King/Cello Tape Stage Coupling Caps
- Thread starter John Chapman
- Start date
In my experience, a coupling cap will sound better with voltage bias on, means with different DC voltage in two side, in the position of in put should not with bias, in put transformer always come in smaller shape, a silver wire wound in nickel core 1 to 1 ratio (if you don't need for impedance match ) in put transformer can not been beat by any capsActually I've never heard the K/C w/o the cap in the unitCharlie played with that after I bought my piece. But Rich has certainly heard it and Charlie was going to bring a unit down for me to hear for comparison! What I felt was the Mundorf ran rings around the cap Charlie was originally using. I might have gone with a Teflon V-cap but the cost was prohibitive
Not to put words in Charlie's mouth but as I understand it, the cap is there to prevent DC output. As far as a transformer sounding better than a cap, that's not been my experience in general. And that transformer that might sound better would cost a heck of a lot more than the corresponding cap.
tony ma
Myles,
Are you referring to the Ypsilon PST-100 tube preamplifier?
That might be one. The other was the Allnic H3000 phono stage
That might be one. The other was the Allnic H3000 phono stage
i have one of those Allnic H3000's (the newer version with larger trannies) which replaced my earlier version.
the Yipsilon is more than twice as costly as the (not cheap) H3000. yikes!
Will be getting the new Dueland VSF Black caps (the same ones used in Merlin, Tidal and Vandersteen speakers as well as several electronics line) in a couple of weeks to try in the K/C. Might be a little delayed since there's been bad flooding in the town that Frederik lives in and his factory. But hope to have by end of month!
This is the link but it's not working at the moment due to the flooding
www.duelundaudio.com/VSFBlackCapacitor.asp
This is the link but it's not working at the moment due to the flooding
www.duelundaudio.com/VSFBlackCapacitor.asp
Good one, Mike
Haha...sorry for the tardy response -- I think I must have unchecked the wrong check box Anyway, I thought I was gonna score on an 820, but, can you believe this...the deck was sold --literally-- within about an hour...AND I was quick, too -- I guess I called about 30' after it was sold...probably to some #%& -- ugh!
I looked at an A80RC MK II, but after discussion with a tech on what was required to optimize the deck between 1/2" and 1/4" conversions and EQ's -- it was no longer a relevant consideration
When you snooze -- you lose...HAPPY FOURTH, EVERYONE
Sam,
so now you want sympathy for having to change heads on your A820?
i guess things are tough all over.
Mike
Haha...sorry for the tardy response -- I think I must have unchecked the wrong check box
Anyway, I thought I was gonna score on an 820, but, can you believe this...the deck was sold --literally-- within about an hour...AND I was quick, too -- I guess I called about 30' after it was sold...probably to some #%& -- ugh! I looked at an A80RC MK II, but after discussion with a tech on what was required to optimize the deck between 1/2" and 1/4" conversions and EQ's -- it was no longer a relevant consideration
When you snooze -- you lose...HAPPY FOURTH, EVERYONE
Haha...sorry for the tardy response -- I think I must have unchecked the wrong check box
I looked at an A80RC MK II, but after discussion with a tech on what was required to optimize the deck between 1/2" and 1/4" conversions and EQ's -- it was no longer a relevant consideration
When you snooze -- you lose...HAPPY FOURTH, EVERYONE
hi Sam,
Happy 4th!
when you did not repond i was afraid i had offended you, i had thought i was being funny but maybe i touched a nerve.
are you saying that you were about to buy the 1/2" A820 from the guy in Pasadena (from a Craig's list ad) but i (really Ki) got there first? sorry about that....and i mean that. and i'll let Ki know if he runs across another one to let you know (and you know he will
).best regards,
Mike
hi Sam,
Happy 4th!
when you did not repond i was afraid i had offended you, i had thought i was being funny but maybe i touched a nerve.
are you saying that you were about to buy the 1/2" A820 from the guy in Pasadena (from a Craig's list ad) but i (really Ki) got there first? sorry about that....and i mean that. and i'll let Ki know if he runs across another one to let you know (and you know he will
best regards,
Mike
Hiya Mike!
Happy Fourth to you and Pam, too!
SO, you and your cohort Ki were the #%& that appropriated/seized the deck
Just KIDDING
Actually, I'm looking at a Nagra at the moment, but it's in Europe.
I picked-up an Audio Precision Portable One Dual Domain the other day...between that and the Amplitrex --I don't have time for reels
On a serious note, I appreciate the sentiment...it's a small world and I'm glad you and Ki are a part of mine
Did some more testing. We do need a cap or transformer of some kind at the input to the tape stage - or at least most folks need one. Without that DC blocking at the input to the tape stage we get a DC offset at the output. If your pre-amp is AC coupled and is fine with a DC offset at it's input then maybe you can get away with removing / jumping around the input caps. I had hoped since we are feeding that stage from the tape heads (which inherently have no DC offset of their own) we would not get any DC at the input but it seems the input stage itself develops a small dc offset across the input load and then the gain of the stage magnifies that up. With those input caps jumpered I get about 0.15V of DC offset and the autoformers I use as my pre-amp would not be so happy with that long term so for me it is a no go...... Dave Slagle is going to do a pair of nice nickel transformers up for me to test here in place of the cap - but I expect it'll be September before I get those in place.
I also had a concern that DC across the inputs (with the caps removed) would maybe magnetize the heads over time. My heads have a DC resistance of about 500 ohms (I think they were higher than typical) Using a load to mimic the heads and measuring the current that would flow through the heads shows a very small amount of current. About 0.003mA (3 microamps) for my setup. Tape heads with lower DCR values would show more current but still it would be very small I expect. If you choose to go naked and skip the caps then I highly suggest measuring that current flow to make sure it is very low.
I was able to run the wire jumper / vs cap comparison on my test gear here. As for the size of the cap - Todays testing of a small cap vs the wire seems to indicate that the cap need not be too big. Comparing a quite small 0.47uF to the wire jumper I only get about 2db down from 10 hz to about 22hz and above that they are identical. Some posts were talking about coupling cap size suggestions but the size of the cap needed will depend very much on the impedances surrounding it so there is no universal 'right' value to use. I am going to leave the 0.47's in here and as posted before I have removed the electrolytic and the small bypass around that. My gut says 1 to 2 uF might be ideal but I don't have one handy As a side note it would seem better to pull the electrolytic cap and use a very decent film type than to leave that electrolytic in place and go nuts on something like the Dueland in parallel with with that electrolytic - after all a bunch-o-electrons are still sliding on through the electrolytic when they are run in parallel......Myles - please if you have time try the Dueland with and without that electrolytic cap in the circuit.
Also I expect that a nice transformer will be much more cost effective than an exotic cap - but that testing is still to come.... Having said that if I manage to scoop time I still might lash in the 10uF Dueland I have around just to see how it compares to the 0.47uf vcap in there now.
Thansk!
John
I also had a concern that DC across the inputs (with the caps removed) would maybe magnetize the heads over time. My heads have a DC resistance of about 500 ohms (I think they were higher than typical) Using a load to mimic the heads and measuring the current that would flow through the heads shows a very small amount of current. About 0.003mA (3 microamps) for my setup. Tape heads with lower DCR values would show more current but still it would be very small I expect. If you choose to go naked and skip the caps then I highly suggest measuring that current flow to make sure it is very low.
I was able to run the wire jumper / vs cap comparison on my test gear here. As for the size of the cap - Todays testing of a small cap vs the wire seems to indicate that the cap need not be too big. Comparing a quite small 0.47uF to the wire jumper I only get about 2db down from 10 hz to about 22hz and above that they are identical. Some posts were talking about coupling cap size suggestions but the size of the cap needed will depend very much on the impedances surrounding it so there is no universal 'right' value to use. I am going to leave the 0.47's in here and as posted before I have removed the electrolytic and the small bypass around that. My gut says 1 to 2 uF might be ideal but I don't have one handy As a side note it would seem better to pull the electrolytic cap and use a very decent film type than to leave that electrolytic in place and go nuts on something like the Dueland in parallel with with that electrolytic - after all a bunch-o-electrons are still sliding on through the electrolytic when they are run in parallel......Myles - please if you have time try the Dueland with and without that electrolytic cap in the circuit.
Also I expect that a nice transformer will be much more cost effective than an exotic cap - but that testing is still to come.... Having said that if I manage to scoop time I still might lash in the 10uF Dueland I have around just to see how it compares to the 0.47uf vcap in there now.
Thansk!
John
Thanks for the suggestion John. I imagine Charlie is reading this post too and will either respond or think about it more
so last night 'super' Ki came over and (1) checked out the recently arrived 1/2" A820, and (2) installed the Mundorf 1.0 mfd caps. the A820 had arrived a few days ago, but i had not plugged it in yet.
the 1/2" A820 turns out to be in super shape. the software is all up to date and in MkII status, Ki figured maybe 100 hours since the heads had been re-laped. Ki at first powered it up slowly with his 'veritech' or whatever you call it, and all the 'correct' lights came on. we openned my 1/2" MRL calibration tape box and Ki went thru the set-ups and it was already very close to spot on. too bad i don't yet have any 1/2" tapes with music. cosmetically it is very good, the leather bumper is in good shape, one small chip in one wood side panel and some surface scratching on the aluminum top panels, but overall very nice. it's not absolutely perfect like my 1/4" machine but very very good.
Ki then installed the Mundorf caps in the King/Cello repro. it took him about 20-25 minutes. he replaced all three of the paralleled caps with the Mundorf. i then put the new TP tape 'Nojima Plays Listz' on and we listened for a few minutes, no doubt much more dimentional and suave, maybe more foundation......and different sounding. then Ki had to leave.
i played another 2 hours of tape last night, and now another hour this morning. at first while i liked some things, it was a bit lacking the prior openness and maybe a little closed in. that last bit of leading edge transients are slightly muted. the bass is slightly fuller.
it is starting to open up a little now and the transients are getting more lively. i wonder how many hours it might take to fully open up?
on the positive side instruments and voices do sound more real and correct, with more body and more complete textures. it's smoother and and has more ease. really sounds more like tubes in a good way, it's 'wetter'. i love the increase in dimentionality. i'm hearing farther into the noise floor.
overall a nice improvement.....and hopefully will keep improving.
the 1/2" A820 turns out to be in super shape. the software is all up to date and in MkII status, Ki figured maybe 100 hours since the heads had been re-laped. Ki at first powered it up slowly with his 'veritech' or whatever you call it, and all the 'correct' lights came on. we openned my 1/2" MRL calibration tape box and Ki went thru the set-ups and it was already very close to spot on. too bad i don't yet have any 1/2" tapes with music. cosmetically it is very good, the leather bumper is in good shape, one small chip in one wood side panel and some surface scratching on the aluminum top panels, but overall very nice. it's not absolutely perfect like my 1/4" machine but very very good.
Ki then installed the Mundorf caps in the King/Cello repro. it took him about 20-25 minutes. he replaced all three of the paralleled caps with the Mundorf. i then put the new TP tape 'Nojima Plays Listz' on and we listened for a few minutes, no doubt much more dimentional and suave, maybe more foundation......and different sounding. then Ki had to leave.
i played another 2 hours of tape last night, and now another hour this morning. at first while i liked some things, it was a bit lacking the prior openness and maybe a little closed in. that last bit of leading edge transients are slightly muted. the bass is slightly fuller.
it is starting to open up a little now and the transients are getting more lively. i wonder how many hours it might take to fully open up?
on the positive side instruments and voices do sound more real and correct, with more body and more complete textures. it's smoother and and has more ease. really sounds more like tubes in a good way, it's 'wetter'. i love the increase in dimentionality. i'm hearing farther into the noise floor.
overall a nice improvement.....and hopefully will keep improving.
Last edited:
Mike,
I can only speak for the Mundorf supremes. Mine took about 50 hours to smooth out and open up.They will hit their stride in about 80-100 hours and continue to gain nuance from then till 200 hours. The supreme's have very good bass,well defined and with very good sock. The midrange is very liquid and pleasing. Overall one of my favorite caps as the soundstage is wide and open,with holographic qualities.
Your A820 is a great machine.
Tony Gee gives his impressions:
Sound: At this level we are talking about a really serious capacitor, so my findings are relative to other exotic types. They are richer and better layered than the Mundorf Silver/Gold, they seem more open and more spatial. Compared to the Duelund VSF copper they are not as well harmonically structured. The Duelund VSF copper capacitor creates smoother harmonics and a better midrange balance. The Silver/Gold/Oil excels in image depth, call it "bowling alley depth"! In direct comparison the Duelund VSF copper sounds flatter. Like the Mundorf Silver/Gold, the Silver/Gold/Oil has a slight top-end emphasis, this probably contributes to the perceived spatiality and micro-detailing. It will depend on the implementation and personal taste, some may prefer the Mundorf Silver/Gold/Oil, some may prefer the Duelund VSF copper foil capacitor.
Verdict: 12
http://www.humblehomemadehifi.com/Cap.html
yup; it does sound like that....
the Mundorfs are the Supreme 1.0 mdf Silver/Gold/Oil here;
http://www.madisound.com/store/product_info.php?manufacturers_id=142&products_id=8390
and thanks Roger, for the breakin process, it gives me comfort to be able to look forward to that result.
oh and i forgot to mention; the 1/2" Studer A820 includes the 'rare' transformerless output cards. i'll be able to compare those to the King Cello.
Last edited:
Thank you, Mike...I accept the right of first refusal
Say Hi to Ki for me, if you get a chance!
Mike,
Did the deck arrive this way or did KI change the software/firmware? Thanks
Thank you, Mike...I accept the right of first refusal
ok Sam, then i offer you right of first refusal.
i will.
the 1/2" A820 already had all the software added....to version Mk2....and there were updated memeory chips and a newer battery for the programing. Ki said it was a well maintained and updated machine.
ok Sam, then i offer you right of first refusal.
i will.
the 1/2" A820 already had all the software added....to version Mk2....and there were updated memeory chips and a newer battery for the programing. Ki said it was a well maintained and updated machine.
Splendid on all accounts!!
That's great and should be a sonic upgrade over the trafo cards,please let us know.
My A820 had the transformerless cards, too. Just for the experience, it might be worth sourcing the transformer-based cards to make informed comparisons...I wonder if anything at all would require adjustment/calibration when switching between the cards
Similar threads
