Search found 195 matches

by george giblet
Today, 03:33
Forum: Electric Guitar Rewiring
Topic: Ibanez GSR200 Onboard Bass Preamp
Replies: 2
Views: 4984

Re: Ibanez GSR200 Onboard Bass Preamp

It's part of a gyrator (IC1B, R6, R9, C8). It looks like a 1.0H inductor in series with 1k (R9) and in parallel with 2.2M (R6) For this circuit you can ignore the 2.2M part. What you have is a 1H inductor in series with 1k and that's in series with C7 (4.7uF) and that forms a series resonant circuit...
by george giblet
07 Sep 2020, 23:04
Forum: Amplifiers
Topic: Peavey amp
Replies: 33
Views: 1789

Re: Peavey amp

I don't know what resistors or capacitors i would have to add or takeout to add the fx loop. You will need: 10uf electrolytic cap, 1M resistor, 47k resistor 2x 6.5mm Jacks, one with a normally closed switch contact. Using your VSS 20 schematic as reference, - Lift the negative terminal of C31 (2u2)...
by george giblet
07 Sep 2020, 00:00
Forum: Amplifiers
Topic: Peavey amp
Replies: 33
Views: 1789

Re: Peavey amp

Hey if I add a fx loop do u know were I would put it. After the post volume?
Checkout the Bandit 75 schematic, it actually has the FX loop.
by george giblet
06 Sep 2020, 00:10
Forum: Amplifiers
Topic: Peavey amp
Replies: 33
Views: 1789

Re: Peavey amp

It’s just weird why they would build a amp that u can’t have a tone stack on the gain channel. Don’t make no since. They could of least put a fx loop on it were u can run some kind of outboard eq. I suppose it all boils down to economy. The early 80's and 70's Peavey amps were mostly dual channel. ...
by george giblet
05 Sep 2020, 02:26
Forum: Amplifiers
Topic: Peavey amp
Replies: 33
Views: 1789

Re: Peavey amp

The other day played around with getting the Tone stack to have an effect in Gain mode. I tried a couple of things one was along the lines of tweaking the parts in the Supersat patent. A few conclusions we clear, 1) With the tone control it attenuates a good deal of the lower mids. 2) With the large...
by george giblet
02 Sep 2020, 05:05
Forum: Amplifiers
Topic: Peavey amp
Replies: 33
Views: 1789

Re: Peavey amp

Something occurred to me about the goal of getting a notched EQ. On the Peavey circuit the tone control is *before* the clipper, so even if we get the Tone control working in gain mode you probably won't get the notched sound you are looking for. For that you would need to add a notch circuit at the...
by george giblet
01 Sep 2020, 23:38
Forum: Amplifiers
Topic: Peavey amp
Replies: 33
Views: 1789

Re: Peavey amp

It’s a good amp got a good gain channel on it. Been nodding it to Try to get in the high gain territory. Sucks not having a tone stack on the gain channel can’t get a scooped sound. It should be possible to get the tone control in the signal chain. The problem is you want to get a scooped sound but...
by george giblet
31 Aug 2020, 06:03
Forum: Amplifiers
Topic: Peavey amp
Replies: 33
Views: 1789

Re: Peavey amp

I found some schematics of supersat era Peavey's. The two Audition schematics have the supersat-ish circuit but they don't have the switching or the 22k. The Bandit 75 is the Band in the supersat era. It has the 22k. (There is likely to be a Bandit 112 supersat after this model, I can't find the sch...
by george giblet
30 Aug 2020, 23:14
Forum: Amplifiers
Topic: Peavey amp
Replies: 33
Views: 1789

Re: Peavey amp

I haven't had a chance to look into this more deeply. The idea was to see what the manual said about the intended behaviour. Maybe it explains what it should do. From the manual, is the patent for the "Super Sat" circuit. It might explain some stuff. Normally values are given in the patent. The old ...
by george giblet
30 Aug 2020, 15:12
Forum: Amplifiers
Topic: Peavey amp
Replies: 33
Views: 1789

Re: Peavey amp

I notice that R27 is 22k,, holy crap man that will just kill the ability of tone controls. Well spotted. I don't get it. I've seen the C5+R7 thing before on Peavey amps and variations on other amps but I don't remember the low R27 thing. R27 is even a weird connection when SW1-B is to the left. Loo...
by george giblet
28 Aug 2020, 23:18
Forum: Amplifiers
Topic: Peavey amp
Replies: 33
Views: 1789

Re: Peavey amp

See discussion below and patent as this now seems incorrect - in fact it's opposite. Clean: SW1-A is open, SW1-B is to the right In clean mode the LEVEL pot is disconnect the U1A provides the gain control. The tone control operates normally. Gain: SW-1A is closed (9 to 11), and SW-1B is to left In g...
by george giblet
28 Aug 2020, 16:33
Forum: Modern Stompbox Effects (1975 - ...)
Topic: REAGUN DISTORTION traced
Replies: 4
Views: 596

Re: REAGUN DISTORTION traced

The 10n on the switch probably connects to the 1k and ground. The 2x220p connects to the 1k + 10n + 1M point.
by george giblet
28 Aug 2020, 02:51
Forum: Modern Stompbox Effects (1975 - ...)
Topic: Darkglass - Tone Capsule
Replies: 20
Views: 1819

Re: Darkglass - Tone Capsule

I checked the circuits using a python script. I attached the python script as a pdf. It's pretty rough but does the job. The results seem to match spice (frequency, dB) # verify 1kHz 12dB # results: # 975 12.496385024 # 980 12.4968431225 # 985 12.4962321445 # darkglass tone capsule 500Hz 12dB # resu...
by george giblet
27 Aug 2020, 23:52
Forum: Modern Stompbox Effects (1975 - ...)
Topic: Darkglass - Tone Capsule
Replies: 20
Views: 1819

Re: Darkglass - Tone Capsule

. Could you check your values please, and if everything is correct maybe check couple of values from here It worth checking for sure. I checked all I could and the simulation looks like it is working correctly. I also verified the opamp model. As a verification case I took these values: 100k pot 1M...
by george giblet
27 Aug 2020, 07:14
Forum: Modern Stompbox Effects (1975 - ...)
Topic: Darkglass - Tone Capsule
Replies: 20
Views: 1819

Re: Darkglass - Tone Capsule

We might get some idea of the value of C14. Based on the Tech 21 circuit, we might expect a value of 220nF but that only gives about 7.6dB peak at 63Hz. If we up the cap value to 680nF get 12dB (not peak) at 70Hz, and we see a peak of 14dB at 38Hz. We can't get a peak of 12dB at 70Hz unless we play ...
by george giblet
27 Aug 2020, 06:02
Forum: Modern Stompbox Effects (1975 - ...)
Topic: Darkglass - Tone Capsule
Replies: 20
Views: 1819

Re: Darkglass - Tone Capsule

Using the V1c schematic, C1 = C2 = 22n C9 = C10 = 47n C5 = 33p or 68p not sure. I haven't check this matches the specs but have some confidence the values are correct. The reason is dark glass often uses Tech21 tone controls. The Tech21 stuff uses 100k pots but the dark glass circuit use 50k pots, s...
by george giblet
27 Aug 2020, 03:51
Forum: Boutique Stompboxes dissected...
Topic: KMA - Tyler The Freq Splitter
Replies: 6
Views: 618

Re: KMA - Tyler The Freq Splitter

In order for the two band to add to a flat response when set to the same frequency you need an LR2 (Linkwitz-Riley Second order) Crossover. These have Q = 0.5 and a gradual crossover overlap. The reason for this assumption is the form of the high-pass filter, it has two equal resistor values. If we ...
by george giblet
27 Aug 2020, 02:06
Forum: Boutique Stompboxes dissected...
Topic: E.W.S Tri-Logic II Bass Preamp [traced]
Replies: 201
Views: 60792

Re: E.W.S Tri-Logic II Bass Preamp [traced]

Actually I'm using an older Firefox. The more I think about the EWS Tri-logic III the more I think the tone control is like the Xotic Bass RC, https://aionelectronics.com/blog/tracing-journal-xotic-ac-booster-rc-booster-and-bass-rc-booster/# The Tri-logic II uses a single opamp 3-band EQ but the Tri...
by george giblet
26 Aug 2020, 01:54
Forum: Boutique Stompboxes dissected...
Topic: E.W.S Tri-Logic II Bass Preamp [traced]
Replies: 201
Views: 60792

Re: E.W.S Tri-Logic II Bass Preamp [traced]

I couldn't see the pic. Here's a screenshot GG_parametric V1.0 screenshot.png FWIW, the parametric on the EWS Tri-logic III Bass Preamp is +/-10dB with a frequency range of 250Hz to 3kHz. The closest match parts are, C1 = 5n6 C2 = 5n6 which gives +/- 9.5dB and a frequency range of 260Hz to 2.8kHz. T...
by george giblet
24 Aug 2020, 06:26
Forum: Boutique Stompboxes dissected...
Topic: E.W.S Tri-Logic II Bass Preamp [traced]
Replies: 201
Views: 60792

Re: E.W.S Tri-Logic II Bass Preamp [traced]

Regarding the final/not final versions, there were two different circuits traced and analysed. How can the second be the completion of the first? The non-parametric is definitely the one analysed in this thread. I am quite certain John K's parametric version is his own spin on the EWS trilogic III....