# Rangemaster variant opinions/recommendations? Transistor testing



## beachbum (Feb 15, 2021)

There's quite a few options out there, hoping someone else can help pick the most interesting one. 

On this site, there's the 
-Chickenhead
-Aft
-Rangefinder

From Aion, there's the Radian. 

I can't read a circuit to save my life, so are there enough differences to warrant testing them all out? Or is it one circuit with different component values?

I was looking to get this for testing the right transistors. I'm seeing there's also a DIY method using a breadboard and a 1Mohm resistor. Is this something I can put together easily even if I can't read a schematic? I tried watching a video tutorial and couldn't follow what the presenter was showing.


----------



## moonlightpedalbuilds (Feb 15, 2021)

See the catalinbread naga viper diy from rullywow or aionfx


----------



## caiofilipini (Feb 16, 2021)

beachbum said:


> -Chickenhead
> -Aft
> -Rangefinder
> 
> From Aion, there's the Radian.



I can't speak about the Aft, but I built the Chickenhead (a couple, in fact), the Rangefinder and the Radian, as well as the Naga Viper clone from Aion (Hydra) and a few other treble booster variations. Yes, I have a problem, I know! 

Anyway, the Rangefinder is essentially true to the original Rangemaster circuit, the only exception being the rotary switch to select the input capacitor, which is a very popular mod.

The Chickenhead is close, but IMHO, lacks parts of the essential "honk" due to the way it blends the 5nF input capacitor with the resistance of the Range control and the 2.2uF capacitor connected to the pot. Don't get me wrong, it sounds really good and is a very popular choice! Just not my cup of tea when it comes to treble boosters.

The Radian is also, in theory, true to the original Rangemaster, and also has a way of selecting the input capacitor (via a toggle switch, instead of the rotary switch on the Rangefinder). I built a couple of these, and I was disappointed with how it sounded. I don't know enough about it to be sure, but I think the charge pump does something to that circuit that makes it sound weird to my ears. I breadboarded the exact same schematic, using the exact same transistor, but leaving the charge pump out, and it sounded much closer to what I expected. Call me crazy.

I agree with @moonlightpedalbuilds, the Hydra/Naga Viper is, in my opinion, a GREAT take on the original circuit, with a couple of extra features, and the advantage (for some, at least) of using a silicon transistor (2N2222), so not a whole lot of searching, selecting and testing necessary, as it would be the case with the finicky germanium transistors. It sounds immense and was actually the pedal that made me go nuts about treble boosters in the first place... That said, I personally like germaniums better in this circuit.

As for transistor testing, I personally use a Peak DCA55, but the DIY methods should work fine too. I tested a ton of different transistors. If you can find some of the classic OCXX, great, otherwise, good alternatives that I enjoyed would be 2N404 and 2N414, those are a little easier to find, and much cheaper too.

Hope that helps!


----------



## beachbum (Feb 16, 2021)

Thanks! Awesome, yes, this confirms kind of what I thought, that I would have to try out at least the chickenhead, radian and naga viper to see which one I jive with most. Did you try the Naga Viper with a Germanium drop in replacement? Did it just work outright? I think the viper is the most gainy of all the variants, and is therefore the one that least interests me, but if there's an easy way to tame that, it is something I'm willing to look into...

I will have to buy some breadboard to make the transistor tester, it will be the first time making something from scratch and not recipe baking a pcb from a parts list, so it's daunting and I'm getting option paralysis which means I might not move forward with this for months!


----------



## caiofilipini (Feb 16, 2021)

beachbum said:


> Thanks! Awesome, yes, this confirms kind of what I thought, that I would have to try out at least the chickenhead, radian and naga viper to see which one I jive with most. Did you try the Naga Viper with a Germanium drop in replacement? Did it just work outright? I think the viper is the most gainy of all the variants, and is therefore the one that least interests me, but if there's an easy way to tame that, it is something I'm willing to look into...


Sorry, I wasn't very clear, I didn't mean I like germanium transistors in the viper, I meant in general for treble boosters. I didn't try a germanium there. If you have an NPN germanium transistor, you could try that but it would require some adjustments; the viper has a small cap between base and collector to roll off some of the harshness from the silicon transistor to make it sound closer to germanium.

I used a 2N2222 with hFE around 100 and it's not all that gainy, it's daily easy to tame. Especially with the Heat control. Definitely worth a try.

If you're going to get a breadboard, I'd recommend trying all of these out on the breadboard to try and find the one that you enjoy the most.


----------



## beachbum (Feb 16, 2021)

I'd need to understand how a circuit works first! I'm going to start reading this when I have a bit of free time.



			https://www.premierguitar.com/ext/resources/files/DIY-PDFs/Oct14_PGDistortion_BuildGuide_Final_R2.pdf


----------



## caiofilipini (Feb 16, 2021)

This is a great step-by-step guide to breadboarding a Rangemaster:



			Germanium Darlington Pairs


----------



## Chuck D. Bones (Feb 18, 2021)

You can't go wrong with Steve Daniels' projects.


----------



## beachbum (Feb 28, 2021)

Chuck D. Bones said:


> You can't go wrong with Steve Daniels' projects.


Thanks! That was very helpful. I see there’s a lot of useful info on how circuits work using range masters and FFs as layout examples. I just ordered a big batch of Russian pnp and npn germies but I’d ideally like to keep everything center negative if possible.

I’m going to try out the effects layout soleo too that seems like a cool idea of a 1590b combo that is half Sunface and have throbak strangemaster RM variant


----------



## Chuck D. Bones (Feb 28, 2021)

It is easy to build PNP-based pedals with a negative ground without resorting to a charge pump.  Take a look at the *Way Huge Conquistador* for a good example.  

I bought P28 (PNP) and MP38A (NPN) trannys a while back and have used them successfully in quite a few pedals.  Take a look at my Build Reports and Chucks Boneyard to see where I used them.  Their hFE is between 50 and 80 for the most part.  The MP38As are pretty leaky and the P28s are not.  Make sure you have a good way to test them.


----------



## beachbum (Feb 28, 2021)

I have a gm328 that should arrive soonish. I think I understood how to breadboard the small bear HFe tester but I don’t have those resistor values here yet.
I ordered about a dozen of each of mp38a, mp20b, mp41a and mp42b. From other sources I have 2x 2n404 and 2x oc71. 
going to try to match them up to fit in a broadcast, duo cast, ff, rm, and a spaceman Mercury (if I can figure out how to vero the latter)


----------



## Chuck D. Bones (Feb 28, 2021)

Cool.  That GM328 will make testing Ge trannies and diodes a breeze.  As Steve Daniels says: let Ge transistors cool off in the tester for a few minutes before testing because hFE and Iceo are temperature sensitive.

Sockets... get some good ones from Small Bear.  I usually breadboard first and do my transistor swapping there, so I'm using sockets less and less these days.


----------



## beachbum (Feb 28, 2021)

I got a few round sockets from mouser but not enough for everything I’m planning. I have a big pack of those individual sockets that you can snip off that tayda sells, I think they should work ok? I’m just waiting for the Browne protein parts list to come out before completing my order

if the transistors are that sensitive to temperature maybe I should breadboard outside in my frozen backyard that’ll cool them down quick


----------



## Chuck D. Bones (Feb 28, 2021)

Those snap-apart sockets are sized for IC leads and although everyone likes to use them for transistors, I do not recommend them for transistors because the leads fit loosely in those sockets.  It's a recurrent theme in the Troubleshooting forum. You can apply a thin layer of solder to the transistor leads to fatten them up.


----------



## Travis (May 7, 2021)

Hi! I wanna buy one transistor por the RangeFinder build, this could be a good option?









						Transistor Germanio Mullard OC75 NOS Original Premium
					

Transistor Germanio Mullard OC75 NOS Original Premium, comprobados y testeados uno a uno con el analizador de semiconductores Peak DCA75. Precio por unidad y sin emparejar.




					www.retroamplis.com
				




And someone can recommend me the Hfe? 

Thanks


----------



## JamieJ (May 7, 2021)

I built the aft and really love it. It’s really responsive to your volume control and can be a nice clean tone or will overdrive with the volume on 10. It has a switch for a treble boost or a more full frequency boost. The treble boost is great for getting yourself heard in a mix.


----------

