I made a preamp, but it doesnt work.....

[tommorichards]

I made a sabre bass preamp from online schematics, and ive wired everything up, but its not working. Im wondering if someone can help me diagnose the problem from the symptoms...

basically, its very very quiet; the controls dont appear to be working (could be due to volume); and there is also static (i can hear bbc radio merseyside). But mainly the first one.

Are there any common things that would cause the preamp to be quiet?

Here are the schematics im using for reference

[tommorichards]

From here: [url="http://www.sabrotone.com/?page_id=4"]http://www.sabrotone.com/?page_id=4[/url] and it does say not authenticated.

And i made sure to cut the traces, since the diagram went to the trouble of listing the number of them, i counted and made sure

As for the 1 meg reverse pot, i talked to the David at SGD luthiere as to his source for his stingray preamps, but he said he just uses a 1meg linear taper pot, so i decided to. However, i did find a source for them in th uk:

http://uk.mouser.com/Search/ProductDetail.aspx?R=RV16AF-20-15K-C1Mvirtualkey14860000virtualkey313-1550F-1M

Edited March 16, 2012 by tommorichards

[tommorichards]

Thats where i got the proper wiring diagram from. im trying to compare them to see if its a layout problem. Im not sure why the diode is in there though.

[tommorichards]

I took it to my mates genius father, and apparently, im rubbish at following board layouts. Several things were wired incorrectly. The board was fine, just all the jacks etc werent. Ill have a go later. Thanks for your help though.

[LukeFRC]

[quote name='tommorichards' timestamp='1331943785' post='1581411'] I took it to my mates genius father, and apparently, im rubbish at following board layouts. Several things were wired incorrectly. The board was fine, just all the jacks etc werent. Ill have a go later. Thanks for your help though. [/quote]

I just saw this and was going to ask questions along those lines....

[tommorichards]

sure. not too sure what after shots to take, but here is what ive got now. I currently have it in a pedal type enclosure only because i havent made the bass its going in yet, so this is a nice way of actually using it. I also added an extra strip on the board to connect all the grounds to as its easier than connecting the pots together.

here is my enclosure:


the insides:


above view of component layouts:


and lastly, my soldering (the top left was my mates dad having a quick go at correcting my errors):

[tommorichards]

Yeah. Thanks to my mates dad pointing me in the right direction, it now works!!! The bright switch is awesome too! If i would have followed the instructions, then i would have had no problems whatsoever! now to make another one.

Edited March 17, 2012 by tommorichards

[tommorichards]

im planning on making my own sabre bass as i cannot afford a real one, so im using this preamp. The wire ive used to go to the controls is rubbish though as they keep snapping off the board, so ive ordered some copper wire for it.

Once ive installed it on the bass im planning on using, ill probably upload sound clips, but until then, im using it as a pedal. sounds best on my jazz. If you're hesitant about starting, i could always put a board together for you......

[tommorichards]

the hole drilling sounds like it makes sense, and i may do that for the second board as i dont think there is enough room on this one for that to work.

As for parts, the second picture i orginally posted has all the parts required, and all but the pots and 1.8nf capacitor can be had from bitsbox.co.uk if that helps.

[tommorichards]

well i bought enough parts for 5 boards (excluding pots and op-amps) so i might as well stick them together

[tommorichards]

Well, tbh its pretty badass. I Like the boost only bass, and the bright switch adds that little extra zing when you want to hear the zinginess. I reckon ill probably make a few more and stick them on ebay for a reasonable price.

i did also change two things from the diagram too. A 10uf output cap instead of 1uf, and a 4.7nf cap for the bright switch instead of 1.8nf.

[Al Heeley]

[quote name='tommorichards' timestamp='1333109248' post='1597509']
i did also change two things from the diagram too. A 10uf output cap instead of 1uf, and a 4.7nf cap for the bright switch instead of 1.8nf.
[/quote]was this down to inventory restrictions or technical benefits? If the latter, what were the benefits?

[tommorichards]

Yeah, thats what that one was.

the 4.7nf was because it gives better treble boost, and it allows me to get pretty much all my parts from the same place.

I also chose to do the sabre preamp as im making my version of it as i cannot afford a real one. If you dont want a bright switch, then stingray is the way to go.

Edited March 30, 2012 by tommorichards

[brensabre79]

What are you doing for pickups when you build your Sabre out of interest? Are you just going to use Stingray size ones?

[BILL POSTERS]

Mind if I stick my oar in and suggest using this stuff instead of Veroboard ?

[url="http://www.ebay.co.uk/itm/160499593193?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649"]http://www.ebay.co.uk/itm/160499593193?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649[/url]
You can get it at other places, the link is just a convenient example.

Even perf board - the Vero type stuff without the copper - is better than Veroboard. I hate the stuff.

[tommorichards]

[quote name='brensabre79' timestamp='1333124587' post='1597853']
What are you doing for pickups when you build your Sabre out of interest? Are you just going to use Stingray size ones?
[/quote]

I was looking for some sabre sized ones, but the nearest i could find size wise was this one
[url="http://www.ebay.co.uk/itm/130481904642?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649#ht_500wt_969"]http://www.ebay.co.uk/itm/130481904642?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649#ht_500wt_969[/url]
But i got some good deals on here for some bartolini pickups.So theyll do.

[quote name='Johnston' timestamp='1333209403' post='1598780']
Silly questiontime.

C7 is the one that should be 10uf instead of 1uf isn't it?
[/quote]

That is the one that i changed, yes.

[quote name='BRANCINI' timestamp='1333211341' post='1598815']
Mind if I stick my oar in and suggest using this stuff instead of Veroboard ?

[url="http://www.ebay.co.uk/itm/160499593193?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649"]http://www.ebay.co.u...984.m1423.l2649[/url]
You can get it at other places, the link is just a convenient example.

Even perf board - the Vero type stuff without the copper - is better than Veroboard. I hate the stuff.
[/quote]

I dont mind the veroboard stuff, but that is some strange looking stuff in the ebay listing....

[BILL POSTERS]

[quote name='tommorichards' timestamp='1333230667' post='1599102']

I dont mind the veroboard stuff, but that is some strange looking stuff in the ebay listing....
[/quote]

Its great with op amps, use it like vero, but no need to cut the tracks

[tommorichards]

I suppose there is a use but you can't really cut it to a smaller size.

[BILL POSTERS]

[quote name='tommorichards' timestamp='1333240308' post='1599207']
I suppose there is a use but you can't really cut it to a smaller size.
[/quote]

Why not.?? Just needs a little imagination, and some side cutters, or if you prefer, a junior hacksaw.

You can buy smaller sizes, you can also get it without the screw holes.

[Ou7shined]

[quote name='Johnston' timestamp='1333314586' post='1600044']
Well just ordered up thebits for two Pres.

Standard Pre-[b]BB[/b] and a sabre on....
[/quote]

You'll need orange drops for those Boys Brigade ones.

[Al Heeley]

Hoiw cool would it be to fit 2 different circuit pre-amps in one bass then be able to toggle in between them?

[tommorichards]

Probably pretty cool.

also. did you remember that some were polarized?

[tauzero]

[quote name='tommorichards' timestamp='1332017215' post='1582245']
im planning on making my own sabre bass as i cannot afford a real one, so im using this preamp. The wire ive used to go to the controls is rubbish though as they keep snapping off the board, so ive ordered some copper wire for it.
[/quote]

You could use Veropins to do the connections rather than solder flying leads straight to the board.

[Ou7shined]

[quote name='tauzero' timestamp='1333377801' post='1600803']
You could use Veropins to do the connections rather than solder flying leads straight to the board.
[/quote]

Being a hoarder I make my own from the legs off old components which I can't bare to throw away once I've snipped the excess off. They come in handy for all sorts of solder jobs.

Edited April 2, 2012 by Ou7shined

[tauzero]

I use those bits for links, although I think a couple of moves and a total reorganisation of the electronics area have seen them off.

Edited April 2, 2012 by tauzero