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Old 19th May 2022, 5:49 pm   #1
David G4EBT
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Default Bardwell's enigmatic amplifier modules - mystery solved!

These very capable little surplus 5 + 5 Watt stereo amplifier modules sold by Bardwell's in Sheffield before that closed down were discussed in this forum thread and others:

https://www.vintage-radio.net/forum/...d.php?t=113530

The modules were clearly intended to be installed in budget hi-fi systems, but their origins was a mystery.

However, the mystery has now been solved - a forum member has written to me to say:

"I can tell you exactly where the Bardwell amplifier modules came from!"

He wrote to me as follows:

I used to work at a Electronics factory in Brimington, Chesterfield, called Wye Electronics. I started there after I left school in 1979 aged 16 years. I got the job there as when I was 15 - my father knew the secretary there and I was brought in during the school summer holidays where I worked a 5-day week for £20.00! They were happy with what I could do, so I was offered a full-time job the day after leaving school.

I think the amplifier was designed "in House" by Phil Pickering, the then Technical Director of Wye Electronics. I think he is still around running Transtronic, a coil and Transformer company based in Chesterfield. (https://trans-tronic.co.uk/about-us/ ). Wye Elelctronics not only made budget Audio systems, they had a large coil winding section which made IF coils for TV sets (I think one type number was a YT276) and numerous Transformers and Toroids too. When the Audio section eventually closed down I was moved to actually running a Toroid transformer production line.

I learnt a lot about Audio whilst I was at Wye Electronics and am very grateful for that. I was a test and service engineer there from 1979 to 1986. The modules were manufactured there - I used to test them prior to going into record players and music centres, so I know them very well! In fact I tested so many, one lunchtime I managed to build one up from memory as all the parts and PCBs were next to me on the production line.

When the Wye Electronics Factory closed in the late 1980s, I can only presume Bardwells bought all the stock of parts and boards, this amp being one of them! Great to see the amp again after all these years.

The number of the amp board was a 623. Wye made some earlier version called the 615 which used the SN76023 ICs which had a fan shaped heatsink. They were not too reliable though and had no short circuit protection. If a speaker was removed from circuit and plugged back in when powered, it would blow the IC. The cure was to solder a 1 K resistor across the speaker sockets.

The 623 was the later version with those TCA 940 ics. I fitted many of these.

I noticed someone mentioned a while ago whether a ceramic pickup cartridge could be fitted directly to this amp. it could as you can see a couple of extra pins on the input, that had a 1 Meg (I think) resistor to help the input impedance. The cartridges were a BSR SC12M ceramic, which didn’t sound too bad. There was a mod on these boards to increase the low bass response. this was to increase the value of C 108 and C208 from 22uF to 100uF.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

So there we are!

I hope that's of interest - it certainly was to me.
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Old 19th May 2022, 6:06 pm   #2
paulsherwin
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Default Re: Bardwell's enigmatic amplifier modules - mystery solved!

Thanks David, interesting indeed.
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Old 19th May 2022, 8:55 pm   #3
David G4EBT
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Default Re: Bardwell's enigmatic amplifier modules - mystery solved!

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Originally Posted by paulsherwin View Post
Thanks David, interesting indeed.
Thanks Paul.

To solve another mystery, I can reveal that the forum member who provided the information is Paul Godley, who is happy to be unmasked, and deserves the credit for the content.
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Last edited by David G4EBT; 19th May 2022 at 9:03 pm.
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Old 19th May 2022, 8:59 pm   #4
Nickthedentist
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Default Re: Bardwell's enigmatic amplifier modules - mystery solved!

Thanks David and Paul!
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Old 20th May 2022, 7:47 am   #5
FIXITNOW
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Default Re: Bardwell's enigmatic amplifier modules - mystery solved!

Quote:
Originally Posted by David G4EBT View Post
Quote:
Originally Posted by paulsherwin View Post
Thanks David, interesting indeed.
Thanks Paul.

To solve another mystery, I can reveal that the forum member who provided the information is Paul Godley, who is happy to be unmasked, and deserves the credit for the content.
nice info ps the link does not work to previous thread
found
https://www.vintage-radio.net/forum/...t=Bardwell%27s
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Old 20th May 2022, 10:43 am   #6
David G4EBT
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Default Re: Bardwell's enigmatic amplifier modules - mystery solved!

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Originally Posted by FIXITNOW View Post

nice info ps the link does not work to previous thread
found
https://www.vintage-radio.net/forum/...t=Bardwell%27s
Don't know what went wrong there - thanks for spotting it and correcting the link.
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Old 20th May 2022, 10:50 am   #7
JimFromSurrey
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Default Re: Bardwell's enigmatic amplifier modules - mystery solved!

Good to know a bit more background info on these, would you be able to ask him approximately what years these were made in?

I've been a bit busy at work this week so i haven't applied power to the unit yet but hopefully will do this weekend

Cheers, Jim
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Old 20th May 2022, 5:07 pm   #8
Paul Godley
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Default Re: Bardwell's enigmatic amplifier modules - mystery solved!

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Originally Posted by JimFromSurrey View Post
Good to know a bit more background info on these, would you be able to ask him approximately what years these were made in?

I've been a bit busy at work this week so i haven't applied power to the unit yet but hopefully will do this weekend

Cheers, Jim
Hi Jim,

I started at Wye in 1979, those amps dated from about 1977 or thereabouts.
We used to run them at 24v at 1A, and you could get just about 10w RMS per channel albeit with some distortion into 8 Ohms.
Be careful when wiring these boards as you can see the left hand side pins which are supply and output are very close together. if you happen to short that +ve pin to one of the output pins it will kill the TCA 940 pretty quickly.
The earlier TCA940 ICs were made by SGS ates, then later Thompson. These were better. There was a TCA940S too, I think that had a similar performance.
The preamp was a basic common emmiter design, but worked well enough.

We had another amplifier board too, this used TBA800 ics. A longer slimmer board. These were used in a record player, the Wye 96. They sold thousands of those! mostly to catalogues (Grattans etc)

Some later Wye 96s were fitted with a low current DC motor BSR recordeck.
These worked on 2 x PP9 batteries which powered both the amp and deck for quite a while. These were sold exclusively to prisoners who required these in their cells with no fear of electrocution and also the speaker wires were very short for obvious reasons!
These were ordered directly from our factory, it was very interesting to see the various HMP approval stamps on the letter orders!

Another board that was made in house was an IF/ RF Radio PCB. This was fitted to some Music Centres we made. This had an IF amplifer chip with both AM and FM coils and also a stereo decoder chip. This was a Motorola MC1310p later changed to the much better Hitachi HA1156W. This board needed a external FM front end made by TOKO and a ferrite Rod assembly for the AM bit. The AM was never very good though suffering form SW breakthrough on MW! FM was good though.
Never seen these boards since 1985.
Strange how I remember the chip numbers when I have trouble remembering what happened last week!

Best Regards

Paul
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Old 21st May 2022, 2:33 pm   #9
JimFromSurrey
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Default Re: Bardwell's enigmatic amplifier modules - mystery solved!

Hi Paul, that's brill, thanks for the extra info, it must be funny seeing these re-surface after so long! Such a shame all this sort of stuff (other than the few high-end manufacturers still around) is made in China now.

I have a Wye 500 amp in my collection (i collect 'small' [less than 400mm wide] hifi components from 1950's to mid 80's) and i'll probably badge this as a "Wye Pickering" when it's cabineted, and will go nicely with my others.

Re the chip numbers, i think these sort of thing are burnt into the memory somehow - i used to work at Tandy, started on the sales floor and worked my way up to group manager eventually (before being sacked under dubious circumstances) and a huge number of product codes are still floating around in my head - its about time they made way for more important/relevant things!

Thanks again for all the info, my wife has a big to-do list for me this weekend but hopefully i'll still get a chance to get this little amp (i bought the one David was selling recently) set up.

Regards, Jim
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Old 25th May 2022, 1:44 pm   #10
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Default Re: Bardwell's enigmatic amplifier modules - mystery solved!

Thanks for this update David I enquired about this amp in here 13/4/2022 I wished I had stayed on line as you listed yours for sale a month later such is life I defo would have bought it to do an A/B comparison the one ive been working on goes into distortion when the volume is half way then settles back down just past that. I haven't got gear like scopes etc to do a more in in depth test.
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Old 1st Jun 2022, 5:51 pm   #11
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Default Re: Bardwell's enigmatic amplifier modules - mystery solved!

Hi guys,

If anyone would like any of the amps please let me know. I have boxes full of them.
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Old 1st Jun 2022, 9:12 pm   #12
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Default Re: Bardwell's enigmatic amplifier modules - mystery solved!

Hello and welcome to the forums.

How much are you asking for these units and would you be prepared to post them?
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