Page 1 of 1
Here's a What-if Question for ya...
Posted: Tue Apr 07, 2009 1:56 pm
by TwinACStacks
Okay. Say I do My 50watt build and use KT66's with the 139 Output, bias them in and Run them at 3.4 Ohms. Later I decide I want to mis-match the impedances: 8@amp output/ 16@cab input, so I effectively get around 7 Ohms on the primary. WILL I have to RE-bias the tubes for the different impedances???
TWIN
Re: Here's a What-if Question for ya...
Posted: Wed Apr 08, 2009 1:49 pm
by stoo
No.
The bias is set at idle. With no audio the tranny is just resistance. Impedance implies ac (audio).
Stew
Re: Here's a What-if Question for ya...
Posted: Wed Apr 08, 2009 2:53 pm
by novosibir
TwinACStacks wrote:... so I effectively get around 7 Ohms on the primary. WILL I have to RE-bias the tubes for the different impedances???
Isn't this a bit low as for a primary impedance? Just 7 Ohms
Larry
Re: Here's a What-if Question for ya...
Posted: Thu Apr 09, 2009 10:44 am
by TwinACStacks
novosibir wrote:TwinACStacks wrote:... so I effectively get around 7 Ohms on the primary. WILL I have to RE-bias the tubes for the different impedances???
Isn't this a bit low as for a primary impedance? Just 7 Ohms
Larry
I don't know Larry. I'm going to use the Marstran 139 which has a 3.5 KOhm Primary. So if I mismatch 8ohm Out to 16 Ohm cab, wouldn't it be around 7 KOhm at the primary, or doesn't it simply just double? Boy am I glad for Brains to pick around here!!!!
TWIN
Re: Here's a What-if Question for ya...
Posted: Thu Apr 09, 2009 10:48 am
by robert
You forgot the "kilo" in front of the "ohms" of your primary
Re: Here's a What-if Question for ya...
Posted: Thu Apr 09, 2009 2:37 pm
by TwinACStacks
Ooops.... There. Is that better? (as he bangs his head against the computer desk.)
TWIN