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June 07, 2023, 09:02:29 AM

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Amplifier Discussion / Hartke HA5000 biasing
Last post by markorock37 - June 06, 2023, 02:29:18 PM
I have a HA5000 on the bench. After checking the bias at TP1 on both modules, I have one at 36mv and the other at 91mv. Anyone know what the recommended setting is for this amp?
Amplifier Discussion / Re: lab series l5 build workin...
Last post by FleshOnGear - May 28, 2023, 06:13:59 PM
Sounds like a very interesting project! I just started looking into the Lab Series recently, and I'm fascinated by the CA3094 distortion circuit. The clips of the amp that I've heard sound really good, so naturally I'd love to figure out how that distortion circuit works.

Typical op amp distortion usually sounds pretty bad, IMO, though a lot of players can make those circuits sound good in recordings. I just hate the fuzzy trails on the note decay that you usually get from simply overdriving a regular op amp. I've heard a few clips of the L5 where the player was at the edge of distortion and it sounded very natural. Definitely an impressive design!
Amplifier Discussion / Re: lab series l5 build workin...
Last post by Tassieviking - May 28, 2023, 10:42:19 AM
It sounds like the OP made his PCB's by using a printout of the original layout drawing and transferring the tracks to a PCB that he then etched himself.
If that is the case then he would end up with a fairly close copy of the original amp dimensions.
The original amp was 26 inches wide so the original PCB must have been over 24 inches wide (610mm), no wonder he made the PCB in 3 sections.

AIONFX has kits and bare PCB's to make a full L5 pedal minus the reverb, they also have kits for just the clean channel and just the drive channel.
If you don't want a pedal then it would be best to make a new PCB that incorporates the mod that AION made to change from the CA3080 and CA3094 IC's to a single LM13700 IC

I resized the original PCB's drawings to 150DPI approximately and ended up with this:
Amplifier Discussion / Re: lab series l5 build workin...
Last post by Crossfire845 - May 26, 2023, 05:35:57 PM
Quote from: elijahroberts199 on April 11, 2023, 09:43:56 PMStarted out with the schematic and the board layout shown. copied the layout in adobie photoshop . sized it so the op amp sockets would fit. made it in 3 pieces, channel 1, channel 2, and so on. using pnp blue transfer sheets. copied the power supply same way. sounds awesome!!!!!. fan on power supply was hooked to raw full wave diodes positive side and ground  1k resistor on the ground wire of fan. this way you eliminate fan noise into the supply otherwize youll get fan noise. antec 22volt/ 22volt transformer.
I'd be very interested in seeing more about your build. One of my main goals when starting to try to build amps was to eventually build my own L5
Schematics and Layouts / Re: Epiphone 100a Triggerman
Last post by Tassieviking - May 25, 2023, 05:28:34 AM
Schematics and Layouts / Epiphone 100a Triggerman
Last post by OldSchoolRock - May 24, 2023, 06:16:33 PM
I need a schematic for the Amp board in a Epiphone Triggerman 100H DSP. The board info is Firefly300SP Amp
Triggerman60/100HDSP Amp
All I really need is the value for  R219. This one is so burnt I can't read ring 1 and 2.
Amplifier Discussion / Re: Adding current feedback to...
Last post by FleshOnGear - May 23, 2023, 06:07:17 PM
I guess I never really detailed what exactly I was planning to do. Here's the schematic:

On the pcb, the negative side of the speaker wires and external speaker jack go through the headphone Jack, then there's one trace from the headphone jack that connects to the ground fill of the pcb. I cut the one trace and attached a 0.20 ohm 10W resistor from the sleeve tab of the headphone jack to ground. Originally planned on using a 0.22, but mouser was out of them.

From the connection of the 0.20 resistor and the headphone jack, I attached a 100uF cap, ran in series with a 220 ohm resistor, and wired that to the junction of R6 and R8. I changed R6 to 1k ohms. The 220 ohm resistor was originally a 330, but I replaced it with the lower value after a play test.

I will say the difference was not dramatic. The lows are definitely deeper, the highs were a bit more open. In addition to the power amp mod, I changed a couple values in the preamp to boost the treble and enhance the presence of the amp. Now it sounds quite to my liking.
Amplifier Discussion / Re: Adding current feedback to...
Last post by phatt - May 23, 2023, 05:30:41 PM
Great to hear it worked out well, thanks for the feedback as it will give others clues as to how to do such things.
Amplifier Discussion / Re: Adding current feedback to...
Last post by FleshOnGear - May 20, 2023, 09:32:46 PM
So, I went ahead and did the mod. It worked pretty well, and there aren't any stability issues. Thanks for letting me bounce these ideas off of you folks.
Amplifier Discussion / Re: Fender LT50 going for a ri...
Last post by g1 - May 18, 2023, 12:08:45 PM
Also, charity type thrift stores or youth drop-in centres would probably appreciate it.