Xotic - AC Booster [ goop-alarm ] [traced]
... the zipped eagle files cause someone asked for
- Attachments
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- xotic-ac-switch-to-rc-booster_v1.zip
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- xotic-ac-or-rc-booster.zip
- (57.8 KiB) Downloaded 292 times
Reference Low pass filter in diagram R8 (10K) and C4 (0.1uF)
viewtopic.php?f=7&t=503&hilit=xotic+AC+booster&start=40
The corner frequency for these combined values is 160Hz. This doesn’t look right and is probably accounting for the muddy sound as the treble is being attenuated.
You can check this yourself using the following link:
http://www.muzique.com/schem/filter.htm
If the 0.1uf cap (C4) is regarded as correct then ideally this should paired with a 1K (R8) to give a corner frequency of 1.5Khz, this should correct the problem.
viewtopic.php?f=7&t=503&hilit=xotic+AC+booster&start=40
The corner frequency for these combined values is 160Hz. This doesn’t look right and is probably accounting for the muddy sound as the treble is being attenuated.
You can check this yourself using the following link:
http://www.muzique.com/schem/filter.htm
If the 0.1uf cap (C4) is regarded as correct then ideally this should paired with a 1K (R8) to give a corner frequency of 1.5Khz, this should correct the problem.
Hi,sjwebb90 wrote:Reference Low pass filter in diagram R8 (10K) and C4 (0.1uF)
viewtopic.php?f=7&t=503&hilit=xotic+AC+booster&start=40
The corner frequency for these combined values is 160Hz. This doesn’t look right and is probably accounting for the muddy sound as the treble is being attenuated.
You can check this yourself using the following link:
http://www.muzique.com/schem/filter.htm
If the 0.1uf cap (C4) is regarded as correct then ideally this should paired with a 1K (R8) to give a corner frequency of 1.5Khz, this should correct the problem.
it seems that this is a reply to my question at german diy forum http://forum.musikding.de/vb/showthread ... post312502
Thanks lot ... and I am ashamed wondering why I didn't realize this by myself
Greets U.
- MullisMan
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I've taken the AC Booster schematic from madbeanpedals.com and breadboarded it, but I removed the input and output buffers. I've verified the wiring and checked all my voltage levels, but I'm getting a very low output signal. At full volume there's still a slight volume boost, but it's not like the actual AC Booster, which I own. I've tried three different IC's, the 4558, TL072, and the OPA2134, and all have the same volume issue. The tone stack works like it should, and I know that tone stacks can cause loss, but if the original works just fine why shouldn't this one? I've included the schematic to show what i'm working with. Any suggestions?
I can include voltage readings on the IC as well.
On pins 3 and 5 i'm getting 6.8 volts
Pin 8 I'm getting 9.46 volts
Pin 4 is 0
On the output pins and pins 2 and 6 I have 6.8 volts as well.
I can include voltage readings on the IC as well.
On pins 3 and 5 i'm getting 6.8 volts
Pin 8 I'm getting 9.46 volts
Pin 4 is 0
On the output pins and pins 2 and 6 I have 6.8 volts as well.
I want to build it all.
Hi,
2. VB is 4.5V so your RBIAS2 has to be a 22k
http://www.madbeanpedals.com/projects/Q ... Quasar.pdf
or my schematic there (R7 must be 1k):
download/file.php?id=10784&mode=view
U.
1. the gain potentiometer of the ac-booster should be a 500k logMullisMan wrote:I've taken the AC Booster schematic from madbeanpedals.com and breadboarded it, but I removed the input and output buffers. I've verified the wiring and checked all my voltage levels, but I'm getting a very low output signal. ...
2. VB is 4.5V so your RBIAS2 has to be a 22k
http://www.madbeanpedals.com/projects/Q ... Quasar.pdf
or my schematic there (R7 must be 1k):
download/file.php?id=10784&mode=view
U.
- MullisMan
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My mistake, I have a 500k potentiometer for the gain pot, that 100k pot was left over from a different schematic. I'm not sure what you mean when you say the Vbias is 4.5 volts, in your schematic and in the actual pedal there's a 22k and 6.8k voltage divider for the first stage of the Vbias. That works out to around 6.8 volts.
Also in your schematic, R7 should be a 1K, the 10K resistor is used in the RC Booster I believe, not jumpered. The capacitor C4 (0.1uF) creates a really low corner frequency with R7 when using a 10K that causes a lot of muddiness in your signal. The 1K resistor would make it around 1.5Khz.
I've corrected and re-uploaded my schematic, if a mod would like to delete my previous schematic post go ahead.
Also in your schematic, R7 should be a 1K, the 10K resistor is used in the RC Booster I believe, not jumpered. The capacitor C4 (0.1uF) creates a really low corner frequency with R7 when using a 10K that causes a lot of muddiness in your signal. The 1K resistor would make it around 1.5Khz.
I've corrected and re-uploaded my schematic, if a mod would like to delete my previous schematic post go ahead.
I want to build it all.
... and from the 6.8k another 15k is connect to ground so that you have 22k to +9V and 6.8k + 15k to ground for VB - makes +9V / 2MullisMan wrote:... in your schematic and in the actual pedal there's a 22k and 6.8k voltage divider for the first stage of the Vbias. That works out to around 6.8 volts. ....
R7 10k was not correct in the original schematic that ranmusic84 postet a few sides before in this topic:
viewtopic.php?p=22674#p22674
Here you can read about the correct value (1k) for R7 (R8): viewtopic.php?p=141270#p141270
For the RC-Booster R7 is jumpered.
- MullisMan
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Ok thanks I see now. I was disregarding the 15K resistor from the original bias. The original is a split Bias for the input buffer transistor and the opamp. My mistake. Now i'm getting a volume boost, but it still is bunched up at the end of the volume pot taper, past 1 o clock. On the AC Booster that I have, the volume knob is unity at around 10:30 or 11.
I want to build it all.
- MullisMan
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- Posts: 128
- Joined: 23 Feb 2010, 05:22
- my favorite amplifier: Dr. Z Maz 18 Jr.
- Completed builds: Timmy, Klon, Zendrive, King of Tone, Rat, BSIAB2, Riot!, Fuzz Factory, Coloursound Overdriver, Divided by 13 Joyride, 70 Fuzz, BBE Sonic Stomp, Big Muff PI, Xotic EP Booster, Lovepedal Eternity, Jack Orman Minibooster, Dynacomp/Ross/Keeley Compressor, SHO
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Well I tried that, I tried different resistors all the way down to 3.3K, and didn't have much of a change. But that was before I fixed some other problems, so maybe i'll try that again.
Thanks.
Thanks.
I want to build it all.
- MullisMan
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- my favorite amplifier: Dr. Z Maz 18 Jr.
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Yeah this isn't a standard TS configuration. The other input pin of the IC is already biased. I haven't had a chance to mess around with the circuit anymore and correct the Vbias network yet. Hopefully tomorrow i'll get to it.jymaze wrote:No, a resistor between C2 and R5 is not needed since it is an inverting opamp configuration. It would be needed in the non-inverting configuration though.
I want to build it all.
- fretzburner
- Breadboard Brother
I beleive using 10k resistor makes the sound muddy.Just converted my RC booster to AC specs with few parts replaced and before conversion sounds ok,after it is very muddy and very low output.Will try to change 10k to 1k.MullisMan wrote: Also in your schematic, R7 should be a 1K, the 10K resistor is used in the RC Booster I believe, not jumpered. The capacitor C4 (0.1uF) creates a really low corner frequency with R7 when using a 10K that causes a lot of muddiness in your signal. The 1K resistor would make it around 1.5Khz.
- IvIark
- Tube Twister
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Forgot this too, I need to keep things more uptodate!
"If anyone is a 'genius' for putting jacks in such a pedal in the only spot where they could physically fit, then I assume I too am a genius for correctly inserting my legs into my pants this morning." - candletears7 - TGP
built it on vero, sounds pretty good to me! only a couple of things, and it's probably outside the realm of what the original could provide, is a bit more gain/drive. also, i'm using it with a Fender Champion 600 at a fairly low volume, the bass control has a lot of range but the treble doesn't seem to get as bright as it seems like it should..... have to try it out on another amp.
is there anything i can do to get a bit more distortion?
is there anything i can do to get a bit more distortion?