Have this pre-amplifier nearly three years already, and finally have modified it to improve few major flows, well at least those I've found as such.
First of all it was nothing so wrong generally speaking and it's nice sounding device, from the first day just as it was built. Even though that Chinese 'officially' sold as 2x12AX7 and 1x12AU7 combo and PCB board have those misleading marks on it (with Music Prince title too lol), mine is actually wired for Soviet tubes: 2x6N2 and 1x6N1, and there is nothing wrong with that, it's even better cause these tubes cost a lot less and sound if not better but equally good as many 12's. I found more 'issues' in polyester caps they've used.
The other issues I couldn't stand from the first day was the fourth empty step (titled 'Video' but was MUTE in fact), and finally volume knob fixed on that long aluminium rod and so not firm.
Instead of 2+2 polyesters WIMA (interstage) coupling capacitors I've placed two Russian made K40Y-9 200V 0.47uF PIO and two Mundorf MCap EVO 3,3uF 450V
To make one more input I had to drill new holes for RCA at the back, and solder a couple of good quality wires into the empty holes in selector's PCB board (why they have left this empty while the selector has four steps is beyond my comprehension).
I replaced the small volume pot with the larger original NOS Alps made in Japan and fixed it on the front, and here I used quality 26 AWG Shielded Silver Teflon mil. spec. wire made by Thermax to connect all points.
I had to drill a wider hole on the metal case and one also on the frontal wooden plate for that purpose.
Bought three new full aluminium knobs to replace plastic ones, one for power switch and another for selector have that old school 'Luxman' style I really like, and are obviously much easier to turn on/off.
I think that's all, here are some pictures of course.
If somebody made mods on this pre-amplifier it would be interesting to share some story here, I haven't found similar mods so far.
Sound of course is better as expected. Bass is tighter and punchier, details are clearer and that is something I've noticed immediately with the few CD's I play on Pioneer DV-610AV (SACD) player via that new input ('Video') .
However caps are still young and it will take some time for them to settle. But so far everything was worth time, effort and (not so much) money invested in this device!
cheers
First of all it was nothing so wrong generally speaking and it's nice sounding device, from the first day just as it was built. Even though that Chinese 'officially' sold as 2x12AX7 and 1x12AU7 combo and PCB board have those misleading marks on it (with Music Prince title too lol), mine is actually wired for Soviet tubes: 2x6N2 and 1x6N1, and there is nothing wrong with that, it's even better cause these tubes cost a lot less and sound if not better but equally good as many 12's. I found more 'issues' in polyester caps they've used.
The other issues I couldn't stand from the first day was the fourth empty step (titled 'Video' but was MUTE in fact), and finally volume knob fixed on that long aluminium rod and so not firm.
Instead of 2+2 polyesters WIMA (interstage) coupling capacitors I've placed two Russian made K40Y-9 200V 0.47uF PIO and two Mundorf MCap EVO 3,3uF 450V
To make one more input I had to drill new holes for RCA at the back, and solder a couple of good quality wires into the empty holes in selector's PCB board (why they have left this empty while the selector has four steps is beyond my comprehension).
I replaced the small volume pot with the larger original NOS Alps made in Japan and fixed it on the front, and here I used quality 26 AWG Shielded Silver Teflon mil. spec. wire made by Thermax to connect all points.
I had to drill a wider hole on the metal case and one also on the frontal wooden plate for that purpose.
Bought three new full aluminium knobs to replace plastic ones, one for power switch and another for selector have that old school 'Luxman' style I really like, and are obviously much easier to turn on/off.
I think that's all, here are some pictures of course.
If somebody made mods on this pre-amplifier it would be interesting to share some story here, I haven't found similar mods so far.
Sound of course is better as expected. Bass is tighter and punchier, details are clearer and that is something I've noticed immediately with the few CD's I play on Pioneer DV-610AV (SACD) player via that new input ('Video') .
However caps are still young and it will take some time for them to settle. But so far everything was worth time, effort and (not so much) money invested in this device!
cheers
Attachments
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Do you know whether the topology is generically similar to the many Marantz 7 rip-offs? If so you may find this MingDA MC-7R thread worth a look.
http://www.diyaudio.com/forums/tubes-valves/101360-mingda-mc-7r-noise-gain.html
http://www.diyaudio.com/forums/tubes-valves/101360-mingda-mc-7r-noise-gain.html
Thank you for the feedback Kevin. I know this one is on sale as so called 'Marantz 7' Modified Class A Valve Tube Pre-Amplifier but according to claims from people who are more familiar with that old Marantz stuff the circuit is different.
On that MingDa thread I see that the guy had issues with noise and gain, which were never the issues on Music Angel. MingDa pre. has also totally different topology.
Few things I didn't like on my preamp. were:
Sonically - polyester caps WIMA MKS (four of them)
Practical/cosmetic:
distant location for volume pot
shallow plastic knobs
and the fourth input that was missing
It's all done and I'm not planning to make any more modifications, because it sounds fantastic now.
On that MingDa thread I see that the guy had issues with noise and gain, which were never the issues on Music Angel. MingDa pre. has also totally different topology.
Few things I didn't like on my preamp. were:
Sonically - polyester caps WIMA MKS (four of them)
Practical/cosmetic:
distant location for volume pot
shallow plastic knobs
and the fourth input that was missing
It's all done and I'm not planning to make any more modifications, because it sounds fantastic now.
Thank you for the feedback Kevin. I know this one is on sale as so called 'Marantz 7' Modified Class A Valve Tube Pre-Amplifier but according to claims from people who are more familiar with that old Marantz stuff the circuit is different.
On that MingDa thread I see that the guy had issues with noise and gain, which were never the issues on Music Angel. MingDa pre. has also totally different topology.
Few things I didn't like on my preamp. were:
Sonically - polyester caps WIMA MKS (four of them)
Practical/cosmetic:
distant location for volume pot
shallow plastic knobs
and the fourth input that was missing
It's all done and I'm not planning to make any more modifications, because it sounds fantastic now.
Just a note that placing the volume pot in the back of the unit near the inputs with a long shaft is actually a "tweak" often used to shorten the signal path and lessen potential interference pickup. But if you're happier with it in the front and you don't have noise issues, then cool.
Thanks for the input pal
Yes, what helps on one side might be a problem on another, but not always.
I kept the pot on the back at first, when playing with caps, just to see/hear how the thing will work. Before ordering (a bit expensive) Mundorfs from Germany I tried to parallel (unpopular) MKS with Russian orange 'bombs' K40Y-9 of 0,22uf 630V. The sound was improved, however I was eager to remove WIMA's for good. On the pot side - as can be seen on the picture, huge caps were on the way to the bolts on the rod, so the volume knob was going up to 11 o'clock position at max.
not good, and as pointed earlier I didn't like how the whole unit: volume-rod-knob was budging. So I ended up harder way drilling holes in metal and wood and messing around with wires but I've found really good quality silver shielded wire from USA (still available on eBay btw.) to kill potential interference in it's roots 😀 and no hum, no noise, everything is just perfect.
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music angel preamp
Hi,
Can you please advise me on modding this little preamp? i have changed teh tubes, changed the pot and now want to change the caps. My target is to get a better bass response from this preamp.
thanks
Nitin
Hi,
Can you please advise me on modding this little preamp? i have changed teh tubes, changed the pot and now want to change the caps. My target is to get a better bass response from this preamp.
thanks
Nitin
Re: Bass Response
Hi Kaushiknitin,
I have the MA preamp for few months so far driving a NOS Quad 306 to my vintage HB200. I bought it secondhand and it came with a 12AU7 and two 12AT7. The mid and high are very clear, much much better than SS preamp. However, I found the bass was very week until I changed the 12AU7 to the Chinese made 12AU7 came with the Little bear headphone amp I bought. The Chinese tube seems has very good bass extension.
Cheers,
Will
Hi Kaushiknitin,
I have the MA preamp for few months so far driving a NOS Quad 306 to my vintage HB200. I bought it secondhand and it came with a 12AU7 and two 12AT7. The mid and high are very clear, much much better than SS preamp. However, I found the bass was very week until I changed the 12AU7 to the Chinese made 12AU7 came with the Little bear headphone amp I bought. The Chinese tube seems has very good bass extension.
Cheers,
Will
Dear my fellow MA preamp owners,
My one has a minor problem with the top chassis hums. There is no hum if I removed the top cover but I have young kids so it is dangerous. Is there any other way to rectify the problem other than just putting heavy stuff of top of it?
Also, I changed the 12AU7 and 12AT7 tubes to 6N1P and 6N2P two weeks ago. The 6 series sounds better or more suit my taste. However, the new tubes hum, hiss from the beginning and pop after 20 hrs of used. I wonder do I need to adjust the filament voltage for the 6 series. If I have to, how to do it?
I really love the sound of the 6 series but hate the extra noise. Sometimes the random pops make me thought I am listening to LP, then I remind myself I don't have a turntable.
Thanks for any advice,
Will
My one has a minor problem with the top chassis hums. There is no hum if I removed the top cover but I have young kids so it is dangerous. Is there any other way to rectify the problem other than just putting heavy stuff of top of it?
Also, I changed the 12AU7 and 12AT7 tubes to 6N1P and 6N2P two weeks ago. The 6 series sounds better or more suit my taste. However, the new tubes hum, hiss from the beginning and pop after 20 hrs of used. I wonder do I need to adjust the filament voltage for the 6 series. If I have to, how to do it?
I really love the sound of the 6 series but hate the extra noise. Sometimes the random pops make me thought I am listening to LP, then I remind myself I don't have a turntable.
Thanks for any advice,
Will
I haven't checked this thread for ages (also never got any email about new posts?!)
However, @wma, if you are still with this preamp. all I can suggest is - do not mess around with different types of tubes!
There are few various versions of this preamp with the same name. Most older come with three audio tubes + one rectifier. Newer and more expensive have four, 2+2 audio tubes + rectifier tube! Most are configured for Russian tubes; 6N1, 6N2 or even 6N4 tubes and some (very rare) for 12AU7 and 12AX7 tubes!
Although mine came with the PCB that has marks for 12A** tubes it is not wired the way these tubes work, and it is something I've checked with the seller at the time of purchasing.
Mixing wrong tubes will result in malfunction, very short life of tubes, and/or other undesirable situations!
More info about 6N2P-EV / 12AX7 similarities and rewiring, for example, can be found here;
6N2P-EV / 12AX7 / ECC83 tube - PREAMP / DRIVER tubes - Tubes-Store.com
or about 6N1P Russian Tube run on 12V like a 12AU7
I never had intentions to do any of these extra mods. Russian tubes are excellent, robust, and still quite cheap on the market.
@kaushiknitin, I think the answer to your question is in the first post!?
However, @wma, if you are still with this preamp. all I can suggest is - do not mess around with different types of tubes!
There are few various versions of this preamp with the same name. Most older come with three audio tubes + one rectifier. Newer and more expensive have four, 2+2 audio tubes + rectifier tube! Most are configured for Russian tubes; 6N1, 6N2 or even 6N4 tubes and some (very rare) for 12AU7 and 12AX7 tubes!
Although mine came with the PCB that has marks for 12A** tubes it is not wired the way these tubes work, and it is something I've checked with the seller at the time of purchasing.
Mixing wrong tubes will result in malfunction, very short life of tubes, and/or other undesirable situations!
More info about 6N2P-EV / 12AX7 similarities and rewiring, for example, can be found here;
6N2P-EV / 12AX7 / ECC83 tube - PREAMP / DRIVER tubes - Tubes-Store.com
or about 6N1P Russian Tube run on 12V like a 12AU7
I never had intentions to do any of these extra mods. Russian tubes are excellent, robust, and still quite cheap on the market.
@kaushiknitin, I think the answer to your question is in the first post!?
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Thank you Jadran!
I still have this preamp and I love it. It's wired for a 12AU7 and 2 12AX7 tubes alongwith a rectifier. I have compared it to several SS preamps and some tube preamps and I must say it sounds good.
For about a year I used GE 5814A and 2x JAN GE 5751 tubes in it.
After an year I upgraded to Brimar CV4003 (12AU7 socket) - this was a big improvement in sound. recently changed the JAN GE 5751 (12AX7) to TUNG SOL gold pins and it was a further improvement.
Now waiting for Gold Lion 12AU7 to arrive. I am hoping it will have a better sound again.
I am also thinking to include tone controls in this preamp. A friend of mine who is good with tubes and who makes and repairs SS and tube amps says he can do that for me. We haven't yet looked inside the Music Angel yet but he says it should be possible to do. To make space for teh additional knobs I could actually change teh face plate too. What do you guys think? Lately after looking at a few preamps (especially xiansheng728a) and listening to a few others I feel tone controls are a very useful thing.
I still have this preamp and I love it. It's wired for a 12AU7 and 2 12AX7 tubes alongwith a rectifier. I have compared it to several SS preamps and some tube preamps and I must say it sounds good.
For about a year I used GE 5814A and 2x JAN GE 5751 tubes in it.
After an year I upgraded to Brimar CV4003 (12AU7 socket) - this was a big improvement in sound. recently changed the JAN GE 5751 (12AX7) to TUNG SOL gold pins and it was a further improvement.
Now waiting for Gold Lion 12AU7 to arrive. I am hoping it will have a better sound again.
I am also thinking to include tone controls in this preamp. A friend of mine who is good with tubes and who makes and repairs SS and tube amps says he can do that for me. We haven't yet looked inside the Music Angel yet but he says it should be possible to do. To make space for teh additional knobs I could actually change teh face plate too. What do you guys think? Lately after looking at a few preamps (especially xiansheng728a) and listening to a few others I feel tone controls are a very useful thing.
Hi kaushiknitin
I know I'd love a set of good subtle tone controls as so many discs these days are mastered so 'hot' a touch of tone-tweaking might even make them enjoyable 🙂
Let us know what your friend says, I'd love some pointers!
All the best
I know I'd love a set of good subtle tone controls as so many discs these days are mastered so 'hot' a touch of tone-tweaking might even make them enjoyable 🙂
Let us know what your friend says, I'd love some pointers!
All the best
Capacitors upgrade
Hey guys! I finally upgraded the caps on my preamp. Long ago I had made a list of the caps to be changed and I made a typo error. Instead of writing 6.8uf value of teh coupling caps i wrote 2.2uf. As a result I ended up ordering 2.2uf 450v Mundorfs Aluminum in oil caps. They cost me just under $30 a pair. This guy from Lithuania on ebay seems to stock almost all variaties of Mundorf caps.
Researching a bit online I found that 2.2uf value will work too in my case keeping in mind the input impedance of my power amp (100k ohm in single ended mode, 30k ohm in balanced mode). I use a Proceed amp 2 by the way.
I also had another pair of 2.2uf Kemet caps (used) to replace those 2 red Wima box caps. I did the swap and i did'nt like the sound much. I was hearing a bit more highs but the bass was weak.
(By the way it is possible to accomodate Mundorfs without moving the pot as suggested in an earlier post above.)
I removed all 4 new caps and put the old ones back. I couldn't believe that a capacitor 'upgrade' will actually worsen the sound .
Plugged in my soldering iron the next day. This time i removed only the coupling caps and put the Mundorfs back again. I cant solder very well so I managed to rip off a tiny part of teh track. One channel stopped working so I had to solder a bit of wire over the track.
Finally I decided to solder pairs of copper wire (normal household wire) and connect the caps to them. This way i will be able to change the caps back and forth for experimenting. Please look at the attached photo and you'll see what i mean.
The sound is better now. its not a night and day difference but i like what i hear and I think I wont be making any further changes in near future.
After giving it a hard thought the tone controls project is not taking off. I just dont think its worth time and effort.
thanks
Hey guys! I finally upgraded the caps on my preamp. Long ago I had made a list of the caps to be changed and I made a typo error. Instead of writing 6.8uf value of teh coupling caps i wrote 2.2uf. As a result I ended up ordering 2.2uf 450v Mundorfs Aluminum in oil caps. They cost me just under $30 a pair. This guy from Lithuania on ebay seems to stock almost all variaties of Mundorf caps.
Researching a bit online I found that 2.2uf value will work too in my case keeping in mind the input impedance of my power amp (100k ohm in single ended mode, 30k ohm in balanced mode). I use a Proceed amp 2 by the way.
I also had another pair of 2.2uf Kemet caps (used) to replace those 2 red Wima box caps. I did the swap and i did'nt like the sound much. I was hearing a bit more highs but the bass was weak.
(By the way it is possible to accomodate Mundorfs without moving the pot as suggested in an earlier post above.)
I removed all 4 new caps and put the old ones back. I couldn't believe that a capacitor 'upgrade' will actually worsen the sound .
Plugged in my soldering iron the next day. This time i removed only the coupling caps and put the Mundorfs back again. I cant solder very well so I managed to rip off a tiny part of teh track. One channel stopped working so I had to solder a bit of wire over the track.
Finally I decided to solder pairs of copper wire (normal household wire) and connect the caps to them. This way i will be able to change the caps back and forth for experimenting. Please look at the attached photo and you'll see what i mean.
The sound is better now. its not a night and day difference but i like what i hear and I think I wont be making any further changes in near future.
After giving it a hard thought the tone controls project is not taking off. I just dont think its worth time and effort.
thanks
Attachments
Tube Rolling on Music Angel preamp
I forgot to mention in my earlier post that about a month ago I changed the (12AU7) tube to Genalex Gold Lion ECC82 gold pin. Purchased from someone in USA. Its a new production tube made in Russia.
My very first impression of this tube was 'sweet but lacks in bass department' because I was coming from an NOS Brimar CV4003. As a result i changed the tubes back and forth several times.
Upon the recommendation of an audiophile friend i let the Gold Lion sit in the preamp for about 2 weeks, playing on an average of an hour daily.
So after approx 15-20 hours of playback this tube has really shined. All 3 frequency bands are awesome: Good tuneful bass, great vocals and sweet highs. I think it was a good decision to select Genalex tube. It's not cheap at $45 though.
So all 3 tubes in my pre are current production tubes and I think that these tubes offer excellent audio quality. I don't think i'll go the NOS way in future. For me it would be a waste of money to shell out hundreds of $$$ for those Telefunkens. No way...
I forgot to mention in my earlier post that about a month ago I changed the (12AU7) tube to Genalex Gold Lion ECC82 gold pin. Purchased from someone in USA. Its a new production tube made in Russia.
My very first impression of this tube was 'sweet but lacks in bass department' because I was coming from an NOS Brimar CV4003. As a result i changed the tubes back and forth several times.
Upon the recommendation of an audiophile friend i let the Gold Lion sit in the preamp for about 2 weeks, playing on an average of an hour daily.
So after approx 15-20 hours of playback this tube has really shined. All 3 frequency bands are awesome: Good tuneful bass, great vocals and sweet highs. I think it was a good decision to select Genalex tube. It's not cheap at $45 though.
So all 3 tubes in my pre are current production tubes and I think that these tubes offer excellent audio quality. I don't think i'll go the NOS way in future. For me it would be a waste of money to shell out hundreds of $$$ for those Telefunkens. No way...
schematic of the Music Angel
Hallo users of the Music Angel. I have this one now two years. I will this pre-amp upgraden for a Phone amplifer with EF85 There for do i need the electric drawing of the M.A. Can some one help me?
Hallo users of the Music Angel. I have this one now two years. I will this pre-amp upgraden for a Phone amplifer with EF85 There for do i need the electric drawing of the M.A. Can some one help me?
Hallo I have the pre amp from 2008 but no time. So now I am working on this pre amp.
In wil use it with a dynamic Phone element and the gain is to low so i am bilding a tube EF 86 in front for more gain. It wil take a few weeks, if you wont i can send some pictures..
Regards Pauloeska
Music angel preamp modifications
Hey guys. I am in process of doing further mods to my preamp. The input selector on my pre became noisy and unreliable so I am putting together a relay based input board. Also installed VU meters on the front panel. Will post photos as soon as it's ready. I had to get a couple of aluminum rings made like the ones around knobs. A friend in machine tool business made those on his hi-tech CNC machining centre. Attaching a photo of him programming the machine.
Pretty excited myself to see the end result. I hope to be able to finish the job in a few days.
Hey guys. I am in process of doing further mods to my preamp. The input selector on my pre became noisy and unreliable so I am putting together a relay based input board. Also installed VU meters on the front panel. Will post photos as soon as it's ready. I had to get a couple of aluminum rings made like the ones around knobs. A friend in machine tool business made those on his hi-tech CNC machining centre. Attaching a photo of him programming the machine.
Pretty excited myself to see the end result. I hope to be able to finish the job in a few days.
Attachments
Here are some images of the modded music angel preamplifier. I installed a 12v transformer for the new boards however it was not necessary. I later found out that the main transformer has a 15 v output which can be tapped into without affecting the sound in any way.
I had to change all the signal wiring too.
The sound has perhaps become clearer after the mods. May be the relays are providing better contact and channel separation.
Attachments
I got the VU meters locally from dealer in New Delhi . However I think these are commonly available on eBay too.
Hello again!
I further rewired this pre using silver coated shielded copper cable. Removed the relay based input selector as I decided to have shortest signal path. Now I have only one RCA pair for input and I don't need more.
As a result the sound has dramatically improved. Much more clarity and detail. The tungsol new issue 12ax7 tubes along with genalex gold lion 12au7 are doing wonders. Just now ordered psvane 12au7 as I have read some great reviews about it.
I further rewired this pre using silver coated shielded copper cable. Removed the relay based input selector as I decided to have shortest signal path. Now I have only one RCA pair for input and I don't need more.
As a result the sound has dramatically improved. Much more clarity and detail. The tungsol new issue 12ax7 tubes along with genalex gold lion 12au7 are doing wonders. Just now ordered psvane 12au7 as I have read some great reviews about it.
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