Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Rockranger on July 16, 2018, 07:20:27 am

Title: Matchless Spitfire
Post by: Rockranger on July 16, 2018, 07:20:27 am

Built this clone and I love it, the only thing I find is that it adds too much treble as soon as you start turning the tone knob, just wondering what is the best way to take some of that treble out of the tone?
http://www.ceriatone.com/ceriatone/wp-content/uploads/2016/08/SpitFireCeriatone.jpg

Thanks

Title: Re: Matchless Spitfire
Post by: sluckey on July 16, 2018, 07:45:08 am

Remove the 180pf bright cap from the volume control. Any better?

Title: Re: Matchless Spitfire
Post by: 66Strat on July 16, 2018, 10:31:44 am

You might try wiring up the tone control 5F2A Princeton style. See attached. This would allow more control over the brightness and roll-off. If the control is still too bright, you could try swapping the 180pf cap for a 120pf or smaller cap.

Title: Re: Matchless Spitfire
Post by: bmccowan on July 16, 2018, 11:01:46 am

As Sluckey suggests, I removed the bright cap from mine, and like it much better. I just unsoldered one leg of the cap so that I could easily add it back it I wanted. I also like this amp better with both the vol and tone knobs on the guitar rolled back a bit.

Title: Re: Matchless Spitfire
Post by: Rockranger on July 16, 2018, 04:44:11 pm

Tried all suggestions clipping the bright cap helped a lot sounds great, thanks guys!

Title: Re: Matchless Spitfire
Post by: Leevi on July 18, 2018, 02:49:28 am

You can also change the 0.002u coupling cap to a bigger one.
Removal of the 180p helps with lower volume.


http://www.prowessamplifiers.com/schematics/post/matchless_spitfire.pdf


/Leevi

Title: Re: Matchless Spitfire
Post by: pompeiisneaks on July 19, 2018, 03:25:57 pm

another option is to put it on a switch so you can have it back for guitars with a bit less treble if you want it back in.  I.e. it may work great with humbuckers but not so much with single coils and P90's etc.

~Phil

Title: Re: Matchless Spitfire
Post by: darkbluemurder on July 20, 2018, 07:29:34 am

I once had a Spitfire build with a pair of 6V6 tubes. I made the bright cap switchable but left it on all the time otherwise it was too dull for me.
Instead of the 2200pf coupling cap I used a 4700pf for more low end.
The only other changes I made were to the phase inverter - instead of the 47k tail resistor I used 33k and instead of the 1k2 bias resistor I used 820 ohms.
That amp no longer exists, though.


Cheers Stephan

Title: Re: Matchless Spitfire
Post by: MFowler on July 21, 2018, 06:29:48 am

I would add a treble cut control so you can decrease that high treble in the power amp section.


The bias using 1k2 gives this amp it's sparkle.