Hart conversion kits for Brenell reel-to-reel

[willybarden]

Hi - I have just found a number of transistor circuits which I made up late 60's early 70's to convert a Brenell reel-to-reel to transistor - but in the end I sold the Brenell in standard form. I believe the circuits are Hart kits, but all the paperwork has gone missing in the 6 house moves I have made since then. Can anybody help me to identify these kits, or better still, supply the kit instructions etc.

regards Willy

[majoconz]

Jeez, that's going back a bit!

IIRC, the Hart kits were based on the circuits in the "Mullard Book of Transistor Circuits" which I have around here somewhere.....

...but of course they were germanium or could have been BC107 series silicon. There must be better schematics around now but not necessarily tailored for the rather geriatric Brenell decks.

[reelguy]

I thought I had some info on the Hart kits but haven't been able to find them up to now.
If I do come across them I'll get back to you.
I was quite interested in this kind of kit in the 60s.
Look forward to any info you might get .
Peter W.....Reelguy

[Nickthedentist]

Originally Posted by majoconz

Jeez, that's going back a bit!

That could be this forum's motto

[m0cemdave]

Hart sold kits in the 1970's for the "Stuart Tape Recorder" electronics - a design published in a series of articles in Wireless World. They were intended for use with Brenell and similar decks.

(That was the same J R Stuart who later formed the Boothroyd-Stuart / Meridian hi-fi company.)

HTH


(edited for typo)

[llama]

I was going to ask what the assembled multitude thought of the Stuart design. That's what I've been using lately, playback only. I find it exceptionally quiet. However, it uses CAxxxx chips which I believe are long-obsolete. Not transistors, anyway.
Anyone know of a replacement chip type?
Graham

[mikkelbreiler]

Originally Posted by m0cemdave

Hart sold kits in the 1970's for the "Stuart Tape Recorder" electronics - a design published in a series of articles in Wireless World. They were intended for use with Brenell and similar decks.

Those kits were still published by Hart in the middle of the next decade, I am trying to locate both the Linsley-Hood and Stuart circuits and so far found only those for cassette (by John Linsley-Hood).
My notes:
My June 1985 issue of Elektor Electronics has a Hart Electronic Kits Ltd ad on page 6-08 which features:
Page 6-08 bottom half
Hart Electronic Kits Ltd
Pennylan Mill
Oswestry, Shropshire
SY 10 9AF
(0691) 652894

Linsley-Hood Cassette Recorder Circuits
Complete record and replay circuits for very high quality low noise stereo cassette recorder. circuits are optimised for our HS16 Super Quality Sendust Alloy Head. Switched bias and equalisation to cater for chrome and ferric tapes. Very easy to assemble on plug-in PCBs. Complete with full instructions.
Complete Stereo Record/Play Kit UKP 25.26
VU Meters ti suit UKP 2.30 each
Reprints of original Articles no vat. UKP 75p

#Notes
Found on archived website

https://web.archive.org/web/20110720...articles-1.htm

Article "Low-Noise, Low-Cost Cassette Recorder Part 1" is found in Wireless World May ’76 p36
Article "Low-Noise, Low-Cost Cassette Recorder Part 2" is found in Wireless World Jun ’76 p62
Article "Low-Noise, Low-Cost Cassette Recorder Part 3" is found in Wireless World Aug ’76 p55
Article "Low-Noise, Low-Cost Cassette Recorder Postscript" is found in Wireless World Feb ’78 p55
#End Notes

Stuart Tape Recorder Circuits
Complete stereo record, replay and bias system for reel-to-reel recorders. These circuits will give studio quality with a good tape deck. Separate
sections for record and replay give optimum performance and allow a third head monitoring system to be used where the deck has this fitted. Standard 250mV input and output levels. Full details are in our lists.
Reprint of Original Articles no VAT UKP 1.30

Linsley Hood 300 Series Amplifier Kits
35 Watt Complete Kit UKP 79.50
45 watt Complete Kit UKP 83.50
Reprints of Original Articles from Hi-Fi News no VAT UKP 1
.

Hope it helps. I am searching myself for the articles on Stuarts tape circuits I already found a PDF online for John Linsley-Hoods for cassette decks. Through here:
http://www.keith-snook.info/wireless...-articles.html
Note only May seems to be snacced but may, June and August articles sequence is scanned and presented in the same PDF file. Neat.

JLH died in 2004 and his website is now only accessible through Archive.org for all I know.

-Mikkel

[Peter.N.]

I would rather have one with valves in it - I understand those.

Peter

[ricard]

Originally Posted by majoconz

the Hart kits were based on the circuits in the "Mullard Book of Transistor Circuits" which I have around here somewhere..... ...but of course they were germanium or could have been BC107 series silicon. There must be better schematics around now but not necessarily tailored for the rather geriatric Brenell decks.

I remember a tape recorder circuit in at least one edition (perhaps there was only one) of the Mullard book which used BC109 and BC108 transistors for the premap, with germanium transistors (AD161/162?) for the output stage. In my early teens I made a fairly feeble attempt at rebuilding the electronics for Grundig TK819 recorder using the Mullard circuit. Never got the amplifier to work though, almost certainly because I didn't really know what I was doing. It would never have worked well anyway because the Grundig heads would have been high impedence as it was a valve machine. Ah, the age of innocence and enthusiasm.

[llama]

The start of this thread is pretty ancient now so I haven't given the Stuart designs any more thought since. However, if anyone's actually interested I'm sure I can find them and scan them. They'll be in my files under "S"...
Graham

[AC/HL]

Define Ancient.

[mikkelbreiler]

Originally Posted by llama

However, if anyone's actually interested I'm sure I can find them and scan them. They'll be in my files under "S".

Please do. I like tubes just as much as the next guy but I am out of my element with them. I have two Teac preamps for reel deck in the basement but both of them urgently require going over by a competent tech before even thinking of applying anything like electricity to them ever again.
I am looking at the mains wire cracked up due to being plastic and old, leaky and melting caps in several places. I am pretty confident they are called TEAC AR-109E or so, but it has been a few years since I visited that part of my basement.
I have been meaning to get a better tube preamp for my reel decks but my luck was always just to gets a Sony SRA-2 or SRA-3 but those will require the same resurrection as my Teacs pre-amps.
Before I got tubes in my collection of dead or dormant project I was looking forward to get the Stuart and Linsley-Hood circuits built. So I am looking into it now that I have a handful of Technics reel decks just begging to be used with tube for outboard amplification.

[jamesperrett]

Originally Posted by majoconz

There must be better schematics around now but not necessarily tailored for the rather geriatric Brenell decks.

I must have missed this thread the first time round...

There was a Mullard tape recorder circuit in the 1972 Henrys catalogue. I built the replay section using parts extracted from an old TV I'd been given and used it with my Brenell MkV transport. It seemed to work but I probably should have paid more attention to screening as it was a little noisy.

[llama]

So far I have found full details of the Hart Stuart replay board. The attached PDF gives the circuit and component details. I shall scan some more later.
Graham

[llama]

Here is the back of the first sheet. It gives details of component values needed to achieve eq curves for the various international standards, at various speeds.

The hand-written notes give details for 2 types of cassette tape. I can't remember where I got those from.

Graham

[llama]

The intro sheet from Hart, attached, quotes the original WW article dates by Stuart of Nov 1970, Dec 1970 and Jan 1971.
Graham

[llama]

Page 2

[llama]

Page 3

[llama]

Page 4.
This completes all the Hart-printed material I've found so far.

My next set of scans will be from documentation created by me. It should cover the erase and record functions, showing PCB layouts. I can't seem to lay my hands on the circuits or original articles just yet.

Graham

[SteveCG]

Graham,

Thanks for the files. The equalisation characteristics quoted make for informative reading for me, as they altered over the years as tape performance improved. So reading an early 1970s snap-shot of the values is useful.

I wonder what the S/N was using those RCA ICs? Relatedly, would the tape (non-low noise or the later low noise) or the amp have been the limit I wonder?