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Transcriptors Skeleton - Help!

Pixel299

Pixel299

Member
Hi all,

As some of you may have seen on this thread, I am @JemHayward 's son James - and I need your help!

As is well documented on these forums my late father bought himself his childhood dream turntable a few years ago, a beautiful Transcriptors Skeleton. It used to live in their second building, a converted barn running through a Radford SC22 and Quad ELS57's.

Since dad passed away we carried on the plans to convert the barn to an AirBNB and as such I suggested we moved the hi-fi out of there for fear of it being damaged or worse by guests. This was a great idea except that the system was dismantled before I had got any reference of how it all worked. Move forward to this week where my step mum invited me round for dinner... the catch being she needed help with the Turntable... Problem I'm facing is that dad had a habit of tinkering with things and using all sorts of bizarre non standard workarounds to achieve his desired results. Furthermore, the even bigger problem is that sadly when he found out his cancer was terminal he didn't have long left and writing us a user guide for the house would have taken about six months.

Where I'm at now through process of elimination is that I believe I've found the power supply and some sort of pre-amp? I have managed to get power to the turn-table, and I can get it to play a record, there is just no sound coming through the rest of the system, and more to the point the Audiolab MDAC shows 'Unlocked' on the coaxial inputs which according to the manual (I know, I've failed as a man for reading the manual) means there is no signal.

From what I can figure out the sequence should go as follows:

PSU -> Skeleton Turntable -> Pre Amp? -> Phono Cable -> Audiolab MDAC (Coax input) - > Radford STA25 -> Martin Logan Summits.

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It might be worth noting that I studied Music Technology and have been a musician for 25 years so I have some understanding of the terminology so feel free to talk technical. If I don't understand I'll let you know!
 
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Apologies I'm having some diffculty uploading all the reference pictures. Is there some sort of limit on how many images one can post? I've been looking for a sticky with a guide but not found anything
 
@Pixel299,

MDAC would have had a digital source going into it and from there into the pre-amp (possibly via USB, see below).

To me, the upper of the two in the stack appears to be a dedicated phono stage (possibly a Naim clone with both MC and MM boards within), with the lower box being the pre-amp. If so, then the connection path is likely to be as follows...

Skeleton Turntable -> Phono Stage -> Pre-Amp (with digital source -> MDAC into USB) -> Radford STA25 -> Martin Logan Summits.​

Also, I don't recall any Trasnscriptors decks having a separate PSU. Unless this was a turntable upgrade project, it could be that this box is what powers the Phono Stage (as what appears to be the Pre-Amp has IEC mains in). Does the PSU have one or more DIN sockets on with mains in? If so, the connection path is likely to be as follows...

Skeleton Turntable -> Phono Stage/PSU -> Pre-Amp (with digital source -> MDAC into USB) -> Radford STA25 -> Martin Logan Summits.​
 
Just open the boxes we'll know all circuit's from looks alone. I suspect box no1 contains a meldano tt psu and either a naim clone phonostage or naim clone psu. I supplied Jem with a meldano board years ago.
 
I was just thinking about this and discussing with step-mother about it. I was thinking there must have been some sort of analog to digital conversion in the line somewhere as she was convinced that the turntable played through the MDAC. Although she struggles with the coffee machine so I'm not taking her word as gospel. My only concern is that he did separate the analog system (turntable etc) and the digital system)

Regarding your thoughts on the separate PSU, this is the sort of thing that dad buggered about with and I think there are some posts here about him doing so. I'm at home at the moment so will wander over to theirs in a bit and see what I can find out. @sq225917 - will do just that, thank you.
 
Pixel299 said:
I was just thinking about this and discussing with step-mother about it. I was thinking there must have been some sort of analog to digital conversion in the line somewhere as she was convinced that the turntable played through the MDAC. Although she struggles with the coffee machine so I'm not taking her word as gospel. My only concern is that he did separate the analog system (turntable etc) and the digital system)

Regarding your thoughts on the separate PSU, this is the sort of thing that dad buggered about with and I think there are some posts here about him doing so. I'm at home at the moment so will wander over to theirs in a bit and see what I can find out. @sq225917 - will do just that, thank you.
Click to expand...
Just back from a search on here and found this from your Dad within an April 2020 DIY thread...

My only Naim 'thing' now is a MM/MC phono stage using modified phono boards and modified Supercap reg boards - I feed it 25V from a relatively 'raw' PSU - big toroid, bridge rectifier, CRC smoothing - lead - then in the box there are the modified Supercap regs, feeding the modified boards about 20V, as far as I can recall. It works brilliantly.

JemHayward, Apr 14, 2020​
 
Good to see inside some of these boxes, then all would be clear.

The Transcriptors is modified, so it needs a PSU. You have this working so all good.

Then you need a phono preamp, your second photo appears to show one of these. This also needs a PSU, which I would expect would be on a 4pin DIN such as fitted to the mysterious box in the top photo.

Then you need a volume control.

And thence to the power amp (STA25) and on to the speakers.

Jem's profile says 'Oxfordshire', if you want a visit to get things cleared up just ask.
 
Paul R said:
Good to see inside some of these boxes, then all would be clear.

The Transcriptors is modified, so it needs a PSU. You have this working so all good.

Then you need a phono preamp, your second photo appears to show one of these. This also needs a PSU, which I would expect would be on a 4pin DIN such as fitted to the mysterious box in the top photo.

Then you need a volume control.

And thence to the power amp (STA25) and on to the speakers.

Jem's profile says 'Oxfordshire', if you want a visit to get things cleared up just ask.
Click to expand...

Hi Paul,

Yes we are North Oxfordshire, between Chipping Norton & Banbury. That's very kind of you and you may end up regretting that... :)

However, I have just got here and found a volume control box too, which I've identified by looking at some old Xmas family photos that happen to have the Hi-Fi in the background!
 
Ok so I've plumbed everything up including the volume control now. However I have subsequently found this box which looks like it might be something to do with it. This to me appears to be some sort of speaker output as it has XLR's for what I'm assuming are the inputs and then speaker posts for the outputs. So I think this is a red herring... Whatever it is it must get quite hot as there are some quite gnarly heatsinks either side.

However, I cannot find any way of going to the STA25 from this ever growing collection of boxes, unless it's via the Audiolab MDAC.


IMG_3498.jpg
 
Pixel299 said:
Ok so I've plumbed everything up including the volume control now. However I have subsequently found this box which looks like it might be something to do with it. This to me appears to be some sort of speaker output as it has XLR's for what I'm assuming are the inputs and then speaker posts for the outputs. So I think this is a red herring... Whatever it is it must get quite hot as there are some quite gnarly heatsinks either side.

However, I cannot find any way of going to the STA25 from this ever growing collection of boxes, unless it's via the Audiolab MDAC.


IMG_3498.jpg
Click to expand...
This looks like a power amp.
 
That looks like a basic power amp with balanced inputs.

Audiolab M-DAC does indeed have volume control but only accepts digital inputs. It does output analog though, so he likely had this plumbed into which ever of the kit boxes is the pre-amp and then on to whichever power amp he was using.

It is also possible that he occasionally alternated between using the Radford with the turntable front end vs. the Audiolab (which includes balanced outputs via XLR sockets) and this balanced XLR input power amp and then on to 'speakers (i.e. a second 'purist' digital setup via transferring the speaker cables between Radford and this project amp).

IOW, consider the Audiolab as a pre-amp and DAC (digital to analog converter) combined. No good with a turntable/phono stage but excellent with digital sources. Here is the Audiolab manual...


In the meantime, how about a peek at that box with the volume control on.
 
If that's quite light its probably a chip amp, defo balanced in, stereo.

Consider the audiolab as a dac with volume control, no in-out analogue throughput or anything else that defines a real dac pre.
 
Ah apologies, I didn't get a photo of it. I'll be popping over tomorrow between meetings at which point I'm going to dismantle the boxes and photograph the circuit boards to see if we can figure this out. I didn't want to start taking boxes apart whilst step-mum was around as she'd have kittens...

There is one potentially missing part of this whole system which is the Radford SC22 but that's making up part of my personal system at home so I'm reluctant to part with that, especially as it's the only part of his system I have. Although it was running without the SC22 beforehand so I don't think it's that important.
 
Pixel299 said:
Although it was running without the SC22 beforehand so I don't think it's that important.
Click to expand...
It does tell us that the project amp had to be working in its place though.

Suggest having a look round for 2 x XLR cables whilst you are there tomorrow. These are what fit into the large 3-pin sockets. With balanced operation there are separate 3-wire cables for Lch vs. Rch.
 
Craig B said:
It does tell us that the project amp had to be working in its place though.

Suggest having a look round for 2 x XLR cables whilst you are there tomorrow. These a what fit into the large 3-pin sockets. With balanced operation there are separate 3-wire cables for Lch vs. Rch.
Click to expand...

Indeed it does.

I've had a look today for two spare XLR cables knocking about in the 'rats nest' as he called it but couldn't see anything. I think what he did was separate the two systems and had one totally analog setup in the barn, and a digital system in the house. There only appear to be two inputs on the STA25, behind the valves on each side of the unit, which means there is probably something further up the chain that is able to split the signal. There is a miniDSP thing that he made, that does have a load of XLR's coming from it, but it's full...

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I think what I'm going to do tomorrow is do a video of the whole system and post an unlisted YT link here. That might help, especially as I can't seem to upload multiple images without upsetting the spam filter.
 
I think he used an 'IcePower' Class D two channel amp to drive the Martin Logan bass units, and the Radford for the panels. The 'MiniDSP' device is the crossover, two inputs, four outputs. So I think you're looking for a pair of XLR-XLR for the bass and XLR-phono for the panels. The MiniDSP thing has two inputs on the right and four outputs on the left.
 
Paul R said:
I think he used an 'IcePower' Class D two channel amp to drive the Martin Logan bass units, and the Radford for the panels. The 'MiniDSP' device is the crossover, two inputs, four outputs. So I think you're looking for a pair of XLR-XLR for the bass and XLR-phono for the panels. The MiniDSP thing has two inputs on the right and four outputs on the left.
Click to expand...

Yea from what I can understand the DSP controls the bass in the Martin Logan Summits and the the panels are controlled by the STA25. This is after dad modified the Summits... Thankfully, in his wisdom he did document a lot of his Hi-Fi activity on here which has proved extremely useful. If only he'd done that with the home automation system, which of course he designed himself... took us three weeks to figure out how to turn the downstairs toilet lights on...

Craig B said:
...In the meantime, how about a peek at that box with the volume control on...
Click to expand...

For your viewing pleasure... I don't know if this is home made or not... It's a bit too 'nice' for his home made stuff... that usually consisted of scratched black cases and badly cut perspex... Also apologies for the terrible image, it's quite hard to get the phone down there and the light is terrible.

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