F4 power amplifier

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lykkedk

lykkedk

Member
Joined 2002
Originally posted by jarthel

does anyone know what is the transformer specs? All I can see is 18VAC. what's the current rating?

Is it okay to use a 10A choke? I'm planning to use a CLC filter but i'm not sure if the power supply draws more than 10A.

Thank you very much
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I bought 2pcs. 18-0-18 600VA (2x300va). 1pcs for 1 monoblock (+ and - balanced for left side) and the other for another monoblock (+ and - balanced for right side), and i am sure it's enough (Read threads a lot of pages before about this)

About the chokes, i am not sure, but if one channel draws 160watt, 10A must be enough...

Jesper :)
 
J

jarthel

Member
Joined 2002
lykkedk said:
Originally posted by jarthel



I bought 2pcs. 18-0-18 600VA (2x300va). 1pcs for 1 monoblock (+ and - balanced for left side) and the other for another monoblock (+ and - balanced for right side), and i am sure it's enough (Read threads a lot of pages before about this)

About the chokes, i am not sure, but if one channel draws 160watt, 10A must be enough...

Jesper :)
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just a clarification: so you're using 1x 300VA transformer for a stereo and unbalanced (the term is single-ended?) F4?

Thanks Jesper :)
 
twitchie

twitchie

Member
Joined 2004
Paid Member
So long as people will respond, questions will continue be repeated in new threads. The problem with asking questions as they come up, you only learn 1 answer instead of reading a thread or an article and learning answers to 100s of questions you don't need to ask anymore.
 
lykkedk

lykkedk

Member
Joined 2002
Posted by Variac:

I thought that the total transformer rating- for both channels-is 300 VA
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Yep, that's right Variac, but i also mentioned this : '' (Read threads a lot of pages before about this) '', when i was writing this ;)...

Well i like big heavy torrid's, so sorry that's my excuse :D ... The price difference for 300-600va where i bought them, was also very small (around 25Euro i think), so i thought it would be a good idea !!!

Jesper.
 
twitchie

twitchie

Member
Joined 2004
Paid Member
I have a 400VA Antek (that they tested to 400W) in my F4 now. When I built my first Pass Labs amp (A30 with Peter's boards), I wasn't sure what size to use and fell into the 'never big enough' trap and bought a 625VA Plitron.

All is not lost though, my next plan is to build a single-chassis 4-channel F4 run in bridged mono (2 bridged channels still) fed by this 625VA transformer.

Now my philosophy is "if it's good enough for NP, it's got to be good enough for me" :D

If the price difference isn't substantial, then go for it. In my case, the 625 (custom order) was a little less than the price of 2 of the 300VA toroids.
 
Zen Mod

Zen Mod

Official Court Jester
Joined 2003
zenmod.in.rs/
Paid Member
twitchie said:
I have a 400VA Antek (that they tested to 400W) in my F4 now. When I built my first Pass Labs amp (A30 with Peter's boards), I wasn't sure what size to use and fell into the 'never big enough' trap and bought a 625VA Plitron.

All is not lost though, my next plan is to build a single-chassis 4-channel F4 run in bridged mono (2 bridged channels still) fed by this 625VA transformer.

Now my philosophy is "if it's good enough for NP, it's got to be good enough for me" :D

If the price difference isn't substantial, then go for it. In my case, the 625 (custom order) was a little less than the price of 2 of the 300VA toroids.
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quoting you just accidentally ;)

so F4 - 2 x 22V x 0,53A x3.........69,96 W .........for two channels thats ~ 140 W.......pretty close to Papa's 160W ( xformers loss,few watts burned in PSU ,few watts through led diodes :clown: etc..

Papa's pdf sez something about 3 times consumption.....for donut watts........

seems that Papa's pdfs aren't visible enough ......... ;)

anyway- 625 decent watts are good enough .......for my liking
 
J

JimT

Member
Joined 2004
korben69 said:
Hi JimT,
I'm a newbie too, 64W is the model number.
More informations there : http://www.nteinc.com/pot_web/64w.html
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Korben69,

Some time ago I was told to use the Bourns pots when repairing an old Marantz. Your message got me to double check this so I looked up the old message and it was the Bourns 3296 pots I was told to use. Seems I did not remember this when trying to pick some for my F4. Thanks for prodding me to think about this again. When I get a chance I will fix my BOM to use the 3296 pots. I expect yours are fine, but the repair guy knows more than I ever will.

It helps for us new guys to bounce these "simpler" things back and forth. I'll be happy to compare notes with you,

Jim
 
luvdunhill

luvdunhill

Member
Joined 2006
JimT said:



Korben69,

Some time ago I was told to use the Bourns pots when repairing an old Marantz. Your message got me to double check this so I looked up the old message and it was the Bourns 3296 pots I was told to use. Seems I did not remember this when trying to pick some for my F4. Thanks for prodding me to think about this again. When I get a chance I will fix my BOM to use the 3296 pots. I expect yours are fine, but the repair guy knows more than I ever will.

It helps for us new guys to bounce these "simpler" things back and forth. I'll be happy to compare notes with you,

Jim
Click to expand...

just check to see if the part in question is pin out compliant with the F4 boards, as often these numbers have to do with pin arrangement and adjuster orientation.
 
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