Hey guys,
I'm looking for some schematics for a preamplifier that uses a 5R4 or similar rectifier tube, such as the MingDa MC-7R or something similar. I have the schematics for the MC-7R, but I was hoping to find some alternatives. I'm not quite familiar enough with electronics to design one myself.
I'm interested specifically in the use of the 5r4 because I spotted some solid state rectifiers that use the 5r4 socket, which gives me an option to play around a bit easier with the effects of tube vs solid state rectification and the impact on sound.
As a side note, I did try googling, but obviously didn't have much luck.
I'm looking for some schematics for a preamplifier that uses a 5R4 or similar rectifier tube, such as the MingDa MC-7R or something similar. I have the schematics for the MC-7R, but I was hoping to find some alternatives. I'm not quite familiar enough with electronics to design one myself.
I'm interested specifically in the use of the 5r4 because I spotted some solid state rectifiers that use the 5r4 socket, which gives me an option to play around a bit easier with the effects of tube vs solid state rectification and the impact on sound.
As a side note, I did try googling, but obviously didn't have much luck.
A slew of types share basing with the 5R4. Those plug in SS rectifiers raise the B+ rail voltage, perhaps dangerously so, and they are noisy.
In a brand, spanking, new build I strongly suggest you employ high peak inverse voltage (PIV) Schottky diodes, which are every bit as quiet as vacuum rectification, and have done with matter.
In a brand, spanking, new build I strongly suggest you employ high peak inverse voltage (PIV) Schottky diodes, which are every bit as quiet as vacuum rectification, and have done with matter.
I am pretty much of a n00b at this, but from my reading and ham experience I can tell you tube diodes have higher internal resistance, and thus more voltage change with changes in current, than a solid state diode.
For what it's worth this pre-amp uses tube diodes and the power amp I just finished up uses solid state.
For what it's worth this pre-amp uses tube diodes and the power amp I just finished up uses solid state.
I would not use that circuit. Also what are the rectifier tubes supposed to be? At first I thought maybe a 6X4 but the pinout doesn't match. Plus you don't need two rectifiers for this circuit.
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I agree with the members that look on the provided schematic negatively.
A substantial amount of gain might have made sense, if the signal source was a ceramic phono cartridge whose O/P was a few tenths of a volt. Line stage gain is rarely needed in combination with modern, digital, sources. Attenuating excess gain harms S/N performance.
If "hollow state" is desired in the control center, buffer the volume control(s) with high transconductance (gm) cathode followers. JMO, effects machines belong on the Instruments and Amps "board".
A substantial amount of gain might have made sense, if the signal source was a ceramic phono cartridge whose O/P was a few tenths of a volt. Line stage gain is rarely needed in combination with modern, digital, sources. Attenuating excess gain harms S/N performance.
If "hollow state" is desired in the control center, buffer the volume control(s) with high transconductance (gm) cathode followers. JMO, effects machines belong on the Instruments and Amps "board".
It is a kit, I didn't design it myself. The amp I built from the same place, Douk Audio, seems to work well enough so I am going to give this a go and see how it does. I can't really say why they used two rectifier tubes unless they just wanted it to look cool with more tubes, the amp kit used a solid state bridge rectifier.
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I'm going to recommend that ksporry read this entire thread. Having built Franks Preamp I find that its superior to most out there. Its worth the effort and if built correctly is hum free.
Frank's Ultimate Tube Preamp.
Frank's Ultimate Tube Preamp.
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