Very Cheap Valve preamplifier

Nay9 · 10th August 2003, 02:35 AM

Would this valve preamplifier be suitable as a headphone amp?

http://www.oatleyelectronics.com/kits/k055.html

http://www.oatleyelectronics.com/pdf/k055.pdf

travis · 10th August 2003, 02:57 AM

http://headwize2.powerpill.org/index.htm

you probably seen that site already

halojoy · 10th August 2003, 04:57 AM

Quote:

VALVE PREAMP KIT: Hear valve sound by connecting this stereo all-valve preamplifier to your existing equipment. Uses two 6J6 double triode valves. Safe kit, as it only uses about 60V for high tension rail. Can be used at line level with guitar amplifiers, hi fi, recording equipment and mixers. Requires 12V / 1A AC power supply. Kit includes a suitable plastic case. PCB: 154 x 89mm.

PUBLISHED: Electronics Australia Magazine September 1996.

KIT PRICE: (K055) $66

It uses 6J6 at low voltage 60V. I don't know about that tube.
Strange that it should have 12VAC as supply ....

I am not sure I would chose this one.
As you say the price is low.
Maybe good for to start with, experimenting,
and maybe you can tweak it a bit.

halo

fdegrove · 10th August 2003, 07:56 PM

Hi,

Quote:

Would this valve preamplifier be suitable as a headphone amp?

Not likely, output impedance is rather too high.

If you look at the circuit you'll also notice the tubes have hardly any gridbias which means they're being driven positive with a CDP as line source already.

Halo,

The 12V AC is simply the two 6.3V heaters wired in series.
The 6J6 is the same as the European ECC91...not exactly an audio tube in my book.

Cheers,

w00t · 12th August 2003, 02:39 PM

Based on the schematic as in the link in post #1. Driving my al' cheapo cans currently.

w00t · 13th August 2003, 02:38 PM

I just heard this tube, the quality of the soudn coming out of it is really bad

. A solid state preamp could so better

anzic · 23rd April 2010, 03:21 AM

Hi all,

I know this is a really old post, but I am desperately trying to track down a copy of the K055.PDF from Oatley Electronics that has the schematic for this 6j6 preamp as mentioned in the first post.

Oatley dont have it anymore and can't get it off their website even with wayback machine/archive.org.

If anyone has a copy and can help it would be very appreciated.

Cheers,
Anzic.

TRANSDUCEReng · 9th June 2010, 10:45 AM

Hi Anzic,
Understand you been looking for the schematic and i do have a copy...and also have the original project kit unassembled and sitting in my store for the last 8 years..... and coincidently getting into this valve project...Would be great if we could discuss about this ...pls drop a me mail at franbargain@yahoo.com...thanks

anzic · 10th June 2010, 01:35 AM

TRANSDUCEReng,

Email sent, thanks :-)

fdegrove · 12th June 2010, 01:05 AM

Hi,

What about a single 12AX7 with current for the first anodoe anode, active RIAA in the loop and a current sink for the CF second triode?

Cheers,

10th August 2003, 02:57 AM	#2
travis diyAudio Member Join Date: Apr 2002 Location: orange ca	http://headwize2.powerpill.org/index.htm you probably seen that site already __________________ donuts

12th June 2010, 01:05 AM	#10
fdegrove diyAudio Senior Member Join Date: Aug 2002 Location: Belgium	Hi, What about a single 12AX7 with current for the first anodoe anode, active RIAA in the loop and a current sink for the CF second triode? Cheers, __________________ Frank

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10th August 2003, 02:35 AM	#1
Nay9 diyAudio Member Join Date: Jan 2003 Location: Australia	Very Cheap Valve preamplifier Would this valve preamplifier be suitable as a headphone amp? http://www.oatleyelectronics.com/kits/k055.html http://www.oatleyelectronics.com/pdf/k055.pdf

12th August 2003, 02:39 PM	#5
w00t diyAudio Member Join Date: Aug 2003 Location: Singapore	Based on the schematic as in the link in post #1. Driving my al' cheapo cans currently.

13th August 2003, 02:38 PM	#6
w00t diyAudio Member Join Date: Aug 2003 Location: Singapore	I just heard this tube, the quality of the soudn coming out of it is really bad . A solid state preamp could so better

23rd April 2010, 03:21 AM	#7
anzic diyAudio Member Join Date: Apr 2010	Hi all, I know this is a really old post, but I am desperately trying to track down a copy of the K055.PDF from Oatley Electronics that has the schematic for this 6j6 preamp as mentioned in the first post. Oatley dont have it anymore and can't get it off their website even with wayback machine/archive.org. If anyone has a copy and can help it would be very appreciated. Cheers, Anzic.

9th June 2010, 10:45 AM	#8
TRANSDUCEReng diyAudio Member Join Date: Sep 2004 Location: Malaysia	Hi Anzic, Understand you been looking for the schematic and i do have a copy...and also have the original project kit unassembled and sitting in my store for the last 8 years..... and coincidently getting into this valve project...Would be great if we could discuss about this ...pls drop a me mail at franbargain@yahoo.com...thanks

10th June 2010, 01:35 AM	#9
anzic diyAudio Member Join Date: Apr 2010	TRANSDUCEReng, Email sent, thanks :-)

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