hi i have got my hands on a Linsley Hood 75 watt thats not fully soldered. looking in the manual page 28, there is a cable pin out list. but it says
cable 1 red to 41. but it not say where cable 1 come from. i cant find what cable 1-19 relates to. any help.. thanks
cable 1 red to 41. but it not say where cable 1 come from. i cant find what cable 1-19 relates to. any help.. thanks
Is this the Powertran kit from the 1970s?
Manual page scans and photos of what you have might help. I built one in the mid 70s and it was intimidatingly complex with the wiring for the banks of switchable preamp filtering.
Manual page scans and photos of what you have might help. I built one in the mid 70s and it was intimidatingly complex with the wiring for the banks of switchable preamp filtering.
hi thanks for the reply, yes its the powertran kit.
IMG-2850 — ImgBB
IMG-2851 — ImgBB
same manual can be viewed here its towards the bottom of the page.
Linsley Hood 75 Watt Amplifier User Manual
IMG-2850 — ImgBB
IMG-2851 — ImgBB
same manual can be viewed here its towards the bottom of the page.
Linsley Hood 75 Watt Amplifier User Manual
Wow. That brings back some memories. Did you manage to test the electrolytics? If they're the originals they may not have aged well. Also, from memory, the trimpots were problematic too.
If you should need it, I think I have one original bdy56 tucked away somewhere. I got one extra after one went bad. Otherwise the amp worked fine for about a decade. I eventually replaced it with a Naim and cannibalised it for parts. I never used the filter switching and eventually jumpered it out.
I'll look at the manual and see if I can remember what went where. No promises, it's a loooong time ago.
If you should need it, I think I have one original bdy56 tucked away somewhere. I got one extra after one went bad. Otherwise the amp worked fine for about a decade. I eventually replaced it with a Naim and cannibalised it for parts. I never used the filter switching and eventually jumpered it out.
I'll look at the manual and see if I can remember what went where. No promises, it's a loooong time ago.
Is that PDF manual complete?
There's no diagram of the preamp board that I can see, and, from memory, the powertran boards had nothing printed on them. I spent almost a week going through the diagram drawing the component & numbers on the boards themselves.
Cables are numbered serially. You need to look at the start and end to work out what they're doing. Switches are numbered S<n> and switch tags lettered, case denoting channel. Pins on the preamp boards are numbered. Din sockets are D<n> with a letter representing tags on the sockets.
So, Cable 1 is part of the input selector switching. Going from pins on the preamp board (the plain numbers) to the input selector switch tags S1a etc.
See the diagram of switches and control knobs on the preceding page. But without the board diagram I don't know how you wire the thing up....
I see that Powertran produced a much better version of the kit with the design broken into a number of pluggable daughter boards that reduced the wiring to virtually nothing and with better shielding around the preamp. Manual available from the HiFi Engine WEB site.
There's no diagram of the preamp board that I can see, and, from memory, the powertran boards had nothing printed on them. I spent almost a week going through the diagram drawing the component & numbers on the boards themselves.
Cables are numbered serially. You need to look at the start and end to work out what they're doing. Switches are numbered S<n> and switch tags lettered, case denoting channel. Pins on the preamp boards are numbered. Din sockets are D<n> with a letter representing tags on the sockets.
So, Cable 1 is part of the input selector switching. Going from pins on the preamp board (the plain numbers) to the input selector switch tags S1a etc.
See the diagram of switches and control knobs on the preceding page. But without the board diagram I don't know how you wire the thing up....
I see that Powertran produced a much better version of the kit with the design broken into a number of pluggable daughter boards that reduced the wiring to virtually nothing and with better shielding around the preamp. Manual available from the HiFi Engine WEB site.
got my hands on another thats already wired up.
<img src="https://i.ibb.co/1snRyPN/12345.jpg" alt="12345" border="0">
the unwired is a mk2 and the wired up one is a mk4 . so there are a few differences but should be able to sort out the wiring.
<img src="https://i.ibb.co/1snRyPN/12345.jpg" alt="12345" border="0">
the unwired is a mk2 and the wired up one is a mk4 . so there are a few differences but should be able to sort out the wiring.
The picture reminded me that the slider balance control was pretty naff. I had nothing but trouble from it almost from the start. Crackles, dropouts etc. Eventually I wired it out at the same time as the various filters the various filters. I never found there to be an advantage to any of the filtering and never ran with it switched in after the initial experiments.
One word of advice, when you're putting the cover on the case it's all too easy to have it make contact with one of the output transistors if you don't make sure it's screwed in place....
I believe this was something Powertran changed with later kits.
One word of advice, when you're putting the cover on the case it's all too easy to have it make contact with one of the output transistors if you don't make sure it's screwed in place....
I believe this was something Powertran changed with later kits.
there looking good now i have cleaned the cases up, i used some beeswax on them. the top one has blown the transistors on the left channel mbd529 cant find them at all. so will put some others in and try.
buttom one is the one that needs wiring up. i have made a start but taking my time.
buttom one is the one that needs wiring up. i have made a start but taking my time.
