Exploring the monster (trafoless mic pre input)

[bcarso]

"Any of the guru's have a good suggestion on making gain adjustable in the monster stage without global feedback or an attenuator? "

Switch in different FETs? (mainly kidding here)

 

[Winston OBoogie]

...

 

[bcarso]

If the output is the darlingnot, loading it down won't do much.

Reminds of Blazing Saddles when the Sheriff, about to deal with the dreaded Mongo, is putting his gunbelt on and the Kid says "Oh no. Don't shoot him. You'll only make him mad."

You can vary the collector resistor of the NPN, but you will start to run out of signal swing.

 

[tk@halmi]

Cap couple the output and put an R load on it ? you could get a bit of gain loss that way.

I like that! That may yield more fuzz than a gorilla's back can take.

I see quite a bit of switch juggling involved though.

No problem, I say the more switching the better.

 

[Winston OBoogie]

...

 

[bcarso]

Ah better. Thanks for clairification. At least I had an excuse to use another Blazing Saddles gag.

I guess (though it adds parts) that I would use an I source and have the loading R at that point a voltage divider to set the approximate bias point to where there was no d.c. in that load R. Then it could be varied without disturbing the operating point.

 

[Winston OBoogie]

...

 

[fum]

"My mind is a raging torrent, flooded with rivulets of thought cascading into a waterfall of creative alternatives" :grin:

I think the PRR circuit would likely get me where I need to go, if I can implement it using +/- 18V.

PRR states that the output impedence is high, ok to drive an API 325 card?

I did a layout for another one of PRR's differential inputs, but couldn't get it down to a small single sided board ( dual layer was no problem).

I'll give this one a whack, and see how it goes =)

ju

 

[bcarso]

Is that in addition to this one?

Hedley Lamarr:

"My mind is aglow with transient nodes of thought---careening through a cosmic vapor of invention." Taggart: "Ditto!" Lamarr: "Ditto!! Ditto!! What do you mean 'Ditto', you provincial putz?!"

I hated it when that movie was shown at the UCLA Student Union, since you could hardly hear the dialogue for all of the people reciting it (shades of Rocky Horror).

 

[Winston OBoogie]

...

 

[bcarso]

Was asking fum if that Blazing S. quote was another one (or just an alteration of the one I posted).

Ah found it in the quote compendium: "(1) My mind is a raging torrent, flooded with rivulets of thought, cascading into a waterfall of creative alternatives. (2) Gal-darnit, Mr. Lamarr, you use your tongue prettier than a 20-dollar whore. "

 

[tk@halmi]

I just finished my set of simulations on PRR's diff circuit without the output stage. It works really nice in model land. I will bread board it soon. :thumb:
I may use a GainBloak as the second stage, use a dual deck six pole switch to set gain simultaneously, andl stick a pot between them to allow fine volume adjustment.

Cheers,
Tamas

 

[fum]

I just finished a layout of PRR's design. I was planning some variants including the monster output, but wanted to get this one working first:

http://www.groupdiy.com/FORUM/viewtopic.php?t=4510&postdays=0&postorder=asc&start=15&sid=0bfd3d39c787e95f80d7c4f474748e97

Regards

ju