Well, I tried a few things... I removed the JRC2043DD from the 1981 TS9 and installed it in my reissue TS9 (reissue has a chip socket so easy swap). This caused the reissue TS9 to behave and sound exactly like the 1981 TS9 did; a slightly gated and funky sound anytime the drive knob is at or near ma...

No improvement after changing out all the caps including the Tantalums. At this point I decided to unsolder the 2043DD and try it in my reissue ts9 which has a chip socket in it so it was an easy swap. Much to my surprise the 1981 JRC2043DD gave the same slightly gated sound at any drive setting abo...

I once repaired a vintage ts9, and I noticed this strange thing, that if you tighten too much (just a little, actually) the potentiometer's hex nut, the pot becomes hard to turn, as if the pot's structure itself was somehow deformed. So maybe the gain pot tests OK outside the box, but not when inst...

^easier, NOT easer... Man I wish there was a way to edit a post after submitting. No matter what, I always notice mistakes after I post.

No. This is not how they should sound and the opamp is in no way prone to be first suspect. Start off replacing all electrolits (including the NP's and the 0.22uF Tantalums) and move on from there. The experiment with a ESR and or capacitance meter is nice but tells little. Doing the measurement wi...

Hello, I found an awesome deal on a mint looking late 1981 or early 1982 Ibanez TS9. Owner still had the org. box! It does have the JRC2043DD op amp which some people think sounds bad but is correct for this era. I don't really subscribe to the idea that the op amps make that much difference, as lon...

These FS36999 transistors are really 2N5133; I just fixed a '73 Ramshead Big Muff that had a transistor that was partially printed as 2N5133 and partially FS36999 https://www.instagram.com/p/B6O7_ISnUuz/?utm_source=ig_web_button_share_sheet Thanks for sharing that!! Very cool find indeed. It has be...

A few years ago I posted the actual hfe of Q1-Q4 from a 1974 Rams Bead Big Muff with FS36999 transistors as measured using a Peak DCA55. They were: Q4: 163, Q3: 214, Q2: 171, Q1: 160. Since that time I've worked on three more pre-1975 Rams Head Big muffs. Two had FS36999 trannys and one had 2N5133 t...

This the circuit as it was before I changed the caps out.

Can you accurately measure transistor specs in circuit? I would think you would need to remove them from the circuit to get accurate measurements. Andrew. +1 Remove these from circuit to use the DCA Analyser. :wink: All components were removed from the transistors pcb traces for the measurements. P...

I bought this big muff as a fixer upper. Whoever owned it before me tried to put new pots on it and did a terrible job. They messed up the wiring so bad that when I first got it home, it wouldn't even work. I installed three new pots, fixed the wiring, played it and it sounded like crap. I then went...

I would like to start by saying my post here is purely informational in nature. I've had the chance to actually measure the hfe of the FS36999 transistors in a Rams Head Big Muff. It needed new pots and all new electrolytic caps. Only one of the org. pots came with the pedal and it was coded for 197...