Simplistic NJFET RIAA - Page 440

merlin el mago · 14th August 2010, 05:07 PM

It's necessary also to connect the NJFET RIAA to the regulator?

Salas · 14th August 2010, 05:08 PM

Connect the 1k5W as load to the regulator, its enough.

merlin el mago · 14th August 2010, 05:45 PM

R5 270R 1W burned

Salas · 14th August 2010, 06:29 PM

You have done damage in more semiconductors than Q5 in your previous experiments it seems. That one resistor burning is fishy for knocked out BJTs in the CCS tail governing the LEDs current. Seek and replace all damage in the reg patiently.

merlin el mago · 14th August 2010, 07:07 PM

Ok I will change BJTs, the leds lit orange instead yellow when resistor burned. Thanks

AndrewT · 14th August 2010, 07:10 PM

Quote:

Originally Posted by Joao@AltheaMusica

there exist CDPs / DACs which deliver up to 6Vac ...

I am not aware of this standard.
Could you mean 6Vpp?

SGregory · 01:06 AM

Merlin, I would recheck the LED's as well, makes sure they are still matched. A color change isn't a good thing in an LED since they are typically mono-chromatic unless it is designed to do that. If not, the junction was over heated. The Orange glow was probably thermal emission and not normal.

In regards to the gain comment presented earlier. If there was more gain than the 58dB I allready have, my speakers would have glowed like the LED above at the same volume settings as my cd player. As it stands now, my volume control is very much in the same range as my cd player for the same volume.

I have some pictures coming of the DL103r on the arm and comments on the RD80 mod. The mods I did were in the wrong direction so don't get too excited.
I spent the day redesinging my 12b4 preamp. It was an old project using bird nest and dead bug technique. The bugs started to rot in the nest, if you know what I mean. I put the tube on a 10m45s CCS load with LED bias. Working well so far, at least the gain between channels is closer.

Salas · 15th August 2010, 01:53 AM

Did you notice any rise in hiss when anode loading with the IXYS?

SGregory · 15th August 2010, 02:19 AM

No. Actually a reduction of hiss. Quite a bit in fact. I remember your comments on the OPUS thread and was wary at first. I did have some tubes that were not stable with this.

I would like to build a discrete CCS for it at some point. Still looking for a good design.

I don't want to get OT however.

Salas · 15th August 2010, 02:24 AM

I had some 12B4s that would hiss with such an anode load but it is not the norm as it proved by asking around. Thanks for the info.

Look around the forum for gyrator constant voltage designs too.

15th August 2010, 12:57 AM	#4397
SGregory Tubie Noobie diyAudio Member Join Date: Apr 2003 Location: Southern Tier NY	Merlin, I would recheck the LED's as well, makes sure they are still matched. A color change isn't a good thing in an LED since they are typically mono-chromatic unless it is designed to do that. If not, the junction was over heated. The Orange glow was probably thermal emission and not normal. In regards to the gain comment presented earlier. If there was more gain than the 58dB I allready have, my speakers would have glowed like the LED above at the same volume settings as my cd player. As it stands now, my volume control is very much in the same range as my cd player for the same volume. I have some pictures coming of the DL103r on the arm and comments on the RD80 mod. The mods I did were in the wrong direction so don't get too excited. I spent the day redesinging my 12b4 preamp. It was an old project using bird nest and dead bug technique. The bugs started to rot in the nest, if you know what I mean. I put the tube on a 10m45s CCS load with LED bias. Working well so far, at least the gain between channels is closer. __________________ Living Life Doing the Waltz in 4/4 meter. Last edited by SGregory; 15th August 2010 at 01:06 AM.

15th August 2010, 02:19 AM	#4399
SGregory Tubie Noobie diyAudio Member Join Date: Apr 2003 Location: Southern Tier NY	No. Actually a reduction of hiss. Quite a bit in fact. I remember your comments on the OPUS thread and was wary at first. I did have some tubes that were not stable with this. I would like to build a discrete CCS for it at some point. Still looking for a good design. I don't want to get OT however. __________________ Living Life Doing the Waltz in 4/4 meter.

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14th August 2010, 05:07 PM	#4391
merlin el mago diyAudio Member Join Date: Sep 2009 Location: Blanes - Costa Brava	It's necessary also to connect the NJFET RIAA to the regulator?

14th August 2010, 05:08 PM	#4392
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	Connect the 1k5W as load to the regulator, its enough.

14th August 2010, 05:45 PM	#4393
merlin el mago diyAudio Member Join Date: Sep 2009 Location: Blanes - Costa Brava	R5 270R 1W burned

14th August 2010, 06:29 PM	#4394
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	You have done damage in more semiconductors than Q5 in your previous experiments it seems. That one resistor burning is fishy for knocked out BJTs in the CCS tail governing the LEDs current. Seek and replace all damage in the reg patiently.

14th August 2010, 07:07 PM	#4395
merlin el mago diyAudio Member Join Date: Sep 2009 Location: Blanes - Costa Brava	Ok I will change BJTs, the leds lit orange instead yellow when resistor burned. Thanks

15th August 2010, 01:53 AM	#4398
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	Did you notice any rise in hiss when anode loading with the IXYS?

15th August 2010, 02:24 AM	#4400
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	I had some 12B4s that would hiss with such an anode load but it is not the norm as it proved by asking around. Thanks for the info. Look around the forum for gyrator constant voltage designs too.

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