So I removed the RelCap RTE's and bought new CD mica and installed yesterday. I also replaced the 47K dale loading resistor with a 39K Riken. Both made a big difference in what I hear. I bought the CD mica's off of the Mouser BOM and were 500 volt rated and 1% vs the 100volt 5% of the parts for the kit. The lead size was larger but they fit. Some people have said higher voltage caps take longer to break-in and sound slower but sound has really come around after about 5 hours. The bottom end is fuller by a large margin and low level detail has gotten better, such as hearing reverb trails and hall ambiance. Overall much more propulsive dynamics, I don't know how to decribe this fully but it is as if the full frequency spectrum is more displayed in dynamic events.
Could any of this be related to the 39K Riken being a 1/2 watt resistor with larger leads?
Could any of this be related to the 39K Riken being a 1/2 watt resistor with larger leads?
I would be surprised if the loading resistor makes a big difference, especially the power rating. At the subjective level, well, anything is possible and I advise you to go with what works for you. Maybe the Riken is lower noise in this application than the Dale, maybe the change to a lower resistance makes some perceptible difference...
Spent some time listening tonight and no doubt the Silver mica caps are what belongs in the preamp. Kudos to Richard for choosing parts that work. Even with the fact that I believe the Riken resistor loading at 39K has changed the tone slightly, the sibilance I eventually could not away from is just totally gone. My only conclusion is somehow the RTE's were at fault, does not make sense at one level because the sound with them was not as clear or duller or less dynamic.
i have just measured the voltages for the phonoclone.
board1 (Right)
in +/- = 0v
out +/- = 0v
ic1 pin 4&G = -9.14v
ic1 pin 7&G = +9.16v
board 2 (left)
in +/- = 0v
out +/- = 0v
ic1 pin 4&G = -9.16v
ic1 pin 7&G = +9.18v
do you now think it's safe to proceed and if so is there anything else i should measure before hooking a cart up?
board1 (Right)
in +/- = 0v
out +/- = 0v
ic1 pin 4&G = -9.14v
ic1 pin 7&G = +9.16v
board 2 (left)
in +/- = 0v
out +/- = 0v
ic1 pin 4&G = -9.16v
ic1 pin 7&G = +9.18v
do you now think it's safe to proceed and if so is there anything else i should measure before hooking a cart up?
Richard, I plan on adding a buffer to my VSPS 300. I also plan on building a Transcendent Sound Gounded Grid preamp and wonder if the buffer would be up to the task to use at the output of that preamp. One of the attributes of the grounded grid is its speed and very wide bandwidth (a few Hz to 300K). The GG preamp could use help driving longer cables so in some ways may be similar in that regard to the VSPS.
Walt
Walt
Hi Walt,
If by buffer you mean the bboard, it can be placed after the VSPS, or after your preamp, anywhere you feel the extra drive and isolation might be useful.
The bboard has well over 1 Mhz bandwidth, closer to 10, so there's no worry that it might drag the preamp down, performance-wise.
If by buffer you mean the bboard, it can be placed after the VSPS, or after your preamp, anywhere you feel the extra drive and isolation might be useful.
The bboard has well over 1 Mhz bandwidth, closer to 10, so there's no worry that it might drag the preamp down, performance-wise.
To sum up the general conclusion: dual mono is good, somewhat over-spec is good (up to about 160 VA), and high quality is good.
The basic recommended power supply is unchanged: one or two 35-50 VA 2x12 VAC toroidals, with 6A 100V or larger bridge rectifiers. This is, in my opinion, where diminishing returns start to kick in.
The absolute minimum is 10 VA 2x12 VAC and 1A, 50V diodes.
The basic recommended power supply is unchanged: one or two 35-50 VA 2x12 VAC toroidals, with 6A 100V or larger bridge rectifiers. This is, in my opinion, where diminishing returns start to kick in.
The absolute minimum is 10 VA 2x12 VAC and 1A, 50V diodes.
Hello all,
A while back I ordered and then built a VSPS kit from rjm. I have integrated it into my modified HLLY AMK-II pre-amp in such a manner that the AUX input on the pre-amp is now a dedicated phono input. The VSPS is powered off the +/- 15v "test points" on the main pre-amp board and the VSPS fits inside the chassis just perfectly.
Initially, I took Richard's advice and installed the included 5532 opamp. I was very satisfied with the sound, overall. Nothing to complain about, that is for sure.
However, on the weekend I decided to go through my supply of opamps and try to identify one that would be a good match. Based on some reading here, the parameters I was most interested in was a GBP less than or equal to 10Mhz and low voltage noise. I have plenty of opamps to choose from, but the one that really stuck out from the crowd was the AD8599. It is a very high performance part which satisfies Richard's prescription for a GBP of ~10Mhz and in all other ways is "superior" (spec-wise) to the NE5532. Also, Analog Devices specifically intended for this part to be used in "professional audio preamps", so I figured I'd go with my gut and give it a shot.
I am very glad that I did. I cannot say that the difference is "night and day", but I must say the AD8599 does a better job of "getting out of the way". It isn't so much that I can "hear" the AD8599; it is that I can't hear it. Or, at least, not as much as the NE5532.
Note: This is a very preliminary observation, conducted with a questionable cartridge/stylus on a Technics SL-10. I have a much better cartridge on the way and I plan to do some more testing.
Note2: I only posted this here because I have found very little info out there about using the AD8599 in the VSPS. What I did find (on a Polish forum) was very encouraging.
A while back I ordered and then built a VSPS kit from rjm. I have integrated it into my modified HLLY AMK-II pre-amp in such a manner that the AUX input on the pre-amp is now a dedicated phono input. The VSPS is powered off the +/- 15v "test points" on the main pre-amp board and the VSPS fits inside the chassis just perfectly.
Initially, I took Richard's advice and installed the included 5532 opamp. I was very satisfied with the sound, overall. Nothing to complain about, that is for sure.
However, on the weekend I decided to go through my supply of opamps and try to identify one that would be a good match. Based on some reading here, the parameters I was most interested in was a GBP less than or equal to 10Mhz and low voltage noise. I have plenty of opamps to choose from, but the one that really stuck out from the crowd was the AD8599. It is a very high performance part which satisfies Richard's prescription for a GBP of ~10Mhz and in all other ways is "superior" (spec-wise) to the NE5532. Also, Analog Devices specifically intended for this part to be used in "professional audio preamps", so I figured I'd go with my gut and give it a shot.
I am very glad that I did. I cannot say that the difference is "night and day", but I must say the AD8599 does a better job of "getting out of the way". It isn't so much that I can "hear" the AD8599; it is that I can't hear it. Or, at least, not as much as the NE5532.
Note: This is a very preliminary observation, conducted with a questionable cartridge/stylus on a Technics SL-10. I have a much better cartridge on the way and I plan to do some more testing.
Note2: I only posted this here because I have found very little info out there about using the AD8599 in the VSPS. What I did find (on a Polish forum) was very encouraging.
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@cogitech
Thanks for posting this information.
The AD8597/8599, like the National LME49710/4562 and a couple of others, belongs to this class of relatively recent, high performance audio op amps which would surely be excellent choices in any of the RJM Audio circuits and are not on my BOMs for the simple reason that they were not in existence when the circuits were developed, or were not available in DIP8 packages.
The 8597 is an example of the latter: it is only SMT at present, so you'll have to use it with an adapter. The LME49710 does come in a DIP8 package, and would definitely be high on my list of parts to try.
Basically if the amp is marketed as being "for audio" and better yet "professional audio", it will be suitable for use in the VSPS, Sapphire, and the Phonoclone IC2,3,4. The Phonoclone IC1 is a little different: this is a low noise, low impedance application so the OPA27 or equivalent (usually marketed as "low noise, precision") op amps are possibly more desirable over the for-audio types, the latter being typically optimized for slightly higher input impedance.
Thanks for posting this information.
The AD8597/8599, like the National LME49710/4562 and a couple of others, belongs to this class of relatively recent, high performance audio op amps which would surely be excellent choices in any of the RJM Audio circuits and are not on my BOMs for the simple reason that they were not in existence when the circuits were developed, or were not available in DIP8 packages.
The 8597 is an example of the latter: it is only SMT at present, so you'll have to use it with an adapter. The LME49710 does come in a DIP8 package, and would definitely be high on my list of parts to try.
Basically if the amp is marketed as being "for audio" and better yet "professional audio", it will be suitable for use in the VSPS, Sapphire, and the Phonoclone IC2,3,4. The Phonoclone IC1 is a little different: this is a low noise, low impedance application so the OPA27 or equivalent (usually marketed as "low noise, precision") op amps are possibly more desirable over the for-audio types, the latter being typically optimized for slightly higher input impedance.
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