Bottlehead Forum

Bottlehead Kits => Crack => Topic started by: mwgrient on July 30, 2014, 07:07:04 AM

Title: Watt usage Crack Bottlehead amp
Post by: mwgrient on July 30, 2014, 07:07:04 AM

Hi all,
I have finished my crack build, and was wondering if 35 watt (almost steady) operation is normal? I have a meridian amp with is using 15 watt, but that is not a tube amp...

Regards,
Marco

Title: Re: Watt usage Crack Bottlehead amp
Post by: mcandmar on July 30, 2014, 08:01:38 AM

Doesn't sound unreasonable to me, the heater for the 6080 alone is 2.5amp which would account for a majority of that.

Title: Re: Watt usage Crack Bottlehead amp
Post by: Doc B. on July 30, 2014, 09:38:19 AM

You can do the math yourself -

6080 heater, 2.5A x 6.3V=15.75W
12AU7 heater, 300mA x 6.3V=1.89W
6080 cathode current, 100V<2>/3000ohms=3.33W (X2 triodes=6.66W)
12AU7 plate current, 80V<2>/22.1Kohms=.29W (X2 triodes=.6W)
Power supply bleeder, 170<2>/270kohms=.1W
Power supply dropping resistors 18V<2>/270 ohms=1.2W (X2 resistors=2.4W)
There are also very small amounts of dissipation in the rectifiers and the output load resistors and some losses in the power transformer.


Total current draw using the numbers above= 27.4W

Title: Re: Watt usage Crack Bottlehead amp
Post by: mwgrient on July 30, 2014, 02:35:59 PM

Cool, thank you both.