Search found 79 matches
- 20 Jan 2022, 16:16
- Forum: Boutique Stompboxes dissected...
- Topic: Analogman - King of Tone [traced]
- Replies: 465
- Views: 240184
Re: Analogman - King of Tone [traced]
Who would have thought there's be a necro post in the infamous KoT thread :o Anywho, I did some more plots on KoT diodes, expanding specifically the 1S1588. I had three different "styles" of (allegedly) 1S1588 in my collection, which I will refer to as "big", "mid", and...
- 21 Jul 2021, 16:50
- Forum: Boutique Stompboxes dissected...
- Topic: Hagerman Amplification (schematics)
- Replies: 9
- Views: 2271
Re: Hagerman Amplification (schematics)
I was wondering when I was going to see someone using those hammond flanged enclosures
- 13 Feb 2021, 03:05
- Forum: Boutique Stompboxes dissected...
- Topic: Benson - Germanium Fuzz [traced]
- Replies: 21
- Views: 8357
Re: Benson Germanium Fuzz [traced]
Curiosity got the better of me...
Tested with Peak DCA75.
Q1
hfe: 98
leak: 20uA
Q2
hfe: 79
leak: 82uA
Q1 is marked 2N527 BSC2040
Q2 is marked 2N527SEL2049
Tested with Peak DCA75.
Q1
hfe: 98
leak: 20uA
Q2
hfe: 79
leak: 82uA
Q1 is marked 2N527 BSC2040
Q2 is marked 2N527SEL2049
- 11 Feb 2021, 12:42
- Forum: Boutique Stompboxes dissected...
- Topic: Benson - Germanium Fuzz [traced]
- Replies: 21
- Views: 8357
Re: Benson Germanium Fuzz [traced]
There's something kinda fun about the benson concept though, like sure, just slap couple hot resistors on there with some thermal paste. Done.george giblet wrote: ↑11 Feb 2021, 06:12
John Hollis's Rock Face (2001) tries to achieve a similar goal but with less power,
http://www.hollis.co.uk/john/rockface.jpg
- 11 Feb 2021, 03:48
- Forum: Boutique Stompboxes dissected...
- Topic: Benson - Germanium Fuzz [traced]
- Replies: 21
- Views: 8357
Re: Benson Germanium Fuzz [traced]
The collector voltage is floating right around -4.2V, obviously fluctuating as the heating circuit turns on and off. You can goop over the power resistors and Ge transistors with polyurethane sealant or other non corrosive compound, in order to have more thermal mass and increase the on time and in...
- 11 Feb 2021, 02:07
- Forum: Boutique Stompboxes dissected...
- Topic: Benson - Germanium Fuzz [traced]
- Replies: 21
- Views: 8357
Re: Benson Germanium Fuzz [traced]
A couple observations; To confirm a couple earlier calculations, the V- is right about 8V, and the threshold voltage at pin 2 is ~1.83V. The collector voltage is floating right around -4.2V, obviously fluctuating as the heating circuit turns on and off. The pots are marked "keeley", sugges...
- 11 Feb 2021, 00:05
- Forum: Boutique Stompboxes dissected...
- Topic: Benson - Germanium Fuzz [traced]
- Replies: 21
- Views: 8357
Re: Benson Germanium Fuzz [traced]
If the battery voltage stays constant, it's sort of a temperature control in that it is using collector voltage vs temperature to control the heating. However, if the battery voltage changes it also try to keep the collector voltage to some ratio of the supply. Not quite as the buffer base-emitter ...
- 10 Feb 2021, 15:31
- Forum: Boutique Stompboxes dissected...
- Topic: Benson - Germanium Fuzz [traced]
- Replies: 21
- Views: 8357
Re: Benson Germanium Fuzz [traced]
Good stuff Jose and George. I understand the concept here, that temperature regulation isn't inherently the purpose of the warming circuit, but because germaniums are so temperature sensitive, holding the trans at a relatively constant temperature is necessary to stabilize the bias point, and theref...
- 10 Feb 2021, 00:21
- Forum: Boutique Stompboxes dissected...
- Topic: Benson - Germanium Fuzz [traced]
- Replies: 21
- Views: 8357
Re: Benson Germanium Fuzz [traced]
A100k seems like a good value for input resistance (impedance) and for the volume pot but it is completely useless for a gain/fuzz pot. I see there's a B1k pot in the picture of the actual pedal. That would make an excellent gain/fuzz pot. Maybe you can check and update the schematic. Thanks for tr...
- 09 Feb 2021, 18:46
- Forum: Boutique Stompboxes dissected...
- Topic: Benson - Germanium Fuzz [traced]
- Replies: 21
- Views: 8357
Re: Benson Germanium Fuzz [traced]
I'm not slick enough to understand the warming circuit, but it looks similar to these thermostat designs: http://www.craig.copperleife.com/tech/thermo/ Maybe someone more technically adept can explain. Also the schematic is unverified. I just moved house and am a bit scatterbrained, might have misse...
- 09 Feb 2021, 02:26
- Forum: Boutique Stompboxes dissected...
- Topic: Benson - Germanium Fuzz [traced]
- Replies: 21
- Views: 8357
Re: Benson Germanium Fuzz [traced]
UPDATE #1: Fixed gain pot value from A100K to B1K
- 08 Feb 2021, 17:05
- Forum: Boutique Stompboxes dissected...
- Topic: Benson - Germanium Fuzz [traced]
- Replies: 21
- Views: 8357
Benson - Germanium Fuzz [traced]
Working on a schematic now
It's a fuzz face, but with an interesting heating circuit using a pair of carbon comp resistors.
It's a fuzz face, but with an interesting heating circuit using a pair of carbon comp resistors.
- 21 Nov 2020, 11:45
- Forum: Boutique Stompboxes dissected...
- Topic: Monster Effects - Mastortion
- Replies: 7
- Views: 3944
Re: Monster Effects - Mastortion
yep. To be fair, I think they admitted as much.
- 21 Nov 2020, 04:13
- Forum: Boutique Stompboxes dissected...
- Topic: Monster Effects - Mastortion
- Replies: 7
- Views: 3944
Re: Monster Effects - Mastortion
Picked up one of these on Reverb as "not working".... seems fine to me :) Enjoy! Image gallery EDIT: I was staring at the schematic, trying to wrap my head around why there's a fudgin' FWBR in there. I knew there must have been something I missed. See updated schematic. Polarity protection...
- 17 Nov 2020, 04:04
- Forum: Boutique Stompboxes dissected...
- Topic: JHS Prestige
- Replies: 9
- Views: 4841
- 13 Nov 2020, 11:54
- Forum: Amplifiers
- Topic: Requesting Laney Klipp circuit analysis.
- Replies: 6
- Views: 2670
Re: Requesting Laney Klipp circuit analysis.
Hi turbofeedus, That schematic looks "almost" like other Hiwatt amps, but the difference lies in the second preamp tube and associated components that are arranged to create insane amounts of distortion. Cheers, Jose Ohhh I see, that's weird I could have sworn the klipp thing was a separa...
- 08 Nov 2020, 23:14
- Forum: Amplifiers
- Topic: Requesting Laney Klipp circuit analysis.
- Replies: 6
- Views: 2670
Re: Requesting Laney Klipp circuit analysis.
Been slowly getting around to learning how to draw load lines and all the stuff related to tube charts but I was wondering how the Klipp circuit on the Laney Klipp amp works. I got an idea how the bypass is executed but I was wondering what is going on in the Klipp tube stage that creates the hybri...
- 28 Oct 2020, 00:50
- Forum: Parts & Tools Sourcing & Trading
- Topic: BF245A ebay testing
- Replies: 0
- Views: 1940
BF245A ebay testing
After some success with the 2SK117, I wanted to push my luck. Obsolete JFETs are still on the menu, this time some (allegedly) Fairchild BF245A ( datasheet ). ebay item link: https://www.ebay.com/itm/284031825834 ebay seller xripley from Czech Republic: https://www.ebay.com/usr/xripley From a batch ...
- 18 Oct 2020, 01:47
- Forum: Boutique Stompboxes dissected...
- Topic: smallsound/bigsound - mini [traced]
- Replies: 51
- Views: 34655
Re: smallsound/bigsound - mini [traced]
This article is a good read for anything regarding JFET amplification.
http://runoffgroove.com/fetzervalve.html
http://runoffgroove.com/fetzervalve.html
- 16 Oct 2020, 05:00
- Forum: Boutique Stompboxes dissected...
- Topic: smallsound/bigsound - mini [traced]
- Replies: 51
- Views: 34655
Re: smallsound/bigsound - mini [traced]
Hello! Just built the ssbs mini and it’s sounds awesome ... ! .. except that I cant get the bias pot and trim to work properly. The lowest voltage on the 5457 drain I can muster is approx 5v via the trim.. the bias pot also only has a 2v range (max is 7v min is 5v). It’s making some difference alth...