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Yaqin MC-5881A amplifier improvements

Hi there,

I have both versions of 6P3C (plenty) but I didn't try the longer one, if you can believe me. I was told and I have read that 6P3C-E is a military release, more rugged and powerful and I only put this tube in amplifier. By the time when I posted my improvements' list the time allocated for this project elapsed too and I didn't change anything since. Nevertheless, I do enjoy the sound of that amplifier almost every day. One year ago I had the chance to compare one untouched MC-5881 with mine and the difference is huge, as I was expected.

I'll let you know how the longer ones sound in the following period, days, I don't know when exactly.

You can see here the tubes side by side (pay attention that the shorter version is ticker):
http://store01.myfastshare.com/FastShareStore/lnk/C47F9828BA2CB772A6290B824870DBD3F6210BB2
 
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Hi there,

I have both versions of 6P3C (plenty) but I didn't try the longer one, if you can believe me. I was told and I have read that 6P3C-E is a military release, more rugged and powerful and I only put this tube in amplifier. By the time when I posted my improvements' list the time allocated for this project elapsed too and I didn't change anything since. Nevertheless, I do enjoy the sound of that amplifier almost every day. One year ago I had the chance to compare one untouched MC-5881 with mine and the difference is huge, as I was expected.

I'll let you know how the longer ones sound in the following period, days, I don't know when exactly.

You can see here the tubes side by side (pay attention that the shorter version is ticker):
Download fisier
I live in my own house, so i can use Yaqin 5881 at full power whenever i want.
My 5881 is helped with nice Yamaha P3500 power plant, both amps are driven thru prototype of Slovenian Stylos tube DAC, as an premplifier.
6moons audio reviews: Stylos sys HAD D/A converter

My Tube DAC proto has almost the same DAC converter as ougly solid state coffin in the link, but it uses ECC88 buffer.
I have 8 drivers per channel in my DIY speakers.

My 5881 is powering per channel 2 Tannoy dynamic tweeters, one dipole bending wawe transformer, one ribbon planar horn, one 13 and one 16cm Tannoy midbass(all other drivers are powered by Yamaha, each driver has it s own speaker wire, 8X per ch) and it is doing this job really excellent! 6 drivers per ch...
Efficency of my driver set is approx. 87Db/m, power of both amps "working" simultaneously, is huge, sound, clear and silky no matter how much power is in "the game".

When i ll finish speakers, i will try some of your tweaks in my Yaqin.
 
Update.
I equipped all tubes with simple and cheap silicone tube dampers.
Bye, bye micro oscillations. Wouldn't believe if someone told me so.
Like someone said. "Why silicone rings aren't fitted on every tube amp in factory?"

Also ordered Tungsram and RFT ECC85 tubes and indeed, Tungsram ECC85 fits like a glove in 5881. Wonderful depth of stage.
Triode Al is wright about ECC85.
Tungsram in combo with Vostok 6N1P EV from 70 ies is tremendously musical, one of my favourites, but RFT is a disappointment.
They have a superb stereo separation,(i don't need it, if there are other tubes showing a stage as a whole), they have no depth, odd two dimensional presentation, they superbly shows micro details, but they sounds boring, graveyard boring.
They have strong and precise bass, but it is bit lifted to the mid tone area, good for people preferring mainstream car audio sound.
Good tubes for audio masochists.:D Pitty, they have also very good gain.
Another good combo is Tungsram ECC85-JJ E88CC.
Rich in subtle musical information, powerful, stage is more in front then with 6N1P EV, pure pleasure.
Power cable im using at the moment is VH Audio DIY on chinese Oyaide079 schuko copy. Good stuff, great slam, very even in whole spectre, more on analytical side, so musicality has to be "milked" from more musical tubes and with changing of some passive components for those with more musical character.
This will probably be Nichicon Muse or Elna Silmic, Dale, and Eichmann Phonopod RCA(dream like non problematic stuff, specially if you use Eichmann Silver and Copper Bullet plugs and Tempoelectric wiring), also I ll try Alps Blue and Gigaworks pottis on Tempoelectric inner wiring bypassing the source selector, no need for more sources, because i have only one source, music server on tube DAC.

I also ordered RCA 9AQ8 / PCC85, to try those ones which have slightly higher gain then 6N1.

I just love sound, good control, slam and speed of transients and rewarding modding potential of 5881.
 
I just want the express my gratitude to you fine folks for figuring out the hard stuff. I have made the mod to my main by tapping into the 3rd winding and cutting out the extra 500 ohm resistors. it took me maybe an hour and now i am running nice and cool. i can turn the volume up more now and really enjoy my tannoy arden's!! Thanks again!

Phil
 
As regarding the mod to remove one of the cathode resistors: the remaining one can get hot; and one failed.
No problem: there is just almost no sound from the one channel.

So I replaced them with a version that can be mounted on a heatsink. (Actually I added a little heatsink on the back of the cabinet - I could not drill a hole in the stainless steel to attach the resistor.) I don't have a picture.
albert
 
In mine 5881 there were Nichicon for audio series and BC electrolytic caps.
I assume that s a result of the constant efforts of the French Yaquin importer, Marc, very helpful and nice character person and his constant travelling in China factories in order to improve their products in a way to suit more EU and USA buyers expectations.

I would like to discuss bit unordinary tubes which makes sonically perfect match for a pair of Tungsram ECC85 in my 5881.
Just love them.

They are NOS, W.Germany originated, i assume from 50ies(decay of cellulose boxes), Canadian branded, army type.

I note in my tube manual that the 6DJ8 is listed as having a nominal u (amplification factor) of 33, while the 7ES8 is listed here as having a nominal u of 65. Perhaps operating the 7ES8 with only 6.3 volts on its filament, as opposed to the specified 7.6 volts, would bring those figures closer together. But I would not expect anything better than a rough approximation, which at best would be good enough sonically only in some circuit applications.

Definiton of difference between ECC-PCC

An electron tube in which the amplification factor varies in a predetermined manner with control-grid voltage; this characteristic is achieved by making the spacing of the grid wires vary regularly along the length of the grid, so that a very large negative grid bias is required to block anode current completely. Also known as remote-cutoff tube.

By all means small and unimportant difference, i think(i could be wrong).
No need to block negative current in preamp, no neeed for controlling variable grid voltage.

7ES8 Amplification factor is considerably higher and in mine 5881 the result is more linearity then with any other signal tube (i have plenty of different ones suitable to tech. specs. of 5881).
 
good to know the single resistor gets hot. i didn't even check that. guess i better get a good replacement.

Thanks!
Hello. Very good result on the heaters. Calculation proved spot on. They get so hot (your 5W resistors) because they get to dissipate almost 7W as a whole. That is why I specified 2X10W. In general, for no long term problems, a resistor must have a rating 3X the actual dissipation and over. So 20W total will be OK.

http://www.diyaudio.com/forums/tubes-valves/97618-yaqin-mc-5881a-amplifier-improvements-2.html
;)
 
In mine 5881 there were Nichicon for audio series and BC electrolytic caps.
I assume that s a result of the constant efforts of the French Yaquin importer, Marc, very helpful and nice character person and his constant travelling in China factories in order to improve their products in a way to suit more EU and USA buyers expectations.

I would like to discuss bit unordinary tubes which makes sonically perfect match for a pair of Tungsram ECC85 in my 5881.
Just love them.

They are NOS, W.Germany originated, i assume from 50ies(decay of cellulose boxes), Canadian branded, army type.

I note in my tube manual that the 6DJ8 is listed as having a nominal u (amplification factor) of 33, while the 7ES8 is listed here as having a nominal u of 65. Perhaps operating the 7ES8 with only 6.3 volts on its filament, as opposed to the specified 7.6 volts, would bring those figures closer together. But I would not expect anything better than a rough approximation, which at best would be good enough sonically only in some circuit applications.

Definiton of difference between ECC-PCC

An electron tube in which the amplification factor varies in a predetermined manner with control-grid voltage; this characteristic is achieved by making the spacing of the grid wires vary regularly along the length of the grid, so that a very large negative grid bias is required to block anode current completely. Also known as remote-cutoff tube.

By all means small and unimportant difference, i think(i could be wrong).
No need to block negative current in preamp, no neeed for controlling variable grid voltage.

7ES8 Amplification factor is considerably higher and in mine 5881 the result is more linearity then with any other signal tube (i have plenty of different ones suitable to tech. specs. of 5881).

After a month of using ancient NOS Canadian-W.Germany originated PCC189, i can only say, that that is the far best signal tube i have in my collection.
GE Sylvania 6922, RCA PCC85(probably made on Mullard tooling) are good ones(just today arrived Philips PCC85 to "compete" with those), also Tungsram PCC85 and 6N1P-EV are also very nice.
All those have nice, but, very different characters. All of my other tubes PCC,ECC,E88CC, i have are not so suitable for 5881.

Considering that only that German PCC189 sounds, lets say, almost like perfect of all those, despite that, that a lot of audiophiles are claiming, that PCC189 can not work as audio signal tube.
Praxis shows opposite.
PCC189 in my case is more then "seaworthy" signal tube in ECC85 audio application. Period.
 
After a month of using ancient NOS Canadian-W.Germany originated PCC189, i can only say, that that is the far best signal tube i have in my collection. GE Sylvania 6922, RCA PCC85(probably made on Mullard tooling) are good ones(just today arrived Philips PCC85 to "compete" with those), also Tungsram PCC85 and 6N1P-EV are also very nice. All those have nice, but, very different characters. All of my other tubes PCC,ECC,E88CC, i have are not so suitable for 5881.

Considering that only that German PCC189 sounds, lets say, almost like perfect of all those, despite that, that a lot of audiophiles are claiming, that PCC189 can not work as audio signal tube. Praxis shows opposite. PCC189 in my case is more then "seaworthy" signal tube in ECC85 audio application. Period.

Further improvements on 5881 are.. Changed all electrolytic caps with RIFA, since i change all mkp s with Jantzen Superior, combo RIFA-Superior brings this amp to an high end level. Performing even classical music in "full body" is now for my 5881 piece of cake, thanks to RIFAs. RIFA needs almost a month to burn in. I use 5881 in very serious DIY setup as one of two amps driving simultaniously DIY speakers with 7 drivers per channel, speakers are omnipole-dipole-BR uniphase principle. my invention. Both amps are producing somewhere 700W sin per channel and they can be driven full power somewhere 1KW and more, peak per channel. No distortion, source is top end digital, nothing similar advanced on the market yet, it has no jitter, flutter, there is no moving parts in it..

Thanks to Triode Al i made a vast buying of all kinds of ECC85 for testing in 5881. Conclusion. Medium quality ECC85 is better then almost any ECC88. Not just less hum from tuner bottles, they seems to be built more rigid then signal bottles. Clear winner over Mullard, Telefunken(i use those also) and other famous, is this bottle, capable of wiping off even famous 6N6P with more gain, clarity, huge musicality(Mullard and Telefunken sounds perfect, but this one sounds perfect and musical to die for) and 6N6P compared to this one has no punch, because of much lesser gain. It has Rhodium coated pinout, thats very rare, and it looks similar to Bugle Boy, but it is far better performing then other Philips bottles from my stash and it has almost no hum!

1 PC. PCC85 Philips Double Triode 9AQ8 Tube Valve NOS | eBay

Somekind of "holly grail" of signal bottles(it is tuner bottle, but it works great as a signal). I tested it in few different top end tube DACs of my friends, same result, they happily get rid of their s ECC88-6N6Ps for this one. Tubes in my 5881 are now: KT77 Genalex Gold Lion, pair of Telefunken PCC189 in the middle and Philips PCC85. Same Philips tubes in tube DAC.
 
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Hi I have a Yaqin MC-10 running on 6dj8/6922 is it safe to subsitute with pcc85 pcc189..it seems that heater voltage is different.Did you mean the Philips PCC85 was the best replacment for ECC88?Thanks
Triode Al in this topic suggested PCC85 for 5881 on basis of measured values.
MC-10 is a different model, so i wouldnt suggest it.

hi does it mean that this amp can run any of these tubes 12ax7, 6n1,6n1p -ev, 6n6 , pcc85 , 9aq? without any modification ?

which ones are most reccomended ? thanks a lot
Philips PCC85, if you find them, are real thing from start of 50ies, they are the same as Bugle Boys ECC88. Philips JAN 6992 from 80ies i have also, they are a joke compared to those. PCC189, no problem, if you can find Telefunken, go for them. I found them under different, Canadian brand name, made for Canadian army. Bugle Boys and Telefunken on the 5881, paired, marriage made in heaven. Generally all those you listed. 6N6P, second best, but those are microphone tubes with lower signal, so amp will "lost some watts". Dont use two pairs of them, it will "lost almost all watts". Other PCC85s i tried in 5881 are generally-better then all ECC88(goes only for 5881).

I improved mine 5881 further by throwing out source selector and by adding simple DACT Type 21 Stepped Attenuator 20K FOR PASS B1 DIY | eBay instead pottentiometer which wore out quickly. Good result. In same step i added a pair of massive rhodium covered aux RCAs and i also added 30AWG silver-golden plated wire from attenuator to aux RCAs. I dont have earphones, so i bypassed knob in back for them.

Somebody also likes the sound of tweaked 5881, as i like mine...

JACQUES HIFI PAGES hifi tube amps
 
Triode Al in this topic suggested PCC85 for 5881 on basis of measured values.
MC-10 is a different model, so i wouldnt suggest it.

Hi citypooh thanks for keeping this tread going !! After going thru the schematic details ,i find that the MC10 front input stage is almost indentical to the Mc5881.

like your experiments i`m going try out the NOS tubes below which i have in hand

Telefunken PCC189
Siemens PCC85
Philips PCC85 and PCC189
Valvo PCC85 and PCC189
Egro PCC85
Hoges PCC85
Tungsram PCC85
ITT PCC85
RSD PCC85
Mazda PCC85
Toshiba PCC85

Will update the results soon....
 
Hola. I went further on improving it. All electrical wires to the IEC out and on-off knob i changed for solid core silver 12AWG in teflon insulation, IEC aux i changed with the massive one- gold coated(some original wires were corroded-fire hazard!) i throw out source selector and i wire directly on potti and aux, i changed all wiring on the signal path with 30AWG silver-gold coated, i changed potti which started to malfunction with DACT Type 21 Stepped Attenuator .Good result, also with the wiring.

Same 12AWG silver wiring i added on speakers aux to the banana binding posts and i change those with silver coated. Much more depth and detail. I also throw away RCA aux plastic fantastic and it changed with the massive Gaofei rhodium plated non soldering one.

I have on my tube DAC a testing station, a bunch of different RCA aux for testing and Eichmann Phonopod and Gaofei are real jam, bit different in character and ability, but both open and musical, both capable of showing all micro goodies of the good transient response(CMC silver coated, dissapointment, worse then cheap ones, restrained, filters details) .

I bettered transient response and dynamic of the amp with bypassing power elko, i canibalized from the new Unison Simply, with the massive 4,7uf Mundorf Supreme MKP between + and- in company with Vishay 1837(yes, 1837 can stand that voltage!), on all MKPs(they are Jantzen Superiors-800V) i also add Vishay 1837 and that wiped off micro oscilations and with them the last shreds of the nasality. Mundorf-or every good MKP in such addition is stabilizing power resource and it boosts dynamic capability of the amp in such way, that one couldnt believe. I got this "trick" from an old tubophile.

===
I will always be thankfull to Triode Al for ECC85 idea. There are still a lots of NOS Philips PCC85 made in fifties to buy them online and they are exactly made like Bugle boys of the ECC82-83-88, but they are at least twenty times cheaper. They have codes printed on them, so everybody can by the Philips code ladders on the internet get to know when and where his tubes are made. I putted four of them in liquid nitrogene at my job, cryo process. Two of them in tube DACa and two in 5881.

Lets leave elfs and trolls and miracles aside. I asked some old gentlemen, scientists of pshycal chemistry what should happen with bottles during cryogenisation. Only one said that maybe barium molecules of the barium coating became more homogene, but that was hypothesis. Snake oil or not. My ears told me that cryo treated ones had, talking in percents(%) few percents more stable transients,etc. They just "sing" better, more musical. How i know that? Sure they dont sound worse, monkey test of my right hand shows that i will always pick cryo one, just more likeable for the listening music. Uga, uga. PS.

One of the Russian 6n6p from 80ies(Russians say that 80ies made were worst made, problems with the management and materials in factories ) didnt stood CRYO treatment well, glass on the side cracked. Philips PCC85 are jam. Forget about Philips JAN fakes from, story for little children says, made in 80ies. JAN 6922. It is not a bad tube for undemanding listener, especially for R&R music. It enlighten sound of electric guitars roughness, superb attack, pushes electric guitars forward in recordings, i like them a lot for my Fender Strat, but not for audio. Most of the sound potential on my system are showing PCCs, Philips, Telefunken and Mullard. Mullard are different sounding, electrodes are different, but they are worth of the sin. Far worst are RFT. They said that they used them for the studio recordings. I believe that. They have superb stereo, micro details, but their sound is so depressive, like it was the life behind the Berlin wall, completely without musicality, ripped off feelings of performing musicians. Those are perfect choice for the funeral homes or for the audio scenery, when the mother in law comes too often on visit, to "advise" you by force, how to raise your children...

I remember certain Focal speaker wires which had the same ability to depress the musicality of the system to the cellar and combo of those cables and RFT PCC85, should be outmost clinical and non musical one on the planet. Why i dont use sligtly tweaked silver wired Unison Simply two, with Mundorf SIO, instead two factory MKPs, which is really good supermusical amp? Like Triode Al underlined.. 5881 topology is a very rare bird, it can drive low sensitivity speakers without sweat. My minimonitors are such. Only 50W, but 350W sin ch Yamaha, power peddle to the meddle, cant drive them as half such strong and accurate as the 5881.
 
Good news! i managed to find some time to try out the ECC/PCC85 on V1 position on the Yaqin MC-10 in place of the 6n1 / 6DJ8 and it works flawlessly!!
.Suberp sounds from the Telefunken and Valvo .TFK`s were smooth and nuetral while the Valvo`s has an amazing bottom end which really surprised me (as if i pushed up the bass knob by 5db or more!!)
As you said these tubes are indeed amazing !! I spent so much time listening to these tubes that i didn`t check the others yet.Coming soon with the rest....Phlips ,Siemens and the rest ..
 
Isnt it?
Superb NOS tubes for just a fraction of the cost of very similar ECC88.
I cant imagine how those tube works, if one is adjusting working pount of tubes to the spot..I still didnt do that..
I then played with tube dampers of the different kinds, from the thick silicon rings to complete Herbie dampers array and also the combos of both and in for now i ilke more old Herbie models with Herbies on the top of tube and one thick silicone ring in the bottom, over the very "analytical" new Herbies models. I have supertweeters and new models are more clera sounded in highs and supertweeters are acting the same, so no need to boost highs twice.
Positioning of the Herbies dampers in the middle-top-bottom, changes sound a lot.
 
Sonny. Good question for tweakers with the measurement instruments. I my Yaquin i have now KT77s for two years and they "works" as they did, no sweat, first day.
Last improvements. Silver coated banana inlets. Better depth, stiffer more deep bass, bass nuances are now much clearly listenable.

Gaofei rhodium coated RCA inlets(good ones, they looks similar to WBT Nextgens)and Eichmann Phonopod MK1 RCA inlets.
Both of those are having very different, nice "sound character", so it is easy to adjust the sound of the system and tubes with plugging interconnects in Gaofeis and then in Phonpods to find most listenable ones.