Yaqin MC-5881A amplifier improvements

[triode_al]

and the picture
You can see the heater supply,
I scraped the isolation over 1 cm. for soldering
- I did not cut the wire, which is a good option too.

The result is: [b]the amplifier does not get hot even after some 5 hours of running[/]
This repair objective was thus very good.

triode al

[CityPooh]

I had the best results from MC5881 when i was using only solid core wires for speakers and interconnects.
Burklin wire wrap is very good sounding option, with maybe a little less bass. Good news for floorstander owners.

Other ones are Tempoelectric DIY cables, tempered silver, superb on quaility minimonitors.
I m stuck for almost two decades on Tannoy Mercurys M-1 with some changes i made on the internal wiring and tweeter capacitor..

Those little miracles after few tweaks plays like Sonus Faber (or better)and i still after almost two decedes cannot find a speaker to outperform those tiny cheapos, who likes to be positioned at least 1,5 from the wall on very rigid spiked stands with their front side slightly tilted up...

Then i was quite surprised, that low cost Neutrik RCA connects plays on MC5881 more vidid and open, than the Eichmann Silver bullets.

I also tried a handsome of non solid core cables of various brands and types.
Vandenhuls, QEDs, Transparents, etc, from mid, to very high cost range, from friends from my slovenian DIY forum(Slovenija is tiny country, so we all live almost next door), and none of it sounds pleasant on MC5881. Those are meant for transistors.

On our slovenian tube open public trials we achieve best sounded results with some CD players tweaked by Lampizator webpage recepies and on Stylos& HL slovenian tube DAC, connected on Marantz 63Ki Sig. CDP and on cheap Logitech Squeezebox classic musicserver!
Squeezy on tube DAC plays like a dream..

We also tested last spring a complete bunch of NuForce D class power amps in the identical setups, but when(slovenian) tube amp played in one showroom and NuForces in other, the NuForce room was empty and tube room was filled with happy smiling faces for lots of hours...

[CityPooh]

Thank you Albert for Your best wishes and you wouldnt believe.
I live 15 kilometers from Alps, and still there is no serious snow in lower parts of the country, but there is two to five meters of it in the mountains.....

I was seriously thinking of a triode mode upgrade and so i thougt to ask you exactly same answers you already answered to..
So i m completelly queistionless.

For tube laic like me, the most valuable info is, that your improved MC5881 is now driving legendary Quad ESL57, considering fact, that in times they were produced, there was only few amps to drive them properlly.(Quad, Hafler, Carver)..
The next one, is the info of ECC85 compability...
Now i can go for Philips JAN tubes i have in my tube DAC and they sounds both powerfull and full of delicacy and richness on minimonitors(i also use floorstanders, but only for for organ music and some rock, mainly live)..

Thank you a lot for your fresh wind of knowledge and humor from the coasts of the north sea...

[triode_al]

janos, your question:

The next one, is the info of ECC85 compability...

I note that one channel is now running ECC85 and the other 6N1 (due to the availability of the tubes in my stock: i have old tubes, not new ones): the channel with the ECC85 is a slightly little bit more direct. This probably has todo with the difference in amplification, the ECC giving a higher loop feedback probably.

Anyway, the new feedbackloop with the MICA is important, as the MICA will have no 'delays' in the high frequency, like the ceramic capacitor has, so the ringing is just two or three cycles (compared to more than 5 in the old setting). This shows on the screen with a 10 khz square wave (5 ohm resistance on the 8 ohm tap).

What I also saw is that the yaqin has very smooth clipping, very well behaved, and that the top end goes to about 50 khz before showing a sign of roll-off.

And that the max power does not deviate much (less than 2 db) between the UL and T setting.

And here the winds differ all the time.

albert

[CityPooh]

Yesterday i changed internal wiring for tweeters on my brothers speakers for the identical wires as i put in mine month ago.
Speakers are the same brand, same model than mine, but brother puts MICA capacitors in them, and as you say, the highs sounds less "nervous", when i listened one of his speakers on the one of the channels and one of my speakers on other channel..

I have a small stock of ECC88 and 6922 tubes for my tube DAC.
Some people on US forums are using 6922 tubes in Yaqin s pre stage.. Is that wise?

As your clipping results shows, it was a pleasant surpise for me, that when i turn the power knob almost in the "pedal to the medal" position, on the a lot of recordings there is no distortion...

Ry Cooder & V.M. Bhatt, Meeting by the river or Paco de Lucia and Ramon de Algeciras sounds flawless alive and passionetly invitning...
On Bach Toccata and fugue, Philips edition, on floorstenders i can almost observe what the organ player is doing and enyoying the whole strength nad delicacy of different pipes in the same time ..
Also the Mark knopfler or Red Hot Chilli Peppers rocks properly with no reserves.

That amp is really fine for todays-10 celsius of our alpine winter.
Considering that the Mediteranian sea is only 80 km away, i m hoping for something warmer from there, because i m not a skier or a snowboarder.

Best regards, Jaro

Yaqin open public trial i organized in our youth community centre..

http://www.hiendfi.com/phpBB2/viewto...=asc&&start=30

and DIY& audio festival i organized in 5 showrooms on the same adress..

http://www.hiendfi.com/phpBB2/viewto...asc&&start=540

[triode_al]

Originally posted by CityPooh

Yaqin open public trial and DIY& audio festival i organized in 5 showrooms on the same adress..

Quite a nice array of equipment. I like the small folded horn speakers and the larger Lowther-looking speakers. I appreciate this kind of transducer. I had one for years (and sold to sister).

As to the feedbackloop, my nephew has his yaqin back, likes it now very much.
albert

[CityPooh]

The speakers you like, are the Hedlundhorns.

On the HiendfiFest there was a Lowther PM series.
I also like dualconcentric principle very much..

That s the reason i m stuck with the Tannoy M1s, because they are sounding exactly like dualconcentrics, but in some ways even better.
Both drivers in them are sounding like one, at any signal power.
M1 was produced for a very short time, after that, Tannoy putted those drivers in much more expensive high end cabinets and even in nearfield monotors, but with limited sucess..They changed them just a bit and sucesfully "kill" their amazing musicality...

You can find M1s used, like mint new, for 30-40 Euros and after MKP and MICA tweak on wiring and croosover, you can compare them with Rogers LS minimonitors, but with different character.

I have Burklin wirewrap and Tempolectric silver RCA wire on tweeters and very old QED no name speaker wires, for midbass.
Those Qeds are naming today "Silver anniversary" and Qed SA is surely not similar in any way to Qeds no name. They are a bit thinner.

Stereo of M1(dont buy their "high end" derivates!) is not depending at all on the listeners position and those speakers plays both behind and in the front of the speakers.
You can sit at the front of the left speaker and still you will hear complete right chanell!
On tubes they sounds terrific, without even a hint of sibilance or coldness..
And they could be a pleasant birthday surpise for your nephew, because they are ideal partner for the Yaqin MC5881..

Today i drove to my brother his Tannoy M1s after i changed wires on tweeters.

On my Yaqin, it was obvious, that the coil of the one of midbasses is damaged..
It rattles even at the medium power.

But then on my brothers setup the same speaker plays well!

Brother has Hafler DH-200 and DH101 Mosfet amp and the same player as i, and the top model of Transparent speaker and RCA wires.
It is obvious, that the "magic boxes" on the Transparents are filtering so much, that the damaged speaker plays with no problem..

I wouldnt believe, if anybody told me that is possible..
But considering amazing bass driving ability of the Yaqin MC-5881, it is obvious that brothers setup can not play so low, because of too much filters in the line of the signal.
Even one of my amps, Yamaha P-3500, driven with tube DAC as an preamplifier, on Burklin wire wrap as RCA and speaker cables performs better..

All your conclusions about MC5881 i passed to my close friend, former tube guru of the german Pear audio...
It will take some time, but then i will also very slowly start to upgrade my Yaqin step by step in order to better the abilities of my beloved speakers and listen carefully how the changes sounds on them...

I believe that the first obvious change in my Yaqin, are the link capacitors to MKPs of the higher voltage, then may be change of MICA conductors?

And after that a complete upgrade from ultra linear to triode configuration?

Jaro

[triode_al]

The remark

as obvious, that the coil of the one of midbasses is damaged..
It rattles even at the medium power.

is well known of the D1's. The glue does not keep: the forces are so high, because of the very high accelleration forces of the cone/coil.
The magizine L'Audiophile complained about it when they were introduced.

The
[qote] the link capacitors to MKPs of the higher voltage, then may be change of MICA conductors?[/quote]
is that the coupling cap's are quite good in the amplifier I repaired (400 V MKP) this looks OK.
It is impossible to replace such a device with MICA.
But the feedback capacitor: YES. There is some smearing of the oscilation in the ceramics, I could see that this disappeared. It is now just a clean oscilation.

And with your Pear friend, I might like to test a little design trick I found in a Revox amplifier.
albert

[CityPooh]

Originally posted by triode_al
The remark

is well known of the D1's. The glue does not keep: the forces are so high, because of the very high accelleration forces of the cone/coil.
The magizine L'Audiophile complained about it when they were introduced.

The
[qote] the link capacitors to MKPs of the higher voltage, then may be change of MICA conductors?

is that the coupling cap's are quite good in the amplifier I repaired (400 V MKP) this looks OK.
It is impossible to replace such a device with MICA.
But the feedback capacitor: YES. There is some smearing of the oscilation in the ceramics, I could see that this disappeared. It is now just a clean oscilation.

And with your Pear friend, I might like to test a little design trick I found in a Revox amplifier.
albert [/QUOTE]


I sent you an email considering contact with my ex Pear friend...
Sorry..My english is a bit rusty..
I meant changing ceramics with MICAs..

M1s are with its 50W sin power handling and 87Db/m still a bit of problem to drive with some amplifiers.
And Hafler construction is an amplifier with high current and almost no protection(a bit similar to Elektor Crescendo), so probably my brother wanted to "milk" the Hafler in order to drive speakers powerful, and that causes the damage..
My Yamaha amp, P-3500, has huge power(inside it is almost similar to last of produced Hi-fi Yamahas.. Yamaha didint bother these days about producing much different amps for audio and PA), but it has potis, so i can not overdrive M1.
Also Elektor copied it in a own way and name it, the Titan amp..

MC5881 plays bass area a lot nicer than P-3500 and Hafler, with much more depth and without aggressive bass compression of both amps..
Some of my friends owns much more costly tube amps, and they are always pleasently surpised when we are listening Yagin in my setup.
.
Main sonic advance of my setup is still Stylos DAC, tube prototype..
Stylos DAC is selling in USA from 10 000 US up in an ougly granite box..
I had a mad luck to get my hands on Stylos DACs PAN module upgraded as tube DAC by my ex Pear friend..
Without it, MC5881 performs quite bit less shiny, but still nice..

I must change laser for new one on my NAD 502 CDP and then i will run a few listening tests of MC5881 on NAD502 and Marantz 63Ki Sig(both nice CDPs, but totally different sound character) and maybe on Squeezebox(planning to buy one) with and without tube DAC..

Jaro

is that the coupling cap's are quite good in the amplifier I repaired (400 V MKP) this looks OK. It is impossible to replace such a device with MICA. But the feedback capacitor: YES. There is some smearing of the oscilation in the ceramics, I could see that this disappeared. It is now just a clean oscilation. And with your Pear friend, I might like to test a little design trick I found in a Revox amplifier. albert

[bbbing]

Hi Triode Al

I am impressed with your results on the modification to the power transformer. I have a few questions before I attempt the mod since the power transformer on my amp is overheating.
1) Is the mod easy to do?
2) Does the power transformer still run hot
3) Do you re-seal the tranformer after the mod, or leave the it open without the isolation?

Cheers Bing