F6 Illustrated Build Guide

[freebee]

Could someone give me some sound advice please? I can buy two 2x18v 200VA transformers or one 2x18v 500VA. Which would be the better choice? Or should I get more VA?

 

[silasmellor]

Depends, but either option is fine. 2 x 200 VA requires dual mono psu (or monoblocks), 500 VA would be more than enough for a regular stereo build (400 VA would also be ample). IIRC commercial F6 uses single 300 VA.

 

[Zen Mod]

2 of 250VA

 

[codyt]

If doing as a dual mono PSU (same chassis), what's an ideal grounding scheme? Both boards to star via CL60?

 

[freebee]

I can buy two Block RTE 200/2x18 Ringkerntransformator 200 VA 5.56 A for 64 euros (32E p.p.) or I could go with Ringkerntrafo 500VA 2x115V -> 2x18V / 1x36V Sedlbauer, RSO-825059 (€95). Of cause I can save up to buy a Toroidy TTSAS0500 - SUPREME AUDIO 2x18v 500VA (€184.66).

There's also a cheaper Sedlbauer version which is €65.
Sedlbauer 859780 Ringkerntransformator 1 x 230 V 2 x 18 V/AC 500 VA 13.88 A

Spoilt for choice, but which is the smartest?

 

[coolnose]

2 small ones, but wou will have to double up on diodes and PSU

 

[freebee]

At the time I bought the M2 Power Supply boards from Tea-Bag. Dual Rail Power GB Pass M2 Clone Boards with 120mm UMS spacing by Tea-Bag

 

[silasmellor]

That helps but I would still check that there is space in the box for everything. I like toroidy but you don’t need 500VA if you’re looking to save money.

 

[Ben Mah]

If doing as a dual mono PSU (same chassis), what's an ideal grounding scheme? Both boards to star via CL60?

Each PS board with its own CL60 to chassis ground if dual mono.

 

[codyt]

Each PS board with its own CL60 to chassis ground if dual mono.

Perfect – thanks!

 

[freebee]

thanks for the advice. Will sleep on it. I might go for mono blocks.

 

[6L6]

Monoblocks is the way to go, it gives real advantages in noise and elimination of ground loops.

Also looks very cool.

 

[zman01]

freebee,

The Tea-Bag power supply PCBs are well made, and have space for 8 capacitors if I am not wrong. As silasmellor has already mentioned, you will need more space for two power supply boards - so please check the chassis size and see if 2 x transformers and 2 x power supply boards will fit.

 

[freebee]

Thanks for letting me know. I haven't bought the cases yet, so I will look into that too.

 

[freebee]

@ zman01
Tea-Bag's power supply board has 4 caps per side (you can split the board in half)

 

[fabrice63]

Double mono look's like this as an example :




and it has one CL60 for each 300 VA trafo


.

 

[Acoustic Emotion]

then you could use any of these two, while powering up , to check is there any DC offset on output ?

and there it must be , sole explanation for burned R4 (ref. sch in post #1)

check output mosfets , replace what's burned

best to remove them both and re-check do you have proper function of biasing voltage trimpots.... meaning - observing voltage at gate resistors confirming voltage values on both end trimpot positions

during mounting of mosfets - proper torque , big washer, split washer , continuity with heatsink check ...... all these are necessary details

BuB = Beware of Burrrrrrrrrrrrrrrrrs

Can someone please guide me how to check the conditioning of the mosfets? I will desolder them tonight, but how can I measure to see if they are burned inside? Which legs should I measure with the multimeter to check for proper functioning? I checked the datasheet and diagram of the IRFP240 but I am not sure where to measure.

Thanks in advance,

Koos

 

[zman01]

@ zman01
Tea-Bag's power supply board has 4 caps per side (you can split the board in half)

freebee,

My understanding is that if you split Tea-bag dual-rail PCB in half, you will get 2 single rail power supplies. So for dual mono config, 2 of those PCBs are required.

 

[freebee]

You are right! Dual Rail Power Supply for Power Amplifier - diyAudio

That's probably why I ordered two boards at the time.

 

[JulesOz]

Hello lads,

I almost finished my F6 build and I'm now trying to set the bias.
I'm having my meter across the 0.47ohm source resistor but there is no voltage at all (on both side) =(
I did test my PSU and it works fine.

Am I missing something? Thanks for your help!