Cornish TB-83 Treble Booster?

[nickbungus]

Hi All

Any of you guys that have read any of my posts know that I'm a big fan of the Brian May tone.  So, I've built the ROG May Queen, various treble boosters, the fOXX phaser and loads more fun stuff.

One schematic that I've never seen is the Cornish TB-83 treble booster.  There are plenty of Range Master schematics and Fryer TB layouts etc. floating around on that there internet but no Cornish.

Does anyone have a schematic or gut shots or any leads on this one?

[Elijah-Baley]

Well, of course it is a dual Treble Booster, but I can't say more than it.

[nickbungus]

I think there is a standard TB-83 and then the Extra is just two in one box.   

[Elijah-Baley]

I think so.
And the TB-83's schematic? This is the problem, it isn't?

[nickbungus]

And the TB-83's schematic? This is the problem, it isn't?

Exactly.  Or some gut shots would be nice!

[ElectricDruid]

And the TB-83's schematic? This is the problem, it isn't?

Exactly.  Or some gut shots would be nice!

For the sweepstake, I'd like to put my money on "Something well known, slightly modified". He's generally a great horse, and usually a good runner in races like this.

Sorry not to be able to help more. Let me know when the results are in so I can cash the chitty.

Tom

[nickbungus]

For the sweepstake, I'd like to put my money on "Something well known, slightly modified". He's generally a great horse, and usually a good runner in races like this.

Sorry not to be able to help more. Let me know when the results are in so I can cash the chitty.

Tom

Cheers Tom.  I have no idea what you are talking about though.  Cryptic

[Bill Mountain]

I always just assumed it was the Fryer May style treble booster.  Not sure where I got that idea but I never questioned it until now.

[Cozybuilder]

This article seems to verify what Bill says:

http://www.petecornish.co.uk/queen.html

Edit- maybe not, it says that the CornishTB-83 is the same that Pete designed for Brian May

[nickbungus]

I always just assumed it was the Fryer May style treble booster.  Not sure where I got that idea but I never questioned it until now.

I once thought the same but having read a few bits here and there I don't think that's the case.  It would be interesting to find out

[garcho]

I'd like to put my money on "Something well known, slightly modified".

Cheers Tom.  I have no idea what you are talking about though.  Cryptic

i think he means it's probably say, a rangemaster for instance, with a tweak here or there.

[ElectricDruid]

I'd like to put my money on "Something well known, slightly modified".

Cheers Tom.  I have no idea what you are talking about though.  Cryptic

i think he means it's probably say, a rangemaster for instance, with a tweak here or there.

Thanks Garcho, that's exactly what I meant. But without at least a guts shot, we can't even start to guess what it might be related to.

[Gus]

Look for the Guild Brian May treble boost schematic there was a Guild one on the web in the past.  Could this be the same circuit?

Found a site http://www.next.gr/circuits/guild-brian-may-box-l32329.html

[nickbungus]

Thanks Gus.  I've considered this too, although without a gut shot or schematic we'll never know.

Best I build one just in case!

[nickbungus]

This is just from a post on some forum, but if this guy has his facts right it is interesting stuff regarding the Guild Brian May box.

What you have here is a 1993 Guild Brian May treble booster, this was put on the market along with the Guild Brian May Red Special Pro guitar. The good dr. May has used a treblebooster of some sort during his whole career from the earliest known Queen recordings till today. Starting out with a modded Rangemaster, he later had Pete Cornish build him a unit which can be heard on most of the Queen and solo albums. In the mid-nineties he switched from Cornish to Fryer trebleboosters and more recent to KAT strapboosters specialy designed for the use with a wireless system.

There are many clones available that are mostly based on the Cornish TB-83 and you get the best result with the booster in a Vox AC30 using the 'normal' channel.
The Guild booster was claimed to be an exact clone of the TB-83 but turned out to be a bit of a dissapointment.

I've owned one since it first came out and have tested it against a Rangemaster clone, an Electrolead TB1 and a Covington Fireplace Classic. The Fireplace does sound the same as the TB-1, but it seems to be just a bit louder. The Rangemaster is a very nice pedal as well but does give a different tone, not as smooth as the trebleboosters.

...and the Guild booster, well, it does have a nice sound, but it's nowhere near the Electrolead or the Covington

[nickbungus]

Gus, I built the Guild one.  I didn't have any MPS8098's so I tried a few different trannies.  2n5088s seemed the best although I was always trying them in pairs of the same sort.  I could probably try different combos too but overall it isn't the best treble booster I've built.

This may sound sacrilegious to some but maybe removing the Cornish Buffer and just leaving the treble booster might help.

Anyway, I think I've built most treble boosters available online and I think the Covington one is the best even with its strange pot wiring and unnecessary resistors. 

A confirmed schematic of the TB-83 still alludes me though.

[Gus]

I am not surprised at your post about the Guild build
A bootstrapped buffer can have a high input resistance.
A link http://www.diystompboxes.com/smfforum/index.php?topic=93834.msg808080#msg808080
Some screenshots of sims I posted before guitar volume at max(no series resistance) and tone at max treble Green is 10K Blue is 100k  red is 470K etc.




Note with the bootstrapped buffer you would want to EQ out the upper resonance and then use a standard treble boost after
HOWEVER the upper resonance can disappear with series resistance (50K) as you turn down the volume the resistance part from input to wiper is in series with what follows so
as you turn down the volume control you will still not have the same interaction with a passive guitar to cable to a non buffered low input resistance treble boost

[nickbungus]

To wrap this thread up and to confirm what I had expected all along, a friend had just sent me a YouTube link.  The clip is from Greg Covington of Covington pedals comparing his Treble Booster to the Cornish TB-83. 

I believe the Covingon treble booster is nearly a 100% clone of the Cornish.  I think he's tried to add anti-pop resistors and also the gain pot (to the model I traced), but I'm pretty sure he's just taken the TB-83 apart and traced it.

[nickbungus]

It looks like I might be able to get a lend of one.  As you can see below it looks like its going to be hard to get to.  Has anyone got experience of opening something like this up?  Will I be able to do it and then put it back together?

[ElectricDruid]

It looks like I might be able to get a lend of one.  As you can see below it looks like its going to be hard to get to.  Has anyone got experience of opening something like this up?  Will I be able to do it and then put it back together?

Back years ago I used to work in the repairs department of a company making dataloggers for the utility industries. Most of those were potted, so repair work meant digging out the potting to get to likely faults. It *can* be done using a scalpel to cut the potting and a sharpened flathead screwdriver to dig it out, but it's a risky process and it helps a lot if you already know what's underneath and where so that you can go gently in sensitive spots.

If the potting box itself is plastic, you might do best by cutting that off the outside so you can work in from all directions.

It's a risk though. If it was my unit, I'd try it, but I don't think I'd do it to anyone else's.

HTH,
Tom