solid-state tremolo for tube amps… abram, May 19, 2013July 27, 2020 i’ve have a CBS-era Fender Bantam Bass in for repair that looks like a bowl of spaghetti inside the chassis. it’s a slew of yellow wire spread from one side to the other that resembles the web of a drunken spider. the amp has been modified to include a tremolo,… Continue Reading
Ampeg Super Jet SJ-12T repair… abram, April 5, 2013August 24, 2016 I’ve seen a lot of the same complaints on various forums regarding these amps. Basically, the amp starts to get noisy and the occasional arcing can be heard through the speaker. The problem seems more exaggerated when using the tremolo circuit which is just a phase-shift LFO modulating the negative… Continue Reading
no. 5 re-appropriation… abram, February 16, 2013 this is a re-appropriation of a Fender Frontman 15-B. it’s one 8″ speaker in a closed cabinet primarily designed as a really cheap bass amp to be included in starter packs. having gutted the amp a few years ago and replaced it with the contents from the No. 5 tube… Continue Reading
5W single-ended EL84 amp (before) abram, November 22, 2012 insides of a Fender 15B solid-state bass amp that i gutted and converted into a simple tube circuit. i constructed this several years ago, and it’s not been very functional as of late. it definitely needs a better chassis ground, and i’d like to add in a switch for triode/pentode… Continue Reading
Carvin Pro Bass 200 iPod-Mod abram, November 15, 2012November 15, 2012 And here we have a solid 160W solid-state bass amp with an RCA input on the front. this amp was brought to me with the complaint of really low volume on the RCA input. upon further inspection, this definitely seemed to be true. a reasonable listening volume could be obtained… Continue Reading
Ampeg SVT-CL Repair abram, October 24, 2012November 15, 2012 here’s a 300 watt Ampeg SVT-CL that i had on the bench today. a much different kind of amp from the 70s models that i’ve been more accustomed to working on in the past. this one had no sound or output and the fault light would stay on constantly. i… Continue Reading
TDA2040-based amp schematic with EQ… abram, June 4, 2012 well here’s the first draft of the simplest medium powered solid state design i could muster. TL082 can easily be substituted with a TL072 which is probably better anyhow (i just have all these TL082s laying around). the power supply i’m using more like 14-15V. both ICs should easily be… Continue Reading
TDA2040 amp prototype… abram, May 24, 2012 prototype of a 20-watt TDA2040 based amplifier that i’ve been working on. running a 12-volt power supply and it’s surprisingly loud. Continue Reading
LM386-based “Esteli” demo by Alex Wilson abram, May 12, 2012 an older video, but one i’ve been wanting to post for some time. this is Alex Wilson of Son Cats playing on one of the several cigar-box amps i’ve constructed. this one, in particular, had one of the best sounds during the more work-with-what-is-available days. i thought the video was… Continue Reading