F6 Amplifier

[lohk]

since the search is a bit confusing on this topic: where can I buy two more R100s?

 

[Zen Mod]

tea bag

if....

 

[Tea-Bag]

tea bag

if....

nope. Sorry. All out like a month ago.
I had some obsolete part vendor guys for the military look for them, all without luck. They claimed all further sources were fakes. I totally believe that.

I should have proto boards by this weekend. First attempt is to build a channel with IRF240's.

 

[CeeVee]

since the search is a bit confusing on this topic: where can I buy two more R100s?

Roger Cullen still has 125s but not 100s i think.

cullenhawk@aol.com

 

[lohk]

Thanks.
I have somehow missed that the F6 infos were already out and discussed - otherwise I would have bought more.

 

[flocchini]

After the discussion of twisting , rotating and shouting about transformers given that I am using a choke input I decided to measure the AC at the outputs of PTP F6. I get 4.5mV and 4.7mV - obviously higher that lhquam and Nelson - is this out of acceptance range?

Thanks

 

[Zen Mod]

you can have even 45mV and 47mV , if your speakers are in range of 76db/W/m



choke input - what ?

 

[a.wayne]

Still making fun of my speakers ......

 

[flocchini]

you can have even 45mV and 47mV , if your speakers are in range of 76db/W/m

point taken - F6 is driving PHL 1120s (93dB/W/m)




choke input - what ?

transformer to bridge to inductor to caps

 

[Zen Mod]

probably culprit is in position and proximity of choke to mains xformer

what's PSUD sim sayin' ?

 

[flocchini]

probably culprit is in position and proximity of choke to mains xformer

what's PSUD sim sayin' ?

haven't simulated - will see how to do that

 

[flocchini]

just did hand simulation - moved inductors away from onetics but on top of mains - the AC at output dropped from 4mV to 1 mV

May have to rethink PSU - used this because I had xformers with 2x 30V secondaries and a set of inductors and wanted to get up and running

 

[Zen Mod]

if you ask moi - that's best PSU

common mode choke is even better

re-think positioning , but stay with choke input PSU , if possible

 

[flocchini]

will look at positioning

thanks

 

[Rush]

just did hand simulation - moved inductors away from onetics but on top of mains - the AC at output dropped from 4mV to 1 mV

May have to rethink PSU - used this because I had xformers with 2x 30V secondaries and a set of inductors and wanted to get up and running

I was wondering what your rail voltage is after the 8 mH choke input filter with 30 VAC windings on the transformer?
Do you have two chokes, one for each rail or can you put the choke on the common ground and use only one rated for twice the amps?

Rush

 

[flocchini]

Rush

I have 2 inductors - one in the pos line and one in the negative.
Voltage after inductors is approx +/- 25 V

Best

Bob

 

[Antoinel]

Yes, that is essentially correct.

The simplest way to think about the role of the pot is as follows:

• Let X be the ratio of the wiper-to-source resistance to the end-to-end pot resistance.
• The effective AC degeneration resistance is X times the source resistance.

Ladies and Gents. Is there a certain constant ratio of H1 to H2 to H3 [say at 1KHz] which is a human trait; meaning this ratio which suits lhquam is equally transferrable to buzzforb or any DIYer worldwide regardless of race, age, sex, etc.? Is this ratio expected to be a constant in production F6; strictly from a quality control practice? Besides the F6 amps of Mr. Pass will be bought by diverse people who will use them with unknown loudspeakers and in unknown accoustic environments. Your thoughts please.

Best regards.

 

[buzzforb]

Nope. We are all too da^n peculiar to like the same thing

 

[Zen Mod]

but Pa's will all be the same

 

[Nelson Pass]

And you know they aren't. Each design has a unique signature.