Hello,
A while back I acquired a Yaquin MC 100B in which the valves had already been upgraded by the PO.
It sounds quite good already, but looking at the schematic I can already spot a few areas of improvement.
Short of ripping out the entire input selector and volume circuits and using it as a power amp, at this time I think I'd like to upgrade the volume pot by something more suitable.
If anyone has any suggestions I'd like to hear. I've been reading the forum, but things like *"gigawork" attenuator wintermute* don't mean a thing to me.
Of course I'm open to other suggestions as well.
Thanks,
Pete
A while back I acquired a Yaquin MC 100B in which the valves had already been upgraded by the PO.
It sounds quite good already, but looking at the schematic I can already spot a few areas of improvement.
Short of ripping out the entire input selector and volume circuits and using it as a power amp, at this time I think I'd like to upgrade the volume pot by something more suitable.
If anyone has any suggestions I'd like to hear. I've been reading the forum, but things like *"gigawork" attenuator wintermute* don't mean a thing to me.
Of course I'm open to other suggestions as well.
Thanks,
Pete
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Usually the best way to improve a Chinese amplifier is to remove all of the transformers, the power supply, and the amplification circuit, then replace it all with reputable components based on a reputable design.
Changing the volume pot does nothing to address any of the actual shortcomings.
Changing the volume pot does nothing to address any of the actual shortcomings.
What a useful informed and constructive comment !
Have you considered a career in stand up comedy ?
Have you considered a career in stand up comedy ?
How much money do you want to spend on an inexpensive Chinese amplifier and to where are you trying to go?
Seriously though, there are huge roadblocks in performance in these amps, and they are expensive and time consuming to fix.
Seriously though, there are huge roadblocks in performance in these amps, and they are expensive and time consuming to fix.
The FIRST thing to do with any of these Chinese amps is to get someone who knows what they are doing to check that the amp is safe and that components are within spec.
It is known for them to come with safety earth faults and under spec components.
Then you can think about upgrades.
It is known for them to come with safety earth faults and under spec components.
Then you can think about upgrades.
I am planning to change the 6 film capacitor with Russian PIO.. In my other amps, the PIO sounds better to my ear compare to film caps..
I've had a Yaqin 100b for over 5 years now. I really like mine, I think it sounds very good. I've been told the components are relatively high quality but the general circuit design is a little strange. For example, I have heard running 2 of the same tube on the same channel is not a good idea. (This was rationalized by saying that any distortion inherent to the tube is effectively multiplied by itself in the 2nd tube) I've always wondered it instead of 2sn7's and a 12ax7, if it wouldn't work better if you just had 1 6sl7 1 6sn7 and no 12ax7 at all. Unfortunately since this amp is all PC boards, I think a redesign like that would be very difficult.
I have also noticed that this amp is especially sensitive to the brand of tubes I use. Some of my other amps, I cannot tell any difference between different 12ax7's at all. In the Yaqin it is night and day. I suspect this is the result of a less than optimal circuit design. But again, with certain tubes (I really like sovetech 12ax7's JJ 803 long plates sound very good too) I really enjoy the Yaqin's sound.
As to your potentiometer, do you have a quality pre-amp? I would suggest using something else to control the volume with the Yaqin's volume at max. Switch back and forth and compare the 2. If it sounds worse when using the Yaqin's volume, then replace it, if not I would leave it alone. I have never noticed any noise with mine, though I generally use a pre-amp.
Anyway, just my 2 cents.
Thanks,
Josh
I have also noticed that this amp is especially sensitive to the brand of tubes I use. Some of my other amps, I cannot tell any difference between different 12ax7's at all. In the Yaqin it is night and day. I suspect this is the result of a less than optimal circuit design. But again, with certain tubes (I really like sovetech 12ax7's JJ 803 long plates sound very good too) I really enjoy the Yaqin's sound.
As to your potentiometer, do you have a quality pre-amp? I would suggest using something else to control the volume with the Yaqin's volume at max. Switch back and forth and compare the 2. If it sounds worse when using the Yaqin's volume, then replace it, if not I would leave it alone. I have never noticed any noise with mine, though I generally use a pre-amp.
Anyway, just my 2 cents.
Thanks,
Josh
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