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Messages - Puguglybonehead

Great thread! Thank you for sharing your progress. I hadn't realized that the Pathfinder 10 was such a simple circuit and  all thru-hole to boot. Wishing I'd kept mine now. Eliminating that ridiculous 'Boost' section is a great idea. I never found it to be realistically useable. I'd thought about re-homing mine in a new cabinet with a decent speaker (8"or 10") but never got around to it.

At 18 watts you've got the perfect amp for small club gigs. Currently, that's mostly what there is around here. (besides some occasional busking) Hipsters in our neighborhood want wallpaper music to hang out to so little amps like this are really useful. I hope you'll have some sound samples for us in the near future.
At this point I'm switching to building something for guitar. (and maybe vocals) Going to put the TDA2003 board to good use, I hope.
Still haven't made progress with this project yet due to being sidetracked with other problems. I've decided that building a busking amp for just the guitar or maybe guitar and vocals would be a better approach for now.

I was considering using this Blues Breaker pedal kit as a guitar preamp. (I like the sound)

I already have a premade TDA2003 board around that I could use for a power amp.

Or I could go with this TPA3122 kit to have a channel for guitar and a channel for a mic.

I was just wondering if I would need a buffer between the Blues Breaker and the power amp board?
Thanks for the advice on the TPA3116D2 and the TPA3122D2N. I will definitely look into those. If I use it with a trimpot controlling output I should be able to conserve battery life and avoid ugly clipping as well, no? I will probably use the TDA2003 module I have here for just a guitar amp. 4 watts with a good speaker and a good preamp should be enough for guitar alone.
Thanks for the advice. I'll definitely keep searching for ideas. I would just go out and buy a ready made system but I'm not liking the look of most of what's out there. Speakers are always too small (for bass) and usually too few inputs. A mixer section is definitely something I'm thinking of. Possibly adding a reverb for vocals as well. As for power tool batteries, I've got a couple around here but I'm doubtful of their current capacity. They've been sitting unused for some time. Might just go the gel-cell route.
The Newcomer's Forum / Busking Amp for Bass & Vocals
October 02, 2021, 07:30:43 PM
I've been building pedals for years now and built several guitars over the last few decades but I've never built anything amp-wise other than a very dirty sounding little LM386 amp.

My sweetheart and I were trying out and admiring our neighbors' Yorkville portable/rechargeable PA. It's the ultimate thing for busking. Can handle a guitar, bass and microphone all at once. (while disturbing the entire neighborhood for a 3 block radius) Runs for at least 4 hours on a charge. Wonderful thing, but the $700 price tag is just out of our range for something that would only get used for a handful of gigs per year.

I'm sure I've got at least one or two TDA2003 power amp kits around here somewhere. Rated at 10 watts or something. I was going to use a FET based amp-sim kit as a preamp along with an 8"/25-watt guitar speaker. (there are some nice, efficient ones available now) That would take care of my guitar well enough for busking.

I have a 2x/bridged TDA2003 kit here as well. Claims to be 20 watts. If I used that, with preamps on two separate inputs, would that be enough for bass and vocals? I was thinking of using a 10" bass speaker (Eminence has some nice ones) and maybe a smaller speaker with a crossover as well. (I know nothing about crossovers but it would be a good thing to learn) Would I need more power for busking with bass?

Would I be better off using the 2xTDA2003 amp as the guitar amp? Would I be in danger of blowing the 25-watt speaker?

Also concerned about current consumption. There are 12-volt gel-cell options and there are now plenty of lithium-ion options thanks to 10+ years of e-bikes everywhere.
Nice stuff! That is a very unique and original look you've got going on there. Not an easy thing to achieve, nowadays. I like how it looks almost Cold War Industrial. Your labeling technique is clever. Very cool!
Well, I finally got my hands on one! A Gretsch Gadabout. Canada Customs or somebody in handling had managed to destroy the Jensen C8-R that was in there. Coil had been completely torn from the magnet and the cone was mangled. Had to have happened when the package was opened and "inspected" by some overpaid goon.  >:(

Anyways, tried it out with an Eminence 12" I had around. Sounds great! Flat, but nice, like an old Standel or something. Breaks up nicely when the volume is full. Will post a sound sample when a replacement speaker arrives.

I will also post some gut shots. I've only used it on AC mode so far. The battery leads are cut, and now I'm not sure of the correct polarity. Standard grounded chassis would make sense, but this thing is from the Germanium era, so could it possibly be reverse? I definitely want to get this puppy running on batteries if possible!
Amplifier Discussion / Re: Watts vs Volume (db)
August 01, 2012, 10:23:18 PM
For speaker efficiency, have a look at some decent quality ceramic speakers. The "vintage-tone"snobs seem to love alnico, but those speakers are seldom as efficient. If you can find the full specs (including the all-important SPL rating and frequency range) then you can get some idea.

Eminence make really efficient speakers, full specs available. So do Weber. (but they don't publish their full specs) Also, decide on which speaker size works best for you, tone-wise. The larger the speaker, the better chance of it being more efficient. Lots of loud 15-inch, 12-inch and even 10-inch speakers out there. 8-inch or smaller and you're starting to lose out.

Read lots of the reviews online. They may seem subjective, but they've usually steered me right. Anyways, Eminence and Weber both make great sounding, loud speakers.
Well, eventually I will come across one of these at a reasonable price. (the smaller Gadabout model usually goes for $100 - $150 on EvilBay or Craigslist) I really liked the sounds I heard from these amps. Very Vox-like. If there is no schematic paper pasted in the amp, then I will probably be posting gutshots.
Quote from: joecool85 on June 14, 2012, 04:35:56 PM
The batteries were almost definitely SLA (sealed lead acid) batteries, not gel type.

Well those sound a bit scary to use. I'm sure gel type or Lithium would be a workable replacement.
Thanks for the replies! (both of you) I will get around to purchasing Jack Darr's book soon. The Kay and Harmony amps probably would have been from Danelectro. I don't think they would build for Valco (a competitor at the time) but the approach is probably similar.

The Gretsch Gadabout is listed on one music shop's site as being rated 6 watts. (already sold, unfortunately) Probably the same power output for the Safari. They ran on AC power or on two 6-volt rechargable batteries. (early gel-cells?) They came with an 8-inch alnico Jensen, (a pair of them in the Safari)

I just really liked the sound sample I heard. Sort of like an AC 30 playing in a shoebox. Being able to do small street festivals with that kind of sound would be great. I'll probably end up with the actual amp before I can ever locate a schematic.
Finally got to hear a sound sample of one of these. (on one of the Gretsch forums) Nice, mildly distorted breakup. Not ugly and muffled like a Pignose. More bright sounding, like the early '80s Fender SS amps. Pretty neat. I can see why Lanois uses one in the studio.

Still no luck with finding the schematics and every time these amps turn up on ebay, they're kind of pricey. Anybody out there got a line on one of these, or know somebody who has one with the schematic label intact?
Some of the new model and re-issue amps from Vox have spring reverb. If you want decent reverb without the Fender tone you could try some of the Crate tube amps from the `90s or some of the Peavey tube amps from 1980s to present-day. I had a Crate Club 20 combo that had great reverb and did the Marshall thing perfectly. (but I sold it `cause that sound just really isn't my sound) The Peavey Vintage 30 is another good one. Sort of a cross between a Vox and a Marshall sound-wise.

Just try to find something with EL84 or EL34 power tubes. They usually get you closer to the British tone. Another good one to look for is the Traynor YCV50-Blue. It does the British sounds really well and it comes with a full-size Accutronics reverb tank. I see more of these amps at gigs than any other, lately.

I mention these amps because they were produced in fairly large numbers and they turn up in the used market a fair bit. Just start searching Craigslist and Kijiji.

One thing, most the amps I mention above have probably got transistors driving the reverb. It's generally the approach most companies have taken over the past 30 years or so. Oh, and most of these amps are all PCB. For a point-to-point tube amp, you either have to pay the big bucks or else get very lucky and do lots of research while bargain-hunting.