TREBLE BOOSTERS

67plexi said:
Ivan the Radio Spares dogbone capacitors nice touch.

On a side note 2002 I ordered a copy of my 1960 LPS from the Gibson Shop I put Jim Rolph pickups and wired 50's with Sprague bumble bee
capacitors from the 1950's nice clean sound first band practice of the year every thing fine second practice after an hour the notes are blooming
out of control what did my EF86 Mullard 1965 tube go bad no. I have my boost peddles set at 50% turned them down to 25% OK
All I can say is that Custom shop guitar sounds nothing like it did the bass notes are darker and the treble notes are brighter
and the note bloom is still happening with out boost what happened I guess the guitar opened up ???.

My tone bender build it's ugly but sounds good I used a trim pot on the money transistor AC127

View attachment 36839
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I did the "point to point" soldering the same way you have, just underneath the board. If I showed the board underside it looks just the same as yours. Cheers
 
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I can't believe this. I already have two very nice treble boosters. I've also been downsizing my pedal inventory for the last two years... and now, thanks to this thread, I want to build a treble booster!

I don't want to modify my Rangemaster, but I want to build one like it but substitute the carbon comp resistors with metal film resistors and add a couple "pull down" resistors to the circuit, too. The hunt for an appropriate germanium transistor should be interesting.

But first, here's a pic of the transistor in my Rangemaster after I removed the heat shrink tubing off of it:
IMG_2047.JPG


The one mod I did do to my Rangemaster was to change the .022 Full frequency boost cap to a .01 mid frequency boost cap. Notice the altered values used on the emitter resistor which is originally suppose to be 3.9k and the two electrolytical caps which both are suppose to be at 47uF:
IMG_2045.JPG
Did the builder of this Rangemaster tried to tune the circuit by using that 4.7k?
Why the smaller valued e-caps?


Copy of the Dallas Rangemaster schematic with my own notes showing the voicing switch, original and altered component values, and voltage measurements of the circuit:
Treble Booster Schematic.jpg


The ElectroSmash website also led me to the excellent GEO Fex/R.G. Keen article of the Rangemaster:
 
The substituted 25uf power supply filter won't make a difference, current draw is too small & original Dallas Rangemaster's didn't have a power supply filter at all, being battery supplied it's unnecessary. I'm imagining the substituted 25uf emitter resistor bypass capacitor is to maintain a similar frequency response, the electrosmash site will give you the formula to calculate. I tried to link the electrosmash article yesterday but I'm a digital dummy & failed.
Note in the electrosmash article he says a transistor with 90 ~ 100 HFE is needed for correct biasing (correct), but he fails to mention the (very important) leakage of less than 20uA that is also necessary.
If you search eBay UK for Mullard CV7003 germanium transistors you will find one with the correct specs, I bought another black glass one yesterday. I'll build another pedal with, this time, an etched enclosure & RS dogbone caps to sell (at boutique price, of course).
If you do find a "correct spec" Mullard CV7003/OC44 (high 90's HFE, around 15uA leakage), I will have one last pair of RS dogbone caps left that I could let you have (first in, best dressed, lol). Cheers
Edit: If the voltages marked on the schematic you posted are taken from your pedal, they are very close to perfect (the -7.28 collector voltage is just a tiny smidge high). Cheers
 
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ivan H said:
The substituted 25uf power supply filter won't make a difference, current draw is too small & original Dallas Rangemaster's didn't have a power supply filter at all, being battery supplied it's unnecessary.
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Cool. I plan to build it as battery-only, like my Rangemaster.
ivan H said:
I tried to link the electrosmash article yesterday but...
Click to expand...
Main site:

ElectroSmash - Electronics for Audio Circuits.

Guitar Pedal Circuits, Amplifier Analysis, Chip Internal Schematics, Modifications, PCBs,effects study, frequency response and stompboxes
www.electrosmash.com www.electrosmash.com

Article:

ElectroSmash - Dallas Rangemaster Treble Booster Circuit Analysis

Electronic analysis of the Dallas Rangemaster Treble Booster circuit.
www.electrosmash.com www.electrosmash.com


ivan H said:
Note in the electrosmash article he says a transistor with 90 ~ 100 HFE is needed for correct biasing (correct), but he fails to mention the (very important) leakage of less than 20uA that is also necessary.
If you search eBay UK for Mullard CV7003 germanium transistors you will find one with the correct specs, I bought another black glass one yesterday.
Click to expand...
I think I might have been looking at the same Ebay UK seller yesterday. I noticed the ads having an itemized list on each transistor's HFE's. I don't recall any leakage specs though. I'll look again!!

BTW... Those NOS CV7003s are a little bit of a pricey bullet to bite if I want to get into this game!
 
syscokid said:
Cool. I plan to build it as battery-only, like my Rangemaster.

Main site:

ElectroSmash - Electronics for Audio Circuits.

Guitar Pedal Circuits, Amplifier Analysis, Chip Internal Schematics, Modifications, PCBs,effects study, frequency response and stompboxes
www.electrosmash.com www.electrosmash.com

Article:

ElectroSmash - Dallas Rangemaster Treble Booster Circuit Analysis

Electronic analysis of the Dallas Rangemaster Treble Booster circuit.
www.electrosmash.com www.electrosmash.com



I noticed the ads having an itemized list on each transistor's HFE's. I don't recall any leakage specs though. I'll look again!!
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I think it would be the same seller, he's been selling them for a good while. I got the one I just used off him some time back. If you look at the figures he gives, he lists the HFE figure followed by the leakage current, example 96 .016 for a transistor with 96hfe & 16uA leakage current. I think I got the last suitable transistor in his 45 ~ 100 HFE range, but there are other sellers too. Cheers
Edit: I just noticed that he has a 94 HFE & 95 HFE, both with 17uA leakage current, listed in his 81 ~ 99 HFE (fuzz face) transistor listing. Be quick. Cheers
 
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ivan H said:
I think it would be the same seller, he's been selling them for a good while. I got the one I just used off him some time back. If you look at the figures he gives, he lists the HFE figure followed by the leakage current, example 96 .016 for a transistor with 96hfe & 16uA leakage current. I think I got the last suitable transistor in his 45 ~ 100 HFE range, but there are other sellers too. Cheers
Edit: I just noticed that he has a 94 HFE & 95 HFE, both with 17uA leakage current, listed in his 81 ~ 99 HFE (fuzz face) transistor listing. Be quick. Cheers
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Just ordered two of them from eBay seller: vpg17
The first one is a CV7003 DN Mullard with an HFE/Leakage of 95/.017
The second one is a CV7003 (No brand name) with an HFE/Leakage of 97/.017

Here we go... :celebrate2:
 
syscokid said:
Just ordered two of them from eBay seller: vpg17
The first one is a CV7003 DN Mullard with an HFE/Leakage of 95/.017
The second one is a CV7003 (No brand name) with an HFE/Leakage of 97/.017

Here we go... :celebrate2:
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Nice. Hopefully both are nice, quiet (not noisey) transistors. I'll get them two dogbones sent out to you on Monday morning. Cheers
 
syscokid said:
Oh Hell Yeah!!!!!! Thanks, Ivan... (y)

I gotta start thinking of what type of layout for the pedal... :hmmm: Top mounted jacks? Terminal strip for a circuit board?
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If you like I can include a piece of perfboard, a couple of adhesive backed standoffs & a hand drawn diagram of the simple layout that I used in with the dogbone caps when I send tomorrow. Cheers
 
syscokid said:
Yes, please do. I've never worked with a perfboard before. This is going to be fun! Thanks, Ivan... :cheers:
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Ok Mr Sysco's, your late Xmas present is on its way, I'll send you the tracking No.
I wired the footswitch differently from the way it is shown on the schematic that you posted earlier. Two reasons, (1) so that I could easily mount the 2M2 pulldown resistors on the footswitch.
(2) so that the 0.005uf input cap "grounds" when the circuit is bypassed, rather than left floating. Though this isn't entirely necessary due to 2M2 pulldown resistor, it is good practice.
If you want details of how I wired it give me a yell. Cheers
 
I'm into Fuzzface's too and Sola MKII's … DSCN3624.jpg … shows my age thought but they all do what there known to do! Lots of fun plugin em into a 45/100 stack or even a blackface twin. As a kid we figured out the FF's sound best chilled and mom was always bustin my eggs about certain effects being stashed in the fridge. I tried to explain myself but she just didn't understand. Then I figured what the halibut and put my baseball mitt in there too saying it makes my ballgames better. Then Dad got involved and it was all over. No more non food items in the fridge as whatever I put in there I'd have to eat! hysterical.gifClydeMcCoy.jpg
 
Vox AC30 said:
I'm into Fuzzface's too and Sola MKII's … View attachment 36966 … shows my age thought but they all do what there known to do! Lots of fun plugin em into a 45/100 stack or even a blackface twin. As a kid we figured out the FF's sound best chilled and mom was always bustin my eggs about certain effects being stashed in the fridge. I tried to explain myself but she just didn't understand. Then I figured what the halibut and put my baseball mitt in there too saying it makes my ballgames better. Then Dad got involved and it was all over. No more non food items in the fridge as whatever I put in there I'd have to eat! View attachment 36968View attachment 36967
Click to expand...
Oh yes, very nice pedal collection.
Just a sec while I wipe up this drool I just did all over off my 'phone screen.
Cheers
 
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