Dwarf Tube Rocket Amp

[RJ Guitars]

Here is the first look under the hood. I tend to think of this as a demo of "How not to mount your sub-mini tubes". I knew that tube sockets would be a better choice for this build, but I didn't have any.

In addition to hearing these tubes, I really wanted to know if this layout and my other ideas were on track so I decided to go forward without the tube sockets. These tubes were made to be soldered into place but I really didn't enjoy the idea much. Given the results I suppose I can't say anything bad about the practice except it feels weird. A little more forethought on how to prep the board is needed even if the solder mount is kept.

After I fired it up (it worked the first time I tried it), it clearly had potential and I still had some time available. I tweaked on the circuit and it came into shape to sound really good in just a couple hours.

I'm working through some other early images and I'll get more shots posted over the next few days. At this point this was a great platform to learn from but I'm looking forward to the improved version.

rj

[RJ Guitars]

Are these tubes prone to the microphonics associated with other tubes of similar aspect (e.g. EL84)?

What is the life expectancy of these tubes given that they are soldered onto the board?

I can only talk about the specific tubes in this amp and speculate on the rest of them. I haven't had any indications that they will be problematic, including tapping on them a bit with the amp hot. Considering that these tubes are rated not just in voltage and temperature but also given an altitude and "G" force rating, we can safely guess that they were made to be rattled around.

I suppose all this might eventually get you around to considering their potential for use in a combo amp? If I were to mirror image everything then a very small combo amp just might be a possibility.

rj

[Zippy]

Considering that these tubes are rated not just in voltage and temperature but also given an altitude and "G" force rating, we can safely guess that they were made to be rattled around.

I suppose all this might eventually get you around to considering their potential for use in a combo amp? If I were to mirror image everything then a very small combo amp just might be a possibility.

A combo that sounds like an EL84 output but doesn't rattle?

Hmmm, I dunno. Why would anyone want that?

Time to play with speakers. It'll be fun to see what you can get volume-wise by varying speaker efficiency - low and high.

Consider also including a line out option so one can get great drive and tone at moderately low output levels and feed it directly to a board.

[UR12]

Here is the first look under the hood. I tend to think of this as a demo of "How not to mount your sub-mini tubes". I knew that tube sockets would be a better choice for this build, but I didn't have any.
rj

That looks fine. I also racked my brain trying to figure out how I wanted to mount them. My first prototype had them just soldered to the circuit board like they were intended. Good luck finding sockets. There are some transistor/IC round 8 pin sockets out there but they are not chassis mount and they don't have a gap between pins one and eight which makes it a PITA to try and figure out how the tube needs to be inserted. too much room for error.

[M Fowler]

rj,

Nice amp you have there.

I have attached a wave solder socket but I imagine it is too large for these tubes.

Mark

[JimboM]

"Let me know if you want to help prototype the kits. They are pretty simple amps to build and the parts will not be bad at all. Protoype kits will be my typical no-profit lets have some fun protocol. "

RJ, count me in on the prototype fun. I'm a novice and all but learning... JimboM

[RJ Guitars]

...luck finding sockets. There are some transistor/IC round 8 pin sockets out there but they are not chassis mount and they don't have a gap between pins one and eight which makes it a PITA to try and figure out how the tube needs to be inserted. too much room for error.

I almost didn't start on this several times because I just didn't like those flying leads. The guy that turned me on to these uses an Octal insert and solders the leads to that.... maybe the same one that Mark has mentioned in his recent post. In the attempt to try to make a small footprint amp, the idea is good but the octal is a giant.

I'm leaning toward the little eight pin DIP sockets but they have their issues as well.

...count me in on the prototype fun. I'm a novice and all but learning... JimboM

The idea behind a kit will be to have them all the same which will give you plenty of help as you build. The kit idea is in the early development stages and I'll provide details as they come. So far tubes and transformers are ordered and I'm working on a complete BOM... I was a bit worried about the tubes but I found a good source and bought enough for the first dozen builds.

rj

[kec]

RJ,

I'd like to sign up for the prototype.

[RJ Guitars]

RJ,

I'd like to sign up for the prototype.

Thank you sir

The "V-2 Dwarf" begins.

We've got two signed up, I'll do one more myself, and I have the goods in the mill for nine more.

thanks

rj

[MCK]

Count me in please!

[dreric]

RJ

I'd like to be on the list also.

Eric

[kec]

RJ,

What are the issues with the DIP sockets? It worked well on the 'Lil Devil.

[stompjunkie]

I'd like to help prototype this project as well if you don't mind.

[kec]

Too bad they don't make these anymore...

[M Fowler]

With this talented bunch someone must know how to make a minature tube socket out of plastic molding processing huh? There's not much tempature. I don't know crap about this but it must be possible.

Oh and I hate mini dwarf amps but count me in rj.


Mark