I have one and suggest to have a friend build you one with the same tubes but different circuit.
Reading the German link tho I gotta say the one I have feeding it with 120V > stepdown104V> 72mA bias on the KT88s and I get decent sound from TT. KT88's (original)
1 /2 yrs and still test new, Silvania Chrome top=best, daily driver. Oh .. hey we are about to take a walk upstairs and take another listen.
Cheers,
Bob
Different bias is not the only difference between 6SN7 and 6SL7. 6SN7 have a lower amplification factor but can manage higher current - it has as well a lower impedance which make's it better as driver. The 6SL7 need less current and have a higher amplification factor (higher impedance as well) - goes better to the first stages.
Hi Bob,
some years ago I built KT94 in PP ultralinear configuration and 6SN7 as drivers. First bias was as well at 72 mA - than I tried different values but I did not noticed any change in quality, therefore finally the bias was set at 58 mA. Since 4 years this amplifier is almost daily running without any issues.
Right now I am working on a KT120 PSE configuration and aikido as driver... many do not agree with this configuration but I think it deserve a try...
I was thinking for just the second stage after the 12ax7's, the "Schmit trigger" section where there appears to be less current than is optimal for a 6SN7 anyway, and was thinking/hoping the higher amplification factor of the 6sl7 would offer a cleaner sound (less THD... is this part of the circut kinda like a negative feedback?). You mentioned bias, but it seems to me it's not biased very well for 6SN7 and that's why the overly harmonic sound and maybe more geared for 6SL7 But Maybe I'm out to lunch, I do get funny ideas about things I'm not well educated in, I'm still learning.
I was thinking for just the second stage after the 12ax7's, the "Schmit trigger" section where there appears to be less current than is optimal for a 6SN7 anyway, and was thinking/hoping the higher amplification factor of the 6sl7 would offer a cleaner sound (less THD... is this part of the circut kinda like a negative feedback?). You mentioned bias, but it seems to me it's not biased very well for 6SN7 and that's why the overly harmonic sound and maybe more geared for 6SL7 But Maybe I'm out to lunch, I do get funny ideas about things I'm not well educated in, I'm still learning.
Everyone still learning - me too. Yaquin made some changes and improvements after March 2010 - nevertheless the OTP's have their limits. If your amplifier is made before that date, than you have to consider as necessary a "lift up" as described at: *** frihu.com *** Yaqin MC100B Verstärker-Tuning, Frischer Klang aus billiger Büchse - aber trotzdem kaum High-End (3)
It is not only the 6SN7. There are many components that request replacement in order to obtain a clear and detailed sound (I think this is the real problem and not the amplification factor). Beside, more amplification mean as well more THD. Only changing the SN and using instead SL would not solve much anyway.
Best regards,
Dan
Greetings from Spain and happy new year¡¡¡
I am the proud owner of a Yaqin MC-100b. So far I am fully satisfied with the amp, it sounds incredible good to me, much better than expected. Let me start by saying that I am not a technician at all. I just have very elementary electricity concepts, some soldering skills and of course lots of care. When adjusting bias for the first time I realized one of the pots was broken. Therefore, with some Christmas holidays ahead I decided to take the PCB to replace it and, once being there, I thought it would be worth upgrading the amp caps (I’ve read very good reviews about the Murdoff/Solen oil films and the Wima caps) and ceramic resistors as suggested by many of you in this forum. Which brand and specs should I use to get more bass and if possible greater definition?. The amp does currently have 6 PILKOR X2 0.22uF(220nK) 275v OFC caps and four 5 watts 10 ohms ceramic resistors (regardless of the PCB legend saying that they should be 3 watts 10 ohms¡¡¡). Should I change all the 6 caps to get the best possible results? What about the resistors, any suggestions? Should I go for 3 watts? I am very sorry to post such an elementary question to you guys, but as said before I am a newbie in this world.
I will try to post some pics for further clarification,
Kindest regards, Marianom
I am the proud owner of a Yaqin MC-100b. So far I am fully satisfied with the amp, it sounds incredible good to me, much better than expected. Let me start by saying that I am not a technician at all. I just have very elementary electricity concepts, some soldering skills and of course lots of care. When adjusting bias for the first time I realized one of the pots was broken. Therefore, with some Christmas holidays ahead I decided to take the PCB to replace it and, once being there, I thought it would be worth upgrading the amp caps (I’ve read very good reviews about the Murdoff/Solen oil films and the Wima caps) and ceramic resistors as suggested by many of you in this forum. Which brand and specs should I use to get more bass and if possible greater definition?. The amp does currently have 6 PILKOR X2 0.22uF(220nK) 275v OFC caps and four 5 watts 10 ohms ceramic resistors (regardless of the PCB legend saying that they should be 3 watts 10 ohms¡¡¡). Should I change all the 6 caps to get the best possible results? What about the resistors, any suggestions? Should I go for 3 watts? I am very sorry to post such an elementary question to you guys, but as said before I am a newbie in this world.
I will try to post some pics for further clarification,
Kindest regards, Marianom
Attachments
Good morning and happy new year as well,
Several years are gone since I did on my Yaquin those changes... In the mean time this one left and made place for new built, completely different... well, that is a “taste" decision...
Nevertheless, as I wrote years before, the best description for an upgrade to the MC-100b can be found here:
*** frihu.com *** yaquin MC100B Verstärker-Tuning, Billiges Röhrenverstärker-Vergnügen(?) aus dem Land des Lächelns (1)
It is what I did at that time - it is in German and can be translated with google (even if translation would not be perfect, can be any way understood). I didn’t saw anywhere else a better set-up – and this indeed raised the performance. I remember that Yaquin followed after 2010 with some improvements but I do not know what exactly they changed and since I didn’t kept this amplifier I did not paid attention any more.
The only recommendation: before you start making changes and taking parts away and invest for more expensive components, make a study – eventually contact peoples at Frihu..
Many other would say – use PIO coupling C or take audio grade R’s, use better components here and there…. and so on. Fact is that Yaquin can be improved in certain limits but it makes nonsense to invest in voodoo components as long as the OTP have clear limits.
Good luck and happy building,
Several years are gone since I did on my Yaquin those changes... In the mean time this one left and made place for new built, completely different... well, that is a “taste" decision...
Nevertheless, as I wrote years before, the best description for an upgrade to the MC-100b can be found here:
*** frihu.com *** yaquin MC100B Verstärker-Tuning, Billiges Röhrenverstärker-Vergnügen(?) aus dem Land des Lächelns (1)
It is what I did at that time - it is in German and can be translated with google (even if translation would not be perfect, can be any way understood). I didn’t saw anywhere else a better set-up – and this indeed raised the performance. I remember that Yaquin followed after 2010 with some improvements but I do not know what exactly they changed and since I didn’t kept this amplifier I did not paid attention any more.
The only recommendation: before you start making changes and taking parts away and invest for more expensive components, make a study – eventually contact peoples at Frihu..
Many other would say – use PIO coupling C or take audio grade R’s, use better components here and there…. and so on. Fact is that Yaquin can be improved in certain limits but it makes nonsense to invest in voodoo components as long as the OTP have clear limits.
Good luck and happy building,
I would be pleased if you could send me a better diagram of the Yaqin MC-100B
Thanks, Roger
roger@wyetechlabs.com
Thanks, Roger
roger@wyetechlabs.com
