article in

Any different ideas?
Given the number of complications with the 211/845 (sound completely aside) such as high power, high impedance output transformers and high voltages, why not the russian 6S33 "horny devil"? In SE you can get up to around 18 Watt. Also, something in the style of Lynn Olsons Amity with 300B's will sound excellent (despite not being SE) and give anywahere between 15 - 20W.

I would argue that anyone who "needs a schematic" should perhaps avoid building something as potentially lethal and problematic as a 211/845 untill they have more experience.

Sayonara
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Old 6th January 2004, 08:36 AM   #3
diyAudio Member
 
Join Date: Feb 2002
Location: Flensburg
Thank´s for your good advice. I have built many Class A transistor-amps (Aleph, ZEN, Hiraga, JLH). The JLH and the Hiraga are very, very good sounding amp if 10 Watt are enough.

Now I want to build something different like tube-amps, but with also excellent sound. It need not necesserilly be a 845 or 211 tube. I just want an triode tube amp with minimum 5 Watt SE without using feedback.

I´m dependent on a good scheme, because this would be my first tube project.

regards

Günter
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Old 6th January 2004, 09:37 AM   #4
AKSA is offline AKSA  Australia
diyAudio Member
 
Join Date: Sep 2001
Location: Melbourne, Australia
Another suggestion is the excellent and high duty 6C41C, the little brother of the 6C33B, with much more stable bias.

This tube is rated to 320mA, runs around 160mA at 150Vak and mu 2.8. It will dissipate 25W on the plate, so you can pull around 10W in SE, similar to a 211, or two will deliver almost 20W.

I believe Bas has built one; he has good tips.

Cheers,

Hugh
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Old 6th January 2004, 11:58 AM   #5
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Konnichiwa,

Quote:
Originally posted by Selfmade
Now I want to build something different like tube-amps, but with also excellent sound. It need not necesserilly be a 845 or 211 tube. I just want an triode tube amp with minimum 5 Watt SE without using feedback.
You might want consider this project given your requirements.

http://www.lundahl.se/claus_b_se.html

(sorry, HTTP button seems not work right now)

The same Amplifier Chassis (if implemented well and build with a view to future Modifications/Expansion) can be converted to use 2A3 and/or 300B output valves and different driver circuitry, keeping all the transformers and the chassis, which are the expensive and labour intensive parts of a n amplifier.

Sayonara
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Old 6th January 2004, 10:25 PM   #6
diyAudio Member
 
Join Date: Sep 2003
Location: London
I'm going to build a 845 SET but low voltage. I don't see why not, and others have done it. Bearing in mind also that Chinese 845s are very cheap (£29 in the UK). Possible operating points are, with the Hammond 125ESE (80mA DC) @ 5K
80mA 300v -21v
80mA 350v -31v
80mA 400v -40v

Or with 100mA DC and a bigger OPT:
100mA 300 -15
100mA 350 -25
100mA 400 -33

www.heartofclay.com/eb/vamp.jpg
www.heartofclay.com/eb/vamp2.jpg

the above shows one solution. But surely a good SRPP could drive the 845 directly at these lower voltages. apparently it sounds magical. Plus 125ESE and chinese 845 make a pretty cheap project. why not? Any other suggestions for operating points and a suitable front end?
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Old 7th January 2004, 08:15 AM   #7
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Join Date: Feb 2002
Location: Flensburg
I´m sure now; the 211 and the 845 at high voltage are not a projects for a tube-beginner.

Hugh:
I found a very interessting webside with the 6c45.

http://www.digilander.libero.it/paen...e_CIRCUITS.htm

I think I´m starting with the single ended version.

The low voltage 845 is also very interesting. The output transformer could be the same as in the 6c45 project.

Thank´s for help.

Günter
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Old 8th January 2004, 09:15 PM   #8
diyAudio Member
 
Join Date: May 2003
Location: Poznan
Default GM70

HI


Look hire. Its not so much expensive tube and final efects are very good.

http://republika.pl/diytriode/drugi_eng.htm
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