Patrice B
Super Member
Hello all and Greetings!
I’ve decided to post here instead of « Tape » ´cause those little (!) beast are also tube amps/preamps.
Roberts 1650
I’ve finally buckled up my second reel to reel resto, a Roberts 1650. It’s the first one I’ve bought two years ago with the only goal of using the little amp/preamp inside (6BM8’s).
However, as the Roberts 770X ( https://audiokarma.org/forums/index.php?threads/roberts-770x-aka-akai-m8-safety-question-ac-riding-on-the-chassis.1035851/post-16680529 )
gave me a boost, I’ve done all that was necessary to give a second life to this ugly duck:
- new belts;
- motor and flywheel/capstan cleaning/oiling;
- replacement of some parts: two output transformers as one was not original (and squealing!), one secondary idler wheel and a complete head assembly as the old one was beyond repair;
- cigarette paper and wood glue to repair the numerous tears in the onboard cheap speakers. Fortunately, I can also connect a set of speakers and it automatically switch off the integrated ones…;
- complete recap job and replacement of two 6BM8’s;
- new motor run cap 2uf. Weird, as the schematic indicates 2.2 but there was a 2uf inside and the motor label also calls for 2uf, go figure!
After two days and a lot of adjustments, it runs pretty ok for a not so hifi piece of gear, at 7.5 ips I must add…
About the speed: I’ve tested the « new » heads adjustments (height and azimuth) with a recent recording I’ve made on the 770X… and noticed that the speed was a bit slower on the 1650. As you will see, I’ve corrected it in a crude way by adding a layer of electrical tape around the capstan sleeve. I don’t notice any more wow and flutter as I took care of carefully wrapping it without any gap or overlap. I will take the time to search for a more « permanent » fix (looking if increasing motor run cap value would do it but not sure?).
Tso days ago, I had the idea to check if speed was in spec on the two RTR by measuring and marking a section of 225 inches of tape (225 divided by seconds gives 7.5). Surprise! The measured length of tape took 31 seconds to run on the two machines, this with the 1650 with the crude repair! So, they run at 7.25 ips, meaning that I’ll have to check my other ones (projects: Tandberg model 64, Akai M5 and Akai 1710) so I could play/record tapes on all of them, being sure they run at the same speed.
Surprisingly playing well the Roberts 770X recorded tape and preliminary record/play tests on the 1650 gave satisfying results.
***I’ll be able to impress the kids at school as this one is a bit more portable than the 770X!
Regards and Greetings!
**Follow-up in the second post, the M5
I’ve decided to post here instead of « Tape » ´cause those little (!) beast are also tube amps/preamps.
Roberts 1650
I’ve finally buckled up my second reel to reel resto, a Roberts 1650. It’s the first one I’ve bought two years ago with the only goal of using the little amp/preamp inside (6BM8’s).
However, as the Roberts 770X ( https://audiokarma.org/forums/index.php?threads/roberts-770x-aka-akai-m8-safety-question-ac-riding-on-the-chassis.1035851/post-16680529 )
gave me a boost, I’ve done all that was necessary to give a second life to this ugly duck:
- new belts;
- motor and flywheel/capstan cleaning/oiling;
- replacement of some parts: two output transformers as one was not original (and squealing!), one secondary idler wheel and a complete head assembly as the old one was beyond repair;
- cigarette paper and wood glue to repair the numerous tears in the onboard cheap speakers. Fortunately, I can also connect a set of speakers and it automatically switch off the integrated ones…;
- complete recap job and replacement of two 6BM8’s;
- new motor run cap 2uf. Weird, as the schematic indicates 2.2 but there was a 2uf inside and the motor label also calls for 2uf, go figure!
After two days and a lot of adjustments, it runs pretty ok for a not so hifi piece of gear, at 7.5 ips I must add…
About the speed: I’ve tested the « new » heads adjustments (height and azimuth) with a recent recording I’ve made on the 770X… and noticed that the speed was a bit slower on the 1650. As you will see, I’ve corrected it in a crude way by adding a layer of electrical tape around the capstan sleeve. I don’t notice any more wow and flutter as I took care of carefully wrapping it without any gap or overlap. I will take the time to search for a more « permanent » fix (looking if increasing motor run cap value would do it but not sure?).
Tso days ago, I had the idea to check if speed was in spec on the two RTR by measuring and marking a section of 225 inches of tape (225 divided by seconds gives 7.5). Surprise! The measured length of tape took 31 seconds to run on the two machines, this with the 1650 with the crude repair! So, they run at 7.25 ips, meaning that I’ll have to check my other ones (projects: Tandberg model 64, Akai M5 and Akai 1710) so I could play/record tapes on all of them, being sure they run at the same speed.
Surprisingly playing well the Roberts 770X recorded tape and preliminary record/play tests on the 1650 gave satisfying results.
***I’ll be able to impress the kids at school as this one is a bit more portable than the 770X!
Regards and Greetings!
**Follow-up in the second post, the M5
