6N16B True tube overdrive with SMPS supply

rasta_maleek · Post by **rasta_maleek** » 23 Mar 2011, 09:58

Hi all, i was looking for a protect like this, I have a lot of 6N17b tube that bought for the baja real tube driver. Maybe I'll do the pcb to fit in a 1590B enclosure.
Cheers

DarkRain · Post by **DarkRain** » 22 Apr 2011, 05:37

Finally a finished product

- "Overdose Tube Drive" - 300v SMPS anode supply and 6n17B tubes.
Enjoy!

Best regards,
Gabriel Tudoran
Analog Sound

rasta_maleek · Post by **rasta_maleek** » 22 Apr 2011, 07:34

could you post some guts?
thx dude.

DarkRain · Post by **DarkRain** » 31 May 2011, 18:40

Was a long period of time since i didn't post smth on this topic, but i've worked a lot at a design that will satisfy most of the rock and blues guitarists. There ware a lot of changes that ware made at this stompbox and i will post them in order:

- first i've used other tubes: insted of 6n16b i've used 6n17b
- all tubes are biased @ -1.5v with a lod line from 250v to 5mA per triode (that is the most linear zone with this anode voltage)
- the first 2 stages are bypassed by 2 x 680n capacitors (the 3rd use no bypass cap)
- there is a grid stopper between 1st and 2nd stage (220k)
- there is a attenuation network between 2nd and 3rd stage 1M and 220k to ground
- a bypass cap on the 1st grid stopper (atm is 1n)
That would be it, same SMPS.

I've posted some picts (you will see that this is more of a beta stage), and also you will finde here a clip (various levels of gain are made ony by picking strenghth and guitar volume):http://dl.dropbox.com/u/15275178/Clips/OT.mp3

I will post a schematic ASAP and also pictures when the final product will be ready... 1 month of work ... hope it will worth.

Best regards,
Gabriel Tudoran
Analog Sound

DarkRain · Post by **DarkRain** » 10 Jun 2011, 22:58

A new version (hope it will end soon

) - you can call it RC1 beta version

) .
Enoy!

Best regards,
Gabriel Tudoran
Analog Sound

phatt · Post by **phatt** » 11 Jun 2011, 14:13

Hi Darkrain,
Great effort on your part
LOL if it makes you feel better your boards are neater than mine

This might interest you and others,, though this does need a dedicated Plugpak/Wallwart as it draws 40mA for HT and also has to supply 150mA for heaters.
http://diyaudioprojects.com/Tubes/12AX7_Preamp/
Of course the valve circuit is of no use to guitar players but the Supply does actually work,, As I've built two of these SMPSU and yes the grounding with SMPU's can be a nightmare but with a close eye on your ground path they can be silenced.
ps,
If anyone is clever enough to workout how to get the HT to deliver about 100mA please PM me as that would allow the use of a full PP Amp.
Phil.

ALDOUSCROSS · Post by **ALDOUSCROSS** » 11 Jun 2011, 23:44

ei how much current does a 555 SMPS can supply?

DarkRain · Post by **DarkRain** » 12 Jun 2011, 21:37

phatt wrote:Hi Darkrain,
Great effort on your part
LOL if it makes you feel better your boards are neater than mine

This might interest you and others,, though this does need a dedicated Plugpak/Wallwart as it draws 40mA for HT and also has to supply 150mA for heaters.
http://diyaudioprojects.com/Tubes/12AX7_Preamp/
Of course the valve circuit is of no use to guitar players but the Supply does actually work,, As I've built two of these SMPSU and yes the grounding with SMPU's can be a nightmare but with a close eye on your ground path they can be silenced.
ps,
If anyone is clever enough to workout how to get the HT to deliver about 100mA please PM me as that would allow the use of a full PP Amp.
Phil.

Thank you Phatt for your kind words, as regarding the supply current from 555 SMPS, i've managed to use it with 3 x 12ax7 or 3 x 6n17b without much heat

and running stedy @ 260V.

Best regards,
Gabriel Tudoran
Analog Sound

phatt · Post by **phatt** » 16 Jun 2011, 13:14

Hi Darkrain,
Impressive

Q, Can I assume the heater supply for Ax7 is not derived from a 9Volt battery as it would run down very fast?

Phil.

DarkRain · Post by **DarkRain** » 16 Jun 2011, 19:23

Hey Phatt,

You cant use a battery as a supply - you need 12v @ 2-3A (just to be sure - you can use 1.5A), the heaters are going to eat about 700-800mA (for both tubes) and the SMPS is going to eat at least 100mA.. so a 9v battery is not an option.

Best regards,
Gabriel Tudoran
Analog Sound

DarkRain · Post by **DarkRain** » 31 Aug 2011, 12:21

Hello guys, log time no talk

and i'm verry happy that FSB is back online (i rilly missed this comunity). In this whole time i've made some experiments with submini-triodes.
I've bought some 6n33b wich is a double triode with a maximum anode voltage of 100v and amplifiocation factor of 80 (very nice double triode IMHO).
The latest buid is a submini amp - 6n33b in preamp section and 6n16b in power amp, the OT is a Hammond 125A with 8k primary impedance - the power amp section is self split. The clean power is about 800mW and in at full blast is 1.2w - in a 1x12" cabinet with Celestion (spl 100db) is way too loud for hours over 22:00

and @ full blast is loud for any hour.

I will post the schematic here when i will have a little time to transcribe it in Eagle. Till then, some pictures and a sound clip recorded by a friend of mine (no postprecessing was done).

Picture:

Sound clip:

Best regards,
Gabriel Tudoran
Analog Sound

DarkRain · Post by **DarkRain** » 07 Sep 2011, 07:36

Another build, this time SMPS is on the same boardj and insted of submini tubes i've used 12AX7 tubes, the whole pcb will fit inside a 1590BB type enclosure - i will also post the schematic and PCB later today.

Best regards,
Gabriel Tudoran
Analog Sound

himister · Post by **himister** » 10 Sep 2011, 15:41

Good work mate...can't wait to see this last pcb and schematic.

phatt posted a link above about some other tube preamp projects and I worked pcb design for SMPS on that one long time ago...
it can be found here https://www.freestompboxes.org/viewtopic ... 540#p68000
Cheers

DarkRain · Post by **DarkRain** » 13 Sep 2011, 19:54

Hey guys, this is the schematic for the GTFO (get the fuck out) distortion pedal with the SMPS included on the same board. If you need anything else do not hesitate to ask.

Best regards,
Gabriel Tudoran
Analog Sound

DarkRain · Post by **DarkRain** » 14 Sep 2011, 20:41

Allright guys... i've made some experiments today regarding the SMPS PSU and i've modify it so i can control the duty cycle of the oscillator. There is one big advantage here: the nixie PSU had a little design fault - the output voltage was controlled by the variation of FRQ and in the original config (R1-1k and R2-10k) the duty cycle was ~52%. By rising the FRQ you would put a lot of stress on the FET and Inductor (a lot of heat was disipated) - so you codn't go with the FRQ to high and sometimes, especially in h-gain circuits you would have some switching noise. The work around for this - higher FRQ that would put all noise out of audio spectrum would be to keep the FRQ constant and modify the duty cycle (wich is the right way to modify the output voltage and keep the things clean). So this is the PSU modification:

The instresting part is the construction that was made on pin 7, 6 and 2 - 2 diodes (i used UF4004 - that was on my right hand ) and a little trimmer (i used 20k). This mod will keep things cool and give you an output voltage of 300v without too much heat and without instability.

Hope you will find this little workaround useful for future projects.

Best regards,
Gabriel Tudoran
Analog Sound

earthtonesaudio · Post by **earthtonesaudio** » 14 Sep 2011, 21:40

That PWM circuit changes the frequency and duty cycle simultaneously. Highest freq at 50% duty, etc.

DarkRain · Post by **DarkRain** » 14 Sep 2011, 21:45

Thank you for you post, that is correct, my mistake. Didin't keep in mind the fact that resistor varioation will go on freq variation.

Best regards,
Gabriel Tudoran
Analog Sound

PS: I found it much stable thow the with the classical topology.

earthtonesaudio · Post by **earthtonesaudio** » 15 Sep 2011, 01:55

Right, I was not implying that it would not work. I think the fact that the duty cycle changes with frequency probably helps prevent the overheating problem you were experiencing with changing the frequency alone.

DarkRain · Post by **DarkRain** » 19 Sep 2011, 06:49

Just made some clips with the pedal, hop you will like them - there are clips with various mods done (mainly just caps).

Best regards,
Gabriel Tudoran
Analog Sound

Emanuele II · Post by **Emanuele II** » 10 Sep 2012, 22:34

I resume this post for some questions..

Today I finished my valve pedal..it works flawlessy except for boring HUM, it sounds similar to a 60hz cycle hum, but that's strange since my power adapter is hum free..as soon as I connect other dirt pedals with a daisy chain they became useless as the hum rises up with the gain..

On a side note my build is a bit different:

I put togheter the first two gain stages of a plexi, built around a 12AU7, my SMPS is built from scratch, and while I'm waiting for the right mosfet, it now pumps out 70V from a 9V boss style PSU..