F5 power amplifier

udailey said:
Then Antek transformers are not potted in the center. So the chance for some buzzing is a bit more. I have a 600VA on my LM3886 and the only noise I get on 93db speakers is not discernable until my ear is literally on the cone. Very quiet transformer.
The 400VA was very quiet as well. The price and shipping is also fantastic.
Uriah


I'm wondering if there's any kind of sound difference using different brands of transformers?

Like difference in bass tightness, imaging, low level resolution.
 
http://www.diyaudio.com/forums/showthread.php?s=&threadid=134554

There was no definite answer. Many of us have had success with many vendors.

Actually, there was a recommendation to take the discussion to a new thread as some of the content in that thread was bordering on inappropriate speculation with some undesireable overtones.

I would suggest we also follow the recommendation there that this thread stick to what are the appropriate ratings for an F5 and if we want to do an objective comparison of the merits of various vendors, we move it to another thread.
 
If things like brands of MOSFETs or changing a resistor value change the sound of the amp dramatically, probably more so than in the X circuit, then I would think there are subtle or even audible differences caused by changing power supply components in this amplifier. Now, from reading Nelson's posts on the F5 it seems he does a bit of a balancing act with different brands of components to get his amplifiers sounding right. In the end, when he tweaks the amplifier, it has a Plitron transformer in the power supply. I'd like to know if other transformers change the sound.

There's nothing wrong with discussing transformers in this in this thread because it pertains to using the transformers in the F5. I have concerns about how they will sound in this amplifier before I go and spend money on transformers. Just because someone sells inexpensive transformers that seem like a good value and he's a nice guy doesn't mean I can't question the quality of them for use in this amplifer project. If there were no differences, I would certainly use them. But I'm not convinced that there aren't.
 
Well, if you were to buy two transformers... a Plitron and maybe an Antek and make sure they are same voltage same VA you could do an easy check. I only throw this out there because it is a feasible thing to do. Its expensive but on the other hand if the Plitron sounds better then you have a great transformer to use with a chip amp and the other way around as well. Transformers do not usually go to waste 🙂
Uriah
 
I've got no problem with discussing the transformers as they would function as installed in the amplifier. Let's just stay away from comments about the vendors or the country of manufacture unless we have solid evidence that such things change how the transformer works in the amplifier.
 
labjr said:
If things like brands of MOSFETs or changing a resistor value change the sound of the amp dramatically, probably more so than in the X circuit, then I would think there are subtle or even audible differences caused by changing power supply components in this amplifier. Now, from reading Nelson's posts on the F5 it seems he does a bit of a balancing act with different brands of components to get his amplifiers sounding right. In the end, when he tweaks the amplifier, it has a Plitron transformer in the power supply. I'd like to know if other transformers change the sound.

There's nothing wrong with discussing transformers in this in this thread because it pertains to using the transformers in the F5. I have concerns about how they will sound in this amplifier before I go and spend money on transformers. Just because someone sells inexpensive transformers that seem like a good value and he's a nice guy doesn't mean I can't question the quality of them for use in this amplifer project. If there were no differences, I would certainly use them. But I'm not convinced that there aren't.
Hey, why not do us a favor, buy both transformers to try and let us know your opinion and some measurement data as well. You seem to have more interest in this regard than most of us.
 
zettelsm said:

... F5 ... point to point wiring ... or lead to lead?

Any downside to placing the power FETs at the optimum spacing/location on the heat sinks and using short jumpers to connect them to the rest of the circuit at the perf board?




I have built F1 by point-2-point wiring successfully. Based on that experience, I presume that it would applicable for F5 too. I'm 100% sure.

I support the optimum FETs location using short jumpers. Actually, my F5 has this arrangement.

I don't suffer degradation of high frequency response due to the stray capacitance or the lead inductance which is formed with the rather long leads . . .


Cheers,

🙂
 
Chassis Design Question.

I am thinking about doing an F5 chassis without using the typical enclosure.

Let's call it an open air design, with heatsinks running vertically, and no top or 'hood' on, and possibly no front or back....

Knowing that the FET's and JFets are somewhat thermally sensitive, will the unit run potentially unstable if they are running in a somewhat open way?

I was then thinking that covering the jfets with a dollop of silicone may help here.

😕