And me😀
Service manual shows those rails as +/-10v on the std transformer!
Definately not enough for 9v regs to regulate.......I knew there was a reason I went with 8v regs not 9v when I was messing with the original set up 😱🙄
In the KI it is nearer +/- 12V but with the large voltage drops +/- 10V is probably an RMS value 
Brent
Brent
Over 11.5V, so is safe to regulate to 9V
Observed that Regulator output ranges from 8.8V to 9.25V after testing different brands.
Will select two closest and implement in player
Use ST regs and avoid On Semi if at all possible. We have had issues with many On Semi regs oscillating. They seem cheaply made too
Brent
Brent
I'd go for 8v rails if I was using the original TX as I think you may well be running on the edge especially as Brent points out, you are using cheap regs.
Why not got the whole hog and get a decent sized 12v TX. Bridge and smoothers and you'll have a proper PSU.
Hi Brent, I was wondering: when do you know a regulator oscillates? I guess you need an oscilloscope to find out or maybe you can describe how it deteriorates the sound (in case of analog stage supply)? I have not any experience in hearing if a regulator is oscillating or not. Thanks.
Hi guys, just checking in. I've been busy at work and not had much time to tinker with the 63. I had another go at debugging my display this evening and finally figured out that the little toroid is just DOA. I'll test it first next time. Still no further towards sorting out that mains hum at full volume. Do I need to ground one end of the centre bolt or anything? I'm considering doing a regulated PSU for the servo now, as I'm guessing that will fix it.
Still no word from TentLabs here. Any luck your end, Ray?
Still no word from TentLabs here. Any luck your end, Ray?
Hi Ben,
I received my XO's about two weeks ago. I sent him a third reminder to info and order@tentlabs.com and a few days later they landed on the doormat. Not that I got a reply to my messages though, the radiosilence still continues. So I have no idea what was the reason for the long delay, snow-vacation, illness...??
Regards,
Ray
I received my XO's about two weeks ago. I sent him a third reminder to info and order@tentlabs.com and a few days later they landed on the doormat. Not that I got a reply to my messages though, the radiosilence still continues. So I have no idea what was the reason for the long delay, snow-vacation, illness...??
Regards,
Ray
I have read many, many pages of this very long thread. I have carried out most of the mods suggested. What is not clear to me is insert wire jumper at R619/620".
It seems from the pictures I have seen that most have taken a wire from a point on the board to the L & R phono's. However, again from the pics I have seen there appears to be a wire from the area of U210/U214, to the space left by the removal of caps
C657/C656.
Should I remove C655 - C658 and add the links from U210 to C657 and from U214 to C656 (+ side) ?
Rob.
It seems from the pictures I have seen that most have taken a wire from a point on the board to the L & R phono's. However, again from the pics I have seen there appears to be a wire from the area of U210/U214, to the space left by the removal of caps
C657/C656.
Should I remove C655 - C658 and add the links from U210 to C657 and from U214 to C656 (+ side) ?
Rob.
Hi Rob,
R619 and R620 are resistors/jumpers that can be inserted to bypass the HDAM circuit, while keeping the rest of the player's circuitry intact. If you are planning to bypass the output caps as well, you can use a more direct jumper wire from U210/214 (the opamp outputs) to the output sockets. If you take a look at the schematic, you'll see that the + of C657 and C658 runs to the outputs, so they can be used to connect the other side of the jumper if you remove the caps.
Regards,
Ray
R619 and R620 are resistors/jumpers that can be inserted to bypass the HDAM circuit, while keeping the rest of the player's circuitry intact. If you are planning to bypass the output caps as well, you can use a more direct jumper wire from U210/214 (the opamp outputs) to the output sockets. If you take a look at the schematic, you'll see that the + of C657 and C658 runs to the outputs, so they can be used to connect the other side of the jumper if you remove the caps.
Regards,
Ray
Sadly I have a very distorted sound on both channels🙁
I suspect that I might still have some of the HDAM in circuit?
I have removed the following :-
1. Muting Transistors (linked the pads together)
2. R 651 - 654.
3. R619/620
4. R617/618
5. C655 - 658
6. RH23/24
7.Connected links between 0210 and QN08 (one of the pads left after removal) and the other to 0214 and QN07. I connected to the spare pads as above as I could not get continuity when testing between C657 and C658 and the phono sockets?
I suspect that I might still have some of the HDAM in circuit?
I have removed the following :-
1. Muting Transistors (linked the pads together)
2. R 651 - 654.
3. R619/620
4. R617/618
5. C655 - 658
6. RH23/24
7.Connected links between 0210 and QN08 (one of the pads left after removal) and the other to 0214 and QN07. I connected to the spare pads as above as I could not get continuity when testing between C657 and C658 and the phono sockets?
Last edited:
Hi Rob,
That's no surprise ;-) Is the sound also very low in volume?
1. you shouldn't link the pads together, the muting transistors short the signal to GND you see. And that's just what you don't want.
2. R651...654 removed is o.k.
3. R619/620 removed is o.k.
4. R617/618 removed is o.k. but not really needed
5. C655...658 removed is o.k.
6. RH23/24 removed is o.k. but not really needed
7. remove U210 and U214.
Now insert links between:
- one pad of U210 (the one closest to Q606) and + of C658
- one pad of U214 (the one closest to Q605) and + of C657
Now you should measure around 200 ohms between pin 7 (the opamp outputs) of Q605/606 and the output sockets. This is because R657...R660 are still in the circuit. If you'd like to tweak this further, you can replace R657 and R658 by a jumper.
Hope this helps! 😉
Regards,
Ray
That's no surprise ;-) Is the sound also very low in volume?
1. you shouldn't link the pads together, the muting transistors short the signal to GND you see. And that's just what you don't want.
2. R651...654 removed is o.k.
3. R619/620 removed is o.k.
4. R617/618 removed is o.k. but not really needed
5. C655...658 removed is o.k.
6. RH23/24 removed is o.k. but not really needed
7. remove U210 and U214.
Now insert links between:
- one pad of U210 (the one closest to Q606) and + of C658
- one pad of U214 (the one closest to Q605) and + of C657
Now you should measure around 200 ohms between pin 7 (the opamp outputs) of Q605/606 and the output sockets. This is because R657...R660 are still in the circuit. If you'd like to tweak this further, you can replace R657 and R658 by a jumper.
Hope this helps! 😉
Regards,
Ray
Ray, thank you very much for your reply. It seems I haven't done any damage!
It will probably be tomorrow before I can rectify the error.
Regards
Rob.
It will probably be tomorrow before I can rectify the error.
Regards
Rob.
Managed to get time to correct it this evening. I have sweet music. I have only listened through a very flaky C-Moy (dodgy grd connection), but it all works. Thanks for your help.
Rob.
Rob.
Replaced regulators with closely matched ones the voltages difference is
0.07V Will try for a while before considering a TX
Some tracks I play seem to skip or the Singer seems to hasten
Why? Laser on the last leg?
Thanks for enlightening
Me again! Strange goings on. I thought I had both channels working last night. However the left was silent this evening (could have been the dodgy grd on the headphone amp and I thought it sounded a bit mono). On attaching the L phono lead directly to U210 I got sound. It does not seem to matter that the grd is not connected. However when I attach the link directly from U214 to the phono socket (L) I get no sound (the link was originally attached between U214 and 657)
Is this a grd issue?
Is this a grd issue?