• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Musical Fidelity X10D schematic

Built the x10-d buffer

I am quite happy with the x10-d buffer built this month, no hum, and sparkling sound when added in the audio chain.
 

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It looks to me like X10-D is not an optimal tube buffer. ... Low distortion is achieved but not without rather large amount of feedback.

I agree. Too much global feedback and too many capacitors in the signal path.
A cathode follower should be a better choice. maybe dc coupled, with very few components. no GNF (only local).
Yes, a higher output impedance.
 
Resurrecting an old thread. I have this clone board modified with good quality caps from aliexpress and want to use as a pure preamp tube buffer with volume control. What value of the volume pot should I be using with this X10-D buffer board and I am using ECC82 tubes? I will get the DACT type 21 step potentiometer which I like the most.

thanks
 
Resurrecting an old thread. I have this clone board modified with good quality caps from aliexpress and want to use as a pure preamp tube buffer with volume control. What value of the volume pot should I be using with this X10-D buffer board and I am using ECC82 tubes? I will get the DACT type 21 step potentiometer which I like the most.

thanks



i guessing higher the better. 50k or 100k if the pot goes before the buffer
 
Resurrecting an old thread. I have this clone board modified with good quality caps from aliexpress and want to use as a pure preamp tube buffer with volume control. What value of the volume pot should I be using with this X10-D buffer board and I am using ECC82 tubes? I will get the DACT type 21 step potentiometer which I like the most.

thanks

Putting an unbuffered pot infront of the X10-D is basically negating the whole point of the circuit. What benefit the circuit offers is in presenting a very high load to the output stage of the CD player thus reducing distortion. Reduce that load with your pot and the benefit reduces in direct proportion.
In short this is not the correct circuit for your experiment.

Shoog
 
Both 2 transistor circuits are :cap multiplier and current limit.

Can't believe some are still using this device :eek: You must be hating good sound.

Hi, what do you recommend for a V-out DAC as Technics lowfi CD player?
I actually cleaned the output, little better. Even drew direct wire from the chip but nothing spacial happend. Lower output level.

Apriciate if you point out some good stage.
Regards/Amir
 
Power supply

Hi!
I have already built preamp in 2 copies.
If you use a 12V AC adapter, the pipes will not have enough voltage for heating - you need to measure and see.
15V AC required. The multiplier that produces the supply voltage is a joke in my opinion. It could easily be a higher AC voltage for the multiplier, or a good external supply voltage for the pipes, even higher than 100V DC, but how much should it be? Without changing the component values. Should nutrition be the plus-minus design? Can't be zero and 100 (150) V?
Excellent power supply for ARC PH3, LS7, etc. power supply, professional.
 

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Its guaranteed that this circuit should perform better at higher voltages, but i suspect that probably altering any aspect of it from its original design will degrade its sonic signature. When I had mine many years ago I tried replacing the Jan 6922 valves with Mullard ECC88's and it was not an upgrade - syrupy is not adequate to describe the result.

This is a highly tuned design which uses its valves so far out of their comfort zone that even changing any part has unpredictable outcomes. That unfortunately is the very definition of bad design.

Shoog
 
Reviving this old thread :)
My 12Vac walwart died, I have a 15Vac walwart PS that I can use but before I use it can someone confirm that 15Vac PS can work with the X-10D won't "stress" the voltage multiplier built in the X-10D and kill it?
Assuming it won't kill the voltage multiplier can someone predict how it will affect the whole circuit and the tubes?

Thanks
 
Has anybody ever tried setting this thing up as a true buffer, that is, with no gain? Stock, R104 is 8K2 and R106 is 1K5, so the gain is 1.18x or 1.44 dB. (My unit has these resistors and the schematics in this thread show the same.)

I can clearly hear the extra gain when this is switched in/out of my preamp's tape loop. I might just bypass R106/R206 (and C103/203) with wire links.
 
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