Gut Shots of the Hornby Skewes Treble Booster

[R.G.]

I stumbled over an interview with H.C. Meiser, owner of BSM and a RB maniac, a few month ago in a mag.

They analysed the HS originals and used them for sound reference. Acc. to him the very early units were made with Ge-trannies
and the later ones with a FET. I found the same info on a site from an english amp collector and on a site from an FX-collector.

But there are even more differences in the HS-TB. Most units were made for the use with the Zonk Machine w/o I/O-caps and FET, only a few were made as stand alone units w I/O-caps.

Acc. to Meiser RB used three to six units wired parallel (w FETS)  'cos one unit can't deliver enough output current to drive a longer cable. Maybe that' was the reason to drop the FET on the Stand alone units later.

Cool!! I'd really love to read those. Can you post the web sites? Which mag?

I couldn't care less about duplicating the tone. I'm interested in the electro-archeology.

[Doug_H]

Thanks to everyone for solving some of the mysteries of the treble boost. I always wondered about that one. And thanks to Ammscray for pointing out that it is probably not worth fooling with. Doesn't surprise me after I fooled with the Zonk on the breadboard a few yrs ago. It was okay but if you already have a Fuzz Face I don't really see the point.

I still question the claims that RB used these (and if he needed three of them what does that say?). His stuff sounded like a dimed AC30 or Marshall to me. But whatever...


Doug

[col]

I had some fun with this the other day. I replaced the 62k resistor with a 100k trim pot and socketed the 47u cap and transistor. I could then change the transistor between a pnp and npn, changing the cap around and power supply to suit. The 100k trim could then be adjusted for the best sound. I also tried a 2N7000 fet and could adjust the trim pot for that to get a good sound.
I couldn't get a crap sound out of it apart from when I tried a few 'red spot' Ge trannies which were very hissy. I liked the sound of an npn AC187, the 2N7000 and a BC184. Quite a few pnp Ge trannies also sounded good but as most of my pedals are negative ground i wouldn't be able to use them. 

[lovric]

col, cool!

and, more of these in paralel [] would 'drive' less cable.

[Ammscray]

As far as I know, the early versions use a GE- trannie that HS replaced it with a FET on the later ones.

It was my opinion based on the schematic that I got, the pictures here, and a very few notes I've seen that the early ones may have been germanium and changed to silicon. I haven't seen any evidence to support JFET versions, except the first schemo I worked from, which we now believe to have been wrong.

When you say "As far as I know" can you describe the information that you do know? That is, if you have any information that says (a) the early ones definitely were germanium PNP and (b) the later ones were FETs?

I'm just trying to run down information.



As far as I know, the moon may, in fact, be made of green cheese... 

Hey RG,
the device on the board that I drew the schemo from, that I sent to you, is a 2N4861, which as far as I can tell, is an N-channel JFET

I just re-checked it to make sure, and it's unequivocally the original device too

GUS:
yeah good to see you too! Drop me a PM I'd love to find out about your tube mics

[R.G.]

the device on the board that I drew the schemo from, that I sent to you, is a 2N4861, which as far as I can tell, is an N-channel JFET
I just re-checked it to make sure, and it's unequivocally the original device too

Yep, the datasheet for the 2N4861 says it's an N channel JFET.

But the circuit doesn't make much sense with an N-channel JFET in it. The 2N4061 fits perfectly with the circuit.

Four questions:
(a) How is the pedal wired? Where does input, output, battery black, and battery red go?
(b) what kind of package is the 2N4851 in? A normal TO-92 plastic package?
(c) is there NO way that 2N4861 could be a 2N4061? A zero with a bar through it, perhaps, like is sometimes done?
(d) can you take and post pictures of the board top and bottom?

[R.G.]

I stumbled over an interview with H.C. Meiser, owner of BSM and a RB maniac, a few month ago in a mag.

They analysed the HS originals and used them for sound reference. Acc. to him the very early units were made with Ge-trannies
and the later ones with a FET. I found the same info on a site from an english amp collector and on a site from an FX-collector.

But there are even more differences in the HS-TB. Most units were made for the use with the Zonk Machine w/o I/O-caps and FET, only a few were made as stand alone units w I/O-caps.

Acc. to Meiser RB used three to six units wired parallel (w FETS)  'cos one unit can't deliver enough output current to drive a longer cable. Maybe that' was the reason to drop the FET on the Stand alone units later.

The FET unit, a Strat and a Marshall Major produce that early RB rhythm tone.

The lead tone can't be copied,

Hey - JHS! I'd really love to read those. Can you post the web sites? Which mag?

I couldn't care less about duplicating the tone. I'm interested in the electro-archeology.

[leonhendrix]

Take a look at the end price???

[jonathan perez]

yowza!

DIY anything isnt an option to alot of people, is it? 

[Ammscray]

the device on the board that I drew the schemo from, that I sent to you, is a 2N4861, which as far as I can tell, is an N-channel JFET
I just re-checked it to make sure, and it's unequivocally the original device too

Yep, the datasheet for the 2N4861 says it's an N channel JFET.

But the circuit doesn't make much sense with an N-channel JFET in it. The 2N4061 fits perfectly with the circuit.

Four questions:
(a) How is the pedal wired? Where does input, output, battery black, and battery red go?
(b) what kind of package is the 2N4851 in? A normal TO-92 plastic package?
(c) is there NO way that 2N4861 could be a 2N4061? A zero with a bar through it, perhaps, like is sometimes done?
(d) can you take and post pictures of the board top and bottom?

a) like in the ebay pix, the black wire going to the board is the neg of the battery clip, and I can't see how the switch is wired in there, but on mine I have the red battery lead going to the input jack like a normal pedal would

the mustard cap going to the board closest to the black battery lead is the .022 output cap, and the other mustard cap going into the middle of the board is the .001 input cap

b) the 2N4861 on my board is in the same black plastic package as in the ebay pix...it is the exact same board and component layout too

c) this device is DEFINITELY a 2N4861....YES, PERIOD!
It is my opinion that the person who said it was a 2N4061 is without a doubt misreading the 8 for a 0

sorry folks, it's a J-FET!

d) I'll post some pix later, I don't really have too much time for forums or internet anymore, I just responded to this because it was brought to my attention by somebody else...

I do have some other interesting info though:
I found some pix in my pedal pic archive (which I'll post later) of a HS treble booster that was on ebay about a year ago, an earlier version that is in a housing almost identical to the Dallas Rangemaster...and the pix inside show that although it is the same board, there are many other components with flying leads, at least 1 other cap and 2 other resistors besides the ones you see in the ebay pix...

AND, the tranny on the board is unmistakably a black mullard OC type, most likely OC44, 75, 76, etc

SO, the gentleman who said the early version was germanium is right, and it may just be a complete ripoff of the Dallas unit...

One last tidbit FWIW: When I got one of my Derangemasters to R Blackmore, we talked briefly, and he actually said he NEVER used the HS unit, that he used the Dallas unit with his AC30 til it got lost, and he didn't find a replacement, and switched to marshall pigs soon anyways

again I say FWIW, because  Blackmore is known for lying about his gear more than even EVH is LOL

The thing about this pedal is, it's very bright and doesn't provide a gain boost, BUT in the front end of a distorted, dark-sounding amp like my old 62 Vox AC30 non-top boost, it actually sounds pretty good, makes it clearer and the EQ is pretty even, which makes me think that whoever designed it prolly did use the AC30 normal channel to do it

[Fret Wire]

i just found the site with blackmores custom tone job...but i cant remember!!!!
anyone know what im talking about? he mods guitars, amps and so forth?

http://www.fjamods.com/Dawk.html

http://dawkmods.proboards34.com/

Like Ammscray said, take it all with a grain of salt. Guitar heros aren't the only ones who delight in bs'ing us about their gear. Techs also like to self-promote themselves too. I'd be more interested in what Blackmore's earlier tech has to say than Dawk. I forget his name at the moment, but he later became Malmsteen's tech.

[R.G.]

a) like in the ebay pix, the black wire going to the board is the neg of the battery clip, and I can't see how the switch is wired in there, but on mine I have the red battery lead going to the input jack like a normal pedal would

If the red lead is switched by the input jack, that would indicate that the red lead is being used as a ground lead. The logical conclusion is that the pedal is wired negative ground, and that is at least mildly supportive of PNP heritage, if not actually PNP in the pedal.

b) the 2N4861 on my board is in the same black plastic package as in the ebay pix...it is the exact same board and component layout too
c) this device is DEFINITELY a 2N4861....YES, PERIOD!
It is my opinion that the person who said it was a 2N4061 is without a doubt misreading the 8 for a 0

That's interesting. I'm one of the people that said it looked like a 2N4061. I have taken the liberty of linking to the photo so it shows up here.

So - do you think that says "2N4861" or "2N4061" in that picture?
Could we get a pic of yours to compare to?

sorry folks, it's a J-FET!
d) I'll post some pix later, I don't really have too much time for forums or internet anymore, I just responded to this because it was brought to my attention by somebody else...

I would appreciate it if you do have the time. Because that picture looks like a 2N4061 to me. Maybe it's my failing eyesight.

I do have some other interesting info though:
I found some pix in my pedal pic archive (which I'll post later) of a HS treble booster that was on ebay about a year ago, an earlier version that is in a housing almost identical to the Dallas Rangemaster...and the pix inside show that although it is the same board, there are many other components with flying leads, at least 1 other cap and 2 other resistors besides the ones you see in the ebay pix...
AND, the tranny on the board is unmistakably a black mullard OC type, most likely OC44, 75, 76, etc
SO, the gentleman who said the early version was germanium is right, and it may just be a complete ripoff of the Dallas unit...

Cool! The archeology is so interesting!

The thing about this pedal is, it's very bright and doesn't provide a gain boost, BUT in the front end of a distorted, dark-sounding amp like my old 62 Vox AC30 non-top boost, it actually sounds pretty good, makes it clearer and the EQ is pretty even, which makes me think that whoever designed it prolly did use the AC30 normal channel to do it

I'll go stick a JFET model into what seems to be the agreed set of values and see if I can figure out what it's doing. Maybe yours is an N-channel JFET, and in that circuit, gain really is unity. A PNP might have more (and the sim shows it to have gain). Who knows what they did? But enquiring minds want to know.

[Ammscray]

a) like in the ebay pix, the black wire going to the board is the neg of the battery clip, and I can't see how the switch is wired in there, but on mine I have the red battery lead going to the input jack like a normal pedal would

If the red lead is switched by the input jack, that would indicate that the red lead is being used as a ground lead. The logical conclusion is that the pedal is wired negative ground, and that is at least mildly supportive of PNP heritage, if not actually PNP in the pedal.

b) the 2N4861 on my board is in the same black plastic package as in the ebay pix...it is the exact same board and component layout too
c) this device is DEFINITELY a 2N4861....YES, PERIOD!
It is my opinion that the person who said it was a 2N4061 is without a doubt misreading the 8 for a 0

That's interesting. I'm one of the people that said it looked like a 2N4061. I have taken the liberty of linking to the photo so it shows up here.

So - do you think that says "2N4861" or "2N4061" in that picture?
Could we get a pic of yours to compare to?

sorry folks, it's a J-FET!
d) I'll post some pix later, I don't really have too much time for forums or internet anymore, I just responded to this because it was brought to my attention by somebody else...

I would appreciate it if you do have the time. Because that picture looks like a 2N4061 to me. Maybe it's my failing eyesight.

I do have some other interesting info though:
I found some pix in my pedal pic archive (which I'll post later) of a HS treble booster that was on ebay about a year ago, an earlier version that is in a housing almost identical to the Dallas Rangemaster...and the pix inside show that although it is the same board, there are many other components with flying leads, at least 1 other cap and 2 other resistors besides the ones you see in the ebay pix...
AND, the tranny on the board is unmistakably a black mullard OC type, most likely OC44, 75, 76, etc
SO, the gentleman who said the early version was germanium is right, and it may just be a complete ripoff of the Dallas unit...

Cool! The archeology is so interesting!

The thing about this pedal is, it's very bright and doesn't provide a gain boost, BUT in the front end of a distorted, dark-sounding amp like my old 62 Vox AC30 non-top boost, it actually sounds pretty good, makes it clearer and the EQ is pretty even, which makes me think that whoever designed it prolly did use the AC30 normal channel to do it

I'll go stick a JFET model into what seems to be the agreed set of values and see if I can figure out what it's doing. Maybe yours is an N-channel JFET, and in that circuit, gain really is unity. A PNP might have more (and the sim shows it to have gain). Who knows what they did? But enquiring minds want to know.

RG, really, I'm a tad bit insulted by your queries...no need to be coy, of course that's a 0 in your picture...on my device with a magnifying glass, it looks as much exactly like an 8, as yours does a 0...capice? is there a possibility that they are the same device, and that the font got screwed up? Yes, it could be, but really it's not that important to me if it is or not, I'm just telling you what mine says on it...

I don't know if I can get as good a shot of mine as you showed, but if I have the time to do it, I'll try, and you will see, if it matters so much, that it looks exactly like an "8" and not a "0" FWIW...right now this is not a huge priority if you know what I mean

the bottom line is, going by component type, that this ebay and my HS treble booster are early 70's pedals at best, and when R Blackmore was purportedly using the HS TB with his AC30. it was like 1967 or so...so he was using the germanium version, or, the original dallas rangemaster...which are most likely the same thing

[R.G.]

RG, really, I'm a tad bit insulted by your queries...no need to be coy, of course that's a 0 in your picture...on my device with a magnifying glass, it looks as much exactly like an 8, as yours does a 0...capice? is there a possibility that they are the same device, and that the font got screwed up? Yes, it could be, but really it's not that important to me if it is or not, I'm just telling you what mine says on it...

I do apologize - I guess that I was a tad bit insulted by your comment that in your opinion "the person who said it was a 2N4061 is without a doubt misreading the 8 for a 0." I guess we ought to call it even then?   

I'm perfectly willing to believe yours is a 2N4861, as I have not seen that one at all. The only one I had seen a picture of - it's not mine, it's a picture from ebay - was pretty clear, and I was just checking to see if there was a possibility of smudges, scrapes, and so on to confuse the issue.

I don't know if I can get as good a shot of mine as you showed, but if I have the time to do it, I'll try, and you will see, if it matters so much, that it looks exactly like an "8" and not a "0" FWIW...right now this is not a huge priority if you know what I mean

That's OK. It's not urgent by any means. It's just curiousity. Do your stuff and don't worry about it.

the bottom line is, going by component type, that this ebay and my HS treble booster are early 70's pedals at best, and when R Blackmore was purportedly using the HS TB with his AC30. it was like 1967 or so...so he was using the germanium version, or, the original dallas rangemaster...which are most likely the same thing

There is indeed more archeology to be done.

[Ammscray]

RG, really, I'm a tad bit insulted by your queries...no need to be coy, of course that's a 0 in your picture...on my device with a magnifying glass, it looks as much exactly like an 8, as yours does a 0...capice? is there a possibility that they are the same device, and that the font got screwed up? Yes, it could be, but really it's not that important to me if it is or not, I'm just telling you what mine says on it...

I do apologize - I guess that I was a tad bit insulted by your comment that in your opinion "the person who said it was a 2N4061 is without a doubt misreading the 8 for a 0." I guess we ought to call it even then?   

I'm perfectly willing to believe yours is a 2N4861, as I have not seen that one at all. The only one I had seen a picture of - it's not mine, it's a picture from ebay - was pretty clear, and I was just checking to see if there was a possibility of smudges, scrapes, and so on to confuse the issue.

I don't know if I can get as good a shot of mine as you showed, but if I have the time to do it, I'll try, and you will see, if it matters so much, that it looks exactly like an "8" and not a "0" FWIW...right now this is not a huge priority if you know what I mean

That's OK. It's not urgent by any means. It's just curiousity. Do your stuff and don't worry about it.

the bottom line is, going by component type, that this ebay and my HS treble booster are early 70's pedals at best, and when R Blackmore was purportedly using the HS TB with his AC30. it was like 1967 or so...so he was using the germanium version, or, the original dallas rangemaster...which are most likely the same thing

There is indeed more archeology to be done.

I apologize too, I actually thought the person who said it was the ebay guy for some reason, not you
Peace