Final touch up for Studer A80 RC's modification;

[tony ky ma]

so you´re obviously tapping signal by R47 after first stage and eq, like I did before I went all Todor way
C18 and C30 I use Nichicon Muse BP
C4 and C5 I use BG N

The main change of this time is not only different brand made, is more step down values (1/10) and different construction of caps that will let different frequencies can go through more easily on their own way, result has more firm body in sound stage also more solid in loud and more detail in quiet
next we will do something more to the coupling cap too or try dual power supply by battery and see any more improve
tony ma

 

[christensenleif@msn.com]

Hi T
I think I understand
sounds like cap shunting discussed by Van Alstine in the 1970´s, where he operated with 1/10 (decades) of original value, so if you shunted a 100µ cap, first shunt should be 10µF, then 1µF, then 100nF with different cap types with different characteristics and reconances for spesific freq.
thats what you´re doing?
best
Leif

 

[tony ky ma]

You are right but I am not doing in exactly 1/10 down because of the value of caps in my stocks. the original is 47mf but now is 100mf tantalum 6mf oil 0.5mf oil+ 0.05mf film.that you can see in the picture connect in out side with a plug in, we did ABX with plug in and out, result that never unplug again. I check the price of oil cap in Ebay, they are asking too much to-day and I almost done in my stock. add choke maybe another idea
best
tony ma

 

[christensenleif@msn.com]

a choke is seldom wrong imo
love choke input psu
even built a Pass F5T with choke input psu; a bitch to build, but much better than CRC or even CLC
best
Leif

 

[christensenleif@msn.com]

Hi T
are they in series with signal? if so, youre lowering the highpass frequency by increasing from 47 to 100µF cap
that in it self might well affect tonal colour
the value increase should for controlled result be with same type of caps...
best
Leif

 

[tony ky ma]

Hi T
are they in series with signal? if so, youre lowering the highpass frequency by increasing from 47 to 100µF cap
that in it self might well affect tonal colour
the value increase should for controlled result be with same type of caps...
best
Leif

Hi Leif
The original repro broad by pass cap 47 is electrolytic , we change to tantalum 47, sounded better, next changed to 100 uf tantalum even more better, that is the sound of copy we sent to you. final we added 6 uf and 0,5 uf oil + 0.01 polypropylene in parallel, out side the case connect with wire plug in and out. check by listening. that sound is V's tape.
3 of coupling cap 47 tantalum change to Solen metallized long time ago after we did in record broad parallel add 0,47 uf paper in oil copper on those coupling cap got the much better result then we will do the same to repro too in next . in future release will be in different level again
best
tony ma

 

[christensenleif@msn.com]

ok I see
so you re in stage one of the original repro board C16 and /or C19
C6 and C7 and C8 are very important!
best
Leif

 

[tony ky ma]

ok I see
so you re in stage one of the original repro board C16 and /or C19
C6 and C7 and C8 are very important!
best
Leif

In stage one changed C8 only and C6 we don't use slow speed, C7 quality not bad, Q4 Q5 took off and by pass Q4 make it high speed only more directly contact, same done in stage two Q6 Q7 in this stage C16 C19 change to solen and c18 C30 done as I mentioned so far the repro in this condition of cause the out put stage is WE437A and a silver transformer
ps. our power shielding cables is shielded by voltage only no current interconnect is around 30 to 40 VDC and speaker cable is 60 to 80 VDC in phono of weak signal is under 10 V over voltage will sound too hard and clean like digital too low will too soft and muddy
best
tony ma

 

[christensenleif@msn.com]

ok
C9 I use polyprop
NO shield in whole system
only twisted leads
still dead silent in 112db sensitive horns
shield ruins HF and makes "turbulence" in HF
best
Leif

 

[christensenleif@msn.com]

Hi T
are C18 and 30 more critical for sonic result than C16 and 19 since they only have Solen and you run oilcaps on C18 and 30?
ask because I consider buying these to test in my repro cards, also for C31, where I have BG N----
http://www.hificollective.co.uk/components/mcap_evo_oil.html
Ill need a box too...ha-ha
maybe Ed has a spare violin body......
best
L

 

[tony ky ma]

Hi Leif
C19 and C16 is more important that is why we made first mods on this two, C18 and C30 because of we can't find those mystery noise so we changed those in brand new one of different brand include C33.34.35. result sound changed too clean like digital, that is why we start to play with C18 and 30. actually C3,4,5 +9 need to do the same too but there will be too much to do, better change this stage to tube and transformer I guest, in record broad we change C18 and 36 to solen in long time ago too but after the repro's mod done we did the same to C25 and 28 + add paper in oil copper foil 0.47uf parallel to C18 C36 and found much improved in copying tapes, so we will add paper in oil parallel to C8 C16 C19 of repro too in next, C31 we no use of it because that stage had changed to tube already
tony ma

 

[christensenleif@msn.com]

ok
C3 and C9 I have Wima polyester, and c4 and 5 Black Gate N
best
Leif

 

[tony ky ma]

repro's mod should stay in this level for a while

Since last time ,modified A80's repro card's C18.C30 by pass caps of the second stage with great up grade of sound, there are so many caps using in the first and second stage ( last output stage had been converted to tube and transformer so no coupling cap in using) and they works as coupling or by-pass, different construction of caps has their own sound character specially working in sound path coupling with big effect , C8 C16 C19 is the coulping, stock was using polarity Tantalum 47mf and 10mf, non polarity cap in 47mf must be very big in size only metallized plastic cap can make that so we converted three of them to Solen metallized long time ago that sound much better, but to-day Mundrof make silver/gold/oil metallized cap in same value , after we replaced Solen to Mundrof , that sound even more better, with oil in, sound more smooth . next,we add on Jansen paper in oil copper foil 0.47mf and 0.01mf multi cap (polypo) to C19 C16, it came out sound more clear but too much in high frequency with cool that cover the oil cap's smooth and warm sound, finally we took off the Multi cap then got the sound which we like better,C8 is the output coupling of first stage is more sensitive than other two caps C16 C19 so beside the Mundrof silver/gold/oil , we added a Jansen silver foil paper in oil 0.1 to it and got the best result. finally we did the same thing of C18 C30 to C3 C9 too which is the by pass cap of first stage, right now this is the best sound we had heard so far and will keep it on for a while because no ideas for more modification . maybe it is not Studer's sound any more but for our tape copy quality will have a big jump and will be noticed by our future copies
tony ma

 

[Edward Pong]

Detail of bypass caps paralleled with bypass cap in Studer playback board....

 

[christensenleif@msn.com]

I would ditch the Solens..they re grainy imo
the MITs are no winner either...
you know my recommendation....
and while you re at it...dispose of the teflon tubing.....it smears the hf
try silk tubing...VT4C in HK sells it
http://www.vt4c.com/shop/program/main.php?cat_id=22&group_id=3&hit_cat=

best
Leif

 

[tony ky ma]

Will this time be the real final ?

Recently we did live concert recording of young violinist Tatsuki Narita and pianist Mami Hagiwara with new re-modify A80's record amp, from the pictures which you can see the big cap in white colour is Mondorf silver gold + oil (47uf) combine with silver colour is Jensen paper in oil copper foil (0.47uf)and colour in gold is paper in oil silver foil(0.047uf) to replace the stock use small Tantalum in coupling position, market value is $6 to total $400 of each one, first and third stage still keep in tube version as before, also the repro amp did in the same way too. result big jumped sound quality in master tape recording unbelievable detail and transparency . because of waiting for the shipment of RMG900 blank tape that we can not copy tape to go right away so we did some CD copies from the master tape and sent to some of our subscribers looking for some feed backs, they all came back of unbelievable quality.
I used the Carmen fantasy piece from the CD copy compare listen to the EMI vinyl old Perlmen's recording, although my Lp system is not the real high end level but the CD player is more simple, a Toshiba HD DVD player, and this is the first time I like the CD sound better than the LP but by no mean CD can bit the vinyl, key point is recording quality if we can have a vinyl cutter ( my dreaming) and direct cut a vinyl from the same master tape the result will not be the same !later Ed will put new samples to the website for people can compare the changed quality to our old one
tony ma