F5 increased capacitance

[Hikari1]

I am in the beginning stages of an F5 build, next up is power caps.

I have a 600va transformer, any harm in bumping the 8 x 15,000uf caps to say 8 x 22,000uf? the cost difference is not much and they will fit on the board. The caps I am looking at are Panasonic TSUP 35v.

ECO-S1VP223DA Panasonic Electronic Components | Mouser

Will the CL-60 thermistors still be enough or do I need to look at soft start? Planning on running a 35amp bridge.

Also, the Pass schematic specifies 25 volt caps. There's 24 volts on the rails. Wouldn't 35v be a better choice?

 

[Zen Mod]

with 18Vac secondaries , you'll have aroundish 22Vdc under load

if you are not sure how to maintain voltage under 25Vdc during setup procedure , then buy 35Vdc caps

22mF isn't critical ; I'm having 33mF-0R1-33mF on each rail in FW based sort of monoblock (common 800VA xformer , with 4x18Vac )

 

[WalterW]

Hikari no problem at all, i used the exact same capacitors, see here:

http://www.diyaudio.com/forums/pass...-your-diy-pass-amplifier-159.html#post3358959

 

[danny_66]

You're better off with a softstart that bypasses the CL60 after some seconds.
Plenty of those can be found on ebay

 

[Andersonix]

ApexJr has these 33mF 50V caps for $4 each. Get some Teflon coated wire and some big rubber feet while you're ordering.

For soft start, next time I want to try something with an AC relay like 'Fig. 2' in the attached article.

 

[Zen Mod]

CL60 alone is perfect

 

[Andersonix]

CL60 alone is perfect

For a normal amount of PS capacitance, I agree.

 

[Zen Mod]

it's covering fine 800VA Donut , 8x33mF , all that on 220Vac

4A fuse

 

[Hikari1]

Zen: That's good to know. I'd rather user the Cl-60 than a softstart board.

Apex Jr. looks like a great shop. I may order some wire from them. Don't know if I am ready to point to point a power supply yet though.

I know it's been done to death but you guys have any opinions on IRF vs Fairchild vs Toshiba outputs? It will be a standard F5, One pair N/P per channel.

I am leaning towards IRFs becasue they are easy to get. The Fairchilds seen to be unobtainium and the Toshibas scare me with the different pin out and possible resistor change needed.

 

[Zen Mod]

best thing after wheel is - soft start circuit but filled with series NTCs , instead of fixed resistors

that will give you really soft start

whatever - that's better in just one instance - behavior in case of mains blackout - when you'll need maybe every 10-th time to change fuse

which Toshibas exactly ?

 

[Hikari1]

Probably K1530-Y/J201-Y. But if they are not significantly better than the IRF's I dont know if its worth the hassle.

 

[Andersonix]

... Don't know if I am ready to point to point a power supply yet though.

One more shameless plug: ApexJr has these Euro terminal blocks which if used strategically can be very flexible while safely handling large currents (as they're virtually touch-proof when the wires are stripped to the proper length).
And also 5mH 19AWG inductors for CLC...

 

[dazed2]

I have 6 x 47,000uF caps in my F5 and I only use a CL-60, no soft start. Its been working like that for about a year and a half. Gets switched on almost daily, no problems.

You're ok.

As far as transistors I've tried the Fairchilds and the Toshibas. I like the Toshiba more, more "organic" and sweeter sound.
Farichilds are more sterile to me.

 

[PKI]

Just for the record, I have 0.4F and CL-60 works perfect.

 

[oneplustwo]

I have 10 x 22,000uF caps in my F5, CL-60 no soft start. No worries. I've used both fairchilds and toshibas but in different amps so hard for me to tell if there's a difference. Nothing to lose any sleep over in my opinion.

 

[AndrewT]

.................the Toshibas scare me with the different pin out............

all vertical mosFETs have the drain pin in the middle.

 

[permaneder]

all vertical mosFETs have the drain pin in the middle.

Yes???


Rev.2.00 Sep 07, 2005 page 1 of 5
2SK1056, 2SK1057, 2SK1058
Silicon N Channel MOS FET
Outline
RENESAS Package code: PRSS0004ZE-A
(Package name: TO-3P)

1. Gate
2. Source (Flange)
3. Drain

 

[AndrewT]

all Lateral mosFETs have the source as middle pin.

 

[Hikari1]

Thanks for the info guys. Looks like 22Kuf x8 wont be an issue w/just the CL-60 and no soft start board.

So, I thought the 2SK1530/2SJ201 had a different pinout than the IRF/Fairchild mosfets. If they are the same pinout will they drop into a standard F5 build and bias up with no resistor changes/other changes?

Looks like I can get the Toshibas from Spencer at FET audio and analog metric has them as well. Cost more than the IRF's but could be worth it. Last thing I want to do is build the amp with IRF's and then always wonder if the Toshibas are better. Usually that ends up with me ripping the amp apart about 6 months later to "upgrade".

 

[permaneder]

So, I thought the 2SK1530/2SJ201 had a different pinout than the IRF/Fairchild mosfets. If they are the same pinout will they drop into a standard F5 build and bias up with no resistor changes/other changes?

Same pinout 2SK1530 pdf, 2SK1530 description, 2SK1530 datasheets, 2SK1530 view ::: ALLDATASHEET :::