Desert island R2R 1/4" 2 track master player

[christensenleif@msn.com]

tony:
yes THIS game has started together with some other games that´s been going on for a couple of years..
I know the characteristic of many different caps and resistors used in different places
I agree Solens are better than MOST elytics....but they´re still grainy
MY favourite is Mundorf Supreme silver in oil unless you go bananas and go Duelund Cast
yes according to the schematic I have the 7,5/15 ips CCIR, but it wouldn´t be too much hazzle making switch on repro card front to change to alternative EQ.
btw how are the repro and record pcb´s from ML-5...can they be used in a std A80 without changing psu or anything?
best
Leif

 

[tony ky ma]

Those EQ filter for A80 is switchable you can make one for NAB with 4 resistors but every time you have take one filter off and plug one in. I don't know about ML-5 card
tony ma

 

[christensenleif@msn.com]

hello T
yes I know one have to switch pcb´s but it´s possible to have two pcb´s onboard at the same time and use a multi pole toggle switch to alternate ......
quite easy to implement
btw how critical are those two 22nF caps that connects the eq pcb to the main repro board?C6 and C7, are they any good?
best
Leif

 

[tony ky ma]

Leif
Too many contacts is no good, plug in and plug out is better
I have not try those 22nf to see but will effect to EQ frequency that i suppose, any way you can try and tell me
tony ma

 

[christensenleif@msn.com]

hello folks
I´m BACK

I´ve done lots of research and asking different people both here in this forum and elsewhere, what are the options for updating the A80 repro ams or even going outboard.I´ve had a very enlightening dialogue going with tony ky ma and was intrigued by his WE437 based reproamp-"stunt", where i disconnected the last stage in the origianal A80 repro-amp.
I thought about building myself an external repro-amp based on the Russian WE437 equivalent the 6s45pi, the same tube I use as a driver in my interstaged 300B.
the only trick to not get it cold-sounding as most people think, is to only run it@10-12mA and not to its capacity, which is around 40mA. the higher you go above 12mA, the worse it sounds imo.
Anyway I came to think about an Andrea Ciuffoli based SESS(single ended/single stage/single tube) headphone amp, redesigned to run with 6s45pi , that I build some years ago.It´s an all out approach with a choke input psu with Ez80 followed by LCLC,designed by my friend Gary Dews at Borderpatrol. even the filamnet supply for 6s45 is LC with BG N 4700µF/35v cap.
Later to make it even more versatile, I rebuilt it to double as a SPUD, a 0,75watt single tube power amp. this change is possible by the use of adding a couple of James OPT and the flick of three switches in each channel to go back and forth between the Lundahl LL1630 and the James.
It drove my previous horns 107db Avantgarde Trio to idiotic leves!



any way, after even more discussions with both Tony and a Norwegian buddy and encouragement from Ed Pong of UltraAnalogueRecordings, I launched the idea of maybe just trying the SPUD as it is, either over the Lundahl or worst case, the James transformer.
Tony and I agreed it was worth a try, and he assisted with valuable details as to how and where to "hotrod" the original repro board.





ready to test on headphones

 

[christensenleif@msn.com]

SPUD A80 repro amp

here´s the inside of the SPUD

 

[christensenleif@msn.com]

ready in the bottom of the A80 trolley

 

[christensenleif@msn.com]

first I tried it with my Sennheiser portables
worked perfect
no noise, hum or distortion
then I hooked it up to the TVC in my main system, via the headphone jack and some shitty cables and whow!
the difference in resolution, attack, ambience was enormous!
the cables are absolutely not of any concern at this stage!
next will be to take balanced out from the Lundahl to Neutrik XLR panel male connectors and silver in silk to the TVC
I´ll probably rewire from the Studer pcb as well

Last I have to give a big virtual HUG to both Tony and Ed for practical and moral support to fulfil this dream less than 2 weeks since I picked up the A80
fantastic!.........

Now Robin our scottish sheepdog need to take a leak......and I´ll think about what to do next...
btw Athan pinchroller is already ordered

best
Leif "forward"Christensen

 

[tony ky ma]

Leif you are the fastest speed working DIYER in the world I ever seen !!!!
tony ma

 

[christensenleif@msn.com]

thxs!
and thxs to you guys as well!
I hear what few have heard I guess.....
my motto is:
why wait till tomorrow, when you can have it (done ) today
now I´ll order 0,8mm silver for signal wire
what dimension do they use in line transformer for this purpose?
laquered/insulated of course
best
Leif

 

[Edward Pong]

Leif,
We're very happy you're up & running so fast!
But most impressed that you have the type of circuitry that will allow you to hear deep down into these tapes!! Bravo!
Analogue tape is infinite.... you just have to go get the information out...
Best
Ed

 

[christensenleif@msn.com]

addictive to say the least!
BRAVO guys....
I´m still in a state of shock
best
Leif

 

[tony ky ma]

We use 30 AWG solid silver 4N for wiring, once we had found one of our A80 drop in 10K hz in one channel, final found it is cost by the stock cable (old) from head to amp, so now all of them of rest of decks have been replaced by home made silver wire cable, twist 4 silver wires tie and wrap with thin Teflon tape, on the top of them wrap with aluminium foil and Teflon tape again out side cover with heat shrink tube,this mods not only fix problem also improved in quality too
tony ma

 

[Ki Choi]

Leif:

With your skills, time, and resources, why not bypass the Studer A80 repro amp completely and build yourself a tape head preamp based on your MC phono pre with addition of NAB and IEC EQs for 15ips speed? And then you can share the info and schematics with the rest of WBF members who are willing to do the work to get better sound?

If you'd take a look at the back of the A80RC audio basis board, there are convenient access points for CH1 and CH2 head outputs that you can use.

A80RC Repro circuit is good IMHO and proven to be flexible as well as producing good sound for many mastering studios for various different applications in the world. This is the main reason why Abbey Road studio chose A80 for their latest Beatles remastering work few years ago (by listening... for crying out loud!) when the studio (and EMI I would guess) had access to all the best master recorders available to them.

On the other hand, the basic design was more than thirty years ago...as Dr. Bruce, Tony and others have discovered, our use is just to reproduce good music and not have to worry about stuff that goes on in a real mastering studio with multiple machine interface requirements. etc. Thus, it can be simpler and sonically better if one is willing to add an external tape head preamp.

Still the Studer A80RC's factory repro sound is the best to my ears if one wants to keep the machine in its original configuration without messing with soldering, cabling, and more $$$$(one more $ for Doshi ;-)) spent on an external tape head preamp homemade or store bought.

Ki

 

[christensenleif@msn.com]

great
but it looks like it is some sort of connector below the headblock, that all the cables goes through?
must be better to wire directly to repro pcb? only thing you write that I´m sceptical about is teflon
as a dielectric it smears the HF...I once used a scalpel on a Cardas litz wire and removed the teflon..I then A/B d the cables with and without teflon, and the one without sound vastly superior in the HF
why not twist with silk, natural, undyed/bleached and enjoy
best
Leif

 

[christensenleif@msn.com]

Ki
this is the next level, but It´s limited what I can do in less than two weeks
I´m absolutely sure you´re right and an unavoidable path to follow
BUT as all my friends know.....sailing season is coming up and audio is put in "summer mode"
anyway thxs for your confidence
btw was in contact with Thomas Mayer and asked exactly about what you suggest, but he thought the stages before and after the LCR section didn´t have enough gain ....to me this seems unlogical since it works perfect with the RIAA network
the loss isn´t higher in the tape eq than the RIAA or???
anyway I´ll explore this later
in the meantime I have a DDAC1794 to rebuild with BP choke input psu
besides I have some alternate TAD drivers to test for tweeters instead of the 2001...I´ll test 2002 and ET703 from 8K and up
best
Leif

 

[christensenleif@msn.com]

Ki?
what´s your experience with the various bearings?
are they "drying out" over time and need relubrication?
best
Leif

 

[Ki Choi]

Leif:

There are many Studer experts who make living working on Studers and other studio gear and know a lot more than I can dream of knowing. (I was recently reminded of the fact by a real pro who refused to sell me a Studer part because I was not supporting his company by doing my own stuff...).. So I would be happy to answer your questions based on my experience but at the end - I am just a hobbyist gone mad and am certainly not the last word in Studers... With that out of the way -

Not all Studer bearings are created equal to me even if they meet the mechanical specs and ABEC quality ratings. Studer had their own spec for bearings that was an integral part of their precision tape path and was one of the most critical factors in measurable wow & flutter performance as I understand.

As I had stated elsewhere, the youngest Studer models were made in the early '90s - that's still twenty years ago and too long for any electro-mechanical devices like reel to reel tape machines to work after resting for so long. When people buy a cosmetically "new" and so called low-hour Studers from various online sources, there's a high probability that although the machine and its bearings may have low hours, they are most likely all dried out by now and don't meet Studer specs - unless the previous owner had serviced the machine and replaced the major bearings properly before offering it up for sale - probably not likely.

A much more complex machine like an A820, having any tape tension anomalies - due to bearings being way off, or for that matter, having even the slight slippage of the reel tables from the spooling motor shaft or the hub to reel contact not being perfect - could cause the machine to go into uncontrollable oscillations in tape tension - not a pretty sight.

I used to buy Studer bearings from Japan during my travels but found the bearings from Athan perform better with higher consistencies. I would find only ~ four good ones out of ten best Japanese ABEC 5 bearings for A80 tension rollers on a good day whereas all bearings I had received in the past from Athan worked. I just ordered a bunch of them from Athan for a friend's machine. In Europe, you can buy the Studer bearings directly from Audiohouse (studerservice@audiohouse.ch). Ask Daniela for a quote. They stock them at CHF 33 each for A820 main bearings and A820 take 14 of them just for the tape path guides and rollers excluding motors and limited action pivot bearings.

You can try manually injecting lubrication to the "sealed" bearing to reduce noise... but you have no control of its performance consistencies IMO.

Of course, everything I said above - YMMV.

Ki

 

[christensenleif@msn.com]

thxs for your patience and your very thorough explaination.
my A80 has been in the Norwegian National Broadcasting Company (as a "backup machine"), which have been "overfinanced" throughout its entire existance, and I´m pretty sure it´s gotten all the TLC it could possibly dream of
apart from that I have ordered main and audio PSU cap kits from Mastertapesoundlab, in additon to a few improvements of the first gain stage in front of my hotrod connection
ships tomorrow....nice to have something to fiddle with during easter...
.....to be continued
best
Leif fw Christensen

 

[christensenleif@msn.com]

and Ki...
mailed Switzerland yesterday reg bearings, field upgradability etc and Daniela responded straight away
her Studer service guy would be back monday and would answer me then
very efficient, very Swiss
thxs
best
Leif