Freestompboxes Baja Mini Tube Overdrive [documentation]
- bajaman
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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
In the meantime here are some pictures of the prototype.
cheers
Steve
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
In the meantime here are some pictures of the prototype.
cheers
Steve
be kind to all animals - especially human beings
- bajaman
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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
More soon.
cheers
Steve
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- bajaman
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I have the design 99% finished
I had to play around with the bias to the tube - it biases up completely different to a 12AX7 / ECC83 tube
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
The 6N17B mini tubes seem to be readily available through Urals Shop in Siberia on Ebay for around US$1.00 each
Cheers
Steve
I had to play around with the bias to the tube - it biases up completely different to a 12AX7 / ECC83 tube
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
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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- bajaman
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Hi folks - here it is
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 ) - just kidding
Enjoy
cheers
Steve
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 ) - just kidding
Enjoy
cheers
Steve
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- bajaman
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I forgot to mention
It runs off 10v AC (at least 500mA supply - preferably 1A )
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.
It runs off 10v AC (at least 500mA supply - preferably 1A )
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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- bajaman
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all artwork is 600 dpi
bajaman
bajaman
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- frequencycentral
- Cap Cooler
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!
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!
Thanks a lot, Steve. You know I've just finished a BRTO and you pull this one me!bajaman wrote:I have the design 99% finished
Another one for the build list, me thinks...
- bajaman
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similar - but differenthow does it sound compared to the original Baja real tube overdrive?
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
cheers
bajaman
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- Spazzmatazz
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nice pro job baja!
- borislavgajic
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Thanks....great projectbajaman wrote:similar - but differenthow does it sound compared to the original Baja real tube overdrive?
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
cheers
bajaman
I'll rise glass of vino for you Baja man!!!
some sound clips?
Boris
- rasta_maleek
- Resistor Ronker
hey Baja, great job, you reduce all to a 1590b hammond enclosure, i´m amazed
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
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
- bajaman
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NO - not without a lot of modificationOther question, can i use 6021 subminitube types? have the tube that you use the same pin out??
i have 6111, 6112 and 6021w
cheers
bajaman
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- rasta_maleek
- Resistor Ronker
But only need to change the valvle pcb in your design,isn´t it?bajaman wrote:NO - not without a lot of modificationOther question, can i use 6021 subminitube types? have the tube that you use the same pin out??
i have 6111, 6112 and 6021w
cheers
bajaman
- bajaman
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No - but don't let me stop you - experiment as much as you like - this design is for the Russian 6N17B Other valves WILL NOT WORK CORRECTLYBut only need to change the valvle pcb in your design,isn´t it?
bajaman
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- rasta_maleek
- Resistor Ronker
thanks baja, i only need to know the pinout of the russian one, to make the changes.bajaman wrote:No - but don't let me stop you - experiment as much as you like - this design is for the Russian 6N17B Other valves WILL NOT WORK CORRECTLYBut only need to change the valvle pcb in your design,isn´t it?
bajaman
- bajaman
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bajaman
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