F6 Amplifier

[buzzforb]

Could be milled.

 

[lhquam]

Could be milled.

Not likely -- too much volume of material to remove.

 

[buzzforb]

Machine fitted and then welded is only other option i can think of. Would seem to debink their whole better thermal transfer theory if there was a gap.

 

[labjr]

The flange on the Conrad heatsinks is perpendicular to the extrusion direction, therefore it must be a separately attached part. I wonder how it is attached.

Maybe it's all part of the same casting then machined afterward?

 

[lhquam]

Is it possible to do double extrusion? First extrude the fins in one direction, then extrude the flange?

 

[labjr]

Is it possible to do double extrusion? First extrude the fins in one direction, then extrude the flange?

I believe Conrad heatsinks are sandcast.

 

[labjr]

If you read the technical specification page it describes it.

''The Conrad flanged single piece heatsink"

 

[lhquam]

I believe Conrad heatsinks are sandcast.

You are probably correct. The Conrad "Technical Details" page mentions the CC601 aluminum alloy is used, and CC601 is indeed used for sand casting.

 

[Nelson Pass]

Does anyone have any idea the resistance value of the "white resistor" near the positive side output FET?

I needed a current sensor to bias the circuit, so I put a very low shunt
value in series with the supply. It is not part of the amplifier as such.

 

[Nelson Pass]

I think the transformers took/are taking a long time to get produced...?

I may have cleaned them out, but Jensen often takes a little while.

 

[PKI]

As we talk about heatsinks here, I have a question not exactly about the amp, but nevertheless: I have a transformer — Antek with a static shield. Where you connect it, to the chassis?
http://www.antekinc.com/pdf/AS-4218.pdf

 

[Marra]

Yes just connect it to chassis ground.

 

[Zen Mod]

I needed a current sensor to bias the circuit, so I put a very low shunt
value in series with the supply. It is not part of the amplifier as such.

Baaad Pa , baaad !



(tnx)

 

[generg]

I needed a current sensor to bias the circuit, so I put a very low shunt
value in series with the supply. It is not part of the amplifier as such.

Hi Buzz,

Congratulations, you were right!

And me wrong......

 

[buzzforb]

Am I in error in my thinking that with fets like FQA or IRF, that increased die temperature, we get higher conductance? If so, wouldnt there be an advantage to raising fet temp.

Maybe stupid but, is there any way that placing this shunt on the rail would affect THD. It would not alter upper fet response as more current flowed through the circuit?

 

[Zen Mod]

Am I in error in my thinking that with fets like FQA or IRF, that increased die temperature, we get higher conductance? If so, wouldnt there be an advantage to raising fet temp.......

look at pic - my fave IRFP150N ;

I have slight impression ( NB that I'm often completely wrong ) that you boyz are recently too much in over-engineering (gray) area ......... (been too many times in that trap , while Pa is laughing)

Maybe stupid but, is there any way that placing this shunt on the rail would affect THD. It would not alter upper fet response as more current flowed through the circuit?

if talking about small white power resistor in last F6 incarnation , Pa was talking about series connected small valued one ....... same as you puttin' 10R resistor in tube cathode return - convenient place to measure Iq , nothing else

in this case 10mOhm will do the job , having negligible influence to sound/circuit operation

 

[buzzforb]

Idle minds. Thanks.

 

[Zen Mod]

Idle minds. ....

you mean - perfect state of mind for ........... F7 ?

 

[buzzforb]

Fortunately I am entangled in other thoughts st the moment.

 

[lhquam]

Fortunately I am entangled in other thoughts st the moment.

Is the cat both dean and alive at the same time?