An EBS FAFNER rolled into my hands for repair. The power amplifier appears to be fried. Since no schematics are available, I'm trying to reverse-engineer the relevant sections to identify the broken- and suspect components. The speaker leads had -48V DC on them (that's half the supply voltage!) and one diode seems to have exploded. I'll draw up a schematic this week and would really appreciate some advice. This is just a warm-up post I guess, the real work starts when the schematic...
Dud… :scratch:
I m working on building amplifier based on TDA2822 which receives input from my phone and feeds them into a small 2″ speaker provided by 9 v battery.
I connected the circuit but am not understanding 1 thing…
I bought a new earphone and removed its wires..(cause such wires are not available in my area) then i stripped the insulation of left earphone. I got tho wires inside.
I m not understanding where to connect those wires to input of amplifier …. So please comment on how to...
I'm working up a design for a 2xLM380 bridged practice amp. Planning to run it at 18v, so I'm expecting to need some kind of heatsink for each chip.
Questions:
-Is it a sure thing the chips will need a heatsink running at 18v?
-Anyone have a design or source for one? I'm pretty much a complete newb at making/attaching heatsinks since until now I've really only used your standard pedal design ICs and LM386's.
Would a large ground plane attached to the heatsink pins of the LM380 do...
So i tried a vox AC15C1 yesterday and ... i liked the normal channed and LOVED the top boost channel....
I'm wondering if i could combine that, and my interest in learning to build tube amps (building the madamp J5 kit at the moment, no other experience in amps, made 30 or so pedals).
In fact, i thought about it because i heard that vox amps are basically super simple, but the tremolo section makes it complicated... and i'm not interested in the tremolo so it soudns like a potentially...
Ordering the beefed up Output transformer from Allen tomorrow but still don't know what choke to order for it. Anybody know what choke I should get for the Z 28?
I would like to know if there is a safe way to switch between 2 guitar cabinets?
I'm using a 60W tube (fender style amp) and I would like to build an A/B (or even A+B) (foot)switcher box to chose between 2 cabinets (Both 8 ohm).
I know the Radial box but it's way too expensive for me.
I've heard of a switcher that uses relays, but I haven't got any clear information.
I've also read about a passive box with resistors and a switch but it's not exactly what I was thinking since it's working only...
I came across one of these rare beast at Music Go Round and at first I was like what's with this unholy black beast. When I plugged in a Les Paul into it boy was I wrong. The cleans made a Fender Twin Reverb cry in shame and the second channel, man it made me wanna punch a hole in the wall. It was frickin sick man, in my opinion its the 5150s half brother and makes the 6505 cower in fear. Anyone else out there own or played this rare black beast of an amp ? It'd be nice to hear more about this...
Is there a way to build a good DI BOX like (THE JUNCTION by PALMER or the RADIAL one) for tube amps? Any schematic or layout available?
I need it in order to avoid the cabinet for easy home recording of my 60w tube amp head, without the cabinet at line out levels.
I've been meaning to post these up for awhile, but never got around to it. I was packing stuff up today for the big move this weekend and I found my old notes I used for building these when I worked at Weber. So I figured I'd formally draw up the schematics to share.
Now, you have to keep in mind, Weber has changed the design of these things numerous times already, so these might not match exactly with any random one you may find and it's not necessarily like the current ones (though I'm not...
Hi I have one of these amps (warranty is not transferable internationally :( ) and I have a guy who is more than capable of working on it (over the last 20 years he has worked with all the Marks, Stiletto, SOB, Triaxis and a Lone Star Special). He has a few good mods in mind for it but is reluctant to work on it without a schematic. We have looked everywhere to no avail, so I thought I might try my good friends here. :secret:
Its a long shot I know but it's all I got left :slap:
I am dealing with an Orange Micro Terror where the headphone jack has been removed in an attempt to replace it. In the process of desoldering the jack it looks like the copper pads and traces were damaged. I don't have a lot of experience with PCB or PCB board repair, so before I start trying to fix this I was wondering if it would be better to try to bypass the headphone jack completely in the circuit or try to repair the PCB connection and put a headphone jack in.
I've a Bassman aa864 and the guitar channel make hum thru the speaker and I have'nt any guitar sound. The hum interacts with the volumen pot, if I pull of the V3 valve the hum disapear. The bass channel Works well.
I'm build a Bassman aa864 head, and I read that some people convert the bass side to a marshall style channel. Anybody knows something about this? any shematic?
I have read that it is Deluxe based, and the circuit uses 2 12AX7's and 2 6V6's to give 11 Watts and has a Volume, Treble, Bass and Master Volume configuration.
I am guessing then , that it is cathode biased with a cathodyne PI and the first 12AX7 is cascaded and uses a VOX Top Boost tone stack probably between the first pre amps.
As we all know there are more and more new amps that are using hybrid tube+ss PA. We have orange micro series, joyo bantamp series amp and some other amps that share this technology.
I'm searching for some good chip power amp and buffer section that will work good with tubes and jfets for testing purposes and playing at home, 20W will be ok.
I have see pictures of the orange pcb and it use sta540, but cant find any guts of joyo bantamp pcb.
I've owned a Marshall Valvestate 8080 for 15 years or whenever they came out but only played it for a bit and shelved it.
Should've known better myself but after not being turned on for more than a decade first thing I should've done is change those caps in the power supply(I'm assuming that's what went wrong ).To make a long story short I turn on the amp and start playing and about 20min to half hour later the volume just cuts off,the fuse did not blow,pilot light still on and no fireworks or...
It was absolutely impossible to find a schematic of this footswitch. I had to figure out the circuit myself. Just in case someone else might need it...
Hi,
I finished a small amp based on the AC4 build here>
Just used one half of the 12ax7 as another preamp stage.
The preamp stages are switched by the jacks, giving the four different configurations. Not an AC4 anymore, but still with the character of the EF86.
The cab came from an old transistor amp, I added the 10 speaker, the grill cloth and a new faceplate.
So guys has anyone else wanted to know about it?
I think it could be a great addition for us Diy'ers who love pedals. Kinda a whole rig setup all thats needed would be a cab. I think. Is anyone working on it? Does anyone have one?
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