What is Simplest and Best 6L6 PP circuit? (PK)

zxx123 · 22nd December 2005, 05:52 PM

I am looking for simple 6L6 PP.
Especially, I hople that it will work with PK
circuit because chasis for this project
is very small.

I have collected some schematics, however,
I am not sure how they will work.

Give me some advice please!

Johan Potgieter · 24th December 2005, 02:24 AM

zxx123,

Simplest and best are not always compatible! Your attached EL34 circuit looks OK, but you ask for 6L6, and replacing by 6L6s would slightly strain the concertina phase splitter, as a 6L6 would require about 2x the grid signal. Very generally, stay away from ECC83 (12AX7) in this sort of circuit - regular members will by now get tired of this advice from me. Also stick to UL, not pentodes.

I have an alternative circuit for you but can append that only later (bed time here!) Can you deal with an extra tube? My set-up would use EF86, ECC81 (12AT7) and 2 x 6L6GC.

BTW · 24th December 2005, 03:54 AM

Here's a good link for quite a few commercial amps schematics, take your pick from Heathkit, Eico, Mac....

http://www.one-electron.com/FC_Consumer.html

hacknet · 24th December 2005, 03:54 AM

i've got faith in a williamson. haha

Miles Prower · 24th December 2005, 04:17 AM

Here's one that looks promising. (Yeah, it's originally for the 6V6, but could easily be adapted to the 6L6. NBD.)

Johan Potgieter · 25th December 2005, 10:36 PM

zxx123,

To fulfil a promise, I am going to try and attach a circuit that I have found to give quality response but is quite simple and trouble free. It can be improved, but that is a subsequent action. I apologise if the quality is poor; I had to re-copy it re-scanning - some wicked gentlemen came and collected my PC with un-backed-up info on together with other possessions a few weeks ago while I was out.

For the stability of any circuit with feedback the characteristics of the output transformer is of prime importance. Mine was self-designed with a primary inductance of 60Hy and leakage inductance of 18 mH (measured in the usual way). But interwinding capacitance also plays a role.

I am not going to extend this to an unreasonable length now; if you are intersted at all kindly indicate and I can pass on comments on testing etc., depending on your expertise.

Regards

I share Hacknet's recommendation, but found this slightly less critical.

Johan Potgieter · 25th December 2005, 10:50 PM

Sorry, zxx123,

The info block indicates that the picture exceeds the allowed info content. I will investigate and post later.

Regards

zxx123 · 26th December 2005, 01:48 AM

Quote:

Originally posted by Johan Potgieter
Sorry, zxx123,

The info block indicates that the picture exceeds the allowed info content. I will investigate and post later.

Regards

Thank you guys.

@Johan, I hope you will not forget the promise.

Johan Potgieter · 26th December 2005, 07:27 AM

zxx123,

Here we go again.

Johan Potgieter · 26th December 2005, 07:43 AM

That seems to have worked. You will notice that the #marked capacitors govern feedback stability with a given output transformer - and I have no way to tell what you will use. An oscilloscope and square wave generator will be necessary (ideally essential with any amp one builds). But as said, we can go into that should you be interested in this circuit. BTW input sensitivity is about 200 mVrms

Regards.

24th December 2005, 04:17 AM	#5
Miles Prower diyAudio Member Join Date: May 2005 Location: USA Blog Entries: 2	Here's one that looks promising. (Yeah, it's originally for the 6V6, but could easily be adapted to the 6L6. NBD.) __________________ There are no foxes in atheistholes www.dolphin-hsl.com

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24th December 2005, 02:24 AM	#2
Johan Potgieter diyAudio Member Join Date: May 2005 Location: Pretoria, South Africa	zxx123, Simplest and best are not always compatible! Your attached EL34 circuit looks OK, but you ask for 6L6, and replacing by 6L6s would slightly strain the concertina phase splitter, as a 6L6 would require about 2x the grid signal. Very generally, stay away from ECC83 (12AX7) in this sort of circuit - regular members will by now get tired of this advice from me. Also stick to UL, not pentodes. I have an alternative circuit for you but can append that only later (bed time here!) Can you deal with an extra tube? My set-up would use EF86, ECC81 (12AT7) and 2 x 6L6GC.

24th December 2005, 03:54 AM	#3
BTW diyAudio Member Join Date: Nov 2002 Location: Singapore	Here's a good link for quite a few commercial amps schematics, take your pick from Heathkit, Eico, Mac.... http://www.one-electron.com/FC_Consumer.html

24th December 2005, 03:54 AM	#4
hacknet diyAudio Member Join Date: Nov 2002 Location: sg	i've got faith in a williamson. haha

25th December 2005, 10:36 PM	#6
Johan Potgieter diyAudio Member Join Date: May 2005 Location: Pretoria, South Africa	zxx123, To fulfil a promise, I am going to try and attach a circuit that I have found to give quality response but is quite simple and trouble free. It can be improved, but that is a subsequent action. I apologise if the quality is poor; I had to re-copy it re-scanning - some wicked gentlemen came and collected my PC with un-backed-up info on together with other possessions a few weeks ago while I was out. For the stability of any circuit with feedback the characteristics of the output transformer is of prime importance. Mine was self-designed with a primary inductance of 60Hy and leakage inductance of 18 mH (measured in the usual way). But interwinding capacitance also plays a role. I am not going to extend this to an unreasonable length now; if you are intersted at all kindly indicate and I can pass on comments on testing etc., depending on your expertise. Regards I share Hacknet's recommendation, but found this slightly less critical.

25th December 2005, 10:50 PM	#7
Johan Potgieter diyAudio Member Join Date: May 2005 Location: Pretoria, South Africa	Sorry, zxx123, The info block indicates that the picture exceeds the allowed info content. I will investigate and post later. Regards

26th December 2005, 07:43 AM	#10
Johan Potgieter diyAudio Member Join Date: May 2005 Location: Pretoria, South Africa	That seems to have worked. You will notice that the #marked capacitors govern feedback stability with a given output transformer - and I have no way to tell what you will use. An oscilloscope and square wave generator will be necessary (ideally essential with any amp one builds). But as said, we can go into that should you be interested in this circuit. BTW input sensitivity is about 200 mVrms Regards.

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