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Looks like a fun little kit for under $100....I have always wanted to mod my drri with something like this...swapping out the knobs and tubes in the dry channel for an outboard style reverb. Can anybody vouch for any of the diy amps sold by this guy?

Reverb Kit

Hummmmmmm........... looks like something is missing...... ed

Traditional........speak softly and play through a big blonde amp. Did I mention that I sill like big blonde amps?

I don't have any direct experience with this particular unit, but I do have some experience with reverb circuits in general. This type of circuit can be quite an improvement over the stock Fender combo amp reverb, however, it appears to use a 'small' 9-pin driver tube. As such, it can't produce the 'drip' of a real 6G15 Fender reverb unit.

By the way, I've done that mod where the Normal channel is converted to a three-knob reverb circuit. It is an improvement, but without the 6K6 driver tube, it isn't completely satisfactory. Now that I have a Fender reverb unit, I don't use my modded reverb channel unless I forget to bring my reverb unit with me!

If it ain't broke, fix it until it is.

BJB - good point about the lack of 6K6. Wonder what it would take to add one?

But really, I didn't expect this cheap kit to compete with my outboard tank or fender combos...just thought it would be a fun starter project for someone who would love to build a tube amp someday.

They have a $60 tube amp kit as well and, again, I am curious.

To add the 6K6, you'd start by getting the proper reverb driver transformer. Angelea Electronics used to have them and you can order them from a Fender dealer. However, not all Fender dealers will actually send your order in to Fender. You'll also need to punch the chassis for an octal tube socket (Greenlee makes good punches) and you'll also have to re-work the gains in the circuit to drive the 6K6. The heater filament transformer would need to be able to supply the extra heater current to the 6K6.

There are several suppliers for tube amp kits. I've never built anything (from a kit, at least), but there are many forums out there full of people who have. From what I've seen, pretty much anybody who tries to build a kit eventually gets it to work.

You'd probably be happier with a kit amp that you'd actually use instead of a reverb unit that isn't as capable as the Fender reverb unit you already own.

If it ain't broke, fix it until it is.

BJB, Thanks for the detail...sounds like a project!

You'd probably be happier with a kit amp that you'd actually use instead of a reverb unit that isn't as capable as the Fender reverb unit you already own.

Really, I am just happy fiddling with small projects. I don't have the time or money to invest in better build..yet. I am just looking for experience and hoping to learn more about the circuits, etc.

Kinda looks like some of the chassis work was done with a can opener Smile

The fact that he doesn't advertise any uploaded samples of his unit (youtube, soundcloud etc) makes me reluctant.

Hi All,
"it appears to use a 'small' 9-pin driver tube. As such, it can't produce the 'drip' of a real 6G15 Fender reverb unit."
Not true. In fact, this statement is libelous. Good thing for your I'm a nice guy, and I think your comment ignorant rather than malicious.
I don't wish to start an argument with BJB, but the statement appears to be grounded in the mistaken notion that unless a tube has an octal base, it cannot be a power pentode. You would all be well advised to get an RCA tube manual and look at it a little more closely than he apparently ever has. Take a look, for example, at the 50C5, which is a miniature 7-pin version of a 50L6, which is a 50-volt filament version of a 6L6, which is substantially more powerful than a 6K6.

My circuit uses the power pentode half of a dual triode-pentode to drive the tank and is more than up to producing a dripping wet output. If anyone wants the mp3s that show this they can contact me at tubekit101 at hotmail. There are many big files. Multiple megabytes.

Another mistaken idea that seems rampant in these forums from those whose knowledge is only superficial is that a transformer is needed to drive a reverb tank. It depends on what the reverb tank is designed to be driven by. In this case, the tank has a high impedance input coil (high being very relative here; actually it is only 1450 ohms), not the 8-ohm impedance of the Fender unit. An 8-ohm tank is like a speaker and needs a transformer (which limits its frequency response). A 1450-ohm tank is a suitable load for the plate circuit of a pentode directly, without a transformer (using a capacitor to block DC). Moreover, this direct coupling of the driver output to the tank allows a wider frequency response than sending the signal through a transformer. See the Reverberocket circuit for an example of a transformerless design. Then listen to that amp and tell me a transformerless design can't sound dripping wet, if you still think so.

The Fender design uses five gain stages: Two dual triodes and a pentode driver. One of the Fender gain stages is an "extra" 12AX7 triode gain stage which is used simply to invert the signal. Look at the circuit. The first stage output is thrown away in a resistor divider that feeds only a fraction of the signal to the next stage. All it does is invert the signal to match the polarity at the mix point.

Our design uses only four gain stages, eliminating the redundant inversion only stage by simply reversing the leads at the tank input. (Fender could have done the same thing by reversing the leads of the transformer primary, but they had an "extra" gain stage and used that instead.)

The two tubes are a 6EB8 and a 6KE8. The 6EB8 contains a high gain triode (similar specs to a 12AX7, AF=100) and a power pentode which can feed up to 25 mA into the tank--more than enough to drive a 1450 ohm coil. In fact, you can set the drive conrol so high that you are overdriving the coil so much that it is beginning to distort in the tank, if you want that effect. We haven't tested to see how long you can do that before burning out the tank, but you have the freedom to do that if you wish with our design. If you choose, you can operate it within its rated input specs and get as much dripping wet as you can stand because the mix can be set where there is virtually no dry signal at all.
The 6KE8 is another dual triode-pentode, but in this case, the tank recovery amp pentode is a very sensitive high gain pentode (high voltage gain, not high current gain, like the other) and produces a gain of twice what you can get from a 12AX7. It's partner triode is a medium-mu stage that functions very nicely as the cathode follower to buffer the dry input from the guitar and lower the output impedance.
If you've never heard the device, shame on you for dismissing it as unworthy of your attention with a load of ignorant falsehoods.

I should have contacted you sooner, I built one of these and haven't been able to get it to work. The tubes light up and I get the guitar signal through it into my amp but there's no reverb effect at all. Can you suggest where I should look for my mistake?

Lighten up Frances. If you think that your pissy response is going to make everyone run out and buy your kit, you have a lot to learn about business.

Shawn Martin

tubekit101 wrote:

If you've never heard the device, shame on you for dismissing it as unworthy of your attention with a load of ignorant falsehoods.

Got any soundclips? I would love to hear it to get an impression.

The Hicadoolas

I give the guy credit for doing something different than another confounded digital pedal. There's no 6K6 (or 6V6) in a Peavey Valverb either (12ax7's and a 12at7), and they can reverberate quite well. I'm by no means knockin' the Fender units, just giving my 2 pennies on the subject. And for the record, I have a Boss FRV-1, Tech 21 RVB, and a Valverb. Carry on!

Topic saved in my favorites list.

THREAD RESSURECTION!!! Has anyone actually bought this kit who can give first hand unbiased opinion of it? I emailed the guy about a year ago and asked about it and was a bit rude as I hadn't build anything before and thought I was young and a bit foolish to think I could build it! But I think I could manage now. I am looking at doing a 6g15 clone which will cost me about £50 more, and as it's my second build, this one is cheaper and has instructions, but will it be as good as a full on 6G15?

I couldn't get mine to work, I say go with the tried and true 6g15.

Thunderbolt, if you're still around, want to part with your Valveverb? Big Grin . I had one many years ago, and sold it.. still kicking myself, can't find 'em anywhere.

I'm still around vsd. Still have the Peavey, but it's mounted to my pedalboard for now.


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