Small Dumble-ish combo proposal

[rootz]

This is one great little amp. Never heard cleans this great from anything I build in the past. Very relaxed sounding amp. Sweet highs, punchy lows especially in deep mode. Really something you need to hear. No idea how much the EL84 power stage adds to the sonic signature of this amp, but it has got that bright bell like high end so typical for EL84's. Tomorrow the new reverb tank is coming, a 3 spring full length long delay type. Currently I use a short tank with a medium delay and feel something is missing here. I made some video's, but not sure how to get them here.

[fred.violleau]

Very tight build! Congrats! Any audio clip to share the love ?
Cheers!

Fred.

Fred.

[rootz]

Made a few video's with my Z7, but off course 4 GB 4K video is quite too big as an attachment. I extracted just the audio from it though and here it is. I really should make some decent samples with some nice mics.



Mod Edit: Linked audio file as playable

[fred.violleau]

Nice sustain and overtones in those bends! Great clean sound!

Fred.

Fred.

[pompeiisneaks]

Wow sounds great!

~Phil

[norburybrook]

sounds great, doesn't sound like a Dumble at all though with the EL84's, sounds more like a rocket/AC30 crossed with a blackface fender. It's interesting how much tonal effect EL84's have it would seem even though they are the power tubes. Normally you'd be hard pushed to tell the difference between 6L6's and EL34's on an ODS as it's all in the pre amp, but on your amp the EL84'as have over ridden the normally mid focused Dumble pre amp with their sig tone.


I recon this would be a good candidate for the 'cut' control on the P.I.




Nice build.



M

[Synchu]

Looks and sounds very nice.

If you adjust the design, considering the EL84 specs it can sound quite close to 6L6 and/or EL34, though I'd be inclined to get the sig EL84 goodies (by chance or on purpose) more so than not

Niki

[rootz]

Thanks guys. I must admit, I had the deep and bright switches on. All metal film resistors makes the amp a bit brighter too. Add to that a through neck guitar with EMG SA’s. Jup, bright combo. And of course this is a pretty classic tone stack, much more Fender than for example a Skyliner.

[norburybrook]

Thanks guys. I must admit, I had the deep and bright switches on. All metal film resistors makes the amp a bit brighter too. Add to that a through neck guitar with EMG SA’s. Jup, bright combo. And of course this is a pretty classic tone stack, much more Fender than for example a Skyliner.

OK, that makes sense. Great sounding amp, and it's good to see people trying things different and then posting the results for all to see and hear.


Looking forward to seeing her with her clothes on


M

[rootz]

Now I get really curious how a cut control would sound in this amp. Had it in a Trainwreck Rocket clone. Didn’t really work for me, but that’s in a non-feedback amp. Worth the work to just try and see if I like it though. Currently this amp is more of a SSS without the filters. Oh, speaker is a G12M heritage. Broken in but still a bright speaker. So yeah, about everything used for the recording is on the bright side of the spectrum lol.

There’s not much clothes to talk about. Salvaged an old transistor Marshall a few years back and still use the wood. Need to design a face plate. Would also like to try a bigger brother of this amp. A good machine for small clubs with something like quad el84’s or 6v6’s.

Hope to get some recordings done in the next few days, trying out different settings and speakers. I have a evm12l and s lying around.

[10thTx]

That amp sounds lovely! THANKS for sharing the sound clip, photos and all your work.

Any chance that you have an updated schematic that you'd be willing to share? The only schematic I can open on the front page only has four 12AX7 tubes yet the layout has five 12AX7 tubes?

Are you using a version of this attached schematic with lower voltages going into EL84's?

With respect, 10thtx

[rootz]

I do not have an updated schematic. Tbh I didn’t use a schematic for the preamp board at all! I drew a schematic for the power supply though, because I needed to adjust values for the smaller power section.

The schematic you posted looks correct to me, although there are some minor variations. In the tone stack the mid switch is different. I went for a typical Dumble spec 2n2 followed by an 470p, not 1n and 330p like in your schematic. The larger values should give me a bit more mids. Have a look at the layout by Amplified Nation. That was my starting point. Also please note that the reverb driver is made of two paralleled triodes of a 12at7.

As you can see I changed the layout a bit after suggestions in this thread. So now I have less leads in the same eyelet (maximum of 5 instead of 7). Later I found out the original layout I made was exactly the same one as used by TR for their Mayer prototype.

What I think would be fun to do, is to make provisions for the filter section of a SSS on the Pre amp board. That way I would have ended up with a mini SSS.