u/Pretty-Care-7811

First post here, so howdy.

I've been getting into building pedals, and now I'm "stepping up" to amps, so I thought I'd share this project I'm considering and ask for advice from the experts.

I found this Decca vacuum tube turntable at Goodwill yesterday, and I thought it would make an awesome cabinet for a "vintage" guitar amp. My idea is to basically gut the entire thing, use the (dual 7-pin) tube chassis to put in a dual-stage 6AU6 "starved plate" preamp, and add a 24VDC solid state power amp (actually 2). I'm basically planning to yank out the turntable and replace the base to keep the circuitry separated from the driver. Then, I'm going to add some risers and a top baffle to put either a 10" or 12" driver. The cool thing is the wings, though. In the preamp circuit, I'm going to split the signal to include a reverb (probably a PT2399) that's a wet-only signal, and that is going to the (removable on a hinge) wings. There are 4" speakers in them right now, but I'll probably upgrade to 6", depending on how much room there is once I open them up. Each wing will probably have a 6' extension reach. I think that would add a pretty cool "space reverb" or "space delay" type of thing.

My overall build plan is fairly straightforward: TL072 (input buffer) > tone controls (probably a tilt-style)> tube stages > TL072 (signal split) > Signal A: driver power amp; Signal B: reverb power amp. I might add another recovery stage after the reverb, depending on how many db the reverb cuts. The front panel knobs will be the driver and reverb volume, and the remaining pots (gain, tone, reverb depth, reverb time, and whatever else) will be on the top baffle with the driver.

I'm using the hybrid approach because I'm not ready for high voltage yet (and I have an Orange Micro Terror that uses the "starved plate" and I really like the sound). Soon, but not quite yet.

Any suggestions will be greatly appreciated.

Thanks.

I got some through hole J201s a while back and finally got around to using one. I made a TL072 boost with an on-off-on switch with red and yellow LEDs on one side and zeners on the other. Going to a basic passive treble and bass. Going to a Fetzer valve with a user adjustable bias pot. Running into a 100w class D amp. Going to do some tweaking and put it in a 1590BB I think.

Still a work in progress.

Just saw these selvedge 505s at the local goodwill. They were with a couple pairs of non-selvedge premium. Good deal for someone.

EDIT: I'm leaning toward completely gutting it and turning it into a "stealth" tube amp. I'll keep the front grille speaker and go with high voltage to run the tubes. I'll drill out some holes where the reels are and install a couple 4" or 6" speakers. Still brainstorming.

I found this Pentron reel-to-reel at Goodwill yesterday. Thinking I'm gonna do a conversion to a guitar amp, using the 12AX7 and probably do something with the other tubes. Haven't decided yet. I'll probably gut the whole thing because the power transformer is toast, the internal fan doesn't work, and I'm pretty sure the tape deck motor doesn't work. I put it on a dim bulb tester, and it's definitely shorted.

I'm thinking I'll run the audio through a couple of the tubes, power the whole thing with 12 or 24V DC, and cut holes where the tape reels are now to install a couple speakers. I'll also connect the front grille speaker (under the control panel). I'd like to use it as a preamp/amplifier/speaker cabinet driver. There are two outputs, so I can run one as a line out from the preamp, and wire up the internal speakers and the speaker output with a small class D power amp or something to run like ~5 watts.

Still brainstorming. Does anyone have any ideas?

I found this Pentron reel-to-reel at Goodwill yesterday. Gonna fix 'er up a little. The power transformer is toast, so I think I might turn it into a guitar amp. I'll keep the lower controls and do some re-engineering inside with the vacuum tubes. Then, I'll cut out holes where the tape reels currently sit and put a couple speakers in. It also has a speaker on the front, under the control panel, so I'll probably use that, too.

Haven't decided yet, but I think it's beyond an actual restoration back to its original state, so I'm gonna experiment.

Howdy. Just an FYI that I've noticed. A lot of people don't realize that women's Levi's have a smaller patch than men's (and they leave the sizes blank). This also applies to the workers at secondhand shops, like Goodwill. Here in the Phoenix area, I constantly see women's Levi's on the men's racks. It might be worth a trip through the men's section when you're thrift shopping.

Not sure what happened with the pics on the last one. Here are better images.

I picked this up at Goodwill for $2, and it works as far as I can tell. I haven't checked the 1/4" trigger inputs, but they look good; everything else works like it should.

It's basically a sampler. It's an assistive technology device for individuals with speech disabilities. You know those videos where people teach their dogs to "talk"? It works like that. The 8x 1/4" inputs on the back are for alternative triggers (you know how Stephen Hawking used the breath control thing to "talk"? They're like that).

The red button on the back is the record button, and the black circle next to it is the microphone. The rotary switch selects between 6 banks, so it has a total of 48 samples it can use.

It runs on 4x AA batteries.

For now, my plan is to run the mic input and speaker output wires to a pedal enclosure and add a 1/4" in and out. I'll probably replace the speaker with one a little bigger and mount that on an external box. I'll also replace the batteries with a plug jack.

Other than that, any ideas for mods I could do with it?

Thanks.

Howdy,

I picked up this Gonset Communicator II from Goodwill a while back, and I'm in the process of doing a semi-restoration. I'm just planning to use it for the mic/PA, rear RCA external speaker jack, and headphone jack for audio routing, not as a radio. My goal is to use it for some "old timey" effects and use the preamp for tube saturation for music recording (and as a mini guitar amplifier). I have it all yanked apart, and I'm pretty sure I've identified all of the power caps, but the schematic from the manual isn't exactly lining up with what I'm seeing. I was wondering if anyone might be able to check out what I've identified and maybe point out some other caps that I should be looking for. I'm not trying to do a full restoration, and I'd actually prefer if it sounds a little "beat up"; I'm just trying to make sure it doesn't blow up.

I did a dim bulb test on it, and it powered on, all of the lamps lit, and the "magic eye" lit up. It's getting power, but I didn't want to give it a full test run and burn up a transformer or something.

I've attached the schematic and the component list; the ones in the red boxes are ones I've identified in the pics (I think), and the blue ones I'm not sure about.

Here's the link to the manual: https://archive.org/details/instructionmanua00unse_9/page/14/mode/2up

Any assistance is greatly appreciated.

Thanks.

I found these at Goodwill a couple weeks ago and forgot about them. Kind of cool, I guess, but after I got them, I realized that I'm not going to wear a light wash, so I'll probably put them on eBay or something. Just thought I'd share.

As far as I can tell, they're a Cone Mills LVC repro of a 70s (?) orange tab bootcut. Maybe 517s? I can't tell the date from the tag (nothing on the other side), but I'm guessing around 2010. There's no stamp on the button, but that makes sense if they're a sample pair: they wouldn't have a production stamp if they're not from the production line. And either they were never hemmed at the ankle or they were cut. The tag says they're 32x32, but I'm measuring 32x31ish.

Neat find, but not my style.

This was a Goodwill find. it's a Gonset Communicator II transceiver. Going to see if I can use it for some kind of PA system/preamp for some audio recording. I ran it through a dim bulb tester, and it fired up, so now I'm going to start looking around to see what needs done. I found the schematic, and it looks like there are only a few power caps, so it shouldn't be much trouble.

EDIT: Cool. The "magic eye" works, too. Thinking I'll change out the mic input with a 1/4" mono jack.

EDIT 2: I might have spoken too soon. there are only a few power caps, but they're pretty tough to access. Bigger job than I expected.

First post here.

I picked up this 1960s reel-to-reel at Goodwill for $15 a while back and figured I could use it for some lo-fi effects for recording. It's my first restoration project, and it turned out really well. I just replaced all of the capacitors (not pictured) because everything else worked well: don't need to change the belts, all of the tubes light up, and even the "magic eye" tube still fires up. It still has a little 60hz hum, but it's way better than before the cap replacement.

My plan is to use it for some tape/tube saturation and tape delay/chorus/flanger/ADT-type of stuff. I plugged my guitar into the "radio" input and ran the external output into my DAW, and it sounds really good. It has a really early/mid-60s kind of tone (lows roll off around 200-300hz and highs around 2-3k); with the volume cranked, it gets some pretty nice "classic rock" distortion.

I'm going to mess around with running some dry tracks off of my computer into the recording head, then record the playback into a new track on my computer. Then, I can do whatever time delay/stretch/whatever with it. I'm also going to see what I can do with recording through the preamp.

Should be fun to experiment with.

Howdy,

I picked up this 1950s-1960s reel-to-reel at Goodwill for $20, and I'm looking to do a little restoration (if necessary). I'm new-ish to electronics (I've built 12VAC tube preamps and a few 9VDC guitar pedals), so I want to make sure I'm doing it right. I've fired it up, and everything functions (tape head records, reels spin, tubes fire up, inputs and outputs work); I'm thinking that due to the age and the fact that I'm getting pretty loud 60hz hum, I might want to change out the caps. I'm just going to use it more or less as an "effects processor" for music production (tape delay, flanger, lo-fi preamp, stuff like that).

Given that I'm pretty familiar with a soldering iron and the safety precautions, would it be a worthwhile project to change out all of the caps or just some? If so, any suggestions?

EDIT: I did a quick test video of some of the different diode settings. This is straight into Reaper, with a compressor after the Diodizer to level out some of the volume drops from the different Vf.

Link to audio Test: https://drive.google.com/file/d/1erNdFZzDvbYpr0ew4vTlNWbyh9hMnR8_/view?usp=sharing

I finally got this thing in an enclosure; even with the 1590xx, it's still a pretty tight fit. It's an MXR Distortion + based on the Barbarach design, but I replaced the fixed diodes with a "ladder" daughter board on a sidechain to ground (red circle and arrow in the breadboard diagram). The left rotary switch selects between 6 anode-to-cathode diodes; the right one selects from 6 cathode-to-anode. Both sides are organized from the highest Vf to lowest, in a left-to-right, top-to-bottom matrix. The left switch turns clockwise from highest to lowest; the right turns counter-clockwise from highest to lowest. I should probably switch the red and green LED positions to reflect this, but I've already sealed it up.

The knobs are gain, tone, volume. The tone knob is kind of weird, but it's tied to the diode ladder, so it's kind of a "focus" knob. As you turn it down, it cuts bass around 80hz for the first half of the turn, then it starts cutting treble around 2.5khz for the second half. As it turns, it also reduces the resistance for the diodes, so it sends a little more gain to them (but not really a lot).

Issues that I'll address in future builds:

• This thing takes a LOT of tweaking to dial in the tone/gain/volume, but that's kind of the point. I designed the damn thing, and I still spent a good two hours last night just trying to get the hang of dialing in the levels.
• It REALLY reacts to different guitars and amps; I ran it through a single-coil Telecaster, an SG with alnico humbuckers, and a Les Paul with active Seymour Duncan humbuckers while trying different amps in Amplitube. HUGE differences all around.
• Because of the drastic changes in Vf (3.0 for the blue LED in the first position on the left; 0.14 for a Schottky in the last position on the right), you pretty much have to have a compressor after it in the chain; my next design is going to be an auto compressor with photoresistors that reacts to the LED colors, I think.
• I like the tone/focus knob, but it probably wouldn't be everyone's cup of tea. It really narrows down the frequency spectrum, which a lot of people might not like.
• At full gain, it hits the power rails of the Tl072 and starts to "roar"; not sure if this is a feature or a bug yet.
• Obviously, I'd use higher-quality hardware for a "real" build; this is just a bunch of Amazon stuff, but I needed the smallest I could find to fit it in the enclosure.

Overall, I'm really happy with it, but it's going to take a little work if I make it again. I'd probably replace the TL072 with something that gives a little more leniency before hitting the power rails. Maybe a JFET? I have some through-hole J201s, so that might be an option.

I'll post a link to some audio clips after work.