F5 power amplifier

[h_a]

His Passness: If an F5 has an appreciable amount of 2nd harmonic at 1w, I
adjust resistor values to null it out. Easy to do.

Does that work for complementary source followers as well?

Have fun, Hannes

 

[chrismercurio]

There is always COD.

 

[Tea-Bag]

There is always COD.

defacto trade currency during crisis - food stamps and firearms

 

[ichiban]

Re: Re: Re Paypal

I am thinking of shutting the webstore down,

Noooooooooooooooooooooooooooooooooooooooooooooooooo!!!!!!!

Originally posted by Tea-Bag
Anyways, if these guys on the list are ripping you off. I say call them out and have then banned.

 

[Nelson Pass]

One of the most peculiar and interesting things about the F5 to me is that it is void of capacitors in the signal path. Have you considered (perhaps for a different Fx amplifier) creating a similar amplifier that is SETransistor in nature (capacitorless)? Almost like a DC SET tube amp (without the OPT and the tubes of course)?

I am not particularly hung up about capacitors, and I didn't approach
the F5 with the intent on eliminating them - that just fell out of the
design.

That said, yes, I have several such designs - it's not that difficult.

 

[chrismercurio]

That said, yes, I have several such designs - it's not that difficult.

Are they part of the release schedule of the next few years?

 

[samoloko]

Nelson uses these,

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=P6890-ND

I also would like to try 25 V caps In PSU
why originals can be 25 V and you all recommend at least 35 V

 

[steenoe]

I also would like to try 25 V caps In PSU
why originals can be 25 V and you all recommend at least 35 V

C'mon, put the thinkin' hat on! The PSU calls for 18V secondaries! 18x1,4= 25,2!!!!! This means that your 25V caps are under-rated! Still in doubt?

 

[labjr]

I also would like to try 25 V caps In PSU
why originals can be 25 V and you all recommend at least 35 V

Good question. I always thought you had to allow a larger safety margin. Maybe Panasonic capacitors are rated more conservatively. Looks like the maximum surge is 32V for them. Other brands may not be rated the same.

 

[labjr]

C'mon, put the thinkin' hat on! The PSU calls for 18V secondaries! 18x1,4= 25,2!!!!! This means that your 25V caps are under-rated! Still in doubt?

His question was why does Nelson use the 25V caps then?

 

[steenoe]

Good question. I always thought you had to allow a larger safety margin. Maybe Panasonic capacitors are rated more conservatively. Looks like the maximum surge is 32V for them. Other brands may not be rated the same.

Bad answer! Your whole response is very misleading! Voltage ratings are not to be ignored!

 

[labjr]

Bad answer! Your whole response is very misleading! Voltage ratings are not to be ignored!

Then why did Nelson use the 25V Caps in the F5 !

 

[steenoe]

His question was why does Nelson use the 25V caps then?

Thats because Nelson use them, connected in series so they can tollerate the double voltage! Fairly common knowledge! You can use 25V caps, as long as they are series connected Confused?

 

[labjr]

Thats because Nelson use them, connected in series so they can tollerate the double voltage! Fairly common knowledge!

I'm looking at the schematic right now. I guess I must be missing something.

 

[Diomedian]

Insertion Loss

It is thought that the insertion loss of the rectifiers and the thermistors will bring the voltage down to approx 24V.

-j

 

[cviller]

Yes, you loose approx 0.7V in the diodes which brings you to 24.5V an then you have a constant current driving the dc even further down.

 

[steenoe]

I'm looking at the schematic right now. I guess I must be missing something.

Okay! You are not the first to get this wrong. Anyway, here you go with some basic capacitor wisdom: 2 equal caps in series; halves the value!! (Capacitance value, that is) 2 caps in parralel, doubles the value! (Again, the same capacitance value!!) The drill is that 2 caps in series connection, doubles the voltage rating!! Wow, this is magic!! Not quite, because the caps (assuming the same value) retain only the printed value!! So basically, only half the expected value!! Questions? Just shoot,,,,,,,

 

[Diomedian]

The drill is that 2 caps in series connection, doubles the voltage rating!!

Looking at the published schematic in the F5 service manual seems to show only parallel caps across each rail. The schematic also notes 25V caps and two parallel 18VAC windings.

-j

 

[labjr]

Okay! You are not the first to get this wrong. Anyway, here you go with some basic capacitor wisdom: 2 equal caps in series; halves the value!! (Capacitance value, that is) 2 caps in parralel, doubles the value! (Again, the same capacitance value!!) The drill is that 2 caps in series connection, doubles the voltage rating!! Wow, this is magic!! Not quite, because the caps (assuming the same value) retain only the printed value!! So basically, only half the expected value!! Questions? Just shoot,,,,,,,

Bang Zoom!

 

[steenoe]

I throw the towel in the ring......

Go ahead and use your 25V's for ......... sake...