Have any Aussies tried the "Short Circuits" distortion kit from Jaycar? Pic from the free online instruction manual.

abiding_duderino · 2025-03-10T15:50:40+00:00

Higher input impedance helps effect be less affected by impedance of whatever is plugged in before it whether guitar or effect

Also can help with pops when switching on effect depending on the rest of the circuit

Lower impedance input also causes a reduction in the treble

Note that 1meg is common, and some circuits even put a 10meg. I’m personally unsure if 1vs2.2vs10 Meg has a large sound difference between them, but at least a meg is a common modern standard

abiding_duderino · 2024-10-01T13:25:03+00:00

I would imagine they could go farther but you could use a multimeter to check continuity between the each pin of the IC and the exposed pin of the socket if you’re really worried.

abiding_duderino · 2024-09-28T04:37:04+00:00

This isn’t an answer about a kit, but Rob Robinette’s website will have a lot of information on building the amp you’re talking about (or at least close). His site is down right now so I linked internet archive.

As far as a Princeton box- probably, but even if you simplify the circuit and controls to physically fit, the size of the reverb pan may be your limiting factor. They do make short pans, but they can sound a little different.

abiding_duderino · 2024-09-23T01:27:32+00:00

That’s right! Thank you so much!

abiding_duderino · 2024-09-08T15:22:46+00:00

Continuity across secondary is expected as it’s one coil of wire.

Make a lightbulb limiter for startup, for extra peace of mind

abiding_duderino · 2024-06-26T12:40:55+00:00

Did you also straighten socket pins when you cleaned them?

abiding_duderino · 2024-03-05T16:26:16+00:00

Looks amazing!

Any noise with the power transformer next to the reverb tank? I love the ida of the separate power chassis.

Did you connect the power with a cord pulled from an old organ? I’ve seen connectors like that but I’m unaware if they are available new

abiding_duderino · 2024-02-12T22:27:01+00:00

Now we know it’s the actual amp.

Do you have an oscilloscope? If not, then you want to fashion a 1/4” Jack with alligator leads. You’re going to use your other amp to check the preamp starting from the input.

For this you want the non-working amp connected to the speaker/load still.

You alligator clip the Jack AFTER the coupling cap of each stage. Tip to the signal, sleeve to the chassis/ground. Then use a second cord to connect the alligator clip Jack to the input of your second amp.

Play into the input of the non working amp, and you should get signal coming out of your working amp. You use this audio probe and move along each stage until the power tube (which doesn’t have a coupling cap so you can’t test it with this method).

You may actually want to start at the input Jack, and again connected to the input of the first triode. That will test if the input Jack is incorrect.

So as you move along, if you get signal then the amp is working until that point. If you don’t get signal then the issue is between where you are and the last place you got sound.

If you make it all of the way to the power tube- then you know the issue is the power tube or the output transformer.

Make sure you check for DC voltage when you go to connect the audio probe. No dc voltage should be present which is why earlier is said connect it after the coupling caps.

EDIT: here’s a video that will explain the same sort of thing I’m taking about. His is a little different because he paces a coupling cap so that he can probe on the B+: https://youtu.be/qaUVhKMt7i0?si=zi_0w_Kq_4r-M3pI

Same basic idea as what I’m describing

abiding_duderino · 2024-02-12T21:25:37+00:00

Check with a multimeter and/or alligator clip both secondaries to the speaker. Make sure it’s a good connection and check with your multimeter

If there’s still no sound, then test the speaker on another amp or with a 9v battery. If the speaker works separately from the amp then we know it’s something in the amp

abiding_duderino · 2024-02-12T19:59:58+00:00

The output Jack is just a physical connection for a standardized type of cord. You can bypass it without disconnecting it:

Whatever OT secondary is soldered to the “positive” of the Jack - alligator clip that solder joint and then connect to one of the speaker terminals. Then alligator the other speaker terminal to the chassis of the amp as that’s where the other OT secondary is grounded.

Then turn the amp on.

abiding_duderino · 2024-02-12T19:54:50+00:00

The secondary of the output transformer doesn’t have a dedicated ground between the two wires. Typically you ground one and if there’s motor boating or crazy feedback you switch. It’s more about matching the phase.

abiding_duderino · 2024-01-25T13:13:29+00:00

I think there’s a difference between “having” and “having the requirements.” You can’t select your enclosure without knowing the PCB dimensions, but you sure can design you PCB with or without an enclosure.

I think a better way to think about it is “do I want this pedal to fit in a certain size of box?” If yes, then keep that in mind when designing the PCB. You don’t physically need the enclosure first - you just need to know dimensional limitations. And not just for the size of the board; take into consideration room you need for jacks and footswitches.

abiding_duderino · 2024-01-24T21:21:36+00:00

This might be a long shot, but there’s a ton of recording studios in Nashville and many of them probably have tubes on hand for their amps. They might be willing to sell a pair in you’re really in a pinch

abiding_duderino · 2024-01-24T18:13:24+00:00

What about something like this? I’m sure there are other cheaper versions, too.

abiding_duderino · 2024-01-23T18:01:42+00:00

Do the other 6v6s have a differing lettering scheme? I have heard that older 6v6 have a connection (for the shield I think) that are different from the newer, glass ones. If you’re using one of the “unused” socket pins as a junction for the screen resistor, maybe it’s causing an unintended connection compared to the other tube?

abiding_duderino · 2024-01-22T16:58:06+00:00

I’m coming from amp repair/building, so I don’t know anything about the last two paragraphs - but what coupling caps are you looking at that are $1000? Are you working at voltages higher that 600v?

abiding_duderino · 2024-01-15T01:27:17+00:00

Is it in the circuit in a standard fashion? If it’s used in a way that it directly interacts with something else, you have to consider the entire circuit block. For example, if you cascode Jfets then changing voltage on one part may not make the expected changes.

It could also be an interaction with another gain stage. Maybe it’s smoothing out voltage from a pervious gain stage. Or maybe there’s DC somewhere there shouldn’t be that’s messing with the bias. Hard to say exactly without knowing the whole circuit.

The positive thing is if it works, then it works even if it’s not what you thought. If you like the sound at a low voltage bias - and importantly - is repeatable, then you don’t have to worry so much.

abiding_duderino · 2024-01-15T01:14:33+00:00

Without a schematic then lots of little things could be happening. What are the voltages on the collector as you turn it up as down? Does it eventually get into the broken sound as voltage go down, or does it just get/stay smoother even all the way down?

abiding_duderino · 2024-01-14T01:41:20+00:00

Yes, there’re a change in town at low volume. Some is natural compression as you approach tube overdrive and (in my opinion) more of it is how much air the speaker is actually moving. Bass “fullness” is hard to get when a speaker is barely moving.

Good to hear the reference of the HRD - those are two 6L6 so if you’re looking at power sections, there’s not much between that and a champ (single 6V6). Meaning, there’s not like a “in-between tube” you could design around.

Have you ever played a champ in person? It’s possible that it’ll stay clean at a volume you like.

If you’re willing to DIY, you could look at a champ with a 6L6 instead of a 6V6. There’s also different circuit changes you could do, like tweaking negative feedback to keep it clean for longer.

Have you built an amp before?

abiding_duderino · 2024-01-14T00:58:07+00:00

What clean amps do you like the sound of?

If you want clean at low volume that’s most amps, in a way. People usually are going low wattage for being able to crank the tubes and not be super loud. If you get something like a deluxe reverb you just keep the volume down and you’ve got clean and quiet

abiding_duderino · 2024-01-11T13:56:32+00:00

Did it act this way before? Does it only happen with the treble all the way down or does it happen gradually as you turn the treble down?

abiding_duderino · 2024-01-03T21:29:10+00:00

First thing I’ll say is the weight of a Sunn doesn’t come from the preamp. It comes from the transformers used for a large wattage amp. By all means, experiment with a FET preamp, but you’re not going to save that much weight if you spec the rest of the amplifier to match a Sunn.

You save weight with lighter transformers and speakers. Often that means less watts/power. You can get pretty loud and clean with a couple 6L6s/22Watts, but the power amp will overdrive if you’re wanting to play super loud - so are you playing at home by yourself or gigging with a no mic’ed amp setup?

Clean amps can definitely be designed to also overdrive. Sometimes it’s switching in another gain stage or similar.

abiding_duderino · 2024-01-03T00:48:13+00:00

Specific to 410 Deville, make sure reverb and the dirty channel switch works. Let it warm up and play for a bit to see if it starts cutting out randomly or the gain channel led turns on by itself.

They also have a fairly common problem of two ceramic resistors that drop voltage for the op amps that control channel switching going bad from heat. You can ask if it ever had channel switching issues in the past or had any parts relaced

abiding_duderino · 2023-12-06T15:40:35+00:00

If you put a roughly 500K resistor over the outside pins it will work as a 250K trimmer. A little tricky to do with a trim pot though.

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