Beginner Dumble build?

[ToneMerc]

So you don't have figure out how to glue or tie down the floating 20uf cap on the right end of the tone board. A stock Princeton would already have 20/20/20/20 can cap and if a guy was using after market Princeton chassis or a bare chassis you would be ordering parts so why not get the correct can cap or put the axial caps on the tone board. Many ways to build this amp.

Maybe this version of the layout is better.

Or you could do how I did a PR Phonix, just omit the cap can all together and make a separate cap board and use the small Fender dog house.

TM

[M Fowler]

Mike, yup that would be my choice as well if I was starting with blank chassis because I would use a standup PT so no cutout leaving me lots of room for cap board, etc.

Mark

[beasleybodyshop]

Any idea what the value would be on the bias pot?

Also, What is a "1R" resistor? 1 Ohm?

Same for the 1K5 - is that 1KOhm 5 watt?

[steve_p]

Any idea what the value would be on the bias pot?

Also, What is a "1R" resistor? 1 Ohm?

Same for the 1K5 - is that 1KOhm 5 watt?

Generally, fender bias pots are 10k linear pots.
Here is a commonly used component:
http://www.mojotone.com/amp-parts/poten ... ebi1I3VDnE

For the resistor readings, you are correct. 1R = 1 Ohm. 1k5= 1500 Ohms.

Using either the R or K instead of a decimal place is an older common practice, mostly due to decimal points getting lost or added accidentally in copy machines and such.

Good luck,
Steve

[beasleybodyshop]

Any idea what the value would be on the bias pot?

Also, What is a "1R" resistor? 1 Ohm?

Same for the 1K5 - is that 1KOhm 5 watt?

Generally, fender bias pots are 10k linear pots.
Here is a commonly used component:
http://www.mojotone.com/amp-parts/poten ... ebi1I3VDnE

For the resistor readings, you are correct. 1R = 1 Ohm. 1k5= 1500 Ohms.

Using either the R or K instead of a decimal place is an older common practice, mostly due to decimal points getting lost or added accidentally in copy machines and such.

Good luck,
Steve

So would it be safe to say that the 1.5K Ohm resistor is 1 watt? I would assume all the resistors are 1 watt?

[steve_p]

Any idea what the value would be on the bias pot?

Also, What is a "1R" resistor? 1 Ohm?

Same for the 1K5 - is that 1KOhm 5 watt?

Generally, fender bias pots are 10k linear pots.
Here is a commonly used component:
http://www.mojotone.com/amp-parts/poten ... ebi1I3VDnE

For the resistor readings, you are correct. 1R = 1 Ohm. 1k5= 1500 Ohms.

Using either the R or K instead of a decimal place is an older common practice, mostly due to decimal points getting lost or added accidentally in copy machines and such.

Good luck,
Steve

So would it be safe to say that the 1.5K Ohm resistor is 1 watt? I would assume all the resistors are 1 watt?

For the 1k5 cathode resistors, 1 Watt will be fine. You may want to use a precision metal film resistor here, such as an RN65.
RN65s would also be a good choice for the 100k plate resistors on V1.

For the other signal path resistors, 1W carbon film will be perfect.

Good luck,
Steve

[beasleybodyshop]

Would you say that as far as capacitors go, its really just a matter of preference? I'm thinking orange drops...

[steve_p]

Would you say that as far as capacitors go, its really just a matter of preference? I'm thinking orange drops...

Orange drop caps, specifically the Sprague 6ps series, are generally considered the Cap of choice in dumble builds.
Antique Electronic Supply carries the line: http://www.tubesandmore.com/products/C-S-600

[drew]

So would it be safe to say that the 1.5K Ohm resistor is 1 watt? I would assume all the resistors are 1 watt?

The 470R screen resistors (four on the power tube sockets and one on the bias board) and the 6K8 and 19K dropping resistors (left end of the circuit board) need to be higher-rated, probably 3 watt.

A couple of observations, if you don't mind:

1. The questions you're asking kind of indicate that you don't know too much about a lot of amp-building basics. This is not a criticism; it's good that you're at least recognizing that there are a lot of things you need to ask about. But if this is a first amp build for you, you might be better off either starting with some kind of kit amp that has detailed instructions, or a well-documented forum amp, or else just holding off for a while and doing a lot of reading and studying.

2. This amp is a hundred watt Princeton. Are you really sure you want, or need, a hundred watt Princeton? Once you've given everyone you know the "listen to how loud this thing is!" tour, what then?

3. While this amp is somewhat simpler than the later, more familiar Dumble amps, it's not like it's a Champ or something. When you consider that you're going to have to buy the big iron and the quad of power tubes anyway, are you sure you don't want to just go ahead and build a mainstream Dumble? It's just one more preamp tube, a higher parts count, and will take longer to finish. I think you can get a ready-to-use chassis, and maybe boards also, from vendors which are discussed here at TAG. You'll end up with something a lot more versatile than a hundred watt Princeton.

[dobbhill]

drew makes some good points. I'll try to help, also.

There is no such thing as a Dumble build for a beginner builder.

These are as difficult to build as they are rewarding to play. I would also suggest a less ambitious build first. I started with a Super Reverb, then converted it into my first Dumble Build. I had done mods for years before that.

Best of luck.

D

[beasleybodyshop]

Thanks for the frankness guys. I am already in the middle of my very first amp build, a 50 Watt plexi that im stuffing into an older Peavey 212 cabinet/chassis. I don't really plan on building another one until I finish this one. Asking lots of questions is how I learn, and I really enjoy putting the info together bit by bit until I get the job done.

As far as a chassis goes, I have a nice metal brake and aluminum stock. Im just deciding what size chassis/amp head i want to make.

I also have a 8X4 sheet of baltic birch ply that the folks at work tell me I need to take home Im trying to get all my dimensions together so I can rip it up into the pieces I need.

Honestly as I am working my way through my plexi build, I was kind of wanting to build another amp in a nice new chassis/head unit.

Thank you everyone for answering all of my questions

[M Fowler]

Another good simple dumble style amp is Normster's 16x8x2 (chassis) which is a Dlite that Brownnote amps improved upon with relays, etc.

I built mine in a blank Princeton Reverb chassis and head cab.

Mark

[beasleybodyshop]

Another good simple dumble style amp is Normster's 16x8x2 (chassis) which is a Dlite that Brownnote amps improved upon with relays, etc.

I built mine in a blank Princeton Reverb chassis and head cab.

Mark

That is super nice! I really dig the bias probe inserts in the back! I am going to use those on my plexi build.

I really think this design is the way to go for me. Thanks M Fowler, tomorrow im going to go press some chassis from some aluminum stock I have on hand, guess I should crank out a princeton spec one too!