Thoughts / Advice on My 1950's 1X12 'Bell & Howell' Cab Conversion.

[Bone Idol]

8 minutes ago, bremen said:

That's not the preamp schematic. Looks like a radio with small power amp stage.

 

If you can solder, I could help you make a power supply for the preamp.

Wrong schematic... Typical me!

 

Soldering... Funny that, as I've just received delivery of the soldering iron that everyone is going-on about on the 'Soldering Irons' thread!

 

Over the years I have soldered stereo insert cables for mixers, wired up numerous guitar looms and jack leads etc... I have a tin of Baker's Flux and a brand new soldering iron... What could go wrong! 😉 

[bremen]

Yes I just got the Official Basschat Soldering Iron! Very handy.

 

You could make a power supply froma 9V wall wart, one of these

https://www.ebay.co.uk/itm/146033415851?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=fuFx_Xa4SFq&sssrc=4429486&ssuid=hNc7PDPYRJi&var=&widget_ver=artemis&media=COPY

 

to take that down to 6.3V for the heaters and one of these

 

https://www.ebay.co.uk/itm/264785680757?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=HWuPrm7wSWu&sssrc=4429486&ssuid=hNc7PDPYRJi&var=&widget_ver=artemis&media=COPY

 

for the 195V rail.

 

I've used both those modules for valve preamps.

[Bone Idol]

27 minutes ago, bremen said:

Yes I just got the Official Basschat Soldering Iron! Very handy.

 

You could make a power supply froma 9V wall wart, one of these

https://www.ebay.co.uk/itm/146033415851?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=fuFx_Xa4SFq&sssrc=4429486&ssuid=hNc7PDPYRJi&var=&widget_ver=artemis&media=COPY

 

to take that down to 6.3V for the heaters and one of these

 

https://www.ebay.co.uk/itm/264785680757?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=HWuPrm7wSWu&sssrc=4429486&ssuid=hNc7PDPYRJi&var=&widget_ver=artemis&media=COPY

 

for the 195V rail.

 

I've used both those modules for valve preamps.

Cor!.... These look interesting and frightening all at the same time!... I take it I'd have to make some sort an enclosure to put them in?

 

Would it be a good idea for me to open-up the Varislope & take some photos of its innards for you to have a look at?.... Pointless making a power supply if the rest of it is shot... I did take the bottom of it a while back, I think it's point to point not pcb... But I could be wrong...

[Bone Idol]

Inside of my Varislope III....

 

The top view is obviously a little dusty but the underside is like new!

 

Managed to find the original paper label, showing production date of 25 April 1961, so a little later than I thought... Having said that, I was only one and a half years old when this was made.... It's probably in better nick than I am

I didn't realise that I had cut the umbilical lwad and the remote lead, so I do have plugs to use for a re-wire... Result.

 

It has lived in my workshop on top of an old EverReady Sky Queen for longer than I care to remember, so it would be fantastic get it going again.

[bremen]

I think it'd be well worth it, only a few quid and you can reuse them if the varislope is unfixable (which it won't be unless someone's let the air into the valves).

I'd put the switchers, with a little extra filtering, into a plastic box and tape that onto the inside of the lid, put a connector for a wall wart where the redundant power switch connector is now.

 

Happy to share circuits here or by pm.

[Bone Idol]

20 hours ago, bremen said:

I think it'd be well worth it, only a few quid and you can reuse them if the varislope is unfixable (which it won't be unless someone's let the air into the valves).

I'd put the switchers, with a little extra filtering, into a plastic box and tape that onto the inside of the lid, put a connector for a wall wart where the redundant power switch connector is now.

 

Happy to share circuits here or by pm.

Many thanks for your kind offer of help... I'll get the bits ordered and pm you when they arrive

[Bone Idol]

Bit of a silly idea perhaps.... Using a hollowed-out valve radio case as a cab fo the Varislope

 

 

[BassmanPaul]

What a trip down memory lane!! I when I bought my first bass I plugged it into my Dad's hiFi system. A Leak TL12 pushed by the VarislopeIII preamp. I used the tape input on the facia and through his Wharfdale SFB3 speaker system it worked very well.

 

[Bone Idol]

11 hours ago, BassmanPaul said:

What a trip down memory lane!! I when I bought my first bass I plugged it into my Dad's hiFi system. A Leak TL12 pushed by the VarislopeIII preamp. I used the tape input on the facia and through his Wharfdale SFB3 speaker system it worked very well.

 

Excellent!... That's well worth knowing, because if I can get it working, I was wondering about the best way of introducing an instrument into the pre-amp... I thought I'd have to use the inputs at the rear but at least I now know that there is a pathway through the front.

[bremen]

You can use the front panel tape in, but you'll need to bypass the input selector switch, as it will apply tape eq when tape input is selected. It's easy though,just wire it to the junction of C3 and R7 on the schematic I posted (I assume your mono version has the same numbering)

[nekomatic]

By total coincidence I had a look at the Wilkinsons Hi-fi website today, after coming across a link to it in an old post somewhere on here, and they currently have a Varislope III on sale as a ‘restoration project’ for £49:

 

https://www.wilkinsons.tv/product/leak-varislope-iii3/

[Bone Idol]

15 hours ago, nekomatic said:

By total coincidence I had a look at the Wilkinsons Hi-fi website today, after coming across a link to it in an old post somewhere on here, and they currently have a Varislope III on sale as a ‘restoration project’ for £49:

 

https://www.wilkinsons.tv/product/leak-varislope-iii3/

That's a very early one as it has the squared-off front panel, most probably 1950's.

[BassmanPaul]

Off topic comment: I have a nice bottle of Dow's Port sitting in my bar. I should open it!!! LOL

Edited February 10 by BassmanPaul