Upgrade F5 to F6

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I am very curious on your opinion of the sound difference. I never built a F5 because of Nelson saying the F5 tends to be on the bright side and horns have a tendency to be bright already.

The attenuator system that I employ on my horm speakers are quite good and offer me a great tweak range no matter what amp I use ( see photo )
And I use 3 :)


What I am looking for is more multilayer bass extension from this upgrade and I will report my findings as I progress

FR
 

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I know its a little late now, but I found that by doubling the cap bank in the F5 from stock really helped with bass punch and extension.
IF you have a few caps lying around you can try that and see what happens.
Also, if you haven't taken out the protection circuit in the stock F5, do it.
 
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I know its a little late now, but I found that by doubling the cap bank in the F5 from stock really helped with bass punch and extension.
IF you have a few caps lying around you can try that and see what happens.
Also, if you haven't taken out the protection circuit in the stock F5, do it.

My dual mono F-5 does not lack in the least with bass punch.

Russellc
 
I know its a little late now, but I found that by doubling the cap bank in the F5 from stock really helped with bass punch and extension.
IF you have a few caps lying around you can try that and see what happens.
Also, if you haven't taken out the protection circuit in the stock F5, do it.

These are different things.
If he means rich tonal character of the bass then I think he will get that with the F6.
The ACA is syrupy rich in layering and tonal character but you need the right speakers, the F6 is a good compromise for most speakers.
I have a gut feeling I can achieve the same effect with F5, just need to test out the idea. I'm working on it now.
 
Hi Fullrange, does your autoformer in the crossover attenuates just the super treble or the "midrange plus super treble- horns"?

stefan

Hi Stefan
The crossovers have two seperate attenuators
One for the tweeter this one is a PCB based attenuator db steps are 0, 3, 5, 7, 9

One for the midrange this one is a double wound auto former with 15 wire taps X 1 db steps

Cheers
FR
 

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These are different things.
If he means rich tonal character of the bass then I think he will get that with the F6.
The ACA is syrupy rich in layering and tonal character but you need the right speakers, the F6 is a good compromise for most speakers.
I have a gut feeling I can achieve the same effect with F5, just need to test out the idea. I'm working on it now.


I am in a fortunate position of having very sensitive speakers that have that perfect synergy with the room they are in

It's difficult to fault them and I love the pitch black background of the F5
What I'm looking for with the F5 to F 6 upgrade is -
Finer 3D imaging
Delicate instrument separation
And multi layer bass extension

FR
 
These are different things.
If he means rich tonal character of the bass then I think he will get that with the F6.
The ACA is syrupy rich in layering and tonal character but you need the right speakers, the F6 is a good compromise for most speakers.
I have a gut feeling I can achieve the same effect with F5, just need to test out the idea. I'm working on it now.


For rich sound I think twisting P3 will help. If I'm not mistaken the F5 inherently is Third order harmonic dominant, adjusting P3 should be able to get the second order harmonic dominant.

As far as instrument separation and 3D, I've found that the more transistors you put it the more those two characters come out. The F5 Turbo gives you much more of that.
 
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For rich sound I think twisting P3 will help. If I'm not mistaken the F5 inherently is Third order harmonic dominant, adjusting P3 should be able to get the second order harmonic dominant.

As far as instrument separation and 3D, I've found that the more transistors you put it the more those two characters come out. The F5 Turbo gives you much more of that.
It gets you some of the way but I think there is a better way of doing it. At least my ideas work in simulation. I'll need to build it to be certain.
 
I am in a fortunate position of having very sensitive speakers that have that perfect synergy with the room they are in

It's difficult to fault them and I love the pitch black background of the F5
What I'm looking for with the F5 to F 6 upgrade is -
Finer 3D imaging
Delicate instrument separation
And multi layer bass extension

FR

I haven't built F6 yet but I have built F5 and ACA, my gut says F6 should sit right between the two. You will gain some of what you are chasing but possibly lose some of what you already like with F5 (depends on what you like)
I can't really give any definitive advice until I've completed F6.
An F4 may even be the best option with your speakers or possibly a "modified" ACA. None of the amps are bad so you can't go wrong with any of them.
The only certain advice I'd give is to slowly go through and build all of them. If you haven't built one yet a pure single ended design should be on your build list just for comparison.
 
A quick update
The full F6 kit from the DIY shop has arrived
And the matched IRFP240 FETs have also arrived ( Thanks Hannes ) haven't seen so close matching in a long time
The order has also been placed for all parts required from 4 sources
Will post a brand list and why a particular part / brand / model was chosen when time permits

While I await delivery I got my hands busy and I made a set of 4 transistor washers
Material is 2 mm alloy
Shape is square and made to overlap the transistor
A small steel washer will also be used under the cap screw as well when the time comes to fit them to the heatsink
 

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Update

This F5 to F6 upgrade has had a lot of thought go into it, however I have to thank the community for a lot of good ideas :)

This build will be to the latest ZenMod spec modification

Parts are trickling in slowly
Will also order those or similar bespoke transistor washers recommended above

Parts list and brands I have settled for is based on the items musical credo and fair value

Trim pots are 21 turn Bourns

Latest zm change with a few fine touches are

Z1,2 6.2v 1% 1/2w vishay

Elna Silmic RFS Series 2
1000uf 35volt

R1 0.56ohm 5W Mills non inductive wire wound
R2 0.47ohm 5W Mills non inductive wire wound
R3 100ohm 5W Mills non inductive wire wound


R4 18.2ohm 1/4w vishay/dale rn60
R5 1K 0.4w Charcroft Z-Foil Resistor
R6 47K 0.33w caddock tf020
R7,8,3.3k 1/2w vishay/dale cmf60
R9,10 10K 1/2w vishay/dale cmf60
R11,12 110ohm 1/2w vishay/dale cmf60
R13 Not used

FR
 
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