Simplistic NJFET RIAA - Page 268

Salas · 15th November 2009, 05:58 PM

0.32mV on mine's individual spec sheet at 47k. Less on 150R I use. They market it as 0.25mV 100R min load.

RCruz · 06:17 PM

The 56db version is intended to work with what cart output values ?

Salas · 15th November 2009, 06:22 PM

0.5mV as footnoted on the circuits posted. Can work good up to 0.8mV for your Clearaudio Goldfinger second fiddle cart cheapy, going from 0.025% THD to about 0.04% Rather loud but still OK.

With Benz ACE red around 0.4mV works too. With lower cart you start to feel you need extra gain. At least in systems with not too much line preamp gain.

The gain I have set for each version was compared to typical CDP output at same volume level, no much less so to luck, not more so to shout and also to save on second stage distortion. Not in mV, but by playing cds and records.

The MM version's gain is good for 3-5mV. The Medium's for 1-2mV, the Normal MC's for 0.4-0.5mV. The Low MC's (either with 1st stage's Rs bypass or the latest post with 4 njfets and high B+) good for 0.2-0.3mV.

I hope I give you the sum picture.

RCruz · 15th November 2009, 06:27 PM

Yes

Thank you again... I did not have that info in my riaa spreadsheet and I believe it is pertinent.

Ricardo

nicoch58 · 22nd November 2009, 12:53 PM

HI Salas

with a trafo step-up 1:15 ,for the same load of 180r, which r ?

Salas · 22nd November 2009, 01:38 PM

40.5k

RCruz · 23rd November 2009, 08:01 PM

Hi Salas

My new toys are two VTL 160 made by Manley. Manley_160Watt_Amplifier

I am considering building a buffer to place between them and the riaa so I can get volume control.

As a matter of fact I already built two pedja buffers and have the 50k pot and my idea is: 1st Riaa, 2nd pot, 3rd buffer, 4th tube amps.

It feels a little strange to place more caps in the signal path so I am wondering if I can place the pot directly inside the riaa (just before the output buffer)... can it be done without messing with the riaa values ?

Ricardo

nicoch58 · 08:20 PM

Salas · 23rd November 2009, 08:12 PM

After the second stage whatever you do, it does not mess the Riaa. With 750mV sensitivity of the Manley, a buffered volume pot isn't a bad idea. You would have to pass DC through your pot though, because the second stage biases the Simplistic's output buffer. Can be scratchy and short lived. I would just delete the existing buffer, move the existing output cap to the 2nd stage out, then add the pot and drive the external buffer.

nicoch58 · 23rd November 2009, 08:20 PM

Salas what we can do with new Ricardo amp?
put out two tubes and mismatch the speakers ?

lover the b+ and add 6v6

)

15th November 2009, 06:14 PM	#2672
RCruz diyAudio Member Join Date: Sep 2006 Location: Cascais Blog Entries: 1	The 56db version is intended to work with what cart output values ? Last edited by RCruz; 15th November 2009 at 06:17 PM.

22nd November 2009, 12:53 PM	#2675
nicoch58 diyAudio Member Join Date: Oct 2004	ot load HI Salas with a trafo step-up 1:15 ,for the same load of 180r, which r ?

23rd November 2009, 08:11 PM	#2678
nicoch58 diyAudio Member Join Date: Oct 2004	Last edited by nicoch58; 23rd November 2009 at 08:20 PM.

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15th November 2009, 05:58 PM	#2671
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	0.32mV on mine's individual spec sheet at 47k. Less on 150R I use. They market it as 0.25mV 100R min load.

15th November 2009, 06:22 PM	#2673
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	0.5mV as footnoted on the circuits posted. Can work good up to 0.8mV for your Clearaudio Goldfinger second fiddle cart cheapy, going from 0.025% THD to about 0.04% Rather loud but still OK. With Benz ACE red around 0.4mV works too. With lower cart you start to feel you need extra gain. At least in systems with not too much line preamp gain. The gain I have set for each version was compared to typical CDP output at same volume level, no much less so to luck, not more so to shout and also to save on second stage distortion. Not in mV, but by playing cds and records. The MM version's gain is good for 3-5mV. The Medium's for 1-2mV, the Normal MC's for 0.4-0.5mV. The Low MC's (either with 1st stage's Rs bypass or the latest post with 4 njfets and high B+) good for 0.2-0.3mV. I hope I give you the sum picture.

15th November 2009, 06:27 PM	#2674
RCruz diyAudio Member Join Date: Sep 2006 Location: Cascais Blog Entries: 1	Yes Thank you again... I did not have that info in my riaa spreadsheet and I believe it is pertinent. Ricardo

22nd November 2009, 01:38 PM	#2676
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	40.5k

23rd November 2009, 08:01 PM	#2677
RCruz diyAudio Member Join Date: Sep 2006 Location: Cascais Blog Entries: 1	Hi Salas My new toys are two VTL 160 made by Manley. Manley_160Watt_Amplifier I am considering building a buffer to place between them and the riaa so I can get volume control. As a matter of fact I already built two pedja buffers and have the 50k pot and my idea is: 1st Riaa, 2nd pot, 3rd buffer, 4th tube amps. It feels a little strange to place more caps in the signal path so I am wondering if I can place the pot directly inside the riaa (just before the output buffer)... can it be done without messing with the riaa values ? Ricardo

23rd November 2009, 08:12 PM	#2679
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	After the second stage whatever you do, it does not mess the Riaa. With 750mV sensitivity of the Manley, a buffered volume pot isn't a bad idea. You would have to pass DC through your pot though, because the second stage biases the Simplistic's output buffer. Can be scratchy and short lived. I would just delete the existing buffer, move the existing output cap to the 2nd stage out, then add the pot and drive the external buffer.

23rd November 2009, 08:20 PM	#2680
nicoch58 diyAudio Member Join Date: Oct 2004	Salas what we can do with new Ricardo amp? put out two tubes and mismatch the speakers ? lover the b+ and add 6v6 )

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