F6 Amplifier

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#2,763
coming from ultra resolution of J2, it was another sound I had to get customer to....

Botte is right the medium area with the Jensen is similar to the F3 sound with a bit better bottom.

"For reasons unknown" I like the Edcor as an available xformer a bit more....😀

but it is really a matter of taste... Even I could change all day long and enjoy both sounds...🙂
 
#2,767
😀
 

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#2,769
Interest in a phase inverting diy F6?

If yes, a theoretical schematic is attached. The following modifications are principally the re-wiring of the parent.
  • The parent output node is now Ground
  • The output node is now the parent Star Ground
  • Each channel in a stereo enclosure must have its independent power supply.
  • The phase notations of the Jensen's primary windings are reversed.
Will it work? Detriment or value?
Brgds
 

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#2,770
With transformer coupling there is no reason that you cannot float the power supplies, assuming that the feedback is correctly phased and at the correct level.
OTOH, if you are going to float the power supplies why not implement a circlotron? You can even dispense with coupling transformers if you follow the path chosen by Rothacher http://www.diyaudio.com/forums/pass-labs/130810-amazing-fet-circlotron-mike-rothacher.html.

Antoinel said:
If yes, a theoretical schematic is attached. The following modifications are principally the re-wiring of the parent.
  • The parent output node is now Ground
  • The output node is now the parent Star Ground
  • Each channel in a stereo enclosure must have its independent power supply.
  • The phase notations of the Jensen's primary windings are reversed.
Will it work? Detriment or value?
Brgds
Click to expand...
 
#2,771
Antoinel said:
If yes, a theoretical schematic is attached. The following modifications are principally the re-wiring of the parent.
  • The parent output node is now Ground
  • The output node is now the parent Star Ground
  • Each channel in a stereo enclosure must have its independent power supply.
  • The phase notations of the Jensen's primary windings are reversed.
Will it work? Detriment or value?
Brgds
Click to expand...
I did a double phase inversion; once at the primary winding of the Jensen [to implement feedback], and a second at the new output node. I am afraid the schematic in the preceeding post still shows a non-inverting diyF6; like the parent.

Will this mod and its parent perform the same? Is there a practical advantage to this modification over the parent?
 
#2,772
lhquam said:
With transformer coupling there is no reason that you cannot float the power supplies, assuming that the feedback is correctly phased and at the correct level.
OTOH, if you are going to float the power supplies why not implement a circlotron? You can even dispense with coupling transformers if you follow the path chosen by Rothacher http://www.diyaudio.com/forums/pass-labs/130810-amazing-fet-circlotron-mike-rothacher.html.
Click to expand...
Thanks lhquam for your clarification and link. I recall you doing sims with Teaser-6 as a circlotron. I'll look again at Rothacher's paper. Brgds.
 
#2,773
some news from Frankenstein 6....🙂

very different pictures, may explain a bit the different character of sound Jensen versus Edcor with my build ...first picture Jensen, second Edcor...

I have to play with the two pots over the two secondaries..... 500R are a good starting point to mistune the distortion ......😀 ?
 

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#2,774
Edcor looks good to me, but if you can tune out some of the third on the Jensen, you are sitting pretty, I think. I guess that you will probably obly be able to add second, but you never know. Does this show that the Jensen's secondaries are more balanced. This assuming you just swapped the trafos.
 
#2,775
Guys with Semisouth gone poof which alternative you think would be closer alternative to R100?
I know it s a big discussion and the answer could be relative especially considering the versatility of the circuit to accept many types.
I just wanted to hear some thoughts
 
#2,779
buzzforb said:
Edcor looks good to me, but if you can tune out some of the third on the Jensen, you are sitting pretty, I think. I guess that you will probably obly be able to add second, but you never know. Does this show that the Jensen's secondaries are more balanced. This assuming you just swapped the trafos.
Click to expand...

yes I just swaped the trafos...same SS side. But of course the data of the Xformers are different.

I will try some more feedback on the Edcors and when I trim the Jensens to have about 12db more k2 over the k3 I have a THD of 0,086%, unfortunately!
 
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