What is the Ge temp stabilizer diode mod?
I saw it mentioned in another thread and I'd like to do this in my Fuzz Face.
Is there a schematic?
It's a reversed biased "Ge" diode just before Q1 to ground.
This can help stop "thermal runaway" when your pedal gets a bit hot.
Here's a schematic at fuzz central, just scroll down and read !
http://fuzzcentral.tripod.com/axisfacege.html
Marty.
I did it a few years ago on my Easy face (Q1 Ge and Q2 Silicon): it worked great!
I never had to touch the biasing trimpot.
Luck
Miguel
http://www.geocities.com/gfr.geo/britface.html
yeah, i have been meaning to do that to my RM, but can't find a 1n34A ge diode in my area. Is there any other Ge diodes i could use that will function as good as the 1n34a is supposed to?
thanx :D
Thanks everyone! I may get a chance to give this a try tonight.
formerMember1, where are you located?
QuoteformerMember1, where are you located?
i tried radio shack but no luck, they have other ones, but not 1n34a's. I might be making an order to Aron for some, but that is all i need, and that would be alot of shipping for a couple diodes. :icon_lol:
Quote from: formerMember1 on October 06, 2005, 02:31:52 PM
QuoteformerMember1, where are you located?
i tried radio shack but no luck, they have other ones, but not 1n34a's. I might be making an order to Aron for some, but that is all i need, and that would be alot of shipping for a couple diodes. :icon_lol:
formerMember1,
I thought I had some and I was going to send you a couple but I just realized I don't have any more!
I do have a few of the 1N4454 which, according to the mfg, replaces the 1N34A. Does anyone know if these will work for the Ge temp stabilizer diode mod?
formerMember1 send me a PM with your addy. If these will work I'll send you a couple.
yeah that would be cool, i would only need one diode.
First i gotta find out if that diode will work, It should, i don't see why it wouldn't. :icon_biggrin:
Is that your jimihendrix strat or a picture you got offline?
Quote from: formerMember1 on October 06, 2005, 04:06:32 PM
yeah that would be cool, i would only need one diode.
First i gotta find out if that diode will work, It should, i don't see why it wouldn't. :icon_biggrin:
Is that your jimihendrix strat or a picture you got offline?
I don't think the 1N4454 wiil work. I did a search and according to this thread the 1N4454 is a silicon diode.
http://www.diystompboxes.com/smfforum/index.php?topic=31551.0 (http://www.diystompboxes.com/smfforum/index.php?topic=31551.0)
I ordered some 1N314A's from Aron. I'll send you one when I get them if you don't have any by then.
Yup, that's my Jimi tribute Strat that I put together.
(http://www.daville.com/Jimi-strat-3.jpg)
Quotethat's my Jimi tribute Strat that I put together.
THat guitar has one of the nicest aged finishes i have seen! When you say you put it together did your build it?
thanks for the offer of sending me a diode, but i think i might be making an order to ARON very soon for some 3PDTs and other parts(1n34A)
**EDIT*** i just found a few 3PDTS in another box had, i'll send you a PM.
why does the diode have to be Ge??
i think because the transistor we want to stop suffering from temperature is a germanium transistor. i don't know if silicon would work or not?
formerMember1, send me your home address, and I'll send you a couple in the mail in the morning.
QuoteformerMember1, send me your home address, and I'll send you a couple in the mail in the morning.
WOW you guys are really nice on the forum, i am glad that we all stick together and help each other here, unlike other forums on the net.
Thanks for the offer, but
10acErnie has got me covered, i do appreciate it though, :D
AFAIK, here's the page on this and where I first saw it.
http://www.geocities.com/SunsetStrip/Studio/2987/britface.html#tempcomp
Thanks GFR!!!!!
Here's the home page:
http://www.geocities.com/SunsetStrip/Studio/2987/
Quote from: formerMember1 on October 07, 2005, 05:07:16 PM
i think because the transistor we want to stop suffering from temperature is a germanium transistor. i don't know if silicon would work or not?
It has to be Ge so the diode will drift with temperature the same as the transistor. I think other GE diodes should work the same as the 1n34.
Maybe the best would be using the base-emitter diode (reverse biased of course) of an identical Ge transistor. That way compensation would be perfect. Anyone tried this? Of course, you are wasting a good transistor he he.
May be important to mount the diode and the transistor as close as posible, so both are exposed to the same temperature.
Luck
Miguel
my transistor is a Black Glass Mullard OC44 in a Rangemaster. It is built using the terminal strip, Could i solder the Ge diode directly to the tranny's legs or do i have to solder it to the terminals. There is not much room, (if any) on the lugs of the terminal strip.Â
Ok, We all know that Ge transistors sound different in different "room" temperatures, but what actually changes? Because, my pedal will sound unbiased and bassy one day, and perfectly trebly and punchy sounding another day. Is that a sign of a "temperature diode" needed in the circuit?
???
thank you
EDIT** i have the pedal biased at 7.00volts, and i noticed when it sounds "bad" the biasing changes to around 7.09 or higher. And that is with a regulated power supply, not a battery. :icon_wink:
Quote from: formerMember1 on October 08, 2005, 07:11:08 PM
Ok, We all know that Ge transistors sound different in different "room" temperatures, but what actually changes? Because, my pedal will sound unbiased and bassy one day, and perfectly trebly and punchy sounding another day. Is that a sign of a "temperature diode" needed in the circuit?
Quite posibly. Just be carefull to not damage that precious transistor when soldering the diode!
On the other hand, has anyone noticed, the Plate to Plate article Aron linked describes the principles of piggybacking using diodes??!! I thought that was not posible!
Miguel
Quote from: formerMember1 on October 07, 2005, 04:44:42 PM
Quotethat's my Jimi tribute Strat that I put together.
THat guitar has one of the nicest aged finishes i have seen! When you say you put it together did your build it?
Thanks Man! I wish I could take credit for the Oly White finish but it's a Fender '57 RI body I bought on Ebay. It has a Warmoth neck and Texas Special pups. I finished the neck and put the guitar together.
Here's one I recently painted and reliced:
http://marykayestrat.com/ (http://marykayestrat.com/)
Great lookin strat :D
Very nice work !!
Marty.
yeah that strat is really nice!! The marykay is great too!! Really top quality work. :D
.....
again, that is a really great pair of strats. :icon_cool:
http://www.diystompboxes.com/smfforum/index.php?topic=38046.0 (http://www.diystompboxes.com/smfforum/index.php?topic=38046.0)
http://www.diystompboxes.com/smfforum/index.php?topic=37570.0 (http://www.diystompboxes.com/smfforum/index.php?topic=37570.0)
Quote from: formerMember1 on October 09, 2005, 12:54:03 PM
yeah that strat is really nice!! The marykay is great too!! Really top quality work. :D
HOw did you do that aged fingerbaord finish? ???
> SNIP
I never played a total vintage neck, i heard they are hard to play on because of the small frets, but Jimi did it. :icon_evil:
But i just reviewed your post and see that you fixed it by using jumbo frets.
Thanks!
I aged the fretboard with a little bit of lacquer thinner on a Q Tip. Just rub the lacquer till it eats it away. (Won't work on Poly). Then rub in some pencil lead, charcoal, dirt, oil, grease, stain or whatever until you get the right effect. Don't try this on a good neck at first! It may take a few tries to get it right.
The 7 1/4" radius on a vintage neck does make it tougher to bend. The jumbos do help a lot, but I set my action high on purpose so I don't play too fast. I'm about to order a USACG neck for my next project. It'll have a 9 1/2" radius with jumbos. Bending will be easier on that.
Sorry to hijack the thread with non-stompbox talk!
hey guys,
I want to add the 1n34a ge diode ernie has so graciously sent me. I want to add it to my Rangemaster. From reading around, i found out i solder it to the emiiter to base of the germanium transistor,...right?
If so,.then where would i put the cathode(line) on the base or emitter? I always get confused when people say reverse biased...
THe pedal is a Rangemaster, with a OC44 PNP ground. (actually it is an austin treble blaster)
thanks for the replies , :D
and thanks again 10acErnie
As your circuit is PNP, you should put the diode with the line going to the emiter.
Reverse biased means that the cathode is more positive than the anode, so no current can flow (except the leakage)
Luck
Miguel
thanks bioroids ;)
bioroids:
My tranny is biased at 7.02volts. When i add the ge diode, with the cathode to emitter and anode to base. THe tranny changes it's biasing from 7.02volts to 7.53volts. I can't have that change in biasing. Is there a problem? Or is that normal for the biasing to change when adding this diode?
thanks
PS:THere was another thread where someone had the same problem, but then they said that it was their mistake and it only drops the biasing very very minimal.
Do you have that voltage on the collector of the transistor?
I'm not really an expert in this, but I suspect that the diode can have an effect in the biasing.
That's not a problem anyway, if all parameters look normal (base and emitter voltage besides the collector) maybe you can alter the biasing resistors to get to the voltage you want.
Also before doing anything you should give it a little time. The transistor and the diode should be at the same temperature for the "compensation" to ocurr (and that is not probably the case right after soldering). I would mount them as close as posible too. Let it rest a few hours just to be sure and then measure again and adjust the bias to your taste.
I dont know any reason for it to not work (besides putting the diode backwards, wich would have a big effect in gain).
Luck!
Miguel
yeah 7.02 is on the collector.
I didn't solder the ge diode, i attached it via alligator clips. The pedal is built on a terminal strip. THere is virtually no room in there for the diode but i was gonna do my best. THe biasing resistors are not going to be able to be changed since they are on the bottom of the terminal strip, and there is no way to get at them with a soldering iron. Also the terminal strip is epoxy glued in there.
THe diode isn't backwards since i tried it that way, and the biasing changed to around 8.79volts or so.
I guess maybe i can't use the diode in this pedal. And that really sucks becuase the pedal sounds awesome, my favorite pedal, but it really suffers from the Germaniumitis of sounding good one day and terrible another. :icon_mad:
Anyone else try the diode in a RM and have to change biaisng?
thanks for your help bioroids. :D
When i figure out how to get my digital camera that is on my tape video camera to load pictures to computer, then post pictures here, you would see what i mean.
Well, I dont remember if I had to change bias (did it on an easy face) but I suppose that was probably the case. Also I dont think it would work with the diode too far away from the transistor
Maybe you can use it as is, just try not to expose it to sunlight! :)
Or you can build it again with the diode in and a trimpot for biasing ;)
Luck!
Miguel
thanks bioroids!! :D
Well, see my pedal sounds good one day and not as good another. It doesn't sound horrible on those "off" days, but muddier than normal, and not as trebly. I think it is becuase of temp change, but everytime it doesn't sound right i check the biasing and it is fine, it never goes above 7.03volts or below 7.00volts When ge trannys sound different from temp, doesn't the biasing change? Or does the bias still read the same and the pedal just sounds different?
thanks
Quote from: formerMember1 on October 18, 2005, 10:05:45 PM
When ge trannys sound different from temp, doesn't the biasing change? Or does the bias still read the same and the pedal just sounds different?
I really don't know about that... that's a good question.
I'll search the forum, maybe someone answered this before. The article on the Plate-to-plate seite must have some info on this as well.
Luck
Miguel
this is what i found out on Phillips fuzzcentral site, it is under the axis face germanium pedal.
QuoteThe biggest problem with the Germanium transistor version of the Fuzz Face circuit is that Germanium transistors aren't temperature stable like Silicon transistors. When the inside of the enclosure starts to heat up, whether it's from stage light or sunlight, the pedal will start to sound very bad, and eventually if it continues to heat up, it will stop working all together. This is called "thermal runaway." The best way to stop this problem is to add a reverse- biased Germanium diode across the base-emitter of Q1. This process is described in detail in the Britface article at the Plate-to-Plate effects site. Make a note that this problem only happens with Germanium transistors, and in order for this mod to work, the transistor AND diode have to be Germanium and the diode HAS to be reverse biased.. For a PNP circuit, the cathode of the diode would be connected to ground instead of the anode
He says for a PNP pedal run the anode to ground. I wonder if this is what i should do in my Rangemaster? The way i tried it was i connected the cathode to the emitter and the anode to the base.
Maybe i should connect the cathode to emitter and the anode to
ground instead of the anode to base?
Anyone know? bioroids?
Hi!
The diode has to be connected between base and emiter of the transistor for this to work.
Have you checked the Brit-face article linked in that page? It's pretty clear where the anode and cathode should go in the drawing there: the arrow of the diode goes in opposite direction than the arrow in the transistor (on the symbols I mean). So the line of the diode has to go to the emiter, and the other side to the anode.
Is easy to get confused with this (I feel a little dizzy right now :) )
Here's the link to the Brit-face article: http://www.geocities.com/SunsetStrip/Studio/2987/britface.html is a very interesting read in fact
Luck
Miguel
QuoteSo the line of the diode has to go to the emiter, and the other side to the anode.
where
does the anode go?
I read the britface article, a few times but confused about it. When they say the emitter-base junction i thought they meant cathode to emitter and anode to base, but now i take it as cathode to emitter and anode to
ground,...right?
I am sorry i am confused by this mod. :icon_redface:
QuoteThe diode has to be connected between base and emiter of the transistor for this to work.
How do i connect the cathode
between the base and emitter?
I am on a terminal strip and the emitter goes to 4th lug, the base to 3rd lug and the collector to the 2nd
lug.
WHere is
between the base and emitter?
sorry if i sound so stupid :icon_rolleyes:
OK,
QuoteI am on a terminal strip and the emitter goes to 4th lug, base to 3rd lug and the collector to the 2nd
If it is a PNP transistor:
base to 3rd lug - so the diode's anode goes to 3rd lug.
emitter to 4th lug - so the diode's cathode (that's the terminal closer to the stripe in the body of the diode) goes to 4th lug.
like on the article:
http://www.geocities.com/SunsetStrip/Studio/2987/tempcomp.gif (http://www.geocities.com/SunsetStrip/Studio/2987/tempcomp.gif)
This shouldn't change the bias too much (unless your diode is too leaky or you're at a extreme ambient temperature).
If you put it the other way (anode to 4th, cathode to 3rd) it will "lower the gain" and the bias change will be large (useful if your transistor has too much gain).
Probably my bad english confuses you more .
Quote from: formerMember1 on October 19, 2005, 11:18:00 PM
I am on a terminal strip and the emitter goes to 4th lug, the base to 3rd lug and the collector to the 2nd
lug.
Then the cathode goes to the 4th lug and the anode to the 3rd lug.
On the britface, the emmiter is connected to ground, that's why he says connect the cathode to ground. I mean, in that circuit, ground and emmiter is the same point.
Miguel
PS: I tried breadboarding a simple germanium stage yesterday and the diode addition seems to alter the bias, so you have to rebias after setting the diode in (I'd wait a few hours to be sure they catch the same temp)
Oops: GRF posted while I was writing. But he's right on the spot!
clamp them together, mechanically/thermally (and add the white thermo-goop)
thanks that cleared it up! My mistake was not knowing that the base and ground were the same thing in this pedal. :icon_redface:
I have been doing it the way you say, and your right, it does change the bias. Unfortunatly the way the pedal is built i can't change the biasing. But i will try it on my other Rangemasters i am going to build. ;)
thanks for the help you have given me, :D
Quote from: formerMember1 on October 21, 2005, 01:46:18 PM
thanks that cleared it up! My mistake was not knowing that the base and ground were the same thing in this
You mean emmiter and ground right? :)
I'm just working with some leaky AC128s and I have to adjust the bias pot every 10 minutes! I suppose some transistors are worse than others for this.
Luck
Miguel
QuoteI mean, in that circuit, ground and emmiter is the same point.
whooops :icon_redface:
Quote from: 10acErnie on October 06, 2005, 04:19:06 PM
Yup, that's my Jimi tribute Strat that I put together.
(http://www.daville.com/Jimi-strat-3.jpg)
Nice!