Hi everyone, I finally managed to build myself the Dallas Rangemaster treble booster with negative ground and with an OC44 germanium transistor and standard values except for the 3.9K resistor which I don't have and which I replaced with a 3.5k resistor. The pedal works but on the collector of the transistor I measure 1.38 V, so very far from the 7 V required, but it works. Given that I am using a Spot one as a power source. What can it depend on ?
Thanks in advance
try replacing the 68K with a 100K trim pot!
also, what are the base and emitter voltages?
cheers, Iain
Vbase =8,66 V
Vemitter = 8,93 V
Vcollector= 1,43 V
Why do you suggest me to replace 68k with 100k ?
Edit:
ok ok, now I reread and I missed that you were referring to a 100k pot, in order to find the resistance you need for the bias.
I think your measurements are all upside down. 9V - 1.43V = 7.57V.
Quote from: willienillie on November 13, 2020, 08:56:53 PM
I think your measurements are all upside down. 9V - 1.43V = 7.57V.
i think exactly the same!
Quote from: willienillie on November 13, 2020, 08:56:53 PM
I think your measurements are all upside down. 9V - 1.43V = 7.57V.
what do you mean ?
Quote from: willienillie on November 13, 2020, 08:56:53 PM...all upside down. ...
One usually-authoritative site, ElectroSmash, gives it that way.
https://www.electrosmash.com/images/tech/rangemaster/dallas-rangemaster-bias-points.png
https://postimg.cc/Yvf3pycL
Which may be another reminder to say WHICH plan you are working from.
1.5V drop in Rc is not wrong.
How bad does it sound??
Quote from: ricci on November 13, 2020, 06:55:56 PM
Hi everyone, I finally managed to build myself the Dallas Rangemaster treble booster with negative ground and with an OC44 germanium transistor and standard values except for the 3.9K resistor which I don't have and which I replaced with a 3.5k resistor. The pedal works but on the collector of the transistor I measure 1.38 V, so very far from the 7 V required, but it works. Given that I am using a Spot one as a power source. What can it depend on ?
Thanks in advance
How are you achieving negative ground but using the OC44?
Quote from: Big Monk on November 13, 2020, 11:53:06 PM
How are you achieving negative ground but using the OC44?
https://www.electrosmash.com/images/tech/rangemaster/dallas-rangemaster-positive-negative-ground-circuits.png (https://www.electrosmash.com/images/tech/rangemaster/dallas-rangemaster-positive-negative-ground-circuits.png)
Edit: central image
Quote from: PRR on November 13, 2020, 09:54:09 PM
Quote from: willienillie on November 13, 2020, 08:56:53 PM...all upside down. ...
One usually-authoritative site, ElectroSmash, gives it that way.
https://www.electrosmash.com/images/tech/rangemaster/dallas-rangemaster-bias-points.png
https://postimg.cc/Yvf3pycL
Which may be another reminder to say WHICH plan you are working from.
1.5V drop in Rc is not wrong.
How bad does it sound??
I will check the positioning of the multimeter better. The sound is ok.
Looking at the survey posted by PRR, i repeated the measurement and found that the voltage collector is -8.44V with respect to + 9V and 1.56V with respect to ground. Tell me if that's okay.
Arithmetically, it's wrong.. :icon_smile:
(8.44 + 1.56 result into 10V..)
Measure your power supply voltage..
I noticed it and it is also curious because the output voltage from my power supply is 9.50 V. I don't know what to say. Does perpetual motion exist?
:o :icon_eek: :P
For a "clean" amp, drawn this way, we might like 4V across the collector resistor for equal swing both ways.
For a "distortion" amp we offset it so sonic damage happens sooner and happens longer. 2V, 1.5V, maybe little difference.
To play, add a 50k or 100k trim pot in series with that 68k resistor and turn it.
I soldered a 100k pot instead of 68K (not in series with this one) and a 10k pot instead of 3.9k but I get at most -5.60V, putting the black tip on the collector and the red one on -9V. But is there a way to fix the bias by ear?
Positive ground circuit. Red goes to ground. Measure collector voltage with other lead. Set 3.9k. Adjust 100k pot.
EDIT: now i see you used a pnp but use negative ground. I have to ask why as there are npn germaniums around.
So, correct me if I'm wrong, so...in the case of negative ground, like mine, it should be the other way around and that is that black must go to ground and red to collector. I had to invert the leads otherwise the multimeter gives random values.
You mentioned in your first post that you built it negative ground with a (PNP) OC44. There's more than one way to do that, but basically you've built it "upside down" when compared to the original, positive ground PNP circuit. If you want to compare your collector voltage to an original that has roughly -7 volts relative to ground, you should measure between your transistor's collector and the "far end" of the emitter resistor, which in your case is supply (nominally +9V). That's why I said "9V - 1.43V = 7.57V" above. If your actual supply is 9.5V or 10V, it doesn't change much.
Swapping the meter leads should only change the polarity (+/-) of the readings. It doesn't really matter, we know the polarity is correct for the way you built the circuit. It's the |absolute value| that you're looking for. But even that doesn't really matter either, the "target" collector voltage is just a ballpark number. Now that you have a trimmer to adjust bias, you should set it by ear to whatever bias point sounds best to you.
So, if I understand correctly, what matters is whether you like the sound regardless of the value of the resistors.
Well, more or less, yes. I was talking more about collector voltage. If your desire is to mimic the sound of an original unit (it may or may not be), then you should take impedances into consideration. Large changes in resistor values will change impedances (and any HPFs and LPFs) within the circuit, and thus change the sound somewhat, for better or worse. This is a reason to select a transistor that gets close to the "best sounding" bias point with the original circuit resistor values. (Caps influence sound too, but not DC bias). That's where a ballpark "target" collector voltage becomes useful here, in selecting the transistor. But you should still allow yourself to make smaller adjustments to get the "best" sound from the particular transistor you used.
The original Rangemasters didn't have bias adjustment trimmers. Even though they had a much larger supply of Ge transistors to select from, I'm sure there was still quite a bit of sonic variation from one unit to the next. Even at the same ambient temperature and battery voltage.
Another detail to consider in this case, two resistor values were different between the OC44 version and the OC71 version, from online pictures I've eseen. So there is no "one" Rangemaster sound anyway, maybe more reason to feel free to tweak the values a little to get the best performance for your needs.
Thanks for everything you wrote. In fact, I experimented a bit and even made a Rangemaster NPN with an AC127 but, leaving the same resistors and capacitors as the OC44, as I expected it gives me a different sound from the OC44, shifted a little in the mid frequencies which not much I like it. What can I do to get the same sound as the 1044?
I had done the version with AC127 so I would have had no difficulty in daisy chaining pedalboards since the RM with the OC44 in a daisy chain with a power supply needs -9V but with none of my 3 pieces of MAX1044 I get the reverse and negative voltage, always and only positive and then I ordered some ICL7660SCPAZ
Someone told me that the Max1044 works at maximum with 10V but with me it worked until recently and easily converted the + 9V to -9V. I don't understand why it doesn't work anymore.
Quote from: willienillie on November 14, 2020, 10:53:05 PM
from online pictures I've eseen.
Typo, but maybe "eseen" is appropriate for online pictures?
Quote from: ricci on November 15, 2020, 04:53:47 AM
Thanks for everything you wrote. In fact, I experimented a bit and even made a Rangemaster NPN with an AC127 but, leaving the same resistors and capacitors as the OC44, as I expected it gives me a different sound from the OC44, shifted a little in the mid frequencies which not much I like it. What can I do to get the same sound as the 1044?
I've never had either type to mess around with. Maybe there is some inherent difference between them such that they can never sound exactly the same. They would probably be very close if they had similar gain and leakage, and were each biased to their respective sweet spots.
I built mine with a Matsushita 2SB175. It sounds great, but I have no doubt it sounds at least a little different than the OC44 or OC71 originals. But I've never played an original either, so I wasn't really chasing a specific sound. (Don't get me started on Tube Screamers or Fender amp clones, lol)
So for either of your transistors, all I can advise is to tweak that trimmer to the best sound. I also used a 100K trimmer in place of the 68K resistor, and small bumps make a big difference.
Quote from: willienillie on November 14, 2020, 10:53:05 PM
Well, more or less, yes. I was talking more about collector voltage. If your desire is to mimic the sound of an original unit (it may or may not be), then you should take impedances into consideration. Large changes in resistor values will change impedances (and any HPFs and LPFs) within the circuit, and thus change the sound somewhat, for better or worse. This is a reason to select a transistor that gets close to the "best sounding" bias point with the original circuit resistor values. (Caps influence sound too, but not DC bias). That's where a ballpark "target" collector voltage becomes useful here, in selecting the transistor. But you should still allow yourself to make smaller adjustments to get the "best" sound from the particular transistor you used.
The original Rangemasters didn't have bias adjustment trimmers. Even though they had a much larger supply of Ge transistors to select from, I'm sure there was still quite a bit of sonic variation from one unit to the next. Even at the same ambient temperature and battery voltage.
Another detail to consider in this case, two resistor values were different between the OC44 version and the OC71 version, from online pictures I've eseen. So there is no "one" Rangemaster sound anyway, maybe more reason to feel free to tweak the values a little to get the best performance for your needs.
To be honest thats why today most fuzz faces sound good while Jimi selected fuzz faces that sounded good.
Quote from: willienillie on November 14, 2020, 10:53:05 PM
Another detail to consider in this case, two resistor values were different between the OC44 version and the OC71 version, from online pictures I've eseen. So there is no "one" Rangemaster sound anyway, maybe more reason to feel free to tweak the values a little to get the best performance for your needs.
You've probably seen one with a black glass OC44 then. These have a 4k7 instead of the 3k9 or 3k7 found most earlier yellow jacket OC44 and the OC71 units. These often (but not always) have a 680k instead of the usual 470k as well.
There is some variation for the input and output caps, too. Some units have a 0.0082µF output cap. 0.004µF input caps were used in the earliest units. Some OC71 units have a 20k or 22k pot.
Quote from: willienillieTo be honest thats why today most fuzz faces sound good while Jimi selected fuzz faces that sounded good.
There is a huge range of bias voltages that will sound good in a Fuzz Face. 10% resistor tolerance and 20% pot tolerance can mess with the bias a lot, though. So even if you select transistors that work well, each Fuzz Face may sound a little (or even quite a bit) different. That's not a bad thing. It gives you lots of different sounds to choose from. I'm finding it hard to make bad sounding Fuzz Face..
As germanium units get hot, they tend to get spittier sounding with less sustain and eventually will gate in an unpleasant and unusable way. They were often biased quite hot (by today's standards), so they would suffer from temperature related issues easily..
I decided to insert the RM with OC44 in the pedalboard and I'm waiting to pilot it with an ICL 7660 SCPAZ that should arrive in a few days and in the meantime I was making a consideration.
Since I already have a large spectrum booster in the pedalboard, I thought of making a modification to the RM to make it more versatile, perhaps adding a 100nF capacitor to the input and switching from broad spectrum to original RM, via a 6-way rotary switch with 2 positions .
But as there was little space available, I thought about equipping the RM with a simple switch. I wanted to make sure that when the booster pot is at minimum, the volume is the same as the dry guitar when the booster is off. It can be done ?
Quote from: Electric Warrior on November 15, 2020, 08:43:57 AM
As germanium units get hot, they tend to get spittier sounding with less sustain and eventually will gate in an unpleasant and unusable way. They were often biased quite hot (by today's standards), so they would suffer from temperature related issues easily..
Jimi did settle for silicon ;)
Hi There,
The sound you like should be your goal as voltages will differ with transistors used and there is no specific magic with voltages exact numbers more so the workingpoints.
Since the emitter is fully decoupled you gte gain according to gmxRC. You can swap out some noise and make unit to unit more equal by inserting a small resistor between
emitter and decouplig capacitor. There are some funny things happening at the edges of transfer caracteristics and let's say you put in 33R ( Ohms) gain would with an ideal transistor be 10K/33Ω
however this ratio is larger than gmxRC so actual gain will be closer to gmxRC even so a small resistor like that will limit some noise and some distortion and make difference between transistors a little less.
You can take this a step further and set ratio RC/RE equal to hfe;) but even a minimum of resistans will affect distortion and noise
This resistor will also affect hie. In the circuit since emitter is decoupled inputimpedance would be hie// with base bias network. Now hie for a germanium is on the order of a couple of KOhms but differs from transistor to transistor
So corner frequency at input will be less dependent on the bias network than the hie of the transistor used.
DC gain of the circuit is 2,5 times but AC gain is gmxRC because the emitter is decoupled for all audio frequencies.
The circuit has the standard bias setup to allow a number of transistors to clock in fairly equal and in production one would have to look at how to minimize variation between devices so that assembly becomes plug in only.
One can assume quite a bit variation with this circuit because it has its emitter fully decoupled and thus end result will be at heavily dependent of the transistor used.
In most any amplifier the workingpoint is what counts as it will set the overtones produced at overload and you can therefore in the circuit set working point by adjusting the emitter resistor which will be forced to have about 800mV across
it but the resting current produced will affect the workingpoint at Collector or you could adjust say bottom leg of bias network at Base.
For a circuit like this the key to sound lies in where the collector rests not the actual resistor values. You could easily make this circuit with parts you have at hand and then ratios of the components will have bigger impact than their actual value.
Since you use old germanium transistors there are a couple of leakage currents that will influence settings
So the unit is good when it sounds good not necessarily when it meets magic numbers
At your service
BJ
BJF Electronics
Sweden
Quote from: BJF on November 15, 2020, 02:34:05 PM
let's say you put in 33R ( Ohms) gain would with an ideal transistor be 10K/33Ω however this ratio is larger than gmxRC so actual gain will be closer to gmxRC
For a 10k Collector resistor and Vcc/2 bias, Collector quiescent current shoud be 450μΑ so intrinsic Emitter resistor (r
e or 1/g
m) should be about 56R..
This very resistor is set in series with 33R external resistor (Emitter load) so gain should be calculated as 10k/(33+56)..
Additionally, 10k Collector resistor value is "ideal", in the mean of infinite following effect input impedance..
Can you tell me if i'm wrong? I had thought of adding a resistor on the ground lug of the pot to have minimum volume equal to volume with RM bypassed and avoid it starting from zero. Can it work ?
Quote from: ricci on November 16, 2020, 09:38:01 AM
Can you tell me if i'm wrong? I had thought of adding a resistor on the ground lug of the pot to have minimum volume equal to volume with RM bypassed and avoid it starting from zero. Can it work ?
I would just add a level control. My rangemaster has a blend control like the Easy Face and an output control after the boost pot. Covers a lot of sonic territory.
Quote from: Big Monk on November 16, 2020, 12:05:46 PM
I would just add a level control. My rangemaster has a blend control like the Easy Face and an output control after the boost pot. Covers a lot of sonic territory.
Any wiring to refer to?
Quote from: ricci on November 16, 2020, 05:25:57 PM
Quote from: Big Monk on November 16, 2020, 12:05:46 PM
I would just add a level control. My rangemaster has a blend control like the Easy Face and an output control after the boost pot. Covers a lot of sonic territory.
Any wiring to refer to?
I'm not sure what board or wiring you used for your RM, but you would simply take the output of the circuit to lug 3 of a 100kA pot, send the wiper to the circuit output and ground lug 1.
Viola!
Quote from: ricci on November 16, 2020, 09:38:01 AM
I had thought of adding a resistor on the ground lug of the pot to have minimum volume equal to volume with RM bypassed and avoid it starting from zero.
It could be done. The volume pot in a traditional Rangemaster is also the collector resistor. Adding resistance there would change the bias, but it could be compensated for.
Or you could use a lower-value pot and a fixed resistor in series, to equal 10K total (or close). A wild guess, because it's an audio taper pot, maybe a 2K pot and an 8.2K resistor.
Used without other stomp boxes everything is ok but because of the power supply I used an ICL7660S CPAZ that I fixed (I tried 10) together with the two 47uF capacitors on a very small pcb but even if I short circuit pins 1 and 8 I feel the famous hiss that decreases or goes to zero if I approach my hand or if I touch some wire or if I change position to the pcb, while if I decrease the gain from maximum to zero, the hiss increases more and more. With all ten ICL7660s the hiss always behaves the same, so I don't think they are fake.
I'm confused. I thought you built the "upside down" PNP version with negative ground. But a few posts up you mentioned using a charge pump with the OC44.
I confirm, i built a PNP negative ground with OC44 but since the final purpose is to insert it in the daisy chain together with other pedal effects, i followed the advice I read here
https://www.electrosmash.com/dallas-rangemaster (https://www.electrosmash.com/dallas-rangemaster)
where the PNP positive ground is good only with the battery and not with an external DC adapter which causes short circuit if put together with other pedals with negative ground, so i built a PNP Negative Ground but reading the article, it seems that with this version you can hear various noises and to eliminate the latter is recommended the REAL version that uses a MAX1044, which I tried but since I didn't get the -9V, then I used a 7660S which all guarantee that it eliminates the hiss which is there anyway.
A little while ago i tried the RM with negative ground, without other pedals and with my 1-Spot, and in fact i heard a noise that sounded like the ticking described in the article linked above but i had not yet tried to insert it in the daisy chain together with the other stompboxes, so i first checked in daisy chain without charge pump, assuming that i would have suffered the ticking and instead no ticking but i hear ... sssssssssssssssssssss ... typical noise when increasing the treble of an equalizer ....
Can this sssssssssss be reduced ?
Unfortunately, the basic hiss is also present with the AC128, OC84 and BC32, a real disaster. Apparently, it sounds quiet with moderate amp volume, but as soon as I get half a point up it's really a disaster.
Quote from: ricci on November 19, 2020, 10:09:13 AM
Unfortunately, the basic hiss is also present with the AC128, OC84 and BC32, a real disaster. Apparently, it sounds quiet with moderate amp volume, but as soon as I get half a point up it's really a disaster.
Have you tried positive ground and a battery?
I know my NPN Rangemaster has no hiss even at top volume. I use a regulated power supply feeding all my pedals.
What npn transistor did you use ?
Just yesterday I tried the following NPN in negative ground configuration: BC547 2N1711 BC337 AC127 BC237
the rustle was absurd, the BC237 the quietest. I tested this by keeping my 60W amp volume at 50% and the RM gain at maximum. The audio recording has been done with the mobile phone placed on the table at a height of 50 cm with respect to the speaker, therefore not frontally. The circuit is trivial enough to have something wrong. Is it possible that my transistors are all faulty? Could the carbon resistors cause such a noise?
I attach the small audio files.
AC127 https://voca.ro/1oi5RYfzg2dA (https://voca.ro/1oi5RYfzg2dA)
2N1711 https://voca.ro/19oP8NvhoNRm (https://voca.ro/19oP8NvhoNRm)
BC337 https://voca.ro/1j2PWTUxlbS9 (https://voca.ro/1j2PWTUxlbS9)
BC547 https://voca.ro/15cZu1FeUf15 (https://voca.ro/15cZu1FeUf15)
BC237 https://voca.ro/1s8KHZLw4hfl (https://voca.ro/1s8KHZLw4hfl)
Assuming you recorded all these clips the same, the differences in hiss volume are significant. So if the only variable is the transistor, there you go. I built one with a Mullard OC76 a few years ago, it had quite a bit of hiss. My newer build with the 2SB175 is very quiet. Carbon comp resistors can contribute some noise, but in my experience the worst usually comes from the active components. Still I use metal films in this circuit though, just because it's so trebly.
the original range master i played was really noisy as well. the clone was not. they had both used an OC71, the clone has fancy glass capsule wire wound resistors and tropical fish caps and a see through case to show off the fancy components and paper-Bakelite PCB. the guitar player with the clone told us he payed 250 euro for the range master clone. i was dumbfounded... 250 euro?!?!?! granted, it looks cool, but that price is ridiculous
cheers, Iain
here we are, page three. you are still having problems, we still, still, haven't seen any pictures of your board or build or wiring. please can we see some photos of your build?
Quote from: duck_arse on November 20, 2020, 08:35:41 AM
here we are, page three. you are still having problems, we still, still, haven't seen any pictures of your board or build or wiring. please can we see some photos of your build?
OT: you can change the amount of replies per page, i like them as high as possible, which is 50
profile > look and layout > somewhere near the bottom
Guys, if my requests / doubts can annoy someone, tell it now so I will provide. In any case, to dispel any doubts about poorly made wiring or soldering, I am attaching photos of my built.
(https://i.postimg.cc/8jmZXzYF/IMG-20201120-153608.jpg) (https://postimg.cc/8jmZXzYF)
(https://i.postimg.cc/VrtRqfMk/IMG-20201120-155044.jpg) (https://postimg.cc/VrtRqfMk)
(https://i.postimg.cc/H8Ct3q44/IMG-20201120-161131.jpg) (https://postimg.cc/H8Ct3q44)
Quote from: willienillie on November 20, 2020, 06:51:28 AM
Assuming you recorded all these clips the same, the differences in hiss volume are significant.....
I still tried the positive ground pnp but with the charge pump 7660S and that noise has gone away but a hiss remained.
Quote from: ricci on November 20, 2020, 10:29:37 AM
Quote from: willienillie on November 20, 2020, 06:51:28 AM
Assuming you recorded all these clips the same, the differences in hiss volume are significant.....
I still tried the positive ground pnp but with the charge pump 7660S and that noise has gone away but a hiss remained.
Where did you purchase the transistor? Some germanium devices are simply more hissy than others.
Quote from: Big Monk on November 20, 2020, 07:54:52 PM
Where did you purchase the transistor?
at the fair about 15 years ago
ricci, you are not causing any annoy with questions or doubts. carry on.
but, when you show this photo ....
(https://i.postimg.cc/VrtRqfMk/IMG-20201120-155044.jpg)
.... we immediately ask, why do you have a 680k resistor and a 470k resistor when the circuit diagram [a wonderful, enlightening thing] shows a 470k and a 68k?
now, see, why I allays ask? please, use your multimeter, measure that resistor, and tell us what value it reads.
[is everybody/anybody having long waits to load this page?]
(https://i.postimg.cc/HV9DR8Mb/68k.jpg) (https://postimg.cc/HV9DR8Mb)
it is orange not yellow
Quote from: duck_arse on November 21, 2020, 08:52:01 AM...[is everybody/anybody having long waits to load this page?] ...
Image in reply #50 never loads.
Two images in reply #45 load fine but resolve to a different site than the link indicates.
PostImg may be having a bad day (or two).
I'm going to reiterate the obvious here: You may just have hissy transistors.
Quote from: Big Monk on November 21, 2020, 07:40:31 PM
I'm going to reiterate the obvious here: You may just have hissy transistors.
It is very likely. Curious however that using the charge pump all noise go away but that hissing remains. I'll try to use some shielded wire.
To confirm the noisy tranny theory you use the gain tester that also test leakage.
http://www.geofex.com/article_folders/ffselect.htm
Making this is another little rite of passage. If you like Ge. Mine is in a cute little box.
In my experience, leaky transistors are not necessarily noisier in this circuit than low leakage ones. OC44s often have no leakage at all and they're about as noisy as OC75s which leak a lot...
Quote from: ricci on November 21, 2020, 10:54:51 AM
(https://i.postimg.cc/HV9DR8Mb/68k.jpg) (https://postimg.cc/HV9DR8Mb)
it is orange not yellow
excellent. if I'd looked at the other photo, I might have seen the odd differences your camera/ hosting site produces. my apologies.
(https://i.postimg.cc/HV9DR8Mb/68k.jpg) (https://postimg.cc/HV9DR8Mb)
(https://i.postimg.cc/H8Ct3q44/IMG-20201120-161131.jpg) (https://postimg.cc/H8Ct3q44)
[images seem to show ok. redirect code isn't obvious. page seems normal speed now.]
Quote from: duck_arse on November 22, 2020, 07:48:59 AM
...I might have seen the odd differences your camera/ hosting site produces.
Certainly, hosting site ;)
Quote from: Big Monk on November 19, 2020, 10:18:08 PM
Have you tried positive ground and a battery?
Yes, I have tried the positive ground even with the battery and the hiss is the same and I have also verified that the NPN is less noisy.
Quote from: Big Monk on November 19, 2020, 10:18:08 PM
I know my NPN Rangemaster has no hiss even at top volume. I use a regulated power supply feeding all my pedals.
But in order not to hear hiss even at the top of the volume, which NPN transistor did you use?
However, in reality, I already have the Analogguru booster working and very quiet but I wanted to replace it with a two-output Rangemaster, a treble boost with 5nF in input when I use the tube and a full boost with 22nF for the quieter things.
I have adjusted the bias with a trimmer and i would like to know if there could be problems of instability leaving the trimmer without putting the fixed resistance?
I have another question...anyone know about AC142K pnp transistor? I have read that they are very quiet, can anyone confirm this?
Quote from: ricci on November 28, 2020, 08:34:33 PM
I have adjusted the bias with a trimmer and i would like to know if there could be problems of instability leaving the trimmer without putting the fixed resistance?
I have another question...anyone know about AC142K pnp transistor? I have read that they are very quiet, can anyone confirm this?
Have you entertained a transistor from Small Bear Electronics? Steve has RM specific transistors which bias to spec and are quiet.
I bought them on eBay but since the OC44 broke, I wanted to try again with the PNP AC142K.
For the moment, the RM I made is a PNP with AC127.
Hi, I build a RMwith AC127 too, sounds great. I put a B100k pot instead 68K so I can bias 7 volts or some othes config. I put a switch por input cap too 5n/10n/15n. I really like the RM in a dirty channel, it gets a really "colored" bright sound.
I have build a RM with AC127. A b100k pot instead 68k and input cap selector 5n/10n/15n. Sounds great in dirty channels or tube/Dirty amps.
I would like to ask you if the rustle is loud but I realized that if I look for the original RM I have to keep the rustle too, just listen to some isolated tracks of songs from the 70s. I also realized that the rustle is annoying to the listener only if you are not playing otherwise it is as if it were not there because what matters is the signal to noise ratio. Of course, if I manage to reduce it, it's always better.
I don´t know if you are talking about the "hiss" noise. The hiss noise y almost a charateristic of the RM. Even, when I just building I was concern about so I dadecated plaety of time read a lot about it and see some videos then I saved a list which the hiss noise is so noted. If this is the case I let you here some videos where you can hear just the rm is turned on:
https://www.youtube.com/watch?v=gEdekaZC40E
https://www.youtube.com/watch?v=p5PbyqIdjGw
https://www.youtube.com/watch?v=sNYyjWSsm2k
https://www.youtube.com/watch?v=9G-e5_ALWyI
https://www.youtube.com/watch?v=InxLJ9vYFXc
https://www.youtube.com/watch?v=9mv71HCvuE0
https://www.youtube.com/watch?v=z7cG5uzftj4
For my build I design a small pcb that includes the three inpput caps, I don´t like long component´s legs from one side to another of the circuit, this way induces to add weird noises even the hiss increases. The mine has a normal hiss level, it´s there but not too loud and is almost pleaseful to hear.
Some pics of my build:
(https://i.postimg.cc/qt30G6ys/IMG-20200630-175802741.jpg) (https://postimg.cc/qt30G6ys)
(https://i.postimg.cc/5QxV1PGg/IMG-20200704-093528.jpg) (https://postimg.cc/5QxV1PGg)
(https://i.postimg.cc/DSWK24C9/IMG-20200704-170257493.jpg) (https://postimg.cc/DSWK24C9)
(https://i.postimg.cc/S2LhB0Zj/IMG-20200801-221636.jpg) (https://postimg.cc/S2LhB0Zj)
Thanks for sharing !
At 1:27 of this video
https://www.youtube.com/watch?v=9G-e5_ALWyI
the noise is really impressive
but it can also be perceived here in an isolated track by Brian May
https://www.youtube.com/watch?v=8XuhJ7qDV9E
at 1:13
There is too too too much hiss in the first video, something must be wrong with the circuit. I don´t know, maybe the very transistor..
The second one is how it supposed to sound (mine does it very likely), even the hiss is amplified because is using a kind of delay too, you can note it in almost the whole guitar sections.
You have to be aware this hiss sound gets louder if you put a high gain pedal in front, don´t do it... ...just use your RM with a dirty channel or a tube amp, the sounds is beautiful.
Quote from: percyhornickel on November 29, 2020, 09:39:50 PM
There is too too too much hiss in the first video, something must be wrong with the circuit. I don´t know, maybe the very transistor..
Will surely be the transistor, unlikely to make a mistake in such a simple circuit
Quote from: percyhornickel on November 29, 2020, 09:39:50 PM
You have to be aware this hiss sound gets louder if you put a high gain pedal in front, don´t do it... ...
Of course, but the hiss also increases with the RM gain although the pedal is already effective with the gain potentiometer not at 100%
https://www.diystompboxes.com/smfforum/index.php?topic=100982.0 (https://www.diystompboxes.com/smfforum/index.php?topic=100982.0)
P.S.
A 47-100 pF Miller cap (between Collector & Base) never harmed any CE amp.. :icon_wink:
In my NPN I noticed that by replacing the AC127 with a BC237C and adjusting the bias to around 8V the hiss disappears and the sound becomes quite mellow when the guitar volume is turned down. Basically I have more nuances of sound and almost zero hiss. So I'd like to know what can happen if I don't respect the 7V bias.
that tranny is silicon
of course it has less noise.
i had my BD139 range master biased at 8.4V since it sounded the best there, it gave me a punk-rock sound when used in a clean amp and a really tight hard hitting grind when used into a dirty amp, but i biased it really close to gating, just at the brink. so its no problem to bias it anywhere else, just use your ears to where it sounds best!
cheers, Iain
Quote from: antonis on November 30, 2020, 07:31:23 AM
P.S.
A 47-100 pF Miller cap (between Collector & Base) never harmed any CE amp.. :icon_wink:
I did some random tests and, I don't know why but it works better with a 33nF between emitter and collector. However, there is a ticking like an oscillation that decreases as the collector voltage increases until it reaches 9V. What can this ticking depend on? I also feel it when I take off the transistor, albeit to a very small extent so it shouldn't depend on the transistor, right?
Edit:
I add that if I completely turn down the volume of the guitar, the ticking shamefully predominates :o
Edit 2:
Maybe I solved the ticking problem because I also have Arduino in the pedalboard which I was temporarily not powered and when I supplied the 5V to Arduino the ticking disappeared. I hope it never comes back.
Quote from: iainpunk on November 30, 2020, 04:40:11 PM
that tranny is silicon
of course it has less noise.
i had my BD139 range master biased at 8.4V since it sounded the best there, it gave me a punk-rock sound when used in a clean amp and a really tight hard hitting grind when used into a dirty amp, but i biased it really close to gating, just at the brink. so its no problem to bias it anywhere else, just use your ears to where it sounds best!
cheers, Iain
Ok but I wanted to understand if the transistor could be damaged or other damage to other things.
Quote from: ricci on November 30, 2020, 06:02:53 PM
I did some random tests and, I don't know why but it works better with a 33nF between emitter and collector.
ricci - did you really use 33nF? and really between emitter and collector? this is not the usual method, and may well be the cause of your [new] tick problems.
Quote from: ricci on November 30, 2020, 06:06:19 PM
Quote from: iainpunk on November 30, 2020, 04:40:11 PM
that tranny is silicon
of course it has less noise.
i had my BD139 range master biased at 8.4V since it sounded the best there, it gave me a punk-rock sound when used in a clean amp and a really tight hard hitting grind when used into a dirty amp, but i biased it really close to gating, just at the brink. so its no problem to bias it anywhere else, just use your ears to where it sounds best!
cheers, Iain
Ok but I wanted to understand if the transistor could be damaged or other damage to other things.
well, most transistors don't mind whatever you do with them when you work with less than 12V. but biasing the transistor nearer to 9V means that you have less current through the transistor, biasing it further away you will have more current.
but with such large resistors, the current won't ever damage the transistor!
cheers, Iain
Quote from: duck_arse on December 01, 2020, 08:57:42 AM
ricci - did you really use 33nF? and really between emitter and collector? this is not the usual method, and may well be the cause of your [new] tick problems.
With the 33nF cap between E and C I reduce both the frying noise that is in the background and the tick but the latter I solved it as I wrote before.
Quote from: iainpunk on December 01, 2020, 11:33:19 AM
well, most transistors don't mind whatever you do with them when you work with less than 12V. but biasing the transistor nearer to 9V means that you have less current through the transistor, biasing it further away you will have more current.
but with such large resistors, the current won't ever damage the transistor!
ok, so I'm fine ;)
Quote from: ricci on December 01, 2020, 12:33:16 PM
With the 33nF cap between E and C I reduce the frying noise that is in the background
Strange way for inreasing Power Supply Rejection Rate .. :icon_eek:
Quote from: antonis on December 01, 2020, 01:28:59 PM
Quote from: ricci on December 01, 2020, 12:33:16 PM
With the 33nF cap between E and C I reduce the frying noise that is in the background
Strange way for inreasing Power Supply Rejection Rate .. :icon_eek:
I don't know why this happens but it greatly reduces the background air blow noise by slightly modifying the tone of the guitar but which always remains bright.
Quote from: iainpunk on November 30, 2020, 04:40:11 PM
that tranny is silicon
of course it has less noise.
i had my BD139 range master biased at 8.4V since it sounded the best there, it gave me a punk-rock sound when used in a clean amp and a really tight hard hitting grind when used into a dirty amp, but i biased it really close to gating, just at the brink. so its no problem to bias it anywhere else, just use your ears to where it sounds best!
cheers, Iain
I really would like to hear the RM with this transistor, don´t you have any sound on the web or some site?. I just saw the BD139 hfe = 40, perfect for a RM.
Quote from: willienillie on December 01, 2020, 10:22:42 PM
Quote from: percyhornickel on December 01, 2020, 08:54:39 PM
hfe = 40, perfect for a RM.
Maybe with a 25K pot.
Is there a formula to determine which potentiometer to install according to the hfe?
Quote from: percyhornickel on December 01, 2020, 08:54:39 PM
Quote from: iainpunk on November 30, 2020, 04:40:11 PM
that tranny is silicon
of course it has less noise.
i had my BD139 range master biased at 8.4V since it sounded the best there, it gave me a punk-rock sound when used in a clean amp and a really tight hard hitting grind when used into a dirty amp, but i biased it really close to gating, just at the brink. so its no problem to bias it anywhere else, just use your ears to where it sounds best!
cheers, Iain
I really would like to hear the RM with this transistor, don´t you have any sound on the web or some site?. I just saw the BD139 hfe = 40, perfect for a RM.
i'm sorry but i don't have that pedal anymore (the transistor is now part of my DIY class A amp), and i don't have sound recordings either. but it wasn't too different from most range masters, just a bit more broken when into a clean amp but in to a driven amp the difference is really small. i recommend replacing the 68k resistor with a 100k or 220k trim pot so you can change the bias to your liking. i believe i used a 47pF capacitor between the collector and base to simulate a germanium's miller capacitance, but that only makes a small difference.
a range master with such a trim pot, and the miller capacitor and transistor in sockets is easy to experiment with, you can just pull out the cap or transistor and change them for other values/types. and the bias trim pot makes it able to accept most transistors with low-ish gain. i strongly recommend making a flexible board with sockets, so you can mix, match and experiment your own perfect sound!
cheers, Iain
Quote from: willienillie on December 01, 2020, 10:22:42 PM
Quote from: percyhornickel on December 01, 2020, 08:54:39 PM
hfe = 40, perfect for a RM.
Maybe with a 25K pot.
why would that be necessary? especially with a bias trimmer, i don't see the need for a 25k pot, unless you really need that extra gain. the original oc44 transisor is about the same gain and really low leakage (for a germanium). the reason a BD139 is great is the low gain (comparable in range) and relatively high leakage (for a silicon).
cheers, Iain
After I solve one problem, another one occurs. Could you tell me why, with the RM activated, when I set the guitar pot to zero, I hear a noise similar to that of the air coming out of the tire when I press the valve ?
https://voca.ro/1cnflRU94gh5 (https://voca.ro/1cnflRU94gh5)
Quote from: iainpunk on December 02, 2020, 09:17:11 AM
Quote from: willienillie on December 01, 2020, 10:22:42 PM
Quote from: percyhornickel on December 01, 2020, 08:54:39 PM
hfe = 40, perfect for a RM.
Maybe with a 25K pot.
why would that be necessary?
I don't know, I got the idea from RG's Austin Treble Blaster paper.
http://www.geofex.com/article_folders/rangemaster/atboost.pdf (http://www.geofex.com/article_folders/rangemaster/atboost.pdf)
Basically, a higher collector resistor. It worked for me to get a 40ish transistor to bias up well, which wouldn't with a 10k pot. Maybe the base-to-ground trimmer gets there too, but maybe at a fairly extreme setting. But either way, I have had better results with hFE around 70, and a 10k pot.
Personally, I feel the Rangemaster has to be built with a Germanium transistor. Full stop. I've built plenty of Silicon ones myself and the mojo is in a properly tuned Germanium unit.
Quote from: Big Monk on December 02, 2020, 11:24:46 PM
Personally, I feel the Rangemaster has to be built with a Germanium transistor. Full stop. I've built plenty of Silicon ones myself and the mojo is in a properly tuned Germanium unit.
i think it depends on what you want, if you like a riff-raff punk sound, a Si does the job well,
if you like smooth rock/pop sounds, definitely use Ge.
i think the black sabbath sound is to be discounted since Toni's range master was heavily modded, allegedly using a ''really large'' input cap, nicer resistors and another tranny.
cheers, Iain
I read on the web that the last noise I described has it in many users and some say that the cause is germanium but it also happens to me with silicon and with any guitar. Some experts at least to understand if I have to live with it ?
Quote from: ricci on December 05, 2020, 03:14:42 PM
I read on the web that the last noise I described has it in many users and some say that the cause is germanium but it also happens to me with silicon and with any guitar. Some experts at least to understand if I have to live with it ?
can you describe be again the issues you are having?
Quote from: Big Monk on December 06, 2020, 07:13:24 PM
can you describe be again the issues you are having?
I am referring to the volume pot of the guitar. As the volume decreases, when I get to position around 3, I start to hear a white noise that gradually increases as I reduce to position 2 and then to 1 to zero. Here the white noise reaches its maximum intensity
Quote from: ricci on December 07, 2020, 04:33:39 AM
Quote from: Big Monk on December 06, 2020, 07:13:24 PM
can you describe be again the issues you are having?
I am referring to the volume pot of the guitar. As the volume decreases, when I get to position around 3, I start to hear a white noise that gradually increases as I reduce to position 2 and then to 1 to zero. Here the white noise reaches its maximum intensity
Is this the same hiss you were initially assigning to the transistors in the boost circuit?
no, the hiss I said initially is the background white noise that is always present while this white noise, that is accentuated with the closing of the guitar volume potentiometer, I have discovered it only now. Given how the potentiometer works, in my opinion the ground is involved but I don't know what to do, maybe some electrolytic capacitor placed in some strategic point but I can't be sure and I wouldn't want to do other random tests. Does the same thing happen to you ?
Quote from: ricci on December 07, 2020, 08:48:35 AM
no, the hiss I said initially is the background white noise that is always present while this white noise, that is accentuated with the closing of the guitar volume potentiometer, I have discovered it only now. Given how the potentiometer works, in my opinion the ground is involved but I don't know what to do, maybe some electrolytic capacitor placed in some strategic point but I can't be sure and I wouldn't want to do other random tests. Does the same thing happen to you ?
How confident are you that your guitar wiring and the controls within it are wired correctly?
Quote from: Big Monk on December 07, 2020, 09:51:21 AM
How confident are you that your guitar wiring and the controls within it are wired correctly?
to 1000/100
As already mentioned, the problem happens with all my guitars but I begin to think that it is precisely the transistor so much so that in the drawer I found a BD137 that does not produce white noise in the background though at the output I always have the noise in the closing of the volume pot.
Finally, I found that the white noise and hum were caused partly by the power supply but mostly because there is also a digital pedal with which it shared mass. When I used two separate power supplies, the noise disappeared. I also tried an AC142K transistor with HFE equal to 138, which turned out to be quite noisy, and in the end I preferred the AC127 because the PNP was really noisy.
last time I tried, made a 470K resistor as a trimmer and feedback, by connecting it to the collector, like a bigmuff circuit which is not very sensitive to hfe.
Strange thing, I removed the 470K resistor, it still makes sound. I use 2SA102 and I measure the VC voltage is still around 7 Volts, it works like a fet.
After I searched it turned out to be like Tone Bender MK1, which can be without bias.
Maybe it can be made like this circuit,
http://www.till.com/articles/PreampCable/index.html (http://www.till.com/articles/PreampCable/index.html)
Unfortunately the capacitor is too big if it is installed in the jack, maybe in the guitar.
May be I am just lucky, so good luck. ;D