Search found 3253 matches
- Yesterday, 00:01
- Forum: Modern Stompbox Effects (1975 - ...)
- Topic: Tech21 - SansAmp classic
- Replies: 72
- Views: 32072
Re: Tech21 - SansAmp classic
Another small update - on the original traced schematic attributed to an unknown Japanese author, there is a attenuator network after the amplifier drive stage opamp consisting of two 100k resistors. I changed the bottom leg to 22k to further attenuate the signal (the sansamp PSA-1 uses a 10k and 2k...
- 17 Mar 2024, 06:43
- Forum: Boutique Stompboxes dissected...
- Topic: Tech21 SansAmp PSA-1 PCB traces and schematics [traced]
- Replies: 66
- Views: 72758
Re: Tech21 SansAmp PSA-1 PCB traces and schematics [traced]
agung asked me what schematic I used to build my pedal version - this is a snippet i saved of the schematic i used in multisim (up to probe PR11)
It may be helpful for others so i am posting it here
cheers
bajaman
It may be helpful for others so i am posting it here
cheers
bajaman
- 16 Mar 2024, 23:31
- Forum: Modern Stompbox Effects (1975 - ...)
- Topic: Tech21 - SansAmp classic
- Replies: 72
- Views: 32072
Re: Tech21 - SansAmp classic
Okay - it is an old thread and even older design, but I thought I would have a go at building another one of these with a slightly different layout. i ended up using a TL072 followed by a MC33179 in my final build (images show MC33178 which did not work properly when engaging the low drive and clean...
- 13 Mar 2024, 07:49
- Forum: Boutique Stompboxes dissected...
- Topic: Tech21 SansAmp PSA-1 PCB traces and schematics [traced]
- Replies: 66
- Views: 72758
Re: Tech21 SansAmp PSA-1 PCB traces and schematics [traced]
Here is a graph showing the response after each opamp, from the first preamp gain stage up to the send socket. This is with all the controls set to midway - you can see the extent of the heavy low pass filtering involved in this design (PR1 to PR11) The left side shows the response in 3dB increments...
- 12 Mar 2024, 06:36
- Forum: Boutique Stompboxes dissected...
- Topic: Tech21 SansAmp PSA-1 PCB traces and schematics [traced]
- Replies: 66
- Views: 72758
Re: Tech21 SansAmp PSA-1 PCB traces and schematics [traced]
My simplified build in a Tayda 1590BB enclosure - Left out the extra line level input and took the output directly from the send. I had a stash of MC33179 quad opamps, so used them instead of TL074s - sounds good to my ears although i have never heard a real PSA-1 The sound is still there when the l...
- 23 Feb 2024, 23:48
- Forum: Boutique Stompboxes dissected...
- Topic: Tech21 SansAmp PSA-1 PCB traces and schematics [traced]
- Replies: 66
- Views: 72758
Re: Tech21 SansAmp PSA-1 PCB traces and schematics [traced]
There are still some wrong bits to the puzzle ;-) There is no 47n followed by a 100k to ground between U9a and U9b in the "secret" section - U9a output connects directly to U9b input ;-) I wonder what those 14 pin devices with the sanded tops are - they appear to be supplied by the +5 and ...
- 13 Feb 2024, 20:21
- Forum: Boutique Stompboxes dissected...
- Topic: Bogner - Harlow Compressor (gut shots) [traced]
- Replies: 33
- Views: 45868
Re: Bogner - Harlow Compressor (gut shots) [traced]
the turns ratio or impedance ratio of the transformer transformer still needs to be deciphered
excellent work
cheers
bajaman
excellent work
cheers
bajaman
- 13 Feb 2024, 09:54
- Forum: Boutique Stompboxes dissected...
- Topic: Bogner - Harlow Compressor (gut shots) [traced]
- Replies: 33
- Views: 45868
Re: Bogner - Harlow Compressor (gut shots) [traced]
The bjt transistors are most likely MMBT4401 type and the jfet MMBF5457
- 12 Feb 2024, 22:57
- Forum: Boutique Stompboxes dissected...
- Topic: Bogner - Harlow Compressor (gut shots) [traced]
- Replies: 33
- Views: 45868
Re: Bogner - Harlow Compressor (gut shots) [traced]
wow - excellent work here my guess is that the fet is a BF245A smd equivalent (https://www.onsemi.com/pdf/datasheet/bf245a-d.pdf) The vgs and idss fall into line with this device and it was the jfet used in the classic Urei 1176 studio compressor I would think any small signal NPN transistors with a...
- 24 Jan 2024, 06:58
- Forum: Modern Stompbox Effects (1975 - ...)
- Topic: Ibanez AD-80 issue
- Replies: 2
- Views: 501
Re: Ibanez AD-80 issue
I would check all the low voltage electrolytic capacitors - the 10v and 16v ones are prone to failure
- 18 Jan 2024, 10:37
- Forum: DIY Projects
- Topic: I can't find information about this blues driver anywhere
- Replies: 5
- Views: 819
Re: I can't find information about this blues driver anywhere
looks Russian - perhaps ask on a Russian site - definitely not a Boss pedal - lol
- 04 Jan 2024, 19:42
- Forum: DIY Projects
- Topic: Baja Music Man guitar and bass onboard preamps [documentation]
- Replies: 503
- Views: 177733
Re: Baja Music Man guitar and bass onboard preamps [documentation]
that should work fine too
- 31 Dec 2023, 03:40
- Forum: DIY Projects
- Topic: Blue Pilot, an integrated Blues Driver
- Replies: 18
- Views: 5654
Re: Blue Pilot, an integrated Blues Driver
nice design Dylan ;-) I love the use of the gyrator to recover some bottom end which inevitably has to be reduced in drive pedals to prevent "farty" bass On the subject of the TL072, i have noticed some really bad crossover distortion in some I purchased from Ali-Express - moral: ALWAYS bu...
- 11 Dec 2023, 21:58
- Forum: DIY Projects
- Topic: Baja Presence and Resonance 091118 [documentation]
- Replies: 44
- Views: 45721
Re: Baja Presence and Resonance 091118 [documentation]
Hi and thanks for the question The Baja Reactor design was conceived a couple of months later than the Baja Presence and Resonance pedal and was an attempt to incorporate the actual vacuum tube power amplifier output stage into the mix. Yes, they are different implementations of the same basic idea ...
- 12 Nov 2023, 20:08
- Forum: Pedal Debugging & Troubleshooting Support
- Topic: Aion Oceanid (Cornish OC-1) Volume Problem
- Replies: 4
- Views: 707
Re: Aion Oceanid (Cornish OC-1) Volume Problem
all those voltages look ok to my eyes, so maybe a faulty resistor value - i would check R11 and R12 around IC1a - this seems the most likely place to start looking for increased gain
good luck
bajaman
good luck
bajaman
- 12 Nov 2023, 10:09
- Forum: DIY Projects
- Topic: Baja low noise low current drain bass guitar preamp 121218 [documentation]
- Replies: 45
- Views: 26886
Re: Baja low noise low current drain bass guitar preamp 121218 [documentation]
the loading resistor is there to dampen the resonant peak in the pickup's response - usually around 2- 3KHz. This has the effect of smoothing out the high end response of the pickup. You can try experimenting with any value between 100k and 500k (perhaps use a trim pot to zone in on the sweet spot ;...
- 10 Nov 2023, 20:16
- Forum: DIY Projects
- Topic: Baja low noise low current drain bass guitar preamp 121218 [documentation]
- Replies: 45
- Views: 26886
Re: Baja low noise low current drain bass guitar preamp 121218 [documentation]
Don't forget to add a loading resistor (220k) before C1 to gnd
- 04 Nov 2023, 20:56
- Forum: DIY Projects
- Topic: Baja Presence and Resonance 091118 [documentation]
- Replies: 44
- Views: 45721
Re: Baja Presence and Resonance 091118 [documentation]
DC73 - go back to the first page in this thread - post #17 and #18 show the pcb and build for my design, and yes, pcb's are still available - just email me: baja002steve@gmail.com
I do not have the pcb that Herdiss designed - perhaps contact him if you want his particular pcb
cheers
bajaman
I do not have the pcb that Herdiss designed - perhaps contact him if you want his particular pcb
cheers
bajaman
- 18 Oct 2023, 05:39
- Forum: Boutique Stompboxes dissected...
- Topic: DSM and Humboldt Simplifier Bass Station
- Replies: 8
- Views: 1978
Re: DSM and Humboldt Simplifier Bass Station
pity it is on black pcb though
- 25 Sep 2023, 23:10
- Forum: Pimp-My-Cheap-Pedal
- Topic: Behringer Ultra Chorus UC200 Rehouse Issue
- Replies: 6
- Views: 1356
Re: Behringer Ultra Chorus UC200 Rehouse Issue
replace the led and see if that fixes it