Starting to build my first F5 Turbo V3

[2bz]

This is my first non-tube amp build, so I am a little nervous.

I just got the PCBs for the channels and the PS. Populated with the resistors, so far. I'll post more pix as the build progresses. The plan is to try water cooling as is done with high power PCs. Has anyone experience with this?

Cheers.

 

[MEGA_amp]

Yes!! Do it!!

http://www.diyaudio.com/forums/pass-labs/121228-f5-power-amplifier-1264.html#post3231315

 

[spurlte]

PCBs

This is my first non-tube amp build, so I am a little nervous.

I just got the PCBs for the channels and the PS. Populated with the resistors, so far. I'll post more pix as the build progresses. The plan is to try water cooling as is done with high power PCs. Has anyone experience with this?

Cheers.

Where did you purchase PCBs?

 

[2bz]

Where did you purchase PCBs?

Jim's Audio on eBay. Spectacular quality boards!

 

[vdi_nenna]

Did Jim get permission to make the boards and sell them?

 

[6L6]

Has he ever?

 

[vdi_nenna]

Exactly.

 

[6L6]

I actually am asking in all seriousness - Although I have a pretty good idea what the answer will be...

Anyway,

2bz - look for threads started by member ' bcmbob ' he was doing some incredible water-cooled things, and very well illustrated.

 

[2bz]

I actually am asking in all seriousness - Although I have a pretty good idea what the answer will be...

Anyway,

2bz - look for threads started by member ' bcmbob ' he was doing some incredible water-cooled things, and very well illustrated.

Thanks for the link. This is exactly what I have in mind. Bcmbob has solved a lot of the cold plate to MOSFET connection issues that plague my design. Gracias.

 

[2bz]

I have read a lot of posts regarding replacement MOSFETS for the now out of production FQA12P20 / FQA19N20 pair. Here is my question: Has anyone actually built an F5 Turbo (any version) using other MOSFETS? If so, what did you use and how did it turn out?

Thanks.

 

[Marra]

Check with Buzzforb he was selling matched sets of other FQA's.

 

[6L6]

IRFP240 / IRFP9240 Would work in the circuit. Buy a tube or two of each, make a simple match rig, you will probably get enough good matches for a few amps, use one set, you can sell off the rest for what you paid for the lot.

 

[2bz]

IRFP240 / IRFP9240 Would work in the circuit. Buy a tube or two of each, make a simple match rig, you will probably get enough good matches for a few amps, use one set, you can sell off the rest for what you paid for the lot.

Thanks for the tip. BTW, is a FQP12P20 the same as a FQA12P20 except for the packaging? The spec sheets look similar but not exact.

 

[6L6]

Do you mean Buzz's Fets? Yes, that's my understanding. He verified with Fairchild that his are all genuine -- I have used plenty of his Fets and am very, very happy with them.

 

[2bz]

Do you mean Buzz's Fets? Yes, that's my understanding. He verified with Fairchild that his are all genuine -- I have used plenty of his Fets and am very, very happy with them.

No, I meant in general. If I buy a Farichild FQP12P20 from Arrow or Digikey, do I essentially get a FQA12P20 in a TO-220 package?

 

[6L6]

You don't want TO-220, rather TO-3P or TO-247. A TO-220 device will have a much smaller dissipation rating.

 

[2bz]

You don't want TO-220, rather TO-3P or TO-247. A TO-220 device will have a much smaller dissipation rating.

I see. Thank you.

 

[2bz]

IRFP240 / IRFP9240 Would work in the circuit. Buy a tube or two of each, make a simple match rig, you will probably get enough good matches for a few amps, use one set, you can sell off the rest for what you paid for the lot.

This amp has 16 MOSFETS: 2 channels, w/ 4 pos/neg pairs each. If I want to match the Vgs to <100 mV, does that mean: (A) All 16 must fall within 100 mV, (B) All of the positives must fall within 100 mV and all the negatives must fall within 100 mV, (C) Each pos/neg pair must fall within 100 mV, (D) other?

Thanks.

 

[AudioSan]

B. all positive for one ch. and all negativ for 1 ch.

 

[6L6]

B) Match the N-channel to the N-channel and the P-channel to the P-channel. The bias pots will make up for the N's and P's not matching.