Xotic - BB Preamp [traced]
- chicago_mike
- Tube Twister
lm353 or lf353 or something like that. Not your everyday tl072
I'll be building these for bass and will use opa 2134's I think. I really like those.
The npn/pnp's though Im not sure whats used there.
I'll be building these for bass and will use opa 2134's I think. I really like those.
The npn/pnp's though Im not sure whats used there.
Skyline FX 2013
- mrkaploca
- Breadboard Brother
what about the output transistor here?+4,5V is not connected to base but to emmiter???darkglass wrote:Hello, Im posting one layoout I designed with eagle for the BB Preamp, I used the schem traced by KHE founded in this forum...
So here it is!
Schem
http://darkfinn.googlepages.com/BBSchem.jpg
Layout
http://darkfinn.googlepages.com/Layout.jpg
And PCB
http://darkfinn.googlepages.com/BBPreampPCB.pdf
This layout is not verified though, I finished it yesterday, but Im quite sure it should work.
Best Regards
Douglas.
Enjoy
- Silent Fly
- Resistor Ronker
I am not convinced by the Q2 connections either...
"Remember - all I am offering is the truth, nothing more". Morpheus
- mrkaploca
- Breadboard Brother
I tried this version,not working.I fixed output transistor pinouts(original are not correct,Va should go to base not emmiter,and emmiter to ground.)but still doesnt work.does anybody have working layout??darkglass wrote:Hello, Im posting one layoout I designed with eagle for the BB Preamp, I used the schem traced by KHE founded in this forum...
So here it is!
Schem
Layout
And PCB
http://darkfinn.googlepages.com/BBPreampPCB.pdf
This layout is not verified though, I finished it yesterday, but Im quite sure it should work.
Best Regards
Douglas.
Enjoy
- Silent Fly
- Resistor Ronker
The bias of Q2 doesn't look right. As a test, I suggest you try pick up the signal from terminal 2 of the LEVEL potentiometer. If you hear a sound it's Q2. The connections of IC2A also look wrong.
I would recommend you have a look to this version.
I would recommend you have a look to this version.
"Remember - all I am offering is the truth, nothing more". Morpheus
- mrkaploca
- Breadboard Brother
yes but I am realy bad in layout designing so I ask if somebody has working layout.I have a gig in france for 6 days and I realy need to finihs it till then!!!!!!!!HELPSilent Fly wrote:The bias of Q2 doesn't look right. As a test, I suggest you try pick up the signal from terminal 2 of the LEVEL potentiometer. If you hear a sound it's Q2. The connections of IC2A also look wrong.
I would recommend you have a look to this version.
- mrkaploca
- Breadboard Brother
OK,I ve built this version,engaged it and all I got is a HUM.Every pot is responding,difference can be heard when I turn gain pot,bass,treble,and the volume increases,but ll that is comming out is a hum sound no metter what you play(no distortion,no nothing).What could be the problem??
Thnx!!
- mrkaploca
- Breadboard Brother
No,that's not the case,I rechecked all the paths.What else causes only hum sound.Transistors must be ok soldered or else there wouldn't be any sound at all??IC's????Someone help!!madbean wrote:Re-flow your solder. You might have a solder bridge somewhere.
- modman
- a d m i n
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You used a layout that somebody said was/you hope is verified. In that case and in fact always, you should check your build against a correct schematic or use the Audio Probe to trace your guitar signal.mrkaploca wrote:No,that's not the case,I rechecked all the paths.What else causes only hum sound.Transistors must be ok soldered or else there wouldn't be any sound at all??IC's????Someone help!!madbean wrote:Re-flow your solder. You might have a solder bridge somewhere.
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- TheLemon
- Breadboard Brother
You might have a grounding issue, maybe a connection missedmrkaploca wrote:OK,I ve built this version,engaged it and all I got is a HUM.Every pot is responding,difference can be heard when I turn gain pot,bass,treble,and the volume increases,but ll that is comming out is a hum sound no metter what you play(no distortion,no nothing).What could be the problem??
Thnx!!
Hmm, my bb is working fine with this layout i made....
Hum sounds like a ground problem. Check the power filtering diode going to ground - orientation!
Check the schematics kusi posted - i made layout after that one.
And also check the transistors - try 2n5088 or 2n3904.
Hum sounds like a ground problem. Check the power filtering diode going to ground - orientation!
Check the schematics kusi posted - i made layout after that one.
And also check the transistors - try 2n5088 or 2n3904.
- mrkaploca
- Breadboard Brother
I changed 2sc1815 transistors to 2n5088 and I finally made it work.Everything works fine except when I increase the gain potentiometer-then there is alot of background noise(hum)present .It can not be heard when I play but when I stop a noise appears.On a very low gain values it's ok.I put 1M log pot instead of linear one and I put 20k resistor(on the second gain stage of the first IC)instead of 19k.Can that cause the problem?Da Cat wrote:Hmm, my bb is working fine with this layout i made....
Hum sounds like a ground problem. Check the power filtering diode going to ground - orientation!
Check the schematics kusi posted - i made layout after that one.
And also check the transistors - try 2n5088 or 2n3904.
Sorry guys I torture u but I wanna make it right ,I really like the sound of bb preamp!!!
thnx!!!!
- mrkaploca
- Breadboard Brother
So guys what could be the fault??increasing the gain pot a background noise (hum)appears!!!!mrkaploca wrote:I changed 2sc1815 transistors to 2n5088 and I finally made it work.Everything works fine except when I increase the gain potentiometer-then there is alot of background noise(hum)present .It can not be heard when I play but when I stop a noise appears.On a very low gain values it's ok.I put 1M log pot instead of linear one and I put 20k resistor(on the second gain stage of the first IC)instead of 19k.Can that cause the problem?Da Cat wrote:Hmm, my bb is working fine with this layout i made....
Hum sounds like a ground problem. Check the power filtering diode going to ground - orientation!
Check the schematics kusi posted - i made layout after that one.
And also check the transistors - try 2n5088 or 2n3904.
Sorry guys I torture u but I wanna make it right ,I really like the sound of bb preamp!!!
thnx!!!!
Hi!
Could be bad filtering of the power supply --> try with battery.
Could be hum pickup from external source like mains wire, transformers, lighting..... either through guitar pu's or circuitry.
Is the circuit shielded/in a box?
Hope this helps some!
Timo
Could be bad filtering of the power supply --> try with battery.
Could be hum pickup from external source like mains wire, transformers, lighting..... either through guitar pu's or circuitry.
Is the circuit shielded/in a box?
Hope this helps some!
Timo
- diggum12
- Solder Soldier
Has anyone tried this without the buffers? I may try it this weekend if I get time.
"Now we cheer if someone get's a tweed champ working. I feel like the future was here and we traded it away for trinkets." -diagrammatiks
ayayay! on the other site
ayayay! on the other site