Dumble SSS #002 Preamp Build (with SMPS power supply)

[jhjh217]

Hi, I just finished my dumble sss #002 preamp project recently, and wanted to share.

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Inspired by ''peace hill fx' preamp pedals, I decided to make one similar.

I used schematic from here. and only used the preamp portion.
https://github.com/colganr/steel-string-singer-sn-002

Chassis used: Hammond 1550E

Power supply:
12v dc power supply, boost it up to 345v using dc boost converter. $6 from ebay, I was susceptible at first, but it actually works perfectly fine.


Boost converter used:

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12v heats up heater filaments directly (in series)

High voltage(235v) feeds anode of two 12ax7 tubes.
345v needed in the final cathode follower circuit.

Because of cathode follower circuit, low impedance output is possible, which is perfect for building a seperate preamp like this. (Essentially a buffered fx send)

I used eyelet boards from amplifiedparts. And to minimize size, I mounted componoent on both sides of the board. (But of course gave enough space for heating components!!)

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Hand drilled all the holes.
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Downside of using an SMPS for audio is noise. When I first built it it had a very harsh buzzing noise, and at first I had a hard time finding where that noise was coming from (and rewired all the ground wires just to find it.. but it was actually coming from the power supply..)
I filtered out those noise using second order RC filtering on the output of the boost converter, (using 22uF capacitors and 1K ohm resistors) and now it's DEAD quiet.

It's powered with a 12V DC supply. Current draw is about 550mA.
So it can be mounted on a pedal board!

I'm currently building a second version with some upgrades, and a separate power amp to match with it. (Planning on a SMPS powered power amp.)

[rootz]

This is so cool! Really would like to hear this pedal.

I'm al too familiar with SMPS induced hum. On my latest SMPS project, a clone of the Fishman rechargeable backplate, I ended up with extra C-L-C filtering at input and output of the SMPS. That one was dead silent with EMG's.

[rccolgan]

Niicceeeeeee man! This is incredible!

[WhopperPlate]

I want to hear and see the smps power amp

[timrobertson100]

Wow. Impressive work. Would love to see a video of this.

[jhjh217]

Wow. Impressive work. Would love to see a video of this.

This is so cool! Really would like to hear this pedal.

I'm al too familiar with SMPS induced hum. On my latest SMPS project, a clone of the Fishman rechargeable backplate, I ended up with extra C-L-C filtering at input and output of the SMPS. That one was dead silent with EMG's.

I'll soon upload a video playing it
And yes the SMPS noise.. At first it was super noisy. 'Buzzing' noise from the SMPS. For my current build I did 2nd order RC filtering (68uF, 1K ohm) at the output of the SMPS, and it's literally silent. Because of the large capacitance, it has about 2 seconds delay charging up those capacitors when turned on though.
SMPS isn't a popular choice for audio purposes because of the noise, but in my experience, it is very filterable! I think it can be quieter than the original power supply using power transformers maybe..?

[jhjh217]

I want to hear and see the smps power amp

Unlike preamp tubes, power amp tubes need much more power. It was nearly impossible to supply 3 tubes with a single SMPS, so instead of a push-pull design, I decided to build a single-ended design. I tried building it with a 30W 6L6GC powertube, but mosfets were heating up too much, and SMPS was nearly operating at its max. So I decided to step it down a little and decided to use a 23W 5881 powertube. This is my current progress: not quite finished with the poweramp, but soon will be.
When it's finished, I'll start another post about it: SMPS powered Class A(single-ended) 5881 Poweramp

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Why not build a full amp?
I play at church, and sometimes gig at bars. I always hated bringing an amp with me all the time. and usually the place I gig in has an amp. To get consistent tone, I needed a preamp to bring with me, but I always hated the sound from preamp modelers. So I made a analog preamp pedal that is mountable on a pedalboard.
For smaller gigs, I can use that setting I built(preamp+poweramp). And when I need more volume and headroom, I can just bring my preamp separately, and use the amp at the place I gig in.

[bcmatt]

This is so cool! Really would like to hear this pedal.

I'm al too familiar with SMPS induced hum. On my latest SMPS project, a clone of the Fishman rechargeable backplate, I ended up with extra C-L-C filtering at input and output of the SMPS. That one was dead silent with EMG's.

I would love to hear it too!

Also, I'd love to hear more about your rechargeable backplate project and what you had to do to overcome any obstacles....

[jhjh217]

It's been a long time since my last upload..
I've been busy lately..
But, finally here's the video! with a sound demo.

It's paired with a 5881 single ended (class A) power amp, with celestion vintage 30 speaker.

https://youtu.be/Aw5sZy5RcD8

[xtian]

Bitchin'! Great work!

[rccolgan]

siickkk!!! Awesome video!! Great tones. Many WOW!

[j0k3335]

After watching/hearing this video, I thought to myself :

... and would you think of commercializing a such product ?

Even going further: by be able to provide different preamps? (Robben, Ripper, Bluesmaster, ...)?

I wonder if you wouldn't have some success (when I see the success that some have with simple pedals with integrated circuits, transistors and others... with sounds...
"NOT SO" close to Dumble!!! ) ?!

[jhjh217]

siickkk!!! Awesome video!! Great tones. Many WOW!

Bitchin'! Great work!

Thanks for all the complements guys!

After watching/hearing this video, I thought to myself :

... and would you think of commercializing a such product ?

Even going further: by be able to provide different preamps? (Robben, Ripper, Bluesmaster, ...)?

I wonder if you wouldn't have some success (when I see the success that some have with simple pedals with integrated circuits, transistors and others... with sounds...
"NOT SO" close to Dumble!!! ) ?!

Wow! I really appreciate your opinion! Thank you for thinking highly of this project

This started as a personal project; to make a preamp I actually use on gigs. But I did thought of commercializing though.
If I ever commercialize it, I thought of making several standalone preamps (dumble, marshall, fender etc.) and several different standalone poweramps (single-ended, push-pull, with different powertubes etc.) and mix and match whatever preamp and poweramp you like. But I have a long way to go before I can even start selling, and commercializing..
Since I'm finished with this dumble preamp project, I'll start another preamp project so I can slowly expand my library.

For the poweramp: I just finished a 5881 single ended standalone power-amp project recently. You can check this forum & youtube:
https://ampgarage.com/forum/viewtopic.p ... 47#p455347
https://youtu.be/ZmnO8MMYe9k

(and I'm currently building a standalone push-pull power-amplifier right now).

[j0k3335]

Wow! I really appreciate your opinion! Thank you for thinking highly of this project

This started as a personal project; to make a preamp I actually use on gigs. But I did thought of commercializing though.
If I ever commercialize it, I thought of making several standalone preamps (dumble, marshall, fender etc.) and several different standalone poweramps (single-ended, push-pull, with different powertubes etc.) and mix and match whatever preamp and poweramp you like. But I have a long way to go before I can even start selling, and commercializing..
Since I'm finished with this dumble preamp project, I'll start another preamp project so I can slowly expand my library.

...

... I see that you have a "Prince of Tone" for example: when we see how its price is soaring, if we also consider the crazy price of the "original" Zendrive (Hermida), the Ethos, ... when we see the Kingsley pedals (most often with tubes and also very often "Dumble" oriented),

I definitely think there could be a market (?) AND, furthermore, your concept of being able to provide different preamps, different units of power, would be a plus.

... now, stay => ... the market study: how much does it cost you, how much time you spend on it... ... and therefore comparing with the prices above: would it be profitable.

This is an important question: because between the pleasure and pride of designing such creations and then the price at which they could be sold must be considered VERY seriously.

About ten years ago, the rate of the Euro against the Dollar was very advantageous (...this is frankly no longer the case!!! ): I had the idea of buying lots of body, neck, parts, of US strat to make quality partcasters.
... it was a real disaster... because I hadn't done any market research... and, in fact, market, well there had none: no one in France wants to buy "Fender", if they don't come out of a music store (even if mine were cheaper, with selected components, high-end pickups ... ...).

...I sold some to friends...at cost price and had to sell off everything else

... anyway : congratulations for your design and these creations!