Yaqin MS-22b Phono Amp

Currently using these:-
4PCS Capacitor 335k 3.3uF 250V +/-10% Axial Type NEW m | eBay

Lemco 8200pF 1% silver mica capacitors | eBay

I have used 5% silver micas without any problem and my original die cast box model used 2u2 for the outputs. These worked fine and yes they were the original value, I just felt there was a very slight increase in Bass with 3u3 when working into the lower impedance of the Yaqin amps. All really personal preference and as long as you maintain the voltage working I guess anything comparable will do.
 
Thanks for that info Les - really helpful...cures the panic attacks instantly! Muzz - I've ordered the 3.3's and the Lemco 8200's from the links 2 posts above above. The rest of the parts I will order tomorrow from the au.rs-online site. You'll get more parts than you'll need for one unit, but they have everything (including those short caps for C15 and C16) for just under 50 bucks. Looks like we'll be starting this around the same time - good luck!
 
Hi to All!

1st post here :) i have actively listened vinyl couple years. I did service Dual 1249 and replace 2M Blue cart to it. First I listen it with AV-amp's phono input, but later I bought Clearaudio Nano preamp, which did huge improvement in sound quality.

Later I found reasonable priced set of Pro-ject 6Prespex with Speedbox SE II and Ortofon Cadenza Red MC-cart. I bought that and Dual got place on strorage.

But now... I need Dual for my 2nd set, but amp does not have build in RIAA, so I googled for phono stage to buy and found this thread. Just finished reading complete thread.

Since I have already ordered MS-23B and all mod parts, including 3pcs Svets, I would like to join into modder's team....

There might be coming some questions, but bear with me :p

Ok, first I need to receive all the stuff. Then make some soldering and when all is ok then listening too. While waiting, I have also take a look on step-up transformers, that I could test Yaqin on my 1st set with MC-cart and compare it to Clearaudio preamp. Does someone have already experience about SUT and Lesbox? Pretty expensive are those transformers, that would be nice to buy decent ones at once ;)

All the best to You all,

-juha
 
Yes thank you Les!
Foxy - I ordered my parts from Element14 (formerly Farnell), half of them arrived today and the rest should be here by the end of the week including the 8200pFs. Got the 3.3uF caps from soundlabsgroup here in Melbourne, went with Soundlabs Group 3.3uF 400V M-Cap - I'm pretty sure the 400V should be ok?
All up cost me around $70 aud, plus ordered 3 of the Winged C tubes as mentioned by Les much earlier in this thread. Those are also on the way across from the UK.
Keep us in the loop as to your progress, and particularly any tips you pick up during the conversion.

Cheers

Muz
 
Nearly there - got to the replacement of C15 and C16 caps and found that I had ordered 250V caps rather than 350V as specified. I think I was more worried about the height requirement. Beginners question - will the 250V rated caps work in this location? Also, these are the only cap replacements where polarity is mentioned, are all the others up until now non-polarised?

I also haven't got the 2 resistors R3 and R15 - 120K 1W. Is this value critical or can I swap in something close? If not, might be hunting Melbourne tomorrow for an electronics shop!
 
Fitting 250V is being a bit too close, you should try for 350V to prevent a nasty unexpected blow-out :eek:
I have some here if you cannot obtain locally.
Brand Nichicon, Part No. UCS2V101MHD
They are the only polarised caps you need to change.
For R3 and R15 you can fit 100k, I am presently fitting these as they seem to give slight improvement to the HF part of the RIAA but I am being too fussy :)
The 1W rating is a bit of over kill for reliability and no doubt you could use the 100k originally fitted here.
regards, Les
 
WOW!

First night listening to the conversion and stunned. More to come. How are you going Foxy?

Thanks heaps for the offer Les, but feel you've done enough... managed to find those exact caps locally delivered overnight.

I have to apply some finishing touches, mainly for aesthetics, but first impressions are stunning.

Muz
 
That's great Muz. There may be better circuits out there but it does do what is promised and 'Puts Life' into the converted unit and that's the intention. The track cuts are a pain (7) but if you have something like a ball burr on a mini-drill it helps. I also use a 0.8mm drill to make the component spaced holes either side of the cuts. A fiber glass pen makes short work of the Green solder resist and gives a good view of the track cut. The only thing I have not found is a matching color substance that can coat the copper tracks afterwards. I suppose some suitable automobile paint with a fine artists brush may do for that. The new circuit certainly seems to show the difference in quality between brands of tubes. The circuit was originally meant for a kit and as such appears to give very repeatable results, I have had only one failure where the RIAA was like crazy on one channel. This was traced to one of the 8200pF capacitors which measured double? Crazy I know but on the capacitor tester it showed exactly 16400pF. You will probably find Muz like many others, that it is like having a totally new vinyl collection as you will be hearing delicate sounds you never knew were on the record :-D
 
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Congrats Muz - sorry I was no help, I'm still waiting for a couple of caps from the UK and don't want to start until I have everything here. Apart from the couple of component queries, how did you find the work? I'm confident all will be fine, but my eyesight is not what it was and a 100watt lamp has been freshly installed on the workbench! I've also dug out a few old Ei ECC83's that I'll try out - not sure how they'll compare to the Svets...
 
How is it going Foxy?

I'm ashamed to say that I haven't started yet :( . What with setting up the new 'operating theatre' and getting a sudden pile up of work, it's slipped down the list. Poor form. But I have everything I need now so it shouldn't be long now.

I'm looking forward to trying out the Ei's - they seem to have survived the long trip down under.

On a secondary note, I have a question re: earthing. I have a small hum from my Garrard AP76 - I've metered out the return signals and they are all seperate from each other and not common down to the chassis and so follow the RCA's down to the amp's phono inputs. I also have an earth flying lead from the chassis down to the amp's earth lug (now a Technics SU Z780) which is a 2 lead double insulated affair ie no earth lead. This works well as disconnecting it creates a huge hum. The Garrard also has no mains earth connected. I'm tempted to re-connect the AP's mains earth back to it's chassis (as per the manual) but I know that some of these double insulated amps don't like to be earthed and the flying lead would obviously do this. When the Yaqin is up and running, what's the opinion here for the complete earthing set up?

That's as far off topic as I'll get - apologies in advance!
 
I think it will be a case of 'suck it and see' when the Yaqin phono amp is installed. Only a couple of guys have had hum problems even with the converted version but managed to get it undetectable at normal listening level. This was achieved by trial and error with the earthing arrangements or by changing their cartridge.
 
Hello Les
After you did a great job with my MS-23 I thought it was time for some more feed back. I am thrilled with the soundstage. Playing my old LP's is more enjoying than ever. Great work and you should be very proud of yourself ! Helping so many people to get 110 % out of the MS-2X. Anyway went ahead and bought a Audio Space Galaxy 88 and am proud as hell. Found a dealer from China who is very helpful in many ways. Keep up the good work Les, my friends are amazed when I tell them about the effort you put in.
Regards Mike
 
Hi Les, I've really been enjoying my MS-23b after you sent it back to me. The detail, transparency, and sound stage are amazing, I've really been enjoying listening to my old albums. As good as the music sounds there is a characteristic I need to try to change; I'm finding that there is a brightness and lack of low frequency, and subsequently warmth to what I'm hearing. Do the =C= 12AX7 tubes normally sound bright when they're new? I've had tubes in the past that start out bright but mellow out nicely after ~100 hrs. Or maybe these tubes and my turntable aren't agreeable. I have a Music Hall MMF2.2 with an Ortofon 2M blue cartridge. Any thoughts on how to improve this?
Thanks again Les.

Terry
 
Hi Terry, The TT and cartridge should be OK as I know others are running the 'Blue' without any problems. What main amp are you using? The winged =C='s do give a lot more detail in the highs but they don't add anything to the RIAA. It's just that they give something there that is lost with some other tubes but it should not be that much. It's hard to explain, my mate refers to it as 'air' but I know what he means, something coming out of the groove that is otherwise lost and yes it does take a bit of getting used to. I simply cannot play some of the early LP's in my collection as they must have been mastered for teenagers record players in the 60's.:happy1: Has anyone found 'The John Lennon Collection' particularly bad? This is the 1982 compilation pressing (EMI EMTV 37) and is quite nasty on certain tracks. However 98% of my vinyl collection sound superb and the input is FLAT straight into the main amplifier. I am hoping to put together a simple passive EQ circuit (with a bypass switch) just for the odd occasion when one of these badly mastered discs comes along. Have you tried running the MS23 with the stock tubes as these should take the 'air' from the upper frequencies. I just checked the RIAA figures for your amp and to be honest the top end 10k to 20k was giving slightly more attenuation but only 0.5dB at 20kHz, so this should not be the cause of having too much Top.
The low end was virtually spot on too so perhaps the problem lies somewhere else bearing in mind it was given a good listening test here and it sounded great. I am frustrated in not being able to suggest anything else for you to try.
 
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Terry, as part of my guarantee, I can get a stock MS23 out to you if you like.
I think I still have your address somewhere and if I find it I will have a look around the internet for a replacement for you. You may keep the converted one as a small token of my sincere apologies for not providing a unit that interfaces correctly with your other items of equipment, as far as I know this is the first time this has happened. Apologies once again, Les
 
Yep - could be that or many other things, input impedance of main amp, speaker system in use, even room acoustics. The RIAA curves are the same for both except the stock appears to lose out when a mixture of signals are applied rather than a single frequency one. Involved with a mates wedding at present but I hope to contact Tubestein and get a quote for a shipment direct to USA.
It's the least I can do but makes me wary of doing anymore :)
I guess if Terry gets stung customs I can do a Paypal transfer if he tells me how much it is. :(