2SK170 BL MC step up amp

batty · 10th May 2011, 06:20 AM

I have some 2SK170bl lying around and want to make an amp for my Denon DL103 to go into the MM input on my Copland. I have an SUT but wanted to try SS. I'm looking for a simple circuit that has the option of gain switching to allow for lower output MCs further down my MC road.

Anyone know of a cct diag, preverably running off a 9v supply.

No RIAA eq needed.

Salas · 10th May 2011, 08:42 AM

This one fits most spec you described except for gain switching.

h_a · 10th May 2011, 08:54 AM

The Ono front end comes to mind; pretty similar to Salas' version but with a cap multiplier to remove PSU-noise. The LM-regulators however should do pretty well also.

Hannes

Salas · 10th May 2011, 09:00 AM

*The above circuit has a cap multiplier after the 7809 also.

batty · 09:13 AM

Thanks guys.

Is the o/p taken from junction of C3/R5? and could I use a PP3 battery with +ve connected where the bottom of R1 joins?

Cheers

Steve

Salas · 10th May 2011, 09:42 AM

O/P at C3,R5 node. R1 is the load resistor, +Ve goes on top of it. Keep whatever is there after the 7809 or at least put 100R in series from PP3's + to R1's top and keep C2. 430 Ohm R2 loading good for DL103. Will drain 14mA per channel, not too long a listen with a PP3...

batty · 10:41 AM

OK thanks Salas, probably a 12vdc adaptor to feed the 7809s unless I can find a 15v version.

I am thinking of building inside the same box as the SUT just for ease of build and swapping cables over. all for fun you understand.

What type of caps

Salas · 10th May 2011, 11:27 AM

12VDC adaptor far away to avoid fields still OK. Panasonic FC electrolytics or alike low ESR for the 1000uF ones and PP or Teflon (best) for the 0.47uF Cout. The C4,5 0.1uF for 7809 termination can be MKT.

gpapag · 10th May 2011, 12:00 PM

There:
PSU RC multistage filtering

Tony suggests having a minimum of 5Vdc difference between input-output on LM 317.

It is my observation in praxis that this holds true for fixed voltage 3 leg regulators as well. It garantees specified regulation action from the chip.

This 5V difference is hidden in many of the performance curves supplied by the manufacturers of the voltage regulators.

Salas thanks for providing this schematic.

Regards
George

batty · 10th May 2011, 12:15 PM

what would the max input be for a 7809, would 18V be to much to drop to 9v.

10th May 2011, 06:20 AM	#1
batty diyAudio Member Join Date: Jan 2010 Location: Adelaide South Australia	2SK170 BL MC step up amp I have some 2SK170bl lying around and want to make an amp for my Denon DL103 to go into the MM input on my Copland. I have an SUT but wanted to try SS. I'm looking for a simple circuit that has the option of gain switching to allow for lower output MCs further down my MC road. Anyone know of a cct diag, preverably running off a 9v supply. No RIAA eq needed. __________________ Townshend Rock II, My new TT since 1986.

10th May 2011, 08:54 AM	#3
h_a diyAudio Member Join Date: Sep 2006 Location: Graz, Austria	The Ono front end comes to mind; pretty similar to Salas' version but with a cap multiplier to remove PSU-noise. The LM-regulators however should do pretty well also. Hannes __________________ fresh matched IRFP240/IRFP9240 fets \|\| AlephJ/JX-kits F5 transistor kits \|\| Burning Amp BA-1/2/3 transistor kits

10th May 2011, 09:10 AM	#5
batty diyAudio Member Join Date: Jan 2010 Location: Adelaide South Australia	Thanks guys. Is the o/p taken from junction of C3/R5? and could I use a PP3 battery with +ve connected where the bottom of R1 joins? Cheers Steve __________________ Townshend Rock II, My new TT since 1986. Last edited by batty; 10th May 2011 at 09:13 AM.

10th May 2011, 10:34 AM	#7
batty diyAudio Member Join Date: Jan 2010 Location: Adelaide South Australia	OK thanks Salas, probably a 12vdc adaptor to feed the 7809s unless I can find a 15v version. I am thinking of building inside the same box as the SUT just for ease of build and swapping cables over. all for fun you understand. What type of caps __________________ Townshend Rock II, My new TT since 1986. Last edited by batty; 10th May 2011 at 10:41 AM. Reason: fat fingers

10th May 2011, 12:15 PM	#10
batty diyAudio Member Join Date: Jan 2010 Location: Adelaide South Australia	what would the max input be for a 7809, would 18V be to much to drop to 9v. __________________ Townshend Rock II, My new TT since 1986.


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10th May 2011, 09:00 AM	#4
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	*The above circuit has a cap multiplier after the 7809 also.

10th May 2011, 09:42 AM	#6
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	O/P at C3,R5 node. R1 is the load resistor, +Ve goes on top of it. Keep whatever is there after the 7809 or at least put 100R in series from PP3's + to R1's top and keep C2. 430 Ohm R2 loading good for DL103. Will drain 14mA per channel, not too long a listen with a PP3...

10th May 2011, 11:27 AM	#8
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	12VDC adaptor far away to avoid fields still OK. Panasonic FC electrolytics or alike low ESR for the 1000uF ones and PP or Teflon (best) for the 0.47uF Cout. The C4,5 0.1uF for 7809 termination can be MKT.

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