sabbra help

[jorjor]

Greetings to all!
This is a noob-rescue-alert! Just finished my Sabbra build and it doesn't work! ;>(
I'm getting hiss that rises and lowers with both gain and output pots but nothing resembling a musical signal. Now, I have not grounded in and out jacks but relied on case grounding. Is this a possible cause
(I don't see how but...). Another thing...I used snapable 40-pin sockets for the trannys and diode to prevent cooking them but they aren't too secure in them. Any suggestions with that? Also, my soldering skills are not what you would call "mad" but I triple checked all joins with the meter and all seemed fine.
I know I'm prob making some very fundamental mistakes but could surely use some tips and pointers. Tnx.

[El-even]

if the trannies are good soldering them directly to the board
one of your jacks must be connected to ground (dc plug)
anyway, this pedal is insanly "radiophonic", i've built one and receiving foreign radio with it O_o
the guy i built for have no problem with...

[jorjor]

Update....Noob-rescue-alert cancelled! :) I found a note on BC184 pinouts on FSB and yep, that was it!
I ordered a BC184L from Tayda and erroneously assumed it had the same pinout as the regular BC184. It's different though. Twisted the leads and Kablueeeee!!! IOMMI baby! It fired right up and now I'm in Sabbath heaven or hell (whatever the case may be..muuhaaa). It sounds fantastic! This is the first pedal I've built in 20 years so, that'll tell you how good the build info is on this site. It doesn't look pretty but it bites like a gator. Good job Mirosal on the layout and build info...you da man!
One question though, what type of tranny sockets is considered state-of-the-art? The type I'm using are the 40-pin snapable in-line sockets sold at Tayda but the leads are very loose and I know they are gonna work loose to the point of failure in the future. Anyone have any ideas on dealing with this problem or have a better way of installing semi-conductors on boards? Tnx again gang.

[scimitar]

Had exactly the same problem, never thought the pinouts would be different but had already spotted this.

Also have had the same problem with socketing transistors, I don't do it now unless I want to swap them - I know we are always warned against overheating them but I have never had a problem soldering them directly and in this pedal, soldered them, de-soldered them and soldered them in the right way round and they all still work fine - so I can only assume overheating issues are exaggerated?

[induction]

The overheating issues are mostly limited to Ge transistors, they're more heat sensitive.

Most transistor leads are pretty small, so it doesn't take that much heat to solder or desolder them. As long as you observe the 1-second rule you'll usually be fine.

I never socket anything but IC's. But I optimize my circuits on the breadboard before I build the vero, so I don't have a need to swap components afterwards.

[Frank_NH]

You can thicken the legs of your transistor by putting a quick coat of solder on them.  You could then secure the legs, once seated in the socket, with a dot of thin superglue.  This would probably work for light use.  

For long term "industrial" use, I think soldering directly to the board is best.  However, you can solder the transistor legs into the socket with a quick dot of solder, and this may be a good compromise if you want to have the flexibility of using sockets (the purpose of which are to permit trying out different transistors in the circuit, a must if you are using JFETs).

[jorjor]

I always heard that soldering semis was a dicey proposition. But if you guys say it's ok then I'll do it.
Sounds to me like there's a multi-million dollar opportunity for someone to manufacture a tranny socket that is made for them. I actually had the super glue idea myself but was uncertain if the glue had any conductive properties that could create shorts on the board or between pins. I'll have to experiment with both ways I guess. Believe it or not, in the past, I used to remove the pins from DIP sockets to use for this purpose. It's a little tricky at first but works ok once you get the hang of it. The advantage there is you can use the type of DIP's that have that kind of slotted-clip design to them that the flat legs of an IC slide into(as opposed to the round hole design). I went with the 40-pin type this time cause I see them on so many builds on this site. In any event, great info help and much thanks to the GFX peeps!

[rocket88]

I actually always socket transistors even on the pedals I sell. It makes for quick fixing if one dies, and the faster I get it back to my customer the happier they are. The amount of times I've needed to do this on a customers pedal has actually been never so far, but it's something of a piece of mind thing. What I do is I put a tiny kink by the tip of the leg so when I put the transistor in it digs into the socket just enough to hold them tightly, but not enough that they'd get stuck. Works like a charm every time for me.

[Beaker]

As far as I am aware, there is no such thing as a "superior" grade of socket.

Be aware that all sockets will go loose if you swap transistors or diodes on the same socket more than a couple of times. Also there are some components like Russian germanium transistors, that have small diameter leads, that won't hold securely in a socket. Other components have fat leads that don't fit in the sockets at all.

As mentioned above, it's germanium transistors and diodes that are most susceptible to heat damage - silicons are more robust. If in doubt, use a heat sink on the leg you are soldering, and wait a minute before soldering the next leg. This gives the component time to cool down. A simple alligator clip is ideal.

Pesonally I use sockets when trying a new circuit, but on repeat builds, when I know which transistors and diodes work best, I leave them off.

A drop of thick superglue should not hurt if the socket has gone baggy, but Zach's method is better - a secure mechanical connection is good electrical connection.

[jorjor]

Thanks everybody for the really useful tips and help. The brotherhood on this site is awesome!

[jorjor]

Actually, I do have another Question. As I said it works fine but I'm getting a kind of high freq saturated-fuzz sound on a few notes on the fingerboard. The D and E strings at the 12th frets as well as E string at the 5th and I think 7th frets.(Harmonic positions). Is this normal and something to live with or indicative of a fault in one of the parts? I say that cause when I was soldering a couple of the caps I thought I heard a very slight "tic" sound that one would hear when a fuse or filament pops from heat. The problem with that is I'm not sure how to diagnose caps that are bad(gotta research it) Also, so you know, I'm using the trannys that are called for in this build(PN4393). Overall, this box sounds great with good responses from the pots while adjusting levels and so forth. And as a sidenote, the level of noise associated with this circuit doesn't seem too bad at all. Certainly not a deal-breaker in any case. I'm also wondering about wire placement(does it weigh-in on this build...should I have used shielded input and output wires? etc..) Anybody experiencing this fuzz-buzz too?

[Beaker]

Wire placement is a tricky thing for beginners when dealing with "rat's nest" wiring. It's difficult enough just to wire the bloody thing, let alone wire it neatly.

A couple of tips:

#1. Try to separate power and signal wires. Try running power wires down one side of the enclosure, and signal wires down the other. Power noise can and will bleed over from power wires to signal wires (cross talk) if they run close to each other. This gets more apparent, the higher the gain of the circiut, and the higher the volume you run it at.

#2. Try to run both power and signal wires as close to a ground source (either a ground wire or the enclosure itself) as possible.

#3. if you need to cross power and signal wires, try to do it at 90 degrees - this cuts cross talk to a minimum.

#4. Shielded wire is great for avoiding and minimising cross talk and noise.

#5. Always bear in mind that some circuits are very noisy when on your test rig, but will be almost silent when boxed.

Finally, I try to use shielded wiring whenever possible, but I always use it on fuzzes and high gain builds.

[motterpaul]

I thought mine was overly noisy (its been awhile since I made it) - but more of a hiss/hum/static sound.

You have the right transistors so that makes a big difference. Often noise goes away when things get boxed as well.

Be sure to keep audio leads away from power leads, and it is best to come up with a complete ground scheme - point to point. I would not trust case grounding because things can come loose.

[jorjor]

Good info and suggestions. I'm pretty sure I have enough space between power and signal lines and I have it boxed in an old cookie can that is all metal and should provide good shielding from outside sources. The "squeal on some notes" problem I mentioned is completely isolated to those notes only. The rest of the fretboard sounds absolutely great, full of rich harmonics and super chunkiness. I use a steel pick too, so that's gonna add to the tonal buffet. I realize that this is a box that one will have to experiment with to "master " its capabilities. Spend some time with it as well as using the guitars' volume knob as the "fifth control". Right now, since I completed it, I've been playing on a Washburn with two single coils and a HB in the bridge position as my Epi SG is being worked on. My SG has a Mean 90 in the bridge pos and should have a distinctly different sound as I have modded the guitars' circuit to have good control over the Mean 90. I guess I just gotta play with everything to work out the bugs. Thanks again guys.

[motterpaul]

That's right. I forgot how much that one is affected by the guitar input level. Some circuits are really funny that way. I just built one build where if I had my guitar volume at full it would squeal, but back it off to 9.5 and it is fine. I just added a resistor to the input as I recall to fix that.