the difference is the AC amps.
Compare it with a tube follower, with a very small cap (10 nF) and a 1 meg to the kathode resistor for bias, the virtual impedance is magnified greatly (yes there is a formula that also goes for the FET), and the input by consequence needs only that little cap for a 1 Hz bandwidth.
Thanks,
n ow I got it - we often think on rails and sometimes we get the wrong ones.
regards
Flo
ask
hi i am interesting to build F5 PA
there are 2 diff schematics :
2008 version
and 2012 version
both are original from F5 manual.
which one will provide a better sound?
and also, at the manual said:
"You can simply raise the supply rails to +/-32 Volts and get 50
watts into 8 ohms right away without other modification. 24 V AC secondaries
on the power transformer will do it. Don't forget to use higher voltage power
supply capacitors. Probably you should also upgrade R9 through R12 to 5
watt resistors. Depending on your heat sinking, you will probably want to
adjust the bias so that the power transistors don't run too hot."
so, this means i can simply use 2x24vac transformer without any problems?
are there anything i have to adjust? (for +/-32volts rails)
please some advice. thanks a lot.
hi i am interesting to build F5 PA
there are 2 diff schematics :
2008 version
An externally hosted image should be here but it was not working when we last tested it.
and 2012 version
An externally hosted image should be here but it was not working when we last tested it.
both are original from F5 manual.
which one will provide a better sound?
and also, at the manual said:
"You can simply raise the supply rails to +/-32 Volts and get 50
watts into 8 ohms right away without other modification. 24 V AC secondaries
on the power transformer will do it. Don't forget to use higher voltage power
supply capacitors. Probably you should also upgrade R9 through R12 to 5
watt resistors. Depending on your heat sinking, you will probably want to
adjust the bias so that the power transistors don't run too hot."
so, this means i can simply use 2x24vac transformer without any problems?
are there anything i have to adjust? (for +/-32volts rails)
please some advice. thanks a lot.
No no need to change much realy but is question of personal choice
I have been running on 24 volts trafos since last August
As I have 4 homs (nominal speakers) I have used twin outputs from start and did not use the current limiters (got speaker protection to keep woofer safe)
Just bear in mind the reccomendations for the resistors that you already posted and
Enjoy
On the other hand
Few things came up like P3 mod
And lateley Papa Pass mentioned that tweaking feed back resistors values gives more gain.
All this and many more Mods have been made.
Just go for the vanilla version to start and you will not be disapointed.
Till the mod bug bites that is, so my 2 cents get 68 V rated capacitors they came handy for when you will decide to take the rails up.
I have been running on 24 volts trafos since last August
As I have 4 homs (nominal speakers) I have used twin outputs from start and did not use the current limiters (got speaker protection to keep woofer safe)
Just bear in mind the reccomendations for the resistors that you already posted and
Enjoy
On the other hand
Few things came up like P3 mod
And lateley Papa Pass mentioned that tweaking feed back resistors values gives more gain.
All this and many more Mods have been made.
Just go for the vanilla version to start and you will not be disapointed.
Till the mod bug bites that is, so my 2 cents get 68 V rated capacitors they came handy for when you will decide to take the rails up.
Prety good Caps and transformer is right.
Go for it
Are you cooking your own boards?
If that is the case include the traks for P3 You won't need to use it straight away but once bug bites...
Have a good look at what is being said about Heath sinks once that is sorted you are almost done.
Go for it
Are you cooking your own boards?
If that is the case include the traks for P3 You won't need to use it straight away but once bug bites...
Have a good look at what is being said about Heath sinks once that is sorted you are almost done.
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24VCT will not even get you close to +/-32V rails.
24VCT is a 2x12V that is centertaped.
Two 24V 240VA Txrs (sec in series) will be okay for single Txr supply and seperate bridges , etc after that - 8 x 10mF Nichicon are okay, particularly if KG - suggest you start with discrete diodes rather than cheap block bridges - can use one of those 12volt taps to drive a dc protect/delay cct.
Suggest get the pcbs from 'the Store' here, and can easily mod them later.
Suggest get the pcbs from 'the Store' here, and can easily mod them later.
is that true?
i think 24VCT is 24V with center tapped, same with dual 24V transformer.
and 24VAC will be around 33.84V after through the bridge and filter caps (24v x 1.41 = 33.84v)
this will be enough for +/-32v rails. (please correct if i am wrong)
Bksabath, jameshillj:
yes i am building my own pcb
here is the component layout will be:
An externally hosted image should be here but it was not working when we last tested it.
i am putting P3 there, maybe i can use it in the future upgrade.
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Is this for regular F5? Rails would seem a bit high.
Also was mentioned before. Q1 and Q2 should be close enough so they can be thermally coupled.
24VCT is same as 2x12V but massure to be sure.
if you massure 24V from CT to one sec. it is realy a 48VCT.
VCT is massured over both sec at the same time.
if you massure 24V from CT to one sec. it is realy a 48VCT.
VCT is massured over both sec at the same time.
and ad a sec pair of outputs. so you dont need a 20mm baseplate on your sinks.
or just buy PCB's from the store, that got it all 🙂
or just buy PCB's from the store, that got it all 🙂
