Matchless HOT-BOX

[gtudoran]

Hey guys,

After 2 weeks of tweeking i've finished a clone of Matchless HOT Box. The schematic that i used is:

The modes that i've made:

On the first triode i've changed the 0.022uF from the anode with 0.01
On the 3rd triode i've put in parallel with 100k rezistor from anode a 330pf cap
Scale down a the rezistive divider between the 2nd and 3rd triode.

And here we are with some samples: clean and drive.
The 4th is the clean one .

http://blog.analog-sound.com/wp-content/uploads/2010/06/plm3mp3.mp3
http://blog.analog-sound.com/wp-content/uploads/2010/06/plm2mp3.mp3
http://blog.analog-sound.com/wp-content/uploads/2010/06/plmmp3.mp3
http://blog.analog-sound.com/wp-content/uploads/2010/06/plm5mp3.mp3

Any comments are welcomed.

Best regards,
Gabriel Tudoran
Analog Sound

[DiamondDog]

Sounds pretty good. 

Did you do it PTP or...?

[gtudoran]

Yep the layout was made PtP strait on the tube sockets .

Best regards,
Gabriel Tudoran
Analog Sound

[kupfer_m]

I've seen this schematic a few times and I'm confused with how the output potentiometer is wired.
Why not connect the tone-control output to the top of volume-pot and the wiper to the output plug?



Jim

[gtudoran]

I don't think is a big deal regarding this kind of wireing... you could put it in any mode. This is one mode from many other, but i belive in this typical example you use also the pot. resistance (like one more rezistor to ground to limit the signal a little). I wire it in the classic way and is working like a charm.

Best regards,
Gabriel Tudoran
Analog Sound

[Brymus]

How about some pics ?
Its always interesting to see how people build thier HV tube pedals.
What transformer did you use,ect ?
Come on give us the details.

[gtudoran]

How about some pics ?
Its always interesting to see how people build thier HV tube pedals.
What transformer did you use,ect ?
Come on give us the details.

Hey Brymus, i will post some pictures too ... as soon as my brotherinlaw will buy e another camera...at this time i got it on a test chasee (the place where i make most of my tube prototypes). I've user a 40va toroid transformer with the following voltages: 6.3v@2A (2.5 to be exact) and 200v @ 100mA. They are custom made by a friend of mine.
Not much to say about this,i used russian double triodes 6n2p and wima caps, ceramic sokets and point to point connections with ground bus.
Alpha pots and no shilded cable a good ground worth 1000points
And the switching between clean and drive will be made with 6v relay with a standard bistable schematic (didn't do it yet... i'm a lasy person ) ).

And those are the last audio clips with this preamp. Recorded trough a cabsim (a marshall one don't remember well and a little bit of reverb at mix time)
http://blog.analog-sound.com/wp-content/uploads/2010/06/ritmmaxgain.ogg
http://blog.analog-sound.com/wp-content/uploads/2010/06/ritm.ogg
Best regards,
Gabriel Tudoran
Analog Sound

[gtudoran]

Hello guys,

I'm back with a little concept of mine, in case that anyone is interested. This preamp use 2 double triodes (i have used 6n16b for this but any double triode will work: 12ax7, ecc83, ecc82, 6n2p, 6n1p (i even recomand to try and listen Ecc85 (it's a hell of a tube)).
The design is a classic one: the first triode amplify the guitar signal (input impedance set at approx. 1M). In the second stage C8 take off that high-end of the sound. I used 1M gain pot but a 500k will do just fine. WARNING!: The gain pot is very important for 2nd triode polarisation so the 3rd lug must be set to ground potential.
We have a voltage divider formed by 2 x 470 kohm resistors so the 3rd triode is not too hard over-driven.
The 3rd triode is set in a very common configuration for high-gain pre-amps (just adds a little grit to the final tone).
A tone stack formed only with bass and treble controls. And a cathode follower for the output stage so we can use this preamp with mixers/sound-cards etc. without the fear that the signal will be overloaded.

I'm waiting for you opinions regarding this and any improvements that could be made.
Best regards,
Gabriel Tudoran
Analog Sound

PS: This preamp could be used also as a starting point for a self split mini tube amp with 6n16b as output tube and a 8k:8ohm output transformer (this is a very good tube bc. it has a very small internal resistance : max. is 14k @1mA and i used it @7mA so the internal resistance is about 4.7k according to D.S.)
So any tranny with a primary of 8k to 10k and a secondary of 4 to 8 ohm will do the trick.

[gtudoran]

Hey guys,

Just finished this preamp and the output section from firefly and i must say that i'm amazed what can i say...
I recorded a clip with the amp a 10" celestion tube 10 speaker and a computer mike.... not very loud but you get the ideea . The output stage is 1 to 1 with firefly with the mention  that i use 6n1p as output tube and a 70v line transformer (i have about 10 of them from ebay - speco is the company or smth like that) with 8k in primary coil and 4 & 8 ohm in secondary coil.
If you have any questions i will be more then happy to answer.

http://blog.analog-sound.com/wp-content/uploads/2010/06/amp1wmp3.mp3

LE: Volume is about 25%.

Best regards,
Gabriel Tudoran
Analog Sound

[gtudoran]

The power amp section for this mini amp (approx 1w). I took as a template the output section from the D.H. - Firefly and i modified it to fit my needs and tubes (6N1P).
Cathode resistor modified to 800ohm(in the first place i had 460ohm witch give me about 10mA trough the tube but i would like to preserve the life of the tube and run it at 5mA any value witch will keep the current at 5 to 8mA will be ok), that would give me about 5.5mA tube current @ 221v anode voltage.
Coupling cap. modified to 0.01uF.
To compensate a little I've decoupled the cathode resistor with 22u pol. cap (22u/50v should be more then enough).

Best regards,
Gabriel Tudoran
Analog Sound

[gtudoran]

A little audio clip with the amp: guitar squier strat sss, cabinet 1xcelestion tube drive 10", computer mike (the pops are from my asio4all driver).
http://blog.analog-sound.com/wp-content/uploads/2010/07/amp1w-take3-3.mp3

Best regards,
Gabriel Tudoran
Analog Sound

[DougH]

That Hot Box sounds pretty cool. Are the ogg clips through a cab sim or amp? They sound good.

[gtudoran]

That Hot Box sounds pretty cool. Are the ogg clips through a cab sim or amp? They sound good.

Hello Doug,

The ogg clips are recorded trough a cab-sim also. The only recording that was made with a mike is the last one (the one that i used the power amp and the preamp).

Best regards,
Gabriel Tudoran
Analog Sound