new to the forum and looking for el86 info

jcricket · 18th October 2009, 02:37 PM

Hey folks, I just signed up today. I have spent some time over at audiokarma and a friend referred me to this site.

First, I am not to bright on this stuff, at least not yet. I love the sound of tubes and have been dabbling with it for a couple of months. I have learned a ton, but that is a small % of what I have to learn.

I recetnly purchased a set of lafayettes kt-a250's to build one good unit out of. These utilize a pp el86 configuration. Anyway, I am going to have this really nice extra set of iron perfect for the el86's.

I was wondering if anyone has a lint ot or a copy of a SIMPLE set of scheamtics for PP el86 amp???

I could duplicate the lafayette, but there has to be a simpler version around somewhere. I saw tubelab was working on this a while ago. Anyone know if there is a completed version?

Anyway, first and formost, hello!! I hope to get to know some of you well and even make some friends.

TTYL,
Mark

boywonder · 19th October 2009, 05:46 AM

I have no idea if this is relevent, but here it is:

EL86 Push Pull Triode Connection Diffrential Amplifier

It's a triode EL86 PP, yielding about 6W. It appears to use 5K output transformers; do you know the primary impedance of your transformers? Do you also have EL86 tubes? If you know the primary impedance of your transformers and are not married to EL86's, there may be lots of other possibilities..

jcricket · 19th October 2009, 01:05 PM

Thanks for the link. I haven't looked at it yet, thought I would answer first.

I actually bought two Lafayette a250 integrated's to be able to restore to one unit. As it turns out, I have a set of opt's and a ps that are good. The unit uses el86's. MY opt's are 3k pp. They have the b+ and then two wires for the plates on the input side. Also 4,8,16 ouput taps.

I have the schematic for the a250 integrated, but thought I would look to see if I could find just a simple stand alone amp for el86's. Any suggestion for that or any other use of these opt's would be appreciated.

Mark

Shoog · 19th October 2009, 02:26 PM

Consider this. The PL84 is the same as the EL86 with a different heater voltage;

My version of the Simple EL84 or rise of the anti-triode.

Shoog

jcricket · 19th October 2009, 03:55 PM

Quote:

Originally Posted by Shoog

Consider this. The PL84 is the same as the EL86 with a different heater voltage;

My version of the Simple EL84 or rise of the anti-triode.

Shoog

I like this ALOT!

What is a an LM317? I have seen this before, but I don't know what it is. A potentiometer?

Shoog · 19th October 2009, 05:04 PM

The LM317 is acting as a Constant Current Sink. It replaces the Cathode bias resistor, but keeps the Current constant - which is important when using toroidals as outputs.

Shoog

jcricket · 19th October 2009, 07:23 PM

Assuming I build this with the standard transformers, as I already have them, would a standard resistor suffice?

Thanks again for the help!

Shoog · 19th October 2009, 07:29 PM

It would, but I consider the arrangement shown to offer many advantages over a simple resistor and so would recommend building as is shown.

Shoog

jcricket · 19th October 2009, 07:47 PM

SO, just to be sure I understand, would you build these with standard OPT's and the dcm, or go all out with the torodials?

I have the standard OPT's and it would probably save me somtething like $100 plus to use them.

Mark

aardvarkash10 · 08:15 PM

the 317 is cheap, ubiquitous and (at least) an order of magnitude more effective than a resistor in this application. If shoog says use it, I would.

[edit] REGARDLESS of which transformers you end up using, use the 317s as drawn

18th October 2009, 02:37 PM	#1
jcricket diyAudio Member Join Date: Oct 2009 Location: denver area	new to the forum and looking for el86 info Hey folks, I just signed up today. I have spent some time over at audiokarma and a friend referred me to this site. First, I am not to bright on this stuff, at least not yet. I love the sound of tubes and have been dabbling with it for a couple of months. I have learned a ton, but that is a small % of what I have to learn. I recetnly purchased a set of lafayettes kt-a250's to build one good unit out of. These utilize a pp el86 configuration. Anyway, I am going to have this really nice extra set of iron perfect for the el86's. I was wondering if anyone has a lint ot or a copy of a SIMPLE set of scheamtics for PP el86 amp??? I could duplicate the lafayette, but there has to be a simpler version around somewhere. I saw tubelab was working on this a while ago. Anyone know if there is a completed version? Anyway, first and formost, hello!! I hope to get to know some of you well and even make some friends. TTYL, Mark

19th October 2009, 07:52 PM	#10
aardvarkash10 diyAudio Member Join Date: Mar 2007 Location: Auckland, NZ	the 317 is cheap, ubiquitous and (at least) an order of magnitude more effective than a resistor in this application. If shoog says use it, I would. [edit] REGARDLESS of which transformers you end up using, use the 317s as drawn __________________ Yes, conservatism thrives on low intelligence and poor information. But the liberals in politics... continue to back off, yielding to the supremacy of the stupid. It's turkeys all the way down. - George Monbiot, guardian.co.uk, 6 Feb 2012 Last edited by aardvarkash10; 19th October 2009 at 08:15 PM.

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19th October 2009, 05:46 AM	#2
boywonder diyAudio Member Join Date: Jan 2008 Location: So.Cal.	I have no idea if this is relevent, but here it is: EL86 Push Pull Triode Connection Diffrential Amplifier It's a triode EL86 PP, yielding about 6W. It appears to use 5K output transformers; do you know the primary impedance of your transformers? Do you also have EL86 tubes? If you know the primary impedance of your transformers and are not married to EL86's, there may be lots of other possibilities..

19th October 2009, 01:05 PM	#3
jcricket diyAudio Member Join Date: Oct 2009 Location: denver area	Thanks for the link. I haven't looked at it yet, thought I would answer first. I actually bought two Lafayette a250 integrated's to be able to restore to one unit. As it turns out, I have a set of opt's and a ps that are good. The unit uses el86's. MY opt's are 3k pp. They have the b+ and then two wires for the plates on the input side. Also 4,8,16 ouput taps. I have the schematic for the a250 integrated, but thought I would look to see if I could find just a simple stand alone amp for el86's. Any suggestion for that or any other use of these opt's would be appreciated. Mark

19th October 2009, 02:26 PM	#4
Shoog diyAudio Member Join Date: Aug 2002 Location: Eire	Consider this. The PL84 is the same as the EL86 with a different heater voltage; My version of the Simple EL84 or rise of the anti-triode. Shoog

19th October 2009, 05:04 PM	#6
Shoog diyAudio Member Join Date: Aug 2002 Location: Eire	The LM317 is acting as a Constant Current Sink. It replaces the Cathode bias resistor, but keeps the Current constant - which is important when using toroidals as outputs. Shoog

19th October 2009, 07:23 PM	#7
jcricket diyAudio Member Join Date: Oct 2009 Location: denver area	Assuming I build this with the standard transformers, as I already have them, would a standard resistor suffice? Thanks again for the help!

19th October 2009, 07:29 PM	#8
Shoog diyAudio Member Join Date: Aug 2002 Location: Eire	It would, but I consider the arrangement shown to offer many advantages over a simple resistor and so would recommend building as is shown. Shoog

19th October 2009, 07:47 PM	#9
jcricket diyAudio Member Join Date: Oct 2009 Location: denver area	SO, just to be sure I understand, would you build these with standard OPT's and the dcm, or go all out with the torodials? I have the standard OPT's and it would probably save me somtething like $100 plus to use them. Mark

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