Search found 3253 matches

by bajaman
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...
by bajaman
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
complete.png
by 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...
by bajaman
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...
by bajaman
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...
by bajaman
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 ...
by bajaman
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
by 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
by bajaman
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...
by bajaman
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 ;-)
by bajaman
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
by bajaman
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...
by bajaman
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 ...
by bajaman
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
by 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 ;...
by bajaman
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 ;-)
by bajaman
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
by 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

Dsmnoisemaker wrote: 18 Oct 2023, 03:30 What a beautiful design 😉
pity it is on black pcb though :lol:
by bajaman
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 ;-)