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.
You can try this PS but need a resistor and cap to reduce the B+ to 280-300
PT around 270-0-270 with 120mA would be fine
PT around 270-0-270 with 120mA would be fine
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".
You don't need a 5AR4 class of rectifier for this circuit. Is it really a preamp? Gain of 12 and no tone controls? And global NFB? Maybe a headphone amplifier?
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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Looks are everything.
If tubes are good, more tubes are more gooder.
At least that seems to be the idea.
And that Company is Futuristic.
1920's futuristic at least:
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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