6V6 line preamp - Page 138

Salas · 6th January 2013, 10:12 AM

I had built with resistive load non bootstrap and bootstrap and I kept the latter with Teflon input. Its easy for anybody to make the configs and check preference in own system and taste anyway. Tnx for the virtual pots.

stajo · 10:45 AM

LL1668 gapped 50 mA maybe http://www.lundahl.se/pdfs/datash/1667_68.pdf windings in series 100H 680 DCR
http://www.diyparadiso.com/price/transfo/LLchoke.htm

revintage · 6th January 2013, 11:05 AM

Hey Salas,

I don´t understand:

"with resistive load non bootstrap"

Can not work without severe distortion.

Stajo,

1668 was actually one of the std chokes I had in mind.

Salas · 6th January 2013, 11:33 AM

It can at low bias current and highish amp load. At about -60dB THD for ~6VPP.

stajo · 11:55 AM

Heres the breadboarded circuit for starters. By an incident I already had it on my breadboard. Now letz see if I can warp up a PSU b4 the kids storm the barn. 115 H 950 DCR Hinchley chokes (robbed from Perka, Lars

.

Staffan

stajo · 24th January 2013, 08:56 PM

Well I choosed to make a "livingroom proto" instead since I have kids running around. I'm always nervous mounting touchable HV stuff in the livingroom. I made it like a AZ1 - 30 uF motorrun - 10H - 50 uF motorrun common chassie and then I made some plates to fit for different configs.

First out is the 6V6 chokeloaded CF. It sticks a 2,2R and double 47 uF for each channel. Abour 255 on the anode.

It playes right now and it has a clearly stiffer bass then my former passive. Nice voices too but still a hum and some other disturbances. 99 dB speakers is not nice to me. I will clear up the hum and get back to you with some measurements once I get sober. It will happen any month now.

Best
Staffan

buzzforb · 24th January 2013, 09:03 PM

My new speakers I'll be HE Altec based setup. In this situation is Cf recommeneded over standard. It will be driving variety is pass amps ranging from 15-20dB of gain.

stajo · 24th January 2013, 09:03 PM

Forgot to mention: its 115 H Hinchely chokes on the katode. About 930isch dcr if I remember correctly.

made roome for some VRs to or a SSHV2 maybe

/S

stajo · 24th January 2013, 09:12 PM

Quote:

Originally Posted by buzzforb

My new speakers I'll be HE Altec based setup. In this situation is Cf recommeneded over standard. It will be driving variety is pass amps ranging from 15-20dB of gain.

I think this is promising. Thing is that carefulness is needed around a clean ground to, since its a CF. I will up an LL common mode choke b4 anode and ground but I'm not that sure how to mount it in the C-L-C-L-C chain. What happen if I mount it between the last C-C? Can that cause grounding issues? Well, I'll try and find out

/S

buzzforb · 09:22 PM

Those tubes look kinds smoky

Did you compare to modern version yet?

Nice job, BTW.

I got these for my rebuild. Thinking about getting BudP to wind me some for the load

6th January 2013, 10:32 AM	#1372
stajo diyAudio Member Join Date: Jun 2011 Location: Stockholm	LL1668 gapped 50 mA maybe http://www.lundahl.se/pdfs/datash/1667_68.pdf windings in series 100H 680 DCR http://www.diyparadiso.com/price/transfo/LLchoke.htm Last edited by stajo; 6th January 2013 at 10:45 AM.

6th January 2013, 11:40 AM	#1375
stajo diyAudio Member Join Date: Jun 2011 Location: Stockholm	Heres the breadboarded circuit for starters. By an incident I already had it on my breadboard. Now letz see if I can warp up a PSU b4 the kids storm the barn. 115 H 950 DCR Hinchley chokes (robbed from Perka, Lars. Staffan Last edited by stajo; 6th January 2013 at 11:55 AM.

24th January 2013, 09:03 PM	#1377
buzzforb diyAudio Member Join Date: Oct 2010 Location: Burlington, NC	My new speakers I'll be HE Altec based setup. In this situation is Cf recommeneded over standard. It will be driving variety is pass amps ranging from 15-20dB of gain. __________________ ...Shape the sound , Man!

24th January 2013, 09:15 PM	#1380
buzzforb diyAudio Member Join Date: Oct 2010 Location: Burlington, NC	Those tubes look kinds smoky Did you compare to modern version yet? Nice job, BTW. I got these for my rebuild. Thinking about getting BudP to wind me some for the load __________________ ...Shape the sound , Man! Last edited by buzzforb; 24th January 2013 at 09:22 PM.

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6th January 2013, 10:12 AM	#1371
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	I had built with resistive load non bootstrap and bootstrap and I kept the latter with Teflon input. Its easy for anybody to make the configs and check preference in own system and taste anyway. Tnx for the virtual pots.

6th January 2013, 11:05 AM	#1373
revintage diyAudio Member Join Date: May 2007	Hey Salas, I don´t understand: "with resistive load non bootstrap" Can not work without severe distortion. Stajo, 1668 was actually one of the std chokes I had in mind.

6th January 2013, 11:33 AM	#1374
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	It can at low bias current and highish amp load. At about -60dB THD for ~6VPP.

24th January 2013, 08:56 PM	#1376
stajo diyAudio Member Join Date: Jun 2011 Location: Stockholm	Well I choosed to make a "livingroom proto" instead since I have kids running around. I'm always nervous mounting touchable HV stuff in the livingroom. I made it like a AZ1 - 30 uF motorrun - 10H - 50 uF motorrun common chassie and then I made some plates to fit for different configs. First out is the 6V6 chokeloaded CF. It sticks a 2,2R and double 47 uF for each channel. Abour 255 on the anode. It playes right now and it has a clearly stiffer bass then my former passive. Nice voices too but still a hum and some other disturbances. 99 dB speakers is not nice to me. I will clear up the hum and get back to you with some measurements once I get sober. It will happen any month now. Best Staffan

24th January 2013, 09:03 PM	#1378
stajo diyAudio Member Join Date: Jun 2011 Location: Stockholm	Forgot to mention: its 115 H Hinchely chokes on the katode. About 930isch dcr if I remember correctly. made roome for some VRs to or a SSHV2 maybe /S

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