ReVox B77 MkII - HELP - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

TIMTAPE · 29th Dec 2016, 12:07 am

I see from the picture you are recording through the front inputs using the Mic input and with the faders set at about 1 on a scale of 10. That's a recipe for distortion/clipping. Normally you should be using the machine's Line inputs on the back of the machine and the faders should be at about 7 as a guide. At the very least, switch the input selector to Mic Hi.

The pinch roller has a plain bearing which works fine if clean and lightly oiled. There should be a white plastic washer on either side of the pinch roller bearing. For correct operation the pinch roller pressure needs to be adjusted as per the manual.

Do you know about binder issues with some reel to reel tapes? The Ampex 499 tape pictured may be one of those affected. If it is, you will probably have recurring problems. You should use a tape and without binder problems and suited to the B77.

There shouldnt be exaggerated bass on one side and exaggerated treble on the other. Sounds like the machine needs a service/ aligned to the tape.

Tim

cliofreak · 29th Dec 2016, 1:30 am

Thanks Tim, very helpful info. Yeah, I was using the mic ins on the front because I was trying to rule out the issues I was having by trying a different input. Ill try oiling the plain bearing and see if it helps with the binding. The exaggerated bass etc was actually due to me taking a Left out from Output Main on the Prophet 8 and a Right out from Output B on the Prophet 8. There was a short delay in L and R signal that made me check and when I took bother L&R from the main output, the issue was resolved completely.

TIMTAPE · 29th Dec 2016, 6:13 am

Quote:

Originally Posted by cliofreak

Has anyone ever modded a reel to reel to make the reel come to an almost stop to allow really long delays between play and rec head?

I'd suggest this is not a good approach. Slowing the tape to an almost complete stop destroys the fidelity. If you must use tape for delays (digital is so much easier and more versatile) go the other way and separate the record and play heads by large distances - probably using a loop of tape between two machines - as did Robert Fripp/ Brian Eno in the early 70's.

cliofreak · 30th Dec 2016, 3:09 am

Yeah, I hear you on the fidelity loss. I must look into finding a way to separate the play/rec heads (not physically but by lengthening the tapes travel). I don't want to resort to buying a Copicat or the like. Id love to use the Revox for this.

Diabolical Artificer · 30th Dec 2016, 6:48 am

It would perhaps be easier to get a head off another machine, mount it on a plate and make recording amp up on a small PCB then fix the new rec head/s onto the front plate with sticky pads. If mounted on the right after the capstan you'd get big echo's.

That's the best way, or pop the Rexox on it's back and use a mic stand placed near to lengthen the tape path.

The way it used to be done was to use your mixer aux send's return's or whatever and interpose them between play and monitor heads on pro machines that had a sync function. don't think you Revox has that though.

Nice Synth BTW.

Andy.

cliofreak · 1st Jan 2017, 2:41 pm

Cheers Andy! Yeah, Ive made an external box thats basically a mixer/repeater/rate adjuster. It feeds the signal back into the tape machine and it loops or repeats on itself. I just need to get the gap bigger. I had the Marantz slowing way down but, yeah fidelity is lost although it still sounded good. Ill need to have a look at how to lengthen the travel while keeping tape aligned. Mic stand might work!

29th Dec 2016, 12:07 am	#21
TIMTAPE Octode Join Date: Jul 2006 Location: Perth, Western Australia Posts: 1,971	Re: ReVox B77 MkII - HELP I see from the picture you are recording through the front inputs using the Mic input and with the faders set at about 1 on a scale of 10. That's a recipe for distortion/clipping. Normally you should be using the machine's Line inputs on the back of the machine and the faders should be at about 7 as a guide. At the very least, switch the input selector to Mic Hi. The pinch roller has a plain bearing which works fine if clean and lightly oiled. There should be a white plastic washer on either side of the pinch roller bearing. For correct operation the pinch roller pressure needs to be adjusted as per the manual. Do you know about binder issues with some reel to reel tapes? The Ampex 499 tape pictured may be one of those affected. If it is, you will probably have recurring problems. You should use a tape and without binder problems and suited to the B77. There shouldnt be exaggerated bass on one side and exaggerated treble on the other. Sounds like the machine needs a service/ aligned to the tape. Tim

29th Dec 2016, 1:30 am	#22
cliofreak Retired Dormant Member Join Date: Dec 2016 Location: Derry, Northern Ireland, UK. Posts: 17	Re: ReVox B77 MkII - HELP Thanks Tim, very helpful info. Yeah, I was using the mic ins on the front because I was trying to rule out the issues I was having by trying a different input. Ill try oiling the plain bearing and see if it helps with the binding. The exaggerated bass etc was actually due to me taking a Left out from Output Main on the Prophet 8 and a Right out from Output B on the Prophet 8. There was a short delay in L and R signal that made me check and when I took bother L&R from the main output, the issue was resolved completely.

30th Dec 2016, 3:09 am	#24
cliofreak Retired Dormant Member Join Date: Dec 2016 Location: Derry, Northern Ireland, UK. Posts: 17	Re: ReVox B77 MkII - HELP Yeah, I hear you on the fidelity loss. I must look into finding a way to separate the play/rec heads (not physically but by lengthening the tapes travel). I don't want to resort to buying a Copicat or the like. Id love to use the Revox for this.

30th Dec 2016, 6:48 am	#25
Diabolical Artificer Dekatron Join Date: Jul 2009 Location: Sleaford, Lincs. UK. Posts: 7,667	Re: ReVox B77 MkII - HELP It would perhaps be easier to get a head off another machine, mount it on a plate and make recording amp up on a small PCB then fix the new rec head/s onto the front plate with sticky pads. If mounted on the right after the capstan you'd get big echo's. That's the best way, or pop the Rexox on it's back and use a mic stand placed near to lengthen the tape path. The way it used to be done was to use your mixer aux send's return's or whatever and interpose them between play and monitor heads on pro machines that had a sync function. don't think you Revox has that though. Nice Synth BTW. Andy. __________________ Curiosity hasn't killed this cat...so far.

1st Jan 2017, 2:41 pm	#26
cliofreak Retired Dormant Member Join Date: Dec 2016 Location: Derry, Northern Ireland, UK. Posts: 17	Re: ReVox B77 MkII - HELP Cheers Andy! Yeah, Ive made an external box thats basically a mixer/repeater/rate adjuster. It feeds the signal back into the tape machine and it loops or repeats on itself. I just need to get the gap bigger. I had the Marantz slowing way down but, yeah fidelity is lost although it still sounded good. Ill need to have a look at how to lengthen the travel while keeping tape aligned. Mic stand might work!