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Old 5th December 2006, 08:07 AM   #1
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Default Transformer coupled 6AS7/6080

Does anyone have any thoughts on using a 6AS7 on the output of either something like the tubelab se, or a small low watt guitar amp? Is the plate resistance too low, or would it be better to leave out the cathode bypass cap? I remember reading somewhere that they were essentially a pair of indirectly heated 2a3's in a single tube, but that may have just been someone's marketing.
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Old 6th December 2006, 05:11 PM   #2
EC8010 is offline EC8010  United Kingdom
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I don't have any direct experience of 6080 amplifiers but as nobody else has answered...

There's very little similarity between half a 6080 and a 2A3 other than that they're both triodes and about the same anode rating. Mind you, they're cheap... Because they're intended for series regulator use close adherence to published anode curves wasn't necessary, but for SE use that shouldn't be too much of a problem. The low anode resistance means you need a lower primary impedance for the output transformer, making it easier to make a good one. Keep the cathode bypass capacitor.
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Old 6th December 2006, 05:44 PM   #3
316a is offline 316a  England
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Hi ,
Try a 5998 or 7236 which have similar Ra but higher mu than the 6AS7 so are much easier to drive . Alternatively use a Sovtek 2A3

cheers

316A
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Old 6th December 2006, 06:48 PM   #4
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You can build everything with that tube. SE, PP in all classes, CathodeFollower, PPP, Circlotron, Horizon, SEPP, OTL.....

But be careful when paralleling the tubes. You will need matched tubes.

An Advatage is the very low load impedance and output impedance which provides good damping factor and a cheap output transformer.

Connected as Cathode Follower and with big amount of global Feedback, the damping factor is amazing good and the tube can drive every kind of Subwoofer. Of course a cheap solid state Amp is better suited for this job.

The best is when you buy a box of 100 pieces of the cheap russian 6H13C, thats the russian equivalent of the 6080. Doesn't cost that much and you can match them yourself. It's a nice Cockebottle tube.

But they need to be driven properly.

Heres a nice schematic of an SEPP, it was successfull built by a german guy:


The Article (PDF)

The AMP

best regards, Manta
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Old 6th December 2006, 08:56 PM   #5
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Here is my try on a friend schéma. My SEPP is based on ECC83 and 6080/6AS7G.

Click the image to open in full size.

Rest with many pictures are here

Click the image to open in full size.

Click the image to open in full size.

This amp (i need to built second bloc) sound very good to my ears, better than my solid state one. A realy low caost fine project.

Marc

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Old 6th December 2006, 10:48 PM   #6
jarthel is offline jarthel  Australia
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Quote:
Originally posted by the_manta


Heres a nice schematic of an SEPP, it was successfull built by a german guy:


The Article (PDF)

The AMP

best regards, Manta

They're not the same circuit. right?

also do you have a clearer drawing for the first link? I could barely read the values on the schematics.

thank you
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Old 6th December 2006, 10:53 PM   #7
jarthel is offline jarthel  Australia
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Quote:
Originally posted by Idefixes
Here is my try on a friend schéma. My SEPP is based on ECC83 and 6080/6AS7G.


This amp (i need to built second bloc) sound very good to my ears, better than my solid state one. A realy low caost fine project.

Marc


how many watts does can it output? thank you.
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Old 7th December 2006, 05:37 AM   #8
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Quote:
Originally posted by jarthel



how many watts does can it output? thank you.
Between 5 and 10w it depend on 6AS7G cathode resistor value.

Marc
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Old 7th December 2006, 12:49 PM   #9
jarthel is offline jarthel  Australia
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Quote:
Originally posted by Idefixes


Between 5 and 10w it depend on 6AS7G cathode resistor value.

Marc
lower the resistance the higher the wattage?
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Old 7th December 2006, 12:50 PM   #10
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Quote:
Originally posted by jarthel


lower the resistance the higher the wattage?
Yes but pay attention to max plate dissipation.

Marc
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