Great! And I'm back quicker than I thought. You're running 2 HV regs off a single trafo if I'm understanding everything correctly. Is there any benefit to putting HV transformer in one box and building regs themselves on same chassis as audio circuitry? Ignoring filament supplies for now, I'm imagining transformer, diodes, C1, L1 and C3 in PS box with HV off L1 and C3 connected via cable over to signal chassis. Comments?
Hope you're staying warm with the weather you're getting -- a little thermionic energy and good vinyl sounds like the way to go! Thanks again.
Hope you're staying warm with the weather you're getting -- a little thermionic energy and good vinyl sounds like the way to go! Thanks again.
Last edited:
I think it's better to not introduce ripply DC into the pre-amplifier chassis so I would recommend building the entire supply in a separate chassis. Arguably placing the HV regulator closer to the circuitry being powered is not a bad idea - in practice I've found that some local decoupling and if you feel like it litz wire for B+ and returns is good as well.(Helps maintain the low supply impedance at HF)
Great Design
I think that it is well worth the time to build the Muscovite, which is a fairly complex build. I have had mine up and running for almost a year. There were minimal teething problems and the sound is really great. I have heard the iterations of the various Muscovites as they have progressed, and would recommend the Muscovite over the other later models.
The gain is relatively high, which is a big help for low output MC cartridges, such as the Ortofon Windfeld. It is at the same time very quiet. The dynamics are superb, and with the Ortofon cartridges I have tried, with both the Lundahl step ups and some Silk step ups, the sound is dynamic with great imaging. I understand that a lot of this has to do with the turntable and arm, but on two different set ups it shows the same good characteristics.
I would not be too worried about any build difficulties, as Kevin is always there to graciously assist with any questions or issues that arise. He was really of incredible assistance when mine was built.
If you like, Landfall Systems can make the enclosures for you that I posted pictures of earlier in this thread. They are very substantial and well made, and the design for the Muscovite is already done. Landfall is great to work with and their pricing is extremely reasonable for what you are getting.
If you have any questions or want further impressions of the Muscovite, just let me know. Your efforts in building this phono amp should be greatly rewarded in the end. I am really very pleased with what I am hearing all of the time, and all for a cost that is not astronomical.
I think that it is well worth the time to build the Muscovite, which is a fairly complex build. I have had mine up and running for almost a year. There were minimal teething problems and the sound is really great. I have heard the iterations of the various Muscovites as they have progressed, and would recommend the Muscovite over the other later models.
The gain is relatively high, which is a big help for low output MC cartridges, such as the Ortofon Windfeld. It is at the same time very quiet. The dynamics are superb, and with the Ortofon cartridges I have tried, with both the Lundahl step ups and some Silk step ups, the sound is dynamic with great imaging. I understand that a lot of this has to do with the turntable and arm, but on two different set ups it shows the same good characteristics.
I would not be too worried about any build difficulties, as Kevin is always there to graciously assist with any questions or issues that arise. He was really of incredible assistance when mine was built.
If you like, Landfall Systems can make the enclosures for you that I posted pictures of earlier in this thread. They are very substantial and well made, and the design for the Muscovite is already done. Landfall is great to work with and their pricing is extremely reasonable for what you are getting.
If you have any questions or want further impressions of the Muscovite, just let me know. Your efforts in building this phono amp should be greatly rewarded in the end. I am really very pleased with what I am hearing all of the time, and all for a cost that is not astronomical.
Thanks to you both for your suggestions - much appreciated. Do either of you have specific recommendations/warnings for manufacturers for the pass tube? I saw that Jim McShane in the "Is there a "best" hybrid rectifier scheme?..." prefers Genalex and Tung-Sol reissues for the rectifier. In general I've been looking at Tung-Sol, Genalex and Electro-Harmonix as tube manufacturers, except for Reflektor 6S3P of course. TIA.
Toobs
I would defer to Kevin for the ultimate in what tubes to use in the HV power supply circuit, but I can tell you what I am using. As to the rectifier, which I personally do not consider that critical, I have used a cheap and cheery Sovtek with no problems at all, but just for the heck of it, am now using an NOS Sylvania. For the EL84/6BQ positions, I have some Russian 6P14 s which are just fine. Perhaps the one more critical tube would be the 12AX7 family. I have a Sylvania from a Baldwin organ and that seems just fine. Of course there are lots of choices that boil down to personal preference. I do not think that you can go that wrong. In a more critical area, the RIAA part, get good matched capacitors and resistors form a guy like Michael Percy. And of course, just follow Kevin's recommendation as to passive parts choices. He has had a lot of experience optimizing this design and readily shares his experience with people. It will really pay off for you.
I would defer to Kevin for the ultimate in what tubes to use in the HV power supply circuit, but I can tell you what I am using. As to the rectifier, which I personally do not consider that critical, I have used a cheap and cheery Sovtek with no problems at all, but just for the heck of it, am now using an NOS Sylvania. For the EL84/6BQ positions, I have some Russian 6P14 s which are just fine. Perhaps the one more critical tube would be the 12AX7 family. I have a Sylvania from a Baldwin organ and that seems just fine. Of course there are lots of choices that boil down to personal preference. I do not think that you can go that wrong. In a more critical area, the RIAA part, get good matched capacitors and resistors form a guy like Michael Percy. And of course, just follow Kevin's recommendation as to passive parts choices. He has had a lot of experience optimizing this design and readily shares his experience with people. It will really pay off for you.
I'd stick with the generic sovtek 5AR4, they appear to all be identical except for the base and the logo silk-screened on the glass.
For all modern 5AR4 I strongly recommend inserting a UF4007 in series with each plate lead, makes them proof against arcing during warm up and transient events - the rectifier will last longer and not potentially take out the power transformer if it fails.
For all modern 5AR4 I strongly recommend inserting a UF4007 in series with each plate lead, makes them proof against arcing during warm up and transient events - the rectifier will last longer and not potentially take out the power transformer if it fails.
Hadn't quite looked at it like that but yes! That's pretty cool and to think the SG4 would have been the first project except for the SG4 boards I sold to you.
Got all the magnetics ordered today; the other parts - mostly just caps and tubes - are sourced and ready to order after I finish the bench which should happen soon. I have some other parts I need to order from Michael Percy so I can use him for one-stop capacitor shopping. I'm getting a small handful of 0.1u RT or RTX for other projects. You recommend a Clarity cap across the feedback R in the PS. I might use one of RT or RTX's in that spot with Solens for the other big caps in the supply. You foresee any problems? I'm trying to stick as close to possible to your original intent on design.
Exciting times. Thanks again...
Got all the magnetics ordered today; the other parts - mostly just caps and tubes - are sourced and ready to order after I finish the bench which should happen soon. I have some other parts I need to order from Michael Percy so I can use him for one-stop capacitor shopping. I'm getting a small handful of 0.1u RT or RTX for other projects. You recommend a Clarity cap across the feedback R in the PS. I might use one of RT or RTX's in that spot with Solens for the other big caps in the supply. You foresee any problems? I'm trying to stick as close to possible to your original intent on design.
Exciting times. Thanks again...
Based on what I know these days I'd substitute something like a Dynamicap for the Clarity (the MR would be a good choice though) across the HV supply feedback resistor. I've also used teflon, in that case I don't think it brought any benefit over the Dynamicap, but I had them on hand, salvaged from a scrapped project and so used them.
Subjectively I find the RTX to be a bit bright. The RT seems OK.
Subjectively I find the RTX to be a bit bright. The RT seems OK.
I'd recommend a minimum of 50K and here at home my line stage has 100K input impedance. It is capable of driving 10K loads, but there is a price to be paid in terms output coupling size and likely linearity as well.
I'd be surprised if you really need anywhere close to 20dB of gain in the line stage given the very high gain of this phono stage, but if you have vintage line level sources and an insensitive power amplifier you actually might.
Shot me a PM and we can go to email to discuss some older line stage designs I can share with you. One might suit..
I'd be surprised if you really need anywhere close to 20dB of gain in the line stage given the very high gain of this phono stage, but if you have vintage line level sources and an insensitive power amplifier you actually might.
Shot me a PM and we can go to email to discuss some older line stage designs I can share with you. One might suit..