Dwarf Tube Rocket Amp

[RJ Guitars]

Just a word of caution on the cab. This is the same guy I got mine from who advertised his cabs were in stock and would ship with in 3 days of cleared payment. It took him 10 days to ship and 3 weeks for me to get the cab. I know shit happens and I hope it was just a fluke but I just wanted to throw that out there for anyone ordering a cab. Be prepared to wait. You can also builld your own. Here is the link to the plans

http://archives.telex.com/archives/EV/B ... 0Plans.pdf

I think it would be great to get one of our wood working forum members to knock some of these out and offer them for sale here.

I kinda remember reading your notes about that. I looked at the guys EBAY feedback and there was one negative entry indicating a similar story but it didn't look like a chronic problem, all the rest of the feedback was good - hopefully he'll treat us right.

I did get a quote from my cabinet guy on building these but there wasn't any real savings for us on a baltic birch cabinet and I wasn't real sure what impact on the tone it would have to use real hardwood.

These are apparently tuned to be ideal for that the EV speaker. but rumored to be good with a number of other choices. Any thoughts on a good alternative for those without a spare EV sitting around?

thanks,

rj

[UR12]

Any thoughts on a good alternative for those without a spare EV sitting around?

thanks,

rj

I'm using a Fane Medusa 150 in mine and likeing it a lot. You can check with Dartanion on this forum for availability of the Fane. I'm not sure what the price difference is between the Fane and The EV but both sound awesome in this cab.

[MCK]

RJ, glad all is starting to look better. Please take care of yourself & yours.

[RJ Guitars]

Hullo AGF faithful,

The first V-2 in a kit form went out the door today. I am quite pleased with the amps but a little embarrassed at how long it took me to get things rolling. This last week was especially busy in prepping a schematic, BOM, and a layout as well as making sure I had everything else needed to start shipping these out. Glad that is done and excited to learn from you guys as we bring these little amps to life.

I've got the list of interested builders and I'll follow up with you guys in the next few days. In the meantime a picture of the final prototype and the first kit that went out today. These are the two faceplate designs that I have in stock. I have PCB boards as well as some of the eyelet boards left from my earlier prototype work. Otherwise, this is a real simple amp with not so many options. I have updated my web page with info on pricing and such.

http://www.rjguitars.net/Amp_Kits.html

Thanks,

rj

[M Fowler]

rj, that looks killer I can't wait to get started on the kit thanks.

Mark

[FUCHSAUDIO]

A levitating amp...now wouldn't that be cool ......
BTW - was there ever a "Viper" amp...?

Pretty sure Fuch has some metal amp called the Viper.

We did, Peavey had a problem with it (Vypyr was apparently too close for comfort for Hartley)...so it's been discontinued. Hartley was actually very nice about it, and he didn't have to be....

[mclmk8d]

rj,
I emailed you a response this morning...Serge

[mclmk8d]

The Pocket Rocket is going to be for my son, who has an Avatar 2X12 with a Weber Silver Bell and Blue Dog. He is currently using this for his Orange AD30. Is the Pocket Rocket going to be strong enough to run through this cab or should I start looking for a 1X12; if so, what speaker do you recommend?
As usual, thanks in advance for any help.

[rbryerton]

You could hook it up to 2 16 ohm 4x12's if you wanted to.

That would look pretty funny: little rocket head atop a full stack! ...but it would sound great.

[M Fowler]

The OT is 8 ohm so you will need to start there first, probably two 10s or 1-12 cab huh? I don't remember what rj was using.

[RJ Guitars]

Hey guys,

Thanks for keeping up the talk on these little amps. I have been in the shop every night getting packages ready to go. Funny, most of the early interest has shown a preference for the eyelet board over the PCB. I anticipated wrong and had several of the PCB kits ready to go but we are just about ready to go with the others as well.

Speakers - I am using a pair of 10's in an open back cabinet with no complaints. I am planning on getting one of the Theile cabinets with a 12 in it just because I think it's a good match for this amp and I always wanted one of those. The amp will push a 4x12 cabinet if you wanted to do that... it's only a couple watts but a couple watts through a 4x12 cabinet will sound very cool... just don't ask me to help you carry it to the gig.

The output tranny is a replacement for a Fender Pro Junior if that helps you decide anything about speakers.

Feel free to ping me again if you are waiting on an email response from me... I am kinda old and slow, not ignoring you, just busy.

Looking forward to developing this amp with you guys.

thanks,

rj

[RJ Guitars]

Hello Guys,

I have been toying with some of the schematic values on the little Rocket build and decided to call the current revision (1.1) the starting place. If you compare this to the old Matt Taylor Rocket schematic you can see that most of the values are the same.

The differences are all in resistor values that I changed to bring the voltage up on the preamp tubes. Without at least 90 volts on the plate of V1, the amp was a little fizzy sounding. I made it work this way but I don't really believe I've got it right... thus the need for your minds to join me in making this a forum project.

After the fact I started trying to sort out what needed to done to optimize the circuit for the particular tubes that I am using. I began an online discussion with the local "Atomic City Audio Nerdz". This group is mediated by my buddy Jason, head of the "Boozhound Labs" audio research outfit.

The additional posted text is from a guy named Matt who was among the gurus that mentored me and initially turned me on to mini tubes. I'll copy and paste some of that discussion... very cool stuff and a few very smart guys...

Bob,
There are no tube characteristics shared by the 6112 and the 12AX7. The most critical characteristics are Mu, 70 for 6112 and 100 for 12AX7, Rp, 28-30K for 6112 and 60K to 80K 12AX7, VaMax 165V for 6112 and 300V for 12AX7, PaMax, .5W for 6112 and 1W for 12AX7. As you can see there is really nothing in common between the tubes from an engineering perspective. Likewise a power supply designed for the 12AX7 will not work well with the 6112. That the 6112 worked in a circuit designed around the 12AX7 is not surprising, that's a nice thing about tubes, they don't let the smoke out very easily. But if your goal is to get the 6112 to work like the 12AX7 in that circuit than you will have to redesign the amp to match the tube.

As John said load the plate of a 6112 with a 12AX7 plate load and expect the highs to be attenuated. I have found these sub-mini tubes to take over voltage fairly well but they sound best at book operating points.
Matt

[rbryerton]

RJ, what do you use to draw up these schematics? The output looks very nice.

[RJ Guitars]

Thanks Rob,

I do everything in CAD software. I learned mechanical drawing years ago, then that changed into CAD drawings, then I kinda got stuck in time. I prefer to work in an old version of AUTOcad LT but there are plenty of other more modern and affordable products out there... recently I've developed an allergy to steep learning curves.

rj

[rbryerton]

OK, just finished up my little V-2. First off, a big thanks to RJ for all of the work he put into this project building the prototypes, getting the boards/chassis/face plates/head shells fabricated/etc. Awesome job, and mine came out very clean. It looks very sweet in it's little head shell and I really dig the front graphic!

So how does it sound? Faaaaaaantastic! It's got some cool sounding swirl going on when clean, it's very bright w/my Strat, and perfect w/my LTD EC1000 (Les Paul clone type of deal w/EMG's). With the higher output pickups, it gets a great crunchy rhythm sound, and rolls back cleanly. It does the TW clean to mean thing perfectly. With single coils (Strat & Tele) it brings out the character of the guitar beautifully.

I stuck to the schematic Rev 1.1 values w/the following exceptions:

B+ Dropping resistors: 200R, 5.6k, 2.3k, 2.3k
No cathode bypass cap on V1b (no need at all IMO; it's pretty gainy "stock")

I've only had a chance to play it about 45 minutes so far, but I wanted to post a quick report because I'm so stoked with this little guy!

I'll post some voltages later. I'm trying to get some pics, but my camera is acting up... no gut shots for now...