I started a Revox A77 restoration project a while back. Still not finished. Similar quality, except mine is the older low speed version with quarter track stereo heads and 3 3/4 and 7 1/2 ips speeds. This B77 is the later, high speed version with half track heads and 7 1/2 and 15 ips speeds. Instead of this, however, what I would much rather purchase is a used/repairable high speed version of the much older Revox G36 (tube) R2R with a factory supplied half track head assembly that can be re-lapped. That would be quite the machine, if I could find one. Only problem is that the relapping service that can do this type of work is now long gone.
@Nicholas_23 said:
Honest question , what are you guys doing with these R2R units when up and running ?
When I was younger, I did some on-location recording of live events using two high quality microphones. If I can get something running, my thoughts are to perhaps try to do some live events again, like Christmas concerts, or local band performances. I have a Roberts 1630 stereo R2R vacuum tube recorder that is in fairly good shape that I plan to restore. It is 1/4 track stereo with a very simple circuit that only uses 5 tubes. It is a low speed 3 3/4 and 7 1/2 ips machine, but can be modified to do 15 ips with an accessory kit that replaces the capstan bushing and pinch roller.
BMR tower knockoff coming along nicely. Too bad these BMR drivers are NLA. RS-225-4 and GRS tweeter
One of the nice things about those BMR drivers is that they provide a very good horizontal directivity match to a non-waveguided tweeter like you have going there. I hope that PE considers bringing them back again someday. I'm kicking myself for not having ordered another batch of these before they went NLA.
One of the nice things about those BMR drivers is that they provide a very good horizontal directivity match to a non-waveguided tweeter like you have going there. I hope that PE considers bringing them back again someday. I'm kicking myself for not having ordered another batch of these before they went NLA.
Me too. I almost ordered 10 when I got these and didn’t because there were about 250 left at the time.
Which model of BMRs are they? If you REALLY want some more, Soundimports (in the Netherlands) has some of the models in stock. I've ordered twice from them and shipping was actually quite reasonable. (That may not be true anymore with higher shipping costs and tariffs since the time I ordered.)
As a fall back, I'm thinking about picking up a batch of these 2" BMR's that @DrewsBrews was experimenting with. But they are currently out of stock with a note about price uncertainty due to the tariff situation. Bummer. Think that they might make a good, cheap non-waveguided MMTMM or MMMTMMM with the right tweeter. Priced at US $6.70 each at 4+ quantities, the cost should not be too bad, even with tariffs added on.
Comments
I started a Revox A77 restoration project a while back. Still not finished. Similar quality, except mine is the older low speed version with quarter track stereo heads and 3 3/4 and 7 1/2 ips speeds. This B77 is the later, high speed version with half track heads and 7 1/2 and 15 ips speeds. Instead of this, however, what I would much rather purchase is a used/repairable high speed version of the much older Revox G36 (tube) R2R with a factory supplied half track head assembly that can be re-lapped. That would be quite the machine, if I could find one. Only problem is that the relapping service that can do this type of work is now long gone.
Here is my old A77 thread in case anyone is interested:
https://techtalk.parts-express.com/forum/tech-talk-forum/67509-revox-a77-restoration-project
Honest question , what are you guys doing with these R2R units when up and running ?
I admire your ability to rebuild one of these units. While I find turntables interesting, R2Rs are classic (and no snap, crackle, and pop).
When I was younger, I did some on-location recording of live events using two high quality microphones. If I can get something running, my thoughts are to perhaps try to do some live events again, like Christmas concerts, or local band performances. I have a Roberts 1630 stereo R2R vacuum tube recorder that is in fairly good shape that I plan to restore. It is 1/4 track stereo with a very simple circuit that only uses 5 tubes. It is a low speed 3 3/4 and 7 1/2 ips machine, but can be modified to do 15 ips with an accessory kit that replaces the capstan bushing and pinch roller.
BMR tower knockoff coming along nicely. Too bad these BMR drivers are NLA. RS-225-4 and GRS tweeter
aaa> @Colonel7 said:
One of the nice things about those BMR drivers is that they provide a very good horizontal directivity match to a non-waveguided tweeter like you have going there. I hope that PE considers bringing them back again someday. I'm kicking myself for not having ordered another batch of these before they went NLA.
Me too. I almost ordered 10 when I got these and didn’t because there were about 250 left at the time.
Which model of BMRs are they? If you REALLY want some more, Soundimports (in the Netherlands) has some of the models in stock. I've ordered twice from them and shipping was actually quite reasonable. (That may not be true anymore with higher shipping costs and tariffs since the time I ordered.)
Tectonic TEBM46C20N-4B. Parts Express #297-2157
https://www.parts-express.com/Tectonic-TEBM46C20N-4B-BMR-3-Full-Range-Speaker-4-297-2157?quantity=1
As a fall back, I'm thinking about picking up a batch of these 2" BMR's that @DrewsBrews was experimenting with. But they are currently out of stock with a note about price uncertainty due to the tariff situation. Bummer. Think that they might make a good, cheap non-waveguided MMTMM or MMMTMMM with the right tweeter. Priced at US $6.70 each at 4+ quantities, the cost should not be too bad, even with tariffs added on.
https://www.parts-express.com/Tectonic-TEBM35C10-4-BMR-2-Full-Range-Speaker-4-Ohm-297-216?quantity=1
Wow. Maybe I should have kept those extra 2" BMRs I got for Christmas.