Hi, I've been looking at your work, I think it's a good idea to convert a standard motor to another HS, but nothing more. The first thing is that speed is directly related to the EQ of the PCBs, so both playback and recording, as well as the motor control PCB. The values of its capacitors and resistors are different, because the standard model (3 1/4-7 1/2) all its electronics are designed for that model, and not for an HS model. You can get rid of doubts by placing an original recording in 19 and 38 cm, which I mean that, will not sound the same as in an original HS machine with all its original electronics and mechanics. You get these explanations in the REVOX manuals available online. Any way, good job!!!
you are correct that rec and PB preamps have different electronics but I think the speed control board is the same. Proff. conversion would require messing with the electronics of the preamps but I am just a hobbyist so I will not mess more. What I only did was turning the equalization down from the trimmer on the rec preamp. Further more I like the boost on high freqs that result from this. Like that also and keeping the old motor I can revert the machine to normal speed anytime. But yes you are correct. Proffesional conversion would require changing stuff on the preamps.
Unfortunately there is. For my home amateur specifications, it is acceptable. It only comes down to how accurate the workshop's lathe is. The less tolerance there, the better the results. I had to try twice (seen on the video) to get an acceptable result. If anyone tries this, it must be very clear to the store that tolerance must be to the bare minimum. Better to make it a bit bigger (say 9.10-9.15mm) to be able later to take out some material in case it not very well made. Speed is adjustable so diameter accuracy is not that important.
@@dchatz I agree with you. For the capstan shaft you had to do a delicate job. I remember that I simply ordered the high speed capstan back then. Of course all the frequency related components of the amplifiers had to be changed too.
@@wolfgangbachschwelloe1wbs905 nowadays original high speed capstan shaft is rare and expensive. Normal speed capstan shaft must be converted manually but you have to compromise for the accuracy. Very little but audible w/f must be accepted. Since I am an amateur it is perfectly acceptable for me.
Great job. I would like get some help to solve a sensor noise (whistling). It only happens on 7 1/2 speed. I see you removed the motor and so on, although I don't don't how you calibrated the sensor back. Is it so hard? Could you help me on this?
the sensor does not need any calibration. It is moving with motor on the same base so it is as it was. Furthermore the motor runs at the same speed as before. Whistling noise would not come from the sensor. You must see if its mechanical or electronical. Mechanically you might need bearings or lubrication, electronically you might have a bad component. capacitor etc.
I am located in Athens - Greece. If you can bring it to me somehow I'd be happy to give some advise. But, I'm not a professional and I don't repair stuff for money. I don't take responsibility to repair other peoples machines. I'm open for any friendly advise you need. Just for what you mention as problem I can only understand that your machine requires a professional technician for check-repair-calibration.
this messes up the tape path. you'll change the angle that the tape takes off the r/p head. the factory HS machines have the motor mounting drilled differently so that the centre of the fatter capstan sits further back & gives you the same angle off the head. the tape isn't supposed to touch the guide in between except by its edges.
Literally 3/4’s of the fekking video is about how he adjusted the motor mounts to correct the tape path, but nah why watch the video when you can just try to be a smartass instead.
hi did you know there was a deck that used A77 deck in side ut was a 8 track 1/2 deck the thing is the one's i have have very heavy wear all over them yes i know the motors very well i have a slow model same as you it's very ill with wear
It's an honor to sub your channel. These A77 videos are the best on TH-cam.
thank you sir
Love that convertion and you can reverse it any time to original speed👍👏👏
I also love working on Revox, nice channel.
Thank you
Hi, I've been looking at your work, I think it's a good idea to convert a standard motor to another HS, but nothing more. The first thing is that speed is directly related to the EQ of the PCBs, so both playback and recording, as well as the motor control PCB. The values of its capacitors and resistors are different, because the standard model (3 1/4-7 1/2) all its electronics are designed for that model, and not for an HS model. You can get rid of doubts by placing an original recording in 19 and 38 cm, which I mean that, will not sound the same as in an original HS machine with all its original electronics and mechanics. You get these explanations in the REVOX manuals available online. Any way, good job!!!
you are correct that rec and PB preamps have different electronics but I think the speed control board is the same. Proff. conversion would require messing with the electronics of the preamps but I am just a hobbyist so I will not mess more. What I only did was turning the equalization down from the trimmer on the rec preamp. Further more I like the boost on high freqs that result from this. Like that also and keeping the old motor I can revert the machine to normal speed anytime. But yes you are correct. Proffesional conversion would require changing stuff on the preamps.
Is there flutter audible on this?
Unfortunately there is. For my home amateur specifications, it is acceptable. It only comes down to how accurate the workshop's lathe is. The less tolerance there, the better the results. I had to try twice (seen on the video) to get an acceptable result. If anyone tries this, it must be very clear to the store that tolerance must be to the bare minimum. Better to make it a bit bigger (say 9.10-9.15mm) to be able later to take out some material in case it not very well made. Speed is adjustable so diameter accuracy is not that important.
Funny to see this here, I did it around 1984 when I started my sound recording business.
this is the power of technology of today, knowledge sharing etc. I also grew up in the "books and friends" era but the youtube era is a revolution.
@@dchatz I agree with you. For the capstan shaft you had to do a delicate job. I remember that I simply ordered the high speed capstan back then. Of course all the frequency related components of the amplifiers had to be changed too.
@@wolfgangbachschwelloe1wbs905 nowadays original high speed capstan shaft is rare and expensive. Normal speed capstan shaft must be converted manually but you have to compromise for the accuracy. Very little but audible w/f must be accepted. Since I am an amateur it is perfectly acceptable for me.
Done that 40y ago to an old Grundig Tk27
How many A77 machines do you have presently ?
1 mk3 converted to HS, 1 mk4 . 2 total
@@dchatzYou're on your way to collecting - the ReVox acquisition virus is manifesting !
Great video again ! super useful info!
Great job. I would like get some help to solve a sensor noise (whistling). It only happens on 7 1/2 speed. I see you removed the motor and so on, although I don't don't how you calibrated the sensor back. Is it so hard? Could you help me on this?
the sensor does not need any calibration. It is moving with motor on the same base so it is as it was. Furthermore the motor runs at the same speed as before. Whistling noise would not come from the sensor. You must see if its mechanical or electronical. Mechanically you might need bearings or lubrication, electronically you might have a bad component. capacitor etc.
my a77 doesnt record and the sound is not clear,can you see this for me?
I am located in Athens - Greece. If you can bring it to me somehow I'd be happy to give some advise. But, I'm not a professional and I don't repair stuff for money. I don't take responsibility to repair other peoples machines. I'm open for any friendly advise you need. Just for what you mention as problem I can only understand that your machine requires a professional technician for check-repair-calibration.
@@dchatz can u send your whattsapp
wonderful Great stuff keep going
Thank you
this messes up the tape path. you'll change the angle that the tape takes off the r/p head.
the factory HS machines have the motor mounting drilled differently so that the centre of the fatter capstan sits further back & gives you the same angle off the head.
the tape isn't supposed to touch the guide in between except by its edges.
But i did exactly that. i lifted the motor to a new position. I even show exactly how i did it.
@@dchatz my apologies- I didn't get to that bit! 😞
@@jonvincentmusic the man apologized so lets just forget about it.
Literally 3/4’s of the fekking video is about how he adjusted the motor mounts to correct the tape path, but nah why watch the video when you can just try to be a smartass instead.
@@dchatz thanks. & he's deleted his comment & fcked off without apologising himself. 😂
hi did you know there was a deck that used A77 deck in side ut was a 8 track 1/2 deck the thing is the one's i have
have very heavy wear all over them yes i know the motors very well
i have a slow model same as you it's very ill with wear
My A77 runs at 7.5 ips and 15 ips
then you are lucky enough to have an original HS version. You don't need to convert anything
Не проще было купить вал мотора на 15 ips и поставить его в двигатель?