Techtalk

switching the mains needs some power
"off" works fine

but for "on" you need the mains transformer connected.
ok, you could switch the secondaries.

can we just delete these last three posts!

please!

ah! but i could, could i not? just add a small 240 primary / 18v secondry transformer? to power the 7812 circuit?

dare i press submit any more.....

no need to delete anything

this would work
(but I won't suggest it)

yes, i think i'll re-think this one..

lol...what a day..!

night.

Hi Pete,
that was a really amusing discussion!!
regards
Bernd

lol...

was very funny wasn't it!

lesson learned,

must think things through a little bit more, especially before posting to the world to see!

hey you guys, if you fancy checking out my music then please feel free to let me know what you think..i'd be really interested to hear yours too..

www.myspace.com/sinestarproject
www.sinestarproject.com

take care chaps!

Pete

I think if I can find the time I will rewire my first unit. My "Numero Deux" is sooo quiet while the first onestill has a hum if gain is full at about -65db.

I used some high end Gotham 3 conductor cable instead of my special DIY OCC wire invention on the first one to try it out, the results are very different it seems.

Something for everyone to watch for the cable and shielding of cable to the controls is very important!

-ChuckD

Hi Guys,

can i test the unit with out the T4b's in it? looking at the diagram i can see no reason why not, am i correct on this?

Best

Pete

yes, test it without the T4Bs.
it won't compress, but gain should work.

hi all,

well its on an i'm alive...ha ha..

its working as an amplifier just fine, one problem so far though,

i have HUGE amounts of gain!!!! and its all in the first 5mm of knob travel!!

is this some thing to do with no T4b? cant see why it would be though,

any ideas would be most welcome, of course no rush as T4bs are going to be 6 weeks,,,

best

Pete

Hi,
do the silentart mod , which means: instead of the 100K pot take a 25K log pot with 75K resistor in series. Alternative: try another input transformer with 1:1 (10k/10K) ratio. The edcors xsm 10k/10k aren´t the best choice in this circuit (strange frequeny response).
regards
Bernd

congrats

Sine Star Audio hat geschrieben:i have HUGE amounts of gain!!!! and its all in the first 5mm of knob travel!!

this is normal and has nothing to do with the missing T4B

as Bernd mentioned you can do the potentiometer mod I did.
I still never have gone behind the mid position ...

btw, no oscillation with high gain ?
the grid stoppers work, I suppose

Hi Volker,

Ah yes i remember reading some thing about the gain mod...ill have a look through..

as far as oscillation, none what so ever, its clean right up to +22dB, at which point there after it starts to distort and no more level can be had..

which by the way behaves just like my other la2a..

noise floor is quite high, at around -66dB, so ill have to play with this, not sure at the mo as all the wiring seems good..so i think it could be tubes...ill do some swaping out i think..

Thanks Volker,

common T4bs!!

we can reduce the noise to either the wiring, or the tubes.
most times it was the wiring

use shielded cables, ground properly, and all should be fine.

there are some post from ChuckD one or two sites before

...