[systemerror909]

I've been reading a bit more about amplifiers and had a few questions relating the to the Little Dot Mk III I've now owned for the past 8 months.

1. I've heard the design of this amp (and the Mk IV) is Single Ended Push Pull. Does that mean that the Driver tubes run in class A and the Power tubes run in class B or A/B? Looking at the tubes in the amp it appears that the power tubes have two filaments, but the driver tubes only have one filament. A tube amp running class B needs two filaments (or two single filament tubes) to run, because the push/pull design needs one negative, one positive correct?

2. I've come across a list of benefits/negatives in Robert Harley's book the complete guide to high end audio. One of the points he mentions is that amps regularly need to have the bias adjusted in order to perform optimally. I haven't seen anything about biasing in the little dot manual. Is this an issue only for tube amps with larger power outputs, or something I should be concerned about?

Thanks,

Ryan

 

[sunseeker888]

I'd like to know also.

 

[JimSmiley]

x3

 

[Pricklely Peete]

Email David at LD, or head to the LD forum and ask directly. I'm sure either Sword or David would be happy to answer these questions. I believe it's a fixed bias design, although I could be wrong.

Peete

 

[fran]

Bias only needs to adjusted in some kinds of amps - some are self adjusting. This amp doesn't need adjusting. So, no you don't need to worry about it.


Heres alink to some info on SEPP:

The Tube CAD Journal: Mixed Mode Amplifiers

(AFAIK, its all class A only due to the circuit set up)

Fran

 

[systemerror909]

I emailed David, here is his reply:


Hello Ryan,

Great to hear from you!

It looks like you've been doing some great research. Regarding your inquiry, the Little Dots in question run in Class-A and you don't have to worry about manually biasing as all Little Dots are self-biasing. I hope this helps!

Best regards,
David

 

[dantztiludrop]

Good info....thanks for checking into that.

David & Sword are always great about responding back with answers to questions....& with customer service, in general.