Building a Ge SkyRipper

[BetterOffShred]

Hey guys, I'm on a kick to build all my "Big Box" plans before the end of the year (probably wont happen) but Joe Gagan's SkyRipper is on the list, and I figure I'd better get started.   I'm using the schematic and layout from the gallery, and I'm not looking at altering the design too much/at all.   I am having a hard time finding a 1M pot with a push pull switch so I may just make that a toggle (The Ripper pot).   

I emailed Joe and asked him some particulars about the circuit and he indicated he remembers most of the pots be linear taper, but I was hoping anyone else who had built one could weigh-in and share their experience with what they liked where.   

So far I have:
Ge Transistors - AC128's in the suggested hfE range
1590XX box - should fit everything
All resistors/caps
Toggles and Stomp switches
Jacks and power socket

Another thing I'm curious about, is since this is a Positive ground effect, could I use a daughter board producing -9v and then run this off a daisy chain? I mean theoretically?  I'm sure there may be reasons not to, like oscillation etc. but I was curious. 

And then finally, has anyone built the Ge and the Si ones, and can comment on the differences?   This build really honestly looks pretty easy, it's just a lot of pots and switches in a bigger box so I consider it a little more challenging, but from the videos I've watched of the device I don't know how I've made it this long without one!

Thanks for reading guys.  More to come 

[BetterOffShred]

I think I'm going to use one of these for the ripper knob.. It has the spst switch built in, with the turn to activate style actuation:
http://www.mouser.com/Search/ProductDetail.aspx?R=RV24A01F-10-15R1-A1M-3LAvirtualkey14860000virtualkey31XP601-F3
Seems like it fits the bill! 

[digi2t]

Yup, that pot will do fine.

As for the transistors, it will do fine with any number of germanium transistors. I even got great results with very low gain silicon PNP's in place of the germaniums, 2N2904A in Q2, and a 2N2905A in Q4, with success. I recommend socketing, and leaving your options open on this front. Every different transistor will impart it's own sonic qualities to the global sonic picture, so don't be afraid to experiment here.

I built mine using this version;

[BetterOffShred]

Beauty! That is the schematic I have.  I also have your layout too Dino    Though it has 5 trimmers listed on the BOM and only 3 on the layout - I read part of a thread where you had used an additional 100k to trim into a different trimmer or something.  I'll have to read more before I commit!   

I should probably start attempting layouts since I usually use the schematics to troubleshoot my builds anyway. 

I'm just ordering all Linear pots and hoping it will be good.   I have a pretty good ear/feel for sweep on most effects so I can always tinker later.   
Thanks for reading!

[pinkjimiphoton]

makin' popcorn!!

[digi2t]

Yeah, you can ditch the two bias pot trimmers I mentioned, and use a 20k instead of a 50k bias pot. The sweep is plenty useful with a 20k.

The range, preamp, and volume pots should be log pots. Linear's will be too bunched up at one end.

[BetterOffShred]

Well I ordered all linear but I found a couple projects that need a few pots so I may just order up a few.  I built the board for it but I'm waiting on some parts, should arrive this week, and I'll get it put together.   Thanks for the tips   

I hope the 1meg with a switch isn't too much bigger than the rest of my pots. 

I'll update the thread as I go if anyone is interested

[Philthy]

watching with great interest

[digi2t]

Well I ordered all linear but I found a couple projects that need a few pots so I may just order up a few.  I built the board for it but I'm waiting on some parts, should arrive this week, and I'll get it put together.   Thanks for the tips   

I hope the 1meg with a switch isn't too much bigger than the rest of my pots. 

I'll update the thread as I go if anyone is interested

1MEG with a switch??? The only switched pot is the Ripper pot, which is B100K.

If you build this in a 1590DD, the board is small enough to afford all kinds of space for a switched pot. Or, skip the switched pot, and just use a toggle next to the pot. Personally, I find this more convenient, since you can leave the Ripper pot in a fixed position, avoiding having to "dial it in" every time.



For an added bell/whistle, you can add a 1P4T rotary switch, and add four caps at the input of the Range section. Lots more textures available in Ripper mode. Here's a my version, I've added the pot lugs and switch lug numbers. I also added LED's to the footswitches.

[BetterOffShred]

Well I can use that pot as a PPIMV in my Bassman I guess 
Haha that's ok, I had a feeling a pot and a toggle would be better for just what you describe there.  I should get most of the stuff today in the mail so I'll see how much soldering iron time I get!  Thanks for looking

[davent]

Put mine into a 1590BB landscape oriented. Seven pots in a row, three toggles and two stomps. Not crowded and the dual 1M pot was a 25mm monster. Used a single stereo jack for the insert loop. Now if photobucket wasn't jerks...

dave

If you have a photobucket fix you might be able to see this. Wiring in progress.





Eliminated power jack, was going to be an issue, just run on a battery.

From these threads...

http://www.diystompboxes.com/smfforum/index.php?topic=71194.msg574180#msg574180
http://www.diystompboxes.com/smfforum/index.php?topic=73354.msg595262#msg595262

[BetterOffShred]

I am going to "Octopus" my build and see how it all looks and then probably try and get it into the XX box I ordered.  Now that I messed up and will be using a regular B100k with a toggle for the ripper pot, I see no reason why I can't get all 7 pots across the top with toggles below and then 3 stomps at the very bottom.  I do like top mount jacks though, but I should be able to sneak the Neutrik style in between 2 pots.   

One thing I'm still trying to wrap my head around is the Positive ground thing.  As long as I have it wired as in the schematic I just hook the "ground" wire up to the positive pole on the DC jack and the DC- wire will go to the "Ground" lug on the jack?   Or do I need to make a voltage Inverter such as this NE555 based layout from Tagboard  Fx ?   
http://tagboardeffects.blogspot.com/2013/02/ne555-voltage-inverter.html

And lastly if anybody is kind enough to share, can I just use a 1N34A or a 270 or D9E or something for the NKT275 which is hooked up in diode configuration?   This is really the first Ge build I've attempted and my stock of Ge Transistors is pretty low, though I did order up some IT308B's and some 2SB172's for a couple of builds. 
Thanks for looking fellas 

[BetterOffShred]

Davent: after looking through those threads, the power one in particular, it sounds like the voltage inverter will be the Bee's Knees if I can fit it in the box.  Then I just hook it up like in the schematic and I can daisy chain it with other stuff if I want 

Hopefully..

[davent]

I really think i messed up my powering attempt, never lost anything in the process but the potential was there for disaster. Was a long time ago now!

The inverter and board should be pretty small, shouldn't be too much of an issue to squeeze in.

Madbean sells a board or you might get ideas from their build document.

http://www.madbeanpedals.com/projects/RoadRage/docs/RoadRage_2015.pdf

Were you able to see my pictures? I can see my pictures since i installed the fix but have no idea whether i'm seeing other people's who had photobucket images.

Thanks
dave

[BetterOffShred]

Dave: Unfortunately I cannot see your pics.  I appreciate you taking the time to attempt to show me though!  I'm definitely going to try to use that Inverter board, I'm just hoping there isn't a bunch of loss or something so I actually have to put like 10V into the board to get a decent -9V out.   I mean I can do that, it's just another step    I'm really excited to get this one going.   Thanks for looking!

[davent]

With the Skyripper i'm usually running it voltage starved so a little less voltage may not be any sort of issue.

This is a fix for Chrome that's been working for me, there is one around for Firefox but i haven't tried it.

https://chrome.google.com/webstore/detail/photobucket-embed-fix/naolkcpnnlofnnghnmfegnfnflicjjgj?hl=en

dave

[BetterOffShred]

So I have a Mega328 tester which I've been using to test transistors for hfe and the like, but I'd like something a little more .. Precise.. lets say?   So I found a couple layouts for a little board you hook up to your DMM and then do a little math to get hFE and leakage..  Anyone have any opinions on these?  This is probably a low visibility location to ask this, but I figured I'd give it a shot since most of the dudes who are interested in this thread probably have a technique for measuring hFE and leakage on Germanium transistors! 
Thanks for looking

[davent]

Small Bear and Geofex have articles on testing for desirable qualities in Ge transistors and i did  make up a little box (based on the Geofex article), i can plug my meter into and test NPN's or PNP's.

http://www.geofex.com/article_folders/fuzzface/fffram.htm

http://diy.smallbearelec.com/HowTos/FuzzFaceFAQ/FFFAQ.htm

dave

Old thread with photobucket images. I haven't found a new host.

http://www.diystompboxes.com/smfforum/index.php?topic=105996.msg956931#msg956931

[PRR]

> I haven't found a new host.

Use the dingus under the Reply box. It works OK, without reader add-ins.

[davent]

> I haven't found a new host.

Use the dingus under the Reply box. It works OK, without reader add-ins.

Thanks Paul,

I have never noticed that before, how long have i been in the dark?

Does it produce a reasonable sized image or just a thumbnail you need to click on to get to something you can see detail in?

dave