Vacuum State RTP3C

[cjcc67]

Thanks Alex crystal clear now.

 

[jpak]

For anyone that has built the full RTP3D are you able to use cartridges with .2 mv output?

 

[Alex M]

Brad Morrical on the RTP3D, from his Positive Feedback preamp group preamp test:

"The superb behavior continued when switching to phono. It handled my 0.26 mV Dynavector cartridge with no noise, a good sign."

Not quite 0.2 mV, but I also recall Allen saying he had used 0.1 mV Audio Note IO cartridge with the RTP3.

Alex

 

[rollo22]

RTP3

I recommend to order the instruction CD from vacuumstate.com, the money spend will insure that one get the RTP3 build as intended.

Does anyone have a CDR to sell ?

Vacuum State don't sell it anymore.

 

[hidnplayr]

I'm also interessed in this CD, what kind of extra information does it contain compared to the Tube Preamp Cookbook ?

 

[Kim Bay Smidt]

They sadly don't offer the instruction CD anymore. Be aware that the Instruction CD is copyrighted by vacuumstate.com

 

[HVfanatic]

If anyone here in this thread would sell me his CD, I would be very happy...

dirk_dot_bosse_at_gmx_dot_de

Email address edited by moderation to avoid harvest by spambot.

 

[swordsman]

Looking at the RTP3C schematic I noticed the LM329 is bypassed to ground with a 1uf capacitor. I guess the intention is to lower the input impedance to the 6922 at high frequency therefore shorting any possibility of interference noise that might cause oscillation. The thing is this 1uf will load the lm329 that preventing it from working properly.

I've built a similar 2sk146//6922 cascode using lm329 for voltage reference and bypass it with a 1uf Wima cap. In listening there is a lack of airiness, highs seem rolloff. Like there's a veil between me and the music. I found out the hard way that lm329 does not like capacitive load. After I yank the wima, the veil removed but noise floor increases causing soundstage to become more 2D and bass fullness reduced. For experiment, I replaced the lm329 with a resistor and a bypass cap (oscon). This restored the sonic balance n noise floor. Comparing to the lm329 with bypass, the later seem to offer more dynamic contrast and ambient information. Again this I suspect is the lower noise floor of the lm329 combo.

I did a search on some voltage regulator design where lm329 is used as a voltage reference for the error opamp. There is always a RC filter following the lm329 for providing a resistive load, input impedance matching for the opamp, and to reduce the lm329 noise.

Any one out there share a similar experience? The next thing I'm going to try is probably adding a RC filter to the lm329.

 

[Alex M]

Looking at the RTP3C schematic I noticed the LM329 is bypassed to ground with a 1uf capacitor. I guess the intention is to lower the input impedance to the 6922 at high frequency therefore shorting any possibility of interference noise that might cause oscillation. The thing is this 1uf will load the lm329 that preventing it from working properly.

I've built a similar 2sk146//6922 cascode using lm329 for voltage reference and bypass it with a 1uf Wima cap. In listening there is a lack of airiness, highs seem rolloff. Like there's a veil between me and the music. I found out the hard way that lm329 does not like capacitive load. After I yank the wima, the veil removed but noise floor increases causing soundstage to become more 2D and bass fullness reduced. For experiment, I replaced the lm329 with a resistor and a bypass cap (oscon). This restored the sonic balance n noise floor. Comparing to the lm329 with bypass, the later seem to offer more dynamic contrast and ambient information. Again this I suspect is the lower noise floor of the lm329 combo.

I did a search on some voltage regulator design where lm329 is used as a voltage reference for the error opamp. There is always a RC filter following the lm329 for providing a resistive load, input impedance matching for the opamp, and to reduce the lm329 noise.

Any one out there share a similar experience? The next thing I'm going to try is probably adding a RC filter to the lm329.

Thanks for your comments. I note in the LM329 application sheet none of the suggested circuits has a capacitor across the chip. Unlike the case of - say - the LM317 - there is no specific recommendation for a capacitor across the regulated voltage.

Alex

 

[HVfanatic]

Looking at the vacuum state website and some comments spread, the use of a mat02 is recommended over the use of a jfet...

But which type is best suited?

selection AH / CH / EH or FH ? Which is recommended and what is the effect of a different choice???

Dirk

 

[HVfanatic]

Hi,

looking at the datasheet, MAT02E seems best suited. Does anybody disagree with that? I would be happy to get builders feedback...

Thanks, Dirk

 

[vtr]

lm329-rtp3

Looking at the RTP3C schematic I noticed the LM329 is bypassed to ground with a 1uf capacitor. I guess the intention is to lower the input impedance to the 6922 at high frequency therefore shorting any possibility of interference noise that might cause oscillation. The thing is this 1uf will load the lm329 that preventing it from working properly.

I've built a similar 2sk146//6922 cascode using lm329 for voltage reference and bypass it with a 1uf Wima cap. In listening there is a lack of airiness, highs seem rolloff. Like there's a veil between me and the music. I found out the hard way that lm329 does not like capacitive load. After I yank the wima, the veil removed but noise floor increases causing soundstage to become more 2D and bass fullness reduced. For experiment, I replaced the lm329 with a resistor and a bypass cap (oscon). This restored the sonic balance n noise floor. Comparing to the lm329 with bypass, the later seem to offer more dynamic contrast and ambient information. Again this I suspect is the lower noise floor of the lm329 combo.

I did a search on some voltage regulator design where lm329 is used as a voltage reference for the error opamp. There is always a RC filter following the lm329 for providing a resistive load, input impedance matching for the opamp, and to reduce the lm329 noise.

Any one out there share a similar experience? The next thing I'm going to try is probably adding a RC filter to the lm329.

hi,

i use my rtp since 10 years now and i built it from start with a 9V battery supply instead of the 329, and it was an impreovement to change to 2 pcs of 4,5v batteries instead the small 9v and they last several years-maybe a quick fix

 

[vtr]

lm329-rtp3

Looking at the RTP3C schematic I noticed the LM329 is bypassed to ground with a 1uf capacitor. I guess the intention is to lower the input impedance to the 6922 at high frequency therefore shorting any possibility of interference noise that might cause oscillation. The thing is this 1uf will load the lm329 that preventing it from working properly.

I've built a similar 2sk146//6922 cascode using lm329 for voltage reference and bypass it with a 1uf Wima cap. In listening there is a lack of airiness, highs seem rolloff. Like there's a veil between me and the music. I found out the hard way that lm329 does not like capacitive load. After I yank the wima, the veil removed but noise floor increases causing soundstage to become more 2D and bass fullness reduced. For experiment, I replaced the lm329 with a resistor and a bypass cap (oscon). This restored the sonic balance n noise floor. Comparing to the lm329 with bypass, the later seem to offer more dynamic contrast and ambient information. Again this I suspect is the lower noise floor of the lm329 combo.

I did a search on some voltage regulator design where lm329 is used as a voltage reference for the error opamp. There is always a RC filter following the lm329 for providing a resistive load, input impedance matching for the opamp, and to reduce the lm329 noise.

Any one out there share a similar experience? The next thing I'm going to try is probably adding a RC filter to the lm329.

hi,

i use my rtp since 10 years now and i built it from start with a 9V battery supply instead of the 329, and it was an impreovement to change to 2 pcs of 4,5v batteries instead the small 9v and they last several years-maybe a quick fix

 

[Joshua_G]

hi,

i use my rtp since 10 years now and i built it from start with a 9V battery supply instead of the 329, and it was an impreovement to change to 2 pcs of 4,5v batteries instead the small 9v and they last several years-maybe a quick fix

How about a shunt regulator, like the Salas one, instead of LM329?
Also, how about a shunt regulator, like the Salas one, for "C" -25 Volt?

 

[vtr]

shunt reg for -25v

hi,

for -25V i use a simple shunt reg with a ccs and a 24v zener

and allen liked the sound of my rtp too (but i have built it with a 3 phase power supply with tube rectifiers)

 

[jacco vermeulen]

But which type is best suited?

How about best matching ones you can get your hands on ?

(for balanced stages, SSM2210 with less than 1/2% Hfe match smarter choice than a MAT02/A with 2 )

 

[jpak]

Has anyone been able to purchase the tube preamp cookbook from VacuumState recently? I have had no luck contacting them.

 

[Shoog]

You may not be aware that the author recently passed away. I think his company was a sole trader status, so there may no longer be a company to order the book from. Joe Rasmussen handled business in Australia I think and he has been an active member on these boards. Try looking at his JLi amp webpage to see if he can help.

Shoog

 

[hidnplayr]

I ordered mine on july 1 and got it after some delay.
The book was in backorder back then so is probably in stock now.

It was his wife who handled the request.

Have patience.

 

[jpak]

You may not be aware that the author recently passed away. I think his company was a sole trader status, so there may no longer be a company to order the book from. Joe Rasmussen handled business in Australia I think and he has been an active member on these boards. Try looking at his JLi amp webpage to see if he can help.

Shoog

Thanks, I was aware of Allen's passing. I should have been more proactive about ordering it when I asked him my questions earlier in the thread.