Ian, I have sold my Meng to pay for a new project so I am solely going on memory but I think that is what I used. CCS in output stage cathodes as well.
If I remember correctly, the caps in the PS were from the power transformer secondary ends to ground on the PCB. I would have to troll back through this thread to find the values I used.
Sorry I can't be of much more help now that I don't have the amp to refer to.
Gary
If I remember correctly, the caps in the PS were from the power transformer secondary ends to ground on the PCB. I would have to troll back through this thread to find the values I used.
Sorry I can't be of much more help now that I don't have the amp to refer to.
Gary
Hi Bob, if you are happy with the sound, then more changes are not needed I guess. Depends how curious you are, or how much you want to tinker.
One mod that may be beneficial is replace the coupling caps with 716P 0.1uF 630V caps, put "Sprague Orange Drop capacitor 716P" into ebay search or Google, $2 to $3 each is the going rate, you need four of them.
I found an interesting paraphase or "see-saw" phase splitter recently that might work well in the Meng Yue, it appears to be self-balancing. I tried it in a 6L6 amp and like it a lot (it surprised me). Might be a good simple mod for the Meng Yue, here's a schematic . I couldn't help thinking of the Meng Yue when I first saw it. Might be just the ticket. In each channel, 3 resistors and a trimpot need removing, and 3 new resistors refitted. You need 6 x 330K metal film 1/4 or 1/2 watt resistors, very common and cheap, cost less than a dollar.
Ian.
One mod that may be beneficial is replace the coupling caps with 716P 0.1uF 630V caps, put "Sprague Orange Drop capacitor 716P" into ebay search or Google, $2 to $3 each is the going rate, you need four of them.
I found an interesting paraphase or "see-saw" phase splitter recently that might work well in the Meng Yue, it appears to be self-balancing. I tried it in a 6L6 amp and like it a lot (it surprised me). Might be a good simple mod for the Meng Yue, here's a schematic . I couldn't help thinking of the Meng Yue when I first saw it. Might be just the ticket. In each channel, 3 resistors and a trimpot need removing, and 3 new resistors refitted. You need 6 x 330K metal film 1/4 or 1/2 watt resistors, very common and cheap, cost less than a dollar.
Ian.
Meng 6N1P
Just received a specimen, Pardon my ediquete, not satisfying my palate.
I´m a bulb fanatic, tubes are what I like in audio anytime and even my oldest 6v6 ´54 edition RCA mono amp blows away my Denon solid state.
This been said, the meng was a very big disapointment, nasaly sounding, lacking clear top, bottom ok.
Power: enough for me to shake my head at whatever was thrown at it, distoring all at cirka 70%.
This is an failed attempt at HiQ audio and really reaks of it. Barely adequate for filling my small living room with audio, being classical to metal.
I´m a professional musician and have compared a thig or 2.
The hedphone output is actually the only thing worth while, nice output at all herz throughout at no more than 70%, not enough to get your head bobbing.
Nonni.
Nonni.
Just received a specimen, Pardon my ediquete, not satisfying my palate.
I´m a bulb fanatic, tubes are what I like in audio anytime and even my oldest 6v6 ´54 edition RCA mono amp blows away my Denon solid state.
This been said, the meng was a very big disapointment, nasaly sounding, lacking clear top, bottom ok.
Power: enough for me to shake my head at whatever was thrown at it, distoring all at cirka 70%.
This is an failed attempt at HiQ audio and really reaks of it. Barely adequate for filling my small living room with audio, being classical to metal.
I´m a professional musician and have compared a thig or 2.
The hedphone output is actually the only thing worth while, nice output at all herz throughout at no more than 70%, not enough to get your head bobbing.
Nonni.
Nonni.
What most of this thread is about is picking up a soldering iron (DIY) and turning it into something decent, and learning along the way. As a professional musician you might have some idea of how loud 6W will drive some speakers. Regarding nasal sound, never heard that in four of these amps. As a professional muso, who would own perhaps $3000 to $7000 worth of stage gear, or home studio gear, or both, the $200 or whatever this amp cost you would not even buy a decent DI box, or a good stand for your keyboards, or a half-dozen quality cables. That is what makes this amp fun to learn with.
I was a little hasty in my findings. It really takes a whole day of playing before it starts to give what´s expected from a tube amp.
It´s now providing more tops and slightly tighter bass response.
The supplier states 10 watt output, 6 watts sounds right to me.
I´m looking into swaping the preamp tubes of the Meng for 12ax7´s or maybe 12au´s, would provide a lot of more tubes to swap and try out, got a few lying around from my musical gear.
It´s now providing more tops and slightly tighter bass response.
The supplier states 10 watt output, 6 watts sounds right to me.
I´m looking into swaping the preamp tubes of the Meng for 12ax7´s or maybe 12au´s, would provide a lot of more tubes to swap and try out, got a few lying around from my musical gear.
Yeah, maybe I was a little hasty with my response too. 10W is plain wrong, lets call it a Chinese "embellishment". To swap the tubes for 12AX7 you will need to modify the heater wiring, it won't drop straight in from a 6N2P. Those old tubes left lying around from the music gear can sometimes be gems.
I like to have a bit of fun and try different things on these amps. I tried fitting some 6V6 to my amp (Russian 6P6S) it is surprisingly good compared to the 6P1P-EV I had fitted. Obviously very different animals. It solves the overvoltage problem (300V B+ on the 6P1 which some owners were concerned about) and uses a bit less heater current, and seems to give an extended freq response lower and upper, and good detail.
http://i198.photobucket.com/albums/aa160/birdy81260/6P6S1.jpg
http://i198.photobucket.com/albums/aa160/birdy81260/6P6S2.jpg
Some more madness, I have 2 of these amps, this one has an opamp front end/phase splitter, no caps in the signal path. It has strong bass, but I need to get rid rid of the standard cathode load of cap and resistor and replace it with LED's, which will give the slam attack factor down low and extended high end response. I am not finished with it, just early days at this stage.
http://i198.photobucket.com/albums/aa160/birdy81260/MengSSps3a.jpg
http://i198.photobucket.com/albums/aa160/birdy81260/MengSSps1a.jpg
The OPT's are surprisingly good, it has taken me around 2 yrs to work that out.
I like to have a bit of fun and try different things on these amps. I tried fitting some 6V6 to my amp (Russian 6P6S) it is surprisingly good compared to the 6P1P-EV I had fitted. Obviously very different animals. It solves the overvoltage problem (300V B+ on the 6P1 which some owners were concerned about) and uses a bit less heater current, and seems to give an extended freq response lower and upper, and good detail.
http://i198.photobucket.com/albums/aa160/birdy81260/6P6S1.jpg
http://i198.photobucket.com/albums/aa160/birdy81260/6P6S2.jpg
Some more madness, I have 2 of these amps, this one has an opamp front end/phase splitter, no caps in the signal path. It has strong bass, but I need to get rid rid of the standard cathode load of cap and resistor and replace it with LED's, which will give the slam attack factor down low and extended high end response. I am not finished with it, just early days at this stage.
http://i198.photobucket.com/albums/aa160/birdy81260/MengSSps3a.jpg
http://i198.photobucket.com/albums/aa160/birdy81260/MengSSps1a.jpg
The OPT's are surprisingly good, it has taken me around 2 yrs to work that out.
Hey Harvey,
Best to read this entire thread to see what Ian has done and where he came from.
Hum can be caused by a number of issues from poor solder joint to bad tube and more.
What is your level of expertise with electronic? This will determine to some extent what you can expect.
The 6P1P is good for 8-10W if driven with 250-325V in class AB1. In class A at 250V it is good for 6-8W.
As delivered the Meng Yue is good for closer to 6W.
This thread explains one way to optimize the permormance of the amp.
Sven
Best to read this entire thread to see what Ian has done and where he came from.
Hum can be caused by a number of issues from poor solder joint to bad tube and more.
What is your level of expertise with electronic? This will determine to some extent what you can expect.
The 6P1P is good for 8-10W if driven with 250-325V in class AB1. In class A at 250V it is good for 6-8W.
As delivered the Meng Yue is good for closer to 6W.
This thread explains one way to optimize the permormance of the amp.
Sven
Number one: Please be careful not to electrocute yourself. I guess you've read all the warnings...
Maybe start by finding the cause of the power tranny hum. Sounds like it is working too hard. A difficult one, for sure. Here's some ideas...
1) Disconnect the B+ first and see if the tranny stops humming.
2) If it does, with power off, check the power supply caps and diodes to be open circuit. Make sure the voltages have drained from the power supply caps before checking them.
3) See if there are any shorts or low resistances to ground anywhere on the B+, including the B+ feeding the preamp tubes.
4) It could be a bad tube too. Be nice to have a spare set, the 6P1P's and 6N2P's are cheap enough. If you were in Australia I'd send you a full set to try.
5) Another cause could be some sloppy soldering or dry joints. A good inspection of the PCB with a magnifying glass would not hurt. In fact, maybe this should be near the top of the list.
Thats all I can think of for now.
Maybe start by finding the cause of the power tranny hum. Sounds like it is working too hard. A difficult one, for sure. Here's some ideas...
1) Disconnect the B+ first and see if the tranny stops humming.
2) If it does, with power off, check the power supply caps and diodes to be open circuit. Make sure the voltages have drained from the power supply caps before checking them.
3) See if there are any shorts or low resistances to ground anywhere on the B+, including the B+ feeding the preamp tubes.
4) It could be a bad tube too. Be nice to have a spare set, the 6P1P's and 6N2P's are cheap enough. If you were in Australia I'd send you a full set to try.
5) Another cause could be some sloppy soldering or dry joints. A good inspection of the PCB with a magnifying glass would not hurt. In fact, maybe this should be near the top of the list.
Thats all I can think of for now.
MengYue EL84 capacitors question
Lifting up the old thread to ask if anyone has tried or have an idea about those caps, especially four 315V 180uF, those are quite mistery to me and can't find any that are same or even close these spec.
The other two of 220uF 200V I will replace with Nichicon Electrolytic Capacitors, as the originals are either old or damaged.
Lifting up the old thread to ask if anyone has tried or have an idea about those caps, especially four 315V 180uF, those are quite mistery to me and can't find any that are same or even close these spec.
The other two of 220uF 200V I will replace with Nichicon Electrolytic Capacitors, as the originals are either old or damaged.
Attachments
You can use a cap with a higher voltage rating, for example 350V.
EET-UQ2V181BA Panasonic - ECG | P11913-ND | DigiKey
EET-UQ2V181BA Panasonic - ECG | P11913-ND | DigiKey
Thanks Ian, appreciate your feedback. I know that higher voltage is in fact even recommended, but the problem could be the size of those, at least for one because it's too close to transformer. I found NIPPON 450V 180UF that could fit in. Just wonder why they did put such odd value of 315V caps?
Must inspect more closely all interior and will probably replace all the other caps, including those in signal line, and see if I can make more room.
Must inspect more closely all interior and will probably replace all the other caps, including those in signal line, and see if I can make more room.
I guess they had 315V caps available, or had them made. Yes it is an unusual voltage rating, but does the job. I'm still running the originals. Regarding heat, most caps are rated to 85 C and I doubt this amp will ever get that hot. The signal caps should be OK, in fact, I never heard any noticeable improvement from changing any of the caps in my amp. I still have it running, its one of my favorites, but the circuit is not standard.
180uF/350v/ 105c
381LX181M350H042 Cornell Dubilier Aluminum Electrolytic Capacitors - Snap In Opps, they don't sell low amounts.
Here we go 381LX181M350H042 CORNELL DUBILIER | Buy 381LX181M350H042 | Onlinecomponents.com
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.