Transformer coupled 6AS7/6080

dsavitsk · 5th December 2006, 08:07 AM

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.

EC8010 · 6th December 2006, 05:11 PM

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.

316a · 6th December 2006, 05:44 PM

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

the_manta · 6th December 2006, 06:48 PM

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

Idefixes · 6th December 2006, 08:56 PM

Here is my try on a friend schéma. My SEPP is based on ECC83 and 6080/6AS7G.

Rest with many pictures are here

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

jarthel · 6th December 2006, 10:48 PM

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

jarthel · 6th December 2006, 10:53 PM

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.

Idefixes · 7th December 2006, 05:37 AM

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

jarthel · 7th December 2006, 12:49 PM

Quote:

Originally posted by Idefixes

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

Marc

lower the resistance the higher the wattage?

Idefixes · 7th December 2006, 12:50 PM

Quote:

Originally posted by jarthel

lower the resistance the higher the wattage?

Yes but pay attention to max plate dissipation.

Marc

5th December 2006, 08:07 AM	#1
dsavitsk diyAudio Member Join Date: Jan 2005 Location: Chicago	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. __________________ http://www.ecpaudio.com

6th December 2006, 05:11 PM	#2
EC8010 diyAudio Moderator Join Date: Jan 2003 Location: Near London. UK	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. __________________ The loudspeaker: The only commercial Hi-Fi item where a disproportionate part of the budget isn't spent on the box. And the one where it would make a difference...

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Simplest 6080 or 6AS7 OTL Project?	Michael Rothacher	Tubes / Valves	29	26th August 2010 09:05 PM
6as7/6080 Se Otl	desperateaudio	Tubes / Valves	103	6th January 2009 02:19 PM
Parallel Push Pull 6AS7 or 6080	desperateaudio	Tubes / Valves	29	16th March 2008 05:30 PM
Set 6080/6as7	needtubes	Tubes / Valves	34	28th August 2004 05:40 AM
6080/6AS7/6H13C/6H5C in SE?	Colt45	Tubes / Valves	8	18th November 2002 06:56 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read

6th December 2006, 05:44 PM	#3
316a diyAudio Member Join Date: Dec 2002 Location: West London	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

6th December 2006, 06:48 PM	#4
the_manta diyAudio Member Join Date: Nov 2006 Location: Munich, Bavaria	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

6th December 2006, 08:56 PM	#5
Idefixes diyAudio Member Join Date: Dec 2003 Location: Mulhouse - Alsace	Here is my try on a friend schéma. My SEPP is based on ECC83 and 6080/6AS7G. Rest with many pictures are here 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

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)