F5 Turbo Builders Thread

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#1,721
If the pre-amp has a cable driving ability, then an extra buffer stage is not required.
The F5 can output about 21Vpk or ~15Vac. With the standard gain of 6times, the F5 needs a maximum signal of ~2.5Vac (3.5Vpk) to just reach clipping.
A cdp usually has a 0dBfs of 2Vac to 2.3Vac and cannot drive the F5 into clipping.
 
#1,723
jacco vermeulen said:
the welded SS sub-frame is absolutely lovely, most original imo.
Click to expand...

Thanks!

This was made to hold that heavy load of 25Kg in place - 11.0 Kg of heatsinks, 8Kg of transformers, 2Kg of parts and 4Kg of Aluminum plates. Below is image before metal partition sheet to be welded and only frame was ready. Its lightweight only 1.5Kg.

image837k.jpg
 
#1,724
AndrewT said:
If the pre-amp has a cable driving ability, then an extra buffer stage is not required.
The F5 can output about 21Vpk or ~15Vac. With the standard gain of 6times, the F5 needs a maximum signal of ~2.5Vac (3.5Vpk) to just reach clipping.
A cdp usually has a 0dBfs of 2Vac to 2.3Vac and cannot drive the F5 into clipping.
Click to expand...

Thats brilliant, i presume by driving ability you mean the impedance ?
looks like this cdp he has is enough. think ill add the pre-amp with a bypass switch just in case. which i think is a realy good idea!



I had a look on diyaudio and one member was selling matched parts for F5T but hes gone away on holiday for 3 weeks.

Can anyone else offer me the MATCHED IRFP240 AND IRFP9240 for a stereo F5T v2. and possibly the other transistors too.

Thanks

btw lovely amp omishra!
 
#1,726
As I gather parts for my f5t builds, I came across another post in another thread asking about hook up wire. So this brought me to think hey I have a bunch of wire in the basement that might work. So my question is would there be a need or use for some 18 awg stranded wire, 16 awg stranded wire, 18 awg shielded stranded wire, and even some Cat5 wire. I think I actually have some hook up wire I purchased from Roy at tubes4hifi when I built my preamp which I can use as well.
 
#1,733
25 sets of F-5t boards have been shipped to the distribution center. These are the ones that have 2 "p" ch output boards, 2 "n" ch output boards, and one 2 ch gain board that can be snapped in half. That way you can build up to V3 probably.

While the test builders have had various issues getting their amps running initially, there are functioning amps and it seems that the boards haven't been a problem. Still, a high power F-5 isn't a slam dunk although the effort seems to be worth it.

Give us a week to get them listed in the store software.
 
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#1,735
Variac said:
25 sets of F-5t boards have been shipped to the distribution center. These are the ones that have 2 "p" ch output boards, 2 "n" ch output boards, and one 2 ch gain board that can be snapped in half. That way you can build up to V3 probably.

While the test builders have had various issues getting their amps running initially, there are functioning amps and it seems that the boards haven't been a problem. Still, a high power F-5 isn't a slam dunk although the effort seems to be worth it.

Give us a week to get them listed in the store software.
Click to expand...

Thanks you for the news! So any idea when will the next batch be available?

Regards,
 
#1,740
Test results from F5

Hello

Following Zen Mod instructions I have placed one voltmeter at the output and by adjusting P3 can get a figure of 0.37 vdc. Which I guess is higher than it should be?

Then I place two other meters accross source resistors, R7 giving a reading of 0.04 v, reading from accross R8 is nothing, zero despite turing the little screws all the way around many times 😕

Silly question, am I looking for both R7 and R8 to give me a reading of +0.6v dc?

What is the right output voltage I should see for F5 V1 please guys?

Thanks in advance
 
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