Freestompboxes Baja Mini Tube Overdrive  [documentation]

Original effects with schematics, layouts and instructions, freely contributed by members or found in publications. Cannot be used for commercial purposes without the consent of the owners of the copyright.
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bajaman
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Post by bajaman »

Hi folks
here is a new design I have been working on using Russian 6N17B double triodes which I bought from urals shop on Ebay a couple of years ago!!.
a few design challenges - they don't behave the same as 12AX7 or ECC83 twin triodes, but they are small enough to shrink my Real Tube Overdrive down to fit in a 1590B enclosure :lol:
In the meantime here are some pictures of the prototype.
cheers
Steve
DSCF0001.jpg
DSCF0002.jpg
DSCF0003.jpg
DSCF0004.jpg
DSCF0005.jpg
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bajaman
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Post by bajaman »

The 6N17B has a 6.3v heater requiremement, so I am using a 10v AC power pack and a 10 ohm dropper resistor.
More soon.
cheers
Steve
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Post by bajaman »

I have the design 99% finished :D
I had to play around with the bias to the tube - it biases up completely different to a 12AX7 / ECC83 tube :wink:
AND - I had to power it from a 10V AC 1 amp plugpack instead of my usual 16V AC 1.5Amp plugpack, because the tube heaters are internally connected in parallel and require 400mA at 6.3v AC to operate correctly. The dropper resistor was getting WAY TOO HOT to touch at this current demand - dropping 10vAC at 400mA is not a good idea in a very small enclosure.
Using a 10V AC supply rectifies this problem perfectly.
I guess there will be some that ask -"can it run off 9v dc battery?". The short answer is NO - this thing draws over 400mA when you count the op amp and tube ht into the equation - a 9v dc battery would be flat before you have played your first set :lol: :wink:
The 6N17B mini tubes seem to be readily available through Urals Shop in Siberia on Ebay for around US$1.00 each

Cheers
Steve
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Post by bajaman »

Hi folks - here it is :D
The more observant will note some differences between this finished project design and the earlier posted prototype pictures, however the pictures are a good guide as to how the finished mini tube overdrive will look.
Now I do not expect you guys to race off and build one each immediately (next week will be fine :lol: :lol: :lol: ) - just kidding :wink:
Enjoy :hug:
cheers
Steve
label.png
layout.png
PCB.png
notes.png
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Post by bajaman »

I forgot to mention :slap:
It runs off 10v AC (at least 500mA supply - preferably 1A :wink: )
The indicator LED is fitted last and insulated thin wires are fed through the hole in the mainboard and attached to the terminals marked LED+ and LED- on the track side of the board.
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Post by bajaman »

all artwork is 600 dpi :wink:
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Post by frequencycentral »

Looks great Baj, really well thought out implementation too. :wink:

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Post by hgamal »

Baja,

great work!

Can't you post the schematics?

Why not use an standard voltage regulator as 7806 in order source tube filaments? We can use the BOX as thermal dissipator. Actually, AC 10v power source isn't what we call a standard value!

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Post by schemripper »

bajaman wrote:I have the design 99% finished :D
Thanks a lot, Steve. You know I've just finished a BRTO and you pull this one me! :slap:

Another one for the build list, me thinks...

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Post by salocin »

:thumbsup Excellent job as always!

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Post by JOHNO »

Great work Baja and thank you but, how does it sound compared to the original Baja real tube overdrive?

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Post by bajaman »

how does it sound compared to the original Baja real tube overdrive?
similar - but different :?
still have not compared them side by side properly yet - first impressions are the mini tube sounds maybe a bit brighter and perhaps more compressed.
i will test them both at full volume when I practice with the boys next Saturday :wink:
cheers
bajaman
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Post by Spazzmatazz »

nice pro job baja!

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Post by borislavgajic »

bajaman wrote:
how does it sound compared to the original Baja real tube overdrive?
similar - but different :?
still have not compared them side by side properly yet - first impressions are the mini tube sounds maybe a bit brighter and perhaps more compressed.
i will test them both at full volume when I practice with the boys next Saturday :wink:
cheers
bajaman
Thanks....great project
I'll rise glass of vino for you Baja man!!! :thumbsup
some sound clips?

Boris

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Post by rasta_maleek »

hey Baja, great job, you reduce all to a 1590b hammond enclosure, i´m amazed :shock:

could you post the squematic? i´ll be pleased with you

Other question, can i use 6021 subminitube types? have the tube that you use the same pin out??
i have 6111, 6112 and 6021w

thanks a lot for this proyects Baja Man

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Post by bajaman »

Other question, can i use 6021 subminitube types? have the tube that you use the same pin out??
i have 6111, 6112 and 6021w
NO - not without a lot of modification :wink:
cheers
bajaman
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Post by rasta_maleek »

bajaman wrote:
Other question, can i use 6021 subminitube types? have the tube that you use the same pin out??
i have 6111, 6112 and 6021w
NO - not without a lot of modification :wink:
cheers
bajaman
But only need to change the valvle pcb in your design,isn´t it?

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Post by bajaman »

But only need to change the valvle pcb in your design,isn´t it?
No - but don't let me stop you - experiment as much as you like - this design is for the Russian 6N17B :wink: :wink: Other valves WILL NOT WORK CORRECTLY :!: :!: :!:
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Post by rasta_maleek »

bajaman wrote:
But only need to change the valvle pcb in your design,isn´t it?
No - but don't let me stop you - experiment as much as you like - this design is for the Russian 6N17B :wink: :wink: Other valves WILL NOT WORK CORRECTLY :!: :!: :!:
bajaman
thanks baja, i only need to know the pinout of the russian one, to make the changes.

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Post by bajaman »

:roll:
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