F5Turbo Illustrated Build Guide

[nashbap]

I have the older V2 of the boards.
You can use 14awg solid core on the +ve -ve and G of the power input.
And you can use 14awg solid core on FE board.
Stranded 14awg, no way. but you can use 15.5awg stranded

Thanks for that clear cut answer. I feel this info will be useful for all future F5 builders.
Once again for the benefit of future builders, TeaBag's boards allow the use of 12 AWG solid/14AWG stranded in the same holes.

 

[dazed2]

You mean these ones?
Yes they have bigger holes. I've never actually measured them though.

BTW if anyone is interested, PM me.

 

[nashbap]

You mean these ones?
Yes they have bigger holes. I've never actually measured them though.

BTW if anyone is interested, PM me.

Yes and the PSU board. +/_/G on both PSU and amp board are 2.0mm

 

[6L6]

dazed2 - nice PCB!

 

[dazed2]

Yes Teabag made some really nice ones. They are really thick too! 4mm I think.

But I didn't end up using them cause I decided to go monoblock. These are great for a stereo amp.

 

[chuckd]

I plan on emulating this build with the same rail voltages. i.e +/-32V but in a non-cascode build. The Antek 6224 transformer used by 6L6 is no longer available. The closest they have is the Antek 10425 which is a 1000VA with 25V output (AN-10425 - 1000VA 25V Transformer - AnTek Products Corp). Is that suitable to use?

Or would it be preferable to use the Hammond 1182T24 (625VA, 48V @ 13.02A in series/24 @ 26.04A in parallel), or 1182U24 (750VA, 48V @ 15.63A in series/24V @ 31.26A in parallel)?
(Hammond Mfg. - Toroid Power Transformers - (1182 Series))

Or is there another option?

thanks

 

[maxst67]

sorry I have a question: I have a house in dual mono power supply consists of 2 transformers 2x28v 500 goes each and two banks of capacitors from each 6x22000uf, I could use them to build a F5 turbo v2 or 2x28v voltage is too high?
output are about 2x35vdc.
which is the maximum voltage for the 'F5tv2?
and yet, it is true that using the IRFP240 and irfp9240 the sound is sweeter
thanks to all

 

[vdi_nenna]

The output from 28v across a bridge rectifier is 39.6v. Are you figuring for CRC power supply and getting 35v?
I don't think it will make that much difference at 35v, but you could use a larger resistor value to drop the voltage.
Just watch the dissipation on the CRC resistor.

 

[maxst67]

thanks for the reply, now I have 2 resistanze crc to220 equal to 0.1 ohm 20w for each bank, thus putting an appropriate resistance calculated using Ohm's law could achieve the desired V right?

 

[vdi_nenna]

thanks for the reply, now I have 2 resistanze crc to220 equal to 0.1 ohm 20w for each bank, thus putting an appropriate resistance calculated using Ohm's law could achieve the desired V right?

Try this site:
Resistors

I have a mental block that doesn't allow me to understand or remember Ohms law.

 

[AudioSan]

2X28V transformer will give you around +/-35-36VDC under load. Migth be a little more, or a little less. That depends on the transformer and your main voltage.
Cascoding the J-fets is a good idea.

 

[maxst67]

an alternative? crc adequate resistance would not do the same?
how much current a channel?

 

[AudioSan]

CRC resistor is not the way to go for shaving of voltage. you only end up with a hugh loss of dynamics and 0.5V less rail voltage.
bias current must be less then the limit for the diodes to start conducting. and not more then the heatsinks and transistors can handle. i would not og over 1A pr device for the transistors sake. but not over 400mV across 0.5ohm source resistors (to be on the safe side) do to diode conduting.

 

[maxst67]

I'm sorry Audiosan but with translator is not easy to understand:
I realized that the way to reduce V with CRC is not correct,
but I did not understand the rest, perhaps you meant that the solution is to replace the source resistance of 0.5 ohms instead of 1 ohm?

 

[AudioSan]

no. it is dual 1ohm in parallell. that makes it 0.5ohm.

 

[maxst67]

ok

 

[BigE]

So, if V2 fits 14 awg, and v3 fits 20 -- which is thinner than the legs of the mosfet, why was the hole size decreased?

 

[AndrewT]

Because somebody on the "team" forgot to check.
and the change was not sent through the "team" for approval.

 

[pcb121055]

AndrewT... I fully agree. I'm faced with this every day. The original error is just human but the reason it got out the door is usually because the product did not get a proper backcheck. Fortunately, this error has a work-around so throw an ADCN at it and keep going

 

[jdg123]

test points on the N and P channel boards

Hi all,

First thanks 6L6 for the excellent guide! The photography is outstanding and of great help to us newbies!

I have used your guide to set P1 and P2 for a scant 200 Ohms for start up. 4% of maximum seems safe, am I foolish?

(This 200 Ohm figure I got by measureing R between TP1 and TP2 for P2, P1 is measured TP3 to TP4. The correlation of the numbering seems strange/wrong but it does not work the other way around...)

What are the test points on the N and P boards for? Have they a use?

I'd also like confirmation on what exactly is meant by "source resistors". I'm always questioning my take on what "the big boys" mean when they give direction.

Many thanks!