Desert island R2R 1/4" 2 track master player

[Ki Choi]

that´s ok...Herrn Berner explained the procedure and what tools were needed....

best
Leif

It would help us to learn what Martin had explained to you here so that we would be informed as well.

Ki

 

[christensenleif@msn.com]

It would help us to learn what Martin had explained to you here so that we would be informed as well.

Ki

this is his reply in full:



Dear Mr. Christensen,



Thank you for contacting audiohouse in Switzerland



>>> but I suspect the bearings in the tape path are dried out of lubrication or needs replacement

Does the Studer tape recorder shows therefore any disadvantages like mechanical noise or bad wow and flutter values?

Worn out bearings are mainly noisy. In case the A80 is very noisy in wind mode, find out which of the roller(s) is (are) responsible for the noise. The easiest methode for that is the following: Put the tape recorder into wind mode and stop roller after roller by hand. Listen if stopping the roller movement does reduce the noise in wind mode. Replace the ball bearings of the rollers which are noisy.

More difficult is to find ball bearings which produce wow and flutter. However, most of those ball bearing do not run freely. Each roller shall rotate easily when you give them a kick them on by hand. If you feel a resistance when rotating a roller by hand, possibly the ball bearing is the source and need to be replaced.



>>> Is replacement a straight forward issue to replace by myself,

If you have got a mechanically flair, it is more or less an easy process. However, the disassembling of most roller assembly requires a pair of Seeger ring pliers to open the corresponding circlips. To give you an idea, please see attached sketch. If you do not have the necessarily tools it is of course difficult. Make sure you have got circlips avilable if they get destroid when opening it (especially take care of the very small circlips in the tape tension senor rollers, position [7] in the attached drawing).



Please note:

in each roller are 2 ball bearings (position [2] in the attached drawing). This means:

Each of the small tape tension sensor roller contains 2 ball bearings; this would make 4 x 2 bearings = 8 bearings, size: D3x10, order number: 41.04.0102, price: CHF. 36.-- / each

Each of the following roller contains 2 bearings: The pinch roller, the stabilizer roller, the move sensor roller, and the guide roller right makes again 4 x 2 bearings = 8 ball beaings, size: D10x22 order number: 41.99.0103, price: CHF. 76.-- /each

Each spooling motor is equipped as well with 2 ball beaings of the same type as above: 41.99.0103

The capstan motor has got a special kind of bearings and can not be changed by your own; you need to send the motor in for refurbishing or you order an exchange motor.pliers



Please note:

The ball bearings are rather expensive, since these bearings are specially produced for this application and are therfore noise selected and have special lubrication. For this reason, I would just exchange noisy bearings or bearing which do not rotate smoothly.



Important:
If you disassembly any of the mentioned units, take always care on position of the washers inside the unit. There are special spacer washer to adjust the tension on the bearings. When you disassemble the unit make sure where the washer belongs to. Do not mix them up! When you remove the ball bearing make sure no washer sticks on the ball faulty bearing.

 

[christensenleif@msn.com]

and in my opinion this mail kind of "de-mystified" the whole process
and yes they can supply spare circlips....
best
Leif

 

[Ki Choi]

and in my opinion this mail kind of "de-mystified" the whole process
and yes they can supply spare circlips....
best
Leif

Thanks for sharing.

As I had said, I had been using ABEC 5 bearings sourced from Japan on A80s. I have had only ~20% success rate in finding the suitable bearings from Japan. The secret sauce in Studer bearing is the special lub Martin mentioned IMO. When one tries to get their A80s as close to the factory spec as possible, it removes all doubts in bearings when sourced from correct place.

I was hoping Martin would have offered you some unique means to identify bad bearings. By trial and error, I have come to the same process in finding questionable bearings over the years by listening to them in fast winding modes or spinning the rollers by hand and listening. You will find the tension roller bearings have the highest probability of being noisy from having to rotate the fastest.

As you disassemble the rollers and remove the bearings, you can try the ole pencil test where I plug in a pencil into the bearings' ID and turn it by hand while feeling for unevenness and listening for noise. On tension roller bearings, I have found both top and bottom bearings can equally be noisy but in most of the roller bearings, the top one gets noisier than the bottom one from not having to receive heavier side forces. so in a pinch, I would collect good bearings from two different roller shafts and make one good set.

YMMV

Ki

 

[microstrip]

This picture shows a spectrogram of the 3150 Hz signal used to measure the wow and flutter of a poor condition Studer A80 I bough a few years ago with noisy bearings and a worn pinch roller. If we measure or calculate the frequency distance between the symmetrical spikes and the 3150 Hz tone you can find which is the bearing (or roller that originates the noise).

You can find information about the use flutter database at http://www.manquen.net/audio/docs/Using%20the%20Flutter%20Database.htm

It includes the characteristic frequencies of machines such as some Ampex's, Otaris's and Studer's (including the great A80!) at several tape speeds.http://www.manquen.net/audio/docs/Flutter%20database%2002-8-28.htm or www.manquen.net/audio/docs/Flutterdatabase02-4-1.xls?

 

[microstrip]

and in my opinion this mail kind of "de-mystified" the whole process
and yes they can supply spare circlips....
best
Leif

IMHO it is only a start - I have once severely damaged one of the small tape tension sensor rollers because I took the circlips and the bearings were stuck in place. Believe me it looks simple looking at the diagram but sometimes it is not!

 

[c1ferrari]

Great stuff, everyone
For measuring W&F on my A820's, I use an MRL tape and the W&F function on an Audio Precision Portable One Dual Domain
Thank goodness for Herr Berner

 

[christensenleif@msn.com]

new shelf for repro-SPUD

 

[christensenleif@msn.com]

and then I needed some more inputs to my TVC/LCR riaa
here´s interior of separate riaa LCR+TVC section


stepper motored SEIDEN volume switches

 

[christensenleif@msn.com]

top view
SOLEN 100µF/630v metal cans in center
transformers from Stevens&Billington, rear to front: mc/riaa/TVC each side
Cardas terminals by mc transformer is for load resistors
dual mono mm/mc input selector rear
dual mono source selector and gain front

 

[tony ky ma]

Nice job you belong to the high end DIYer ( using high end parts ) those fun and happiness also sound quality only the DIYer can find by themselves and I do believe that there will not have end, always find something to make sound quality change better or worse
tony ma

 

[christensenleif@msn.com]

thxs
it was a bitch to build with dual level gnd planes to make the 70 db circuit silent
especially the 100lbs LCLC psu was a devil to drag up and down from the workshop
but eventually it was worth it
best
Leif

 

[tony ky ma]

For me each tube get one power supply by themselves is better than one big LCLC psu for the whole thing, less ringing from only one transformers (because less current in one transformer )
Electric and electronic equipments are just one of the reason of good sounding repro, but it also count on skill of performer ,quality of the instrument, hall effect etc. try to compare the Meditation and Shindler's list played by Xing Yu of our recording to others', those are my favor
do enjoy the music
tony ma

 

[christensenleif@msn.com]

I agree
same as I do;
each tube has separate powertransformer and LC filamanet supply and LCLC on both pos and neg leg in anodesupply
also my mono 300Bs have separate powertransformers for filament driver, filament 300B, bias, anode driver and anode 300B
all are choke input except driver filament that is AC
best
Leif

 

[tony ky ma]

300B sounds good same as 211 and 845 those in negative bias, why don't try 838 and 805 or 810 (40 to 50W), in positive bias but has to use 2A3 or 300B to drive with a inter stage transformer will give you another taste of sound , detail in Shishedo's design. for your horn speaker will not need big power out-put so 800 or 808 and 812 (8 to 12W) can handle the job too, they are also cheap in price now for NOS compare to 300B also they design for 24 hour use/day which their live time will last longer than mine ( idle for sub-woofer amp ) my 4 amp system are all in this type, if you like I can send you some circuits of my designed
regard
tony ma

 

[christensenleif@msn.com]

sounds interesting.....
my mail is my userid
thxs
best
Leif

 

[tony ky ma]

I will take pictures and send to you by email but will take a while, before that you can search by Google to see Shishido's amplifiers circuit first, they show 811,826,800,808,838,805 and also the biggest 833 too, I don't agree his psu and feed back using. anyway will have reference, you can use the parts in hand to replace for your own design
tony ma

 

[stellavox]

Contest still open?

Hey if it’s not too late I’d like to submit an entry.

In my mind a Desert Island anything also implies “off grid”; so here’s a battery-powered, solar rechargeable deck.

Started life as a Stellavox Si8, the “i” stood for Instrumentation. To sell more decks, Georges Quellet in collaboration with an appropriate partner took an Sp machine and made it into a discrete, four-channel deck for recording information for instrumentation purposes; like temperature, pressure, weight change, whatever. The information was encoded to digital and recorded as ones and zeroes, using PCM analog to digital converters supplied by the partner. A/D recording electronics and the D/A playback decoding was done in a separate box. Inside the Si was a four channel playback preamplifier (based on the analog SPA/SOA modules in the Sp series) and a programmable equalization filter . Even beefed up the capstan electronics to allow for ½ inch tape! - never seen a machine with 1/2" reels and guides for that tho.

SO, to make this into an “integrated” (all in one) analog playback deck, I stripped out all the internal digital and added a new version of Cello pre-amplification, creating in effect a Cellovox - name suggested by Rich Brown. Finishing it up in time for the AXPONA show so I don't have to lug separate electronics along with a deck. Will be playing tapes in Dave Copes Audio Note room towards the end of each show day. Listening to it right now and Ella; Miles; Joe Williams/Basie; Beatles (Rubber Soul); Pittsburg Symphony (Porgy and Bess Suite) sound quite nice.

See some of you there? Myles Astor is heading up a Saturday tape seminar.

Cheers

Charles

 

[christensenleif@msn.com]

fantastic !
a juvel imo
best
Leif

 

[Ki Choi]

Hi Charles:

Is that a homemade 10.5" reel adapter?
It looks a lot simpler than the Nagra QGB setup.

Ki