Great news
Glad to hear they'll soon be available. My tube-based preamp's phono stage is not working so I'm especially motivated to try out the Retro. I'd also like to hear some thoughts on the versatility of the two versions - as in which could best accommodate both MM and MC cartridges?
Thanks for the update. - David
Glad to hear they'll soon be available. My tube-based preamp's phono stage is not working so I'm especially motivated to try out the Retro. I'd also like to hear some thoughts on the versatility of the two versions - as in which could best accommodate both MM and MC cartridges?
Thanks for the update. - David
Russ,
Thanks for the reply and the info. In my setups, the phono needs to coexist with a computer music player (luckily with all linear-supplies, but that doesn't eliminate the noise produced on the motherboard) and a pair of amps with SMPS supplies, so I think it'll make sense for me to leave them in. I'll go ahead and complete the board stuffing after I get the 22pf polystyrenes this week.
David, no one else has answered yet, so I'll take a stab. The low-z version will really only be suitable for low-to-medium output moving coil cartridges as that version is designed to take a current-out device like a LOMC and convert it to a voltage output.
The high-z version should work ok with high output moving coil cartridges and most any moving magnet ones, but will have issues with gain and noise for medium-to-low-output moving coils.
Making phono stages that work well across all types and the full range of magnetic cartridges is very difficult and almost always requires strong tradeoffs and drawbacks!
YMMV!
Greg in Mississippi
Thanks for the reply and the info. In my setups, the phono needs to coexist with a computer music player (luckily with all linear-supplies, but that doesn't eliminate the noise produced on the motherboard) and a pair of amps with SMPS supplies, so I think it'll make sense for me to leave them in. I'll go ahead and complete the board stuffing after I get the 22pf polystyrenes this week.
David, no one else has answered yet, so I'll take a stab. The low-z version will really only be suitable for low-to-medium output moving coil cartridges as that version is designed to take a current-out device like a LOMC and convert it to a voltage output.
The high-z version should work ok with high output moving coil cartridges and most any moving magnet ones, but will have issues with gain and noise for medium-to-low-output moving coils.
Making phono stages that work well across all types and the full range of magnetic cartridges is very difficult and almost always requires strong tradeoffs and drawbacks!
YMMV!
Greg in Mississippi
Well I guess it depends on which cartridge you plan on using the most.Have a favorite?
I have a .25mV favorite. Will the LowZ get this up to balanced Buffalo III/Legato output levels?
It's a moving coil (Denon 103D). I also have a Shelter 501/II. 76-78db of gain sounds perfect.
I have two older TP BPS with two 15VA 15V transformers that I can use in a dual mono setup. Alternatively, I have a single Bipolar Salas shunt with a 100VA transformer not, at least initially, dual mono. Which would be more appropriate?
I am assuming that the power supply requirements would be roughly similar to a Legato
I am planning a large single chassis build. Is this a mistake? While it will be carefully laid out (I think), I’m concerned with noise given the high gain.
Any plans or suggestions for a balanced selector switch? Planning to use a Joshua Tree for the Retro. Will the JT be in stock soon?
BTW, love the Buff IIIse and Legato combo.
Ready to order as soon as you guys are!
I have two older TP BPS with two 15VA 15V transformers that I can use in a dual mono setup. Alternatively, I have a single Bipolar Salas shunt with a 100VA transformer not, at least initially, dual mono. Which would be more appropriate?
I am assuming that the power supply requirements would be roughly similar to a Legato
I am planning a large single chassis build. Is this a mistake? While it will be carefully laid out (I think), I’m concerned with noise given the high gain.
Any plans or suggestions for a balanced selector switch? Planning to use a Joshua Tree for the Retro. Will the JT be in stock soon?
BTW, love the Buff IIIse and Legato combo.
Ready to order as soon as you guys are!
Thanks Ron!
Either power supply should be suitable, what I would do is try both options and use the one the yields the lowest noise floor. The current requirements are modest - I would say < 150ma depending somewhat on your load.
As for a balanced selector switch I don't really have a great suggestion, but you could probably use something like a 4 deck rotary.
Single chassis should be fine if you have the room. Just do the best you can. If necessary you can always move the phono stage out later.
Cheers!
Russ
Either power supply should be suitable, what I would do is try both options and use the one the yields the lowest noise floor. The current requirements are modest - I would say < 150ma depending somewhat on your load.
As for a balanced selector switch I don't really have a great suggestion, but you could probably use something like a 4 deck rotary.
Single chassis should be fine if you have the room. Just do the best you can. If necessary you can always move the phono stage out later.
Cheers!
Russ
Hi Russ:
I am eagerly awaiting the Low Z version to use with my low output MC cartridges.
A couple of questions about the Low Z version:
1. Will the production Low Z version be following a very similar topology to the schematic you posted in post #21?
2. If so, I have a pair of 3.1uf film capacitors I like to use in the c2 (3uf) position in the RIAA EQ network. How much would the capacitance difference affect the RIAA accuracy and overall sound? Is there a way I can adjust the values of the other components in the RIAA EQ network to compensate for it?
Thanks!
I am eagerly awaiting the Low Z version to use with my low output MC cartridges.
A couple of questions about the Low Z version:
1. Will the production Low Z version be following a very similar topology to the schematic you posted in post #21?
2. If so, I have a pair of 3.1uf film capacitors I like to use in the c2 (3uf) position in the RIAA EQ network. How much would the capacitance difference affect the RIAA accuracy and overall sound? Is there a way I can adjust the values of the other components in the RIAA EQ network to compensate for it?
Thanks!
Yes - its the same. Values will probably want to be tweaked to get best noise performance.
It won't make a big enough difference to worry about.
Very close.
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Hi Russ,
1.) You say you intend to build a preamp that incorporates both the hi-Z and low-Z boards. I intend to do likewise, now that you are making your low-Z version available. Could you describe how you are going to go about switching from one board to the other? I expect it is not a good idea to switch the rails on the shunt regulator, but if both boards are on all the time, and you are switching only the signals, that's a lot more dissipation expected from the shunt regs.
2.) Are you going to take advantage of the OPA1632 opamp's "enable" pin to switch from MC to MM?
1.) You say you intend to build a preamp that incorporates both the hi-Z and low-Z boards. I intend to do likewise, now that you are making your low-Z version available. Could you describe how you are going to go about switching from one board to the other? I expect it is not a good idea to switch the rails on the shunt regulator, but if both boards are on all the time, and you are switching only the signals, that's a lot more dissipation expected from the shunt regs.
2.) Are you going to take advantage of the OPA1632 opamp's "enable" pin to switch from MC to MM?
A plug and socket arrangement works well. XLR is the obvious choice, using a female panel socket and an inline male plug in which are housed the resistors and, probably, polystyrene caps.
Redel plugs are compact, lightweight, but expensive and harder to work with, and it is more arduous to make the required panel opening for them, but they would be my choice every time.