Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: TIMBO on February 24, 2013, 03:35:13 pm

Title: Using an unused 12ax7 triode
Post by: TIMBO on February 24, 2013, 03:35:13 pm

Hi guys, An unused 1/2 12ax7 triode is present in my Hiwatt build and i was going to use it as an OD as on sheet 2. This being the usual thing to do. The amp already has some great breakup/distortion when cranked, so to add another gain stage might be too over the top distorted.

Now my limited knowledge but endless ideas has got me thinking that an idea of using it as a CLIPPING circuit at the input of the amp to create an almost Tubescreamer/Fuzzface (but not as harsh or funky) to just clip a little off the top and bottom of the wave to give it some emotion.

Again this is one of my out there ideas, so please tell me if i am way off track.Thanks  :icon_biggrin:

Title: Re: Using an unused 12ax7 triode
Post by: tubeswell on February 25, 2013, 02:25:24 am

Direct coupled CF somewhere?  Parallel stage somewhere? Cascode?

Title: Re: Using an unused 12ax7 triode
Post by: kagliostro on February 25, 2013, 02:36:11 am

Paralleled V1b - V1a ?

CF before ToneStack ?

CF Only Send with LINE level after ToneStack ?

K

Title: Re: Using an unused 12ax7 triode
Post by: TIMBO on February 25, 2013, 03:00:12 am

Thanks guys, I tried it as an extra gain stage off V2 before the TS similar to the DR504OL and things got a bit wiered and lost vol so i took it out. I might try a parallel another day.Thanks

Title: Re: Using an unused 12ax7 triode
Post by: kagliostro on February 25, 2013, 06:54:22 am

Tremolo ?

(http://www.el34world.com/Forum/index.php?action=dlattach;topic=15087.0;attach=35232;image)

K

Title: Re: Using an unused 12ax7 triode
Post by: SILVERGUN on February 25, 2013, 11:06:58 am

On my build, Jojo had me set up my 4th stage as a "soft clipper" based off of a SLO

100K plate and 33K cathode resistor, unbypassed, and I have now dialed that up to 47K,,,SO YES, that's a cool idea

It's a great spot to experiment with a 50K trim pot cathode res. "adjust to taste",,,,,,and I just recently was "experimenting", and got some great OD by using a 1M grid leak, prior to a 100K grid stopper going into that stage (singing OD  :icon_biggrin:).......I'm not sure what the "math" says about that,,,BUT I know what my ears said  :thumbsup:

With that Balance control, you'll be able to set a nice dirty rhythm tone, and then switch to a scorching lead tone  :blob8:

EDIT** I took a look at the schematic and could only picture putting it pre-PI where your (&) is, BUT with that PI, I have no idea what the end result is gonna be...
Next time I'll look at the schematic before I go mouthin' off like that.... :embarrassed: