Mini-Boogie

[Rafa]

I would like to know if anybody has built or has some info about this project. 12ax7 with only 30V  .
What mods would make it sound good?

http://www.diystompboxes.com/smfforum/index.php?topic=18366.0

Cheers
Rafa

[Cliff Schecht]

12AX7's don't need more than 6.3V@300mA or 12.6V@150mA to get the heaters going... Nothing wrong there. Just remember, having tubes doesn't automatically make something sound good.

[JimRayden]

12AX7's don't need more than 6.3V@300mA or 12.6V@150mA to get the heaters going... Nothing wrong there. Just remember, having tubes doesn't automatically make something sound good.

There is another factor called the 'B+' that does also contribute to the sound.

-----------
Jimbo

[MartyMart]

If I were you, I'd skip ALL the "starved plate" stuff, get an EH transformer from aron and
use proper B+ voltages   
Lots of fun to be had, just watch VERY carefully what you're doing .....

MM.

[frickecello]

If I were you, I'd skip ALL the "starved plate" stuff, get an EH transformer from aron and
use proper B+ voltages  
Lots of fun to be had, just watch VERY carefully what you're doing .....

MM.

Yeah try this one, it features voltages around 300 V, you can use one of those small toroidal trannies, Ive built it and it sounds beatiful it uses 3 valves:

www.paginasprodigy.com/guitardoc/nicegirlharddriver.wmf

[Cliff Schecht]

12AX7's don't need more than 6.3V@300mA or 12.6V@150mA to get the heaters going... Nothing wrong there. Just remember, having tubes doesn't automatically make something sound good.

There is another factor called the 'B+' that does also contribute to the sound.

-----------
Jimbo

I figured I was missing something. I still haven't done any real studying on tube design so I'm definetly not the expert here .

[Rafa]

Insert Quote
If I were you, I'd skip ALL the "starved plate" stuff, get an EH transformer from aron and
use proper B+ voltages   
Lots of fun to be had, just watch VERY carefully what you're doing .....

You mean intead of using 30V to use lets say 250V.
thats sounds good but will the sound change much?
Ive read good reviews of this pedal at harmony-central
Cheers
Rafa

[aron]

>Ive read good reviews of this pedal at harmony-central

Of the Mini-Boogie?

Interesting.

[JonFrum]

Insert Quote
If I were you, I'd skip ALL the "starved plate" stuff, get an EH transformer from aron and
use proper B+ voltages   
Lots of fun to be had, just watch VERY carefully what you're doing .....

You mean intead of using 30V to use lets say 250V.
thats sounds good but will the sound change much?
Ive read good reviews of this pedal at harmony-central
Cheers
Rafa

Most people who have tried it say that the starved plate design is not the way to go. Plate voltage doesn't matter much when you're up in standard range - although 50V  does matter in some circuits - but when you take it as low as 30V you're really out of anything you could call a sweet spot.

[aron]

OTOH, there's a lot of development that could go on with these lower voltage tube pedals that I'd like to see. There's still something neat about using the tubes. How about those small tubes that Alfonso and others are using?

[Johan]

you can get good sound out of tubes at low voltage. the problem with most designes are that they are just high voltage circuits run at low voltage...an 12ax7 in a standard marshall or fender circuit disapates about 0.5-1watt. with 100k plate-resitors and running at 9-25volt, you're nowhere near that. also, at low voltage spacecharge start to happen. if that is not taken care of, things get even worse...just measure the voltage on the grid when running a standard circuit at too low voltage...it goes negative...     easiest way to deal with this is to connect the gridresistor to supply as in the Tubedriver or to use a biaspot as in Aron's Shacka-tube...

...perhaps starved tube distortion could be something for the monthly-contest thingy?...

johan

[Rafa]

I made a mistake the real name is not mini-boogie its mini-boogee.

[Mark Hammer]

Insert Quote
If I were you, I'd skip ALL the "starved plate" stuff, get an EH transformer from aron and
use proper B+ voltages   
Lots of fun to be had, just watch VERY carefully what you're doing .....

You mean intead of using 30V to use lets say 250V.
thats sounds good but will the sound change much?
Ive read good reviews of this pedal at harmony-central
Cheers
Rafa

"Good sound" will depend on what you are after.  The higher the B+, the more headroom and dynamics.  If what you want is the sound of tube preamp distortion, then 30V (or less, even) may give you what you desire.  If you are after bright sparkly clean tone that lets a Tele bridge pickup sound different than a Les Paul bridge pickup, then you likely want much higher B+ voltage.  They both have their charm, but different people want different sounds.

[aron]

Rafa,

Can you give me a link? BTW: I own the device in question.

[puretube]

http://reviews.harmony-central.com/reviews/Effects/product/Mini-Boogee/Mini+Matrix/10/1

[aron]

hmmm those reviews are not too good!

[puretube]

http://mywebpages.comcast.net/jroscoe/bkbutler.html

[Rafa]

I can see theres a problem aparently there are two models the audio matrix and the mini matrix the one I read was this one:

http://reviews.harmony-central.com/reviews/Effects/product/Mini-Boogee/Audio+Matrix/10/1