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First One - mosFET amplifier module

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#3,322
I ordered 2x DPS-600/S2-52V (unregulated) plus 2x PBTU-3 from audiopower.it for my FO M 1.4 project - plus an additional set for another DIY-er for a small group buy. The people at audiopower.it are very helpful and knowledgeable both in regards to amplifiers, SMPS-es and combining the two, and have also been running tests with the FO M 1.4 powered by their SMPS-es. Their helpfulness and quick replies are much appreciated, and I now look forward to implementation. 🙂

For others considering the audiopower.it SMPS-es, it might be helpful to know that the DPS-600/S2 supports the "DC sense"-module, which I will be ordering. Other models may also support "DC sense"--protection, but I only inquired about the one I have ordered.

EDIT: FO M 1.4 modules w/ DC sense ordered! 😀
 
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#3,323
I finally completed the transformation of my ugly amp to dual-mono, as LC recommends, and I just forgot how much the SMPS costed me, so better it sounds. Now I will have to wait for complete burn-in and then add even more capacitance. I plan to experiment with big cans parallel with Russian polystyrene caps. 😎

Thanks LC. 🙂
 

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#3,324
maxlorenz said:
I finally completed the transformation of my ugly amp to dual-mono, as LC recommends, and I just forgot how much the SMPS costed me, so better it sounds. Now I will have to wait for complete burn-in and then add even more capacitance. I plan to experiment with big cans parallel with Russian polystyrene caps. 😎
Click to expand...

I also have a tendency to make my amps ugly (and cheap in the chassis department), but you just motivated me to make more of an effort this time 'round. 😀

Congrats on the build - hope it sounds great!
 
#3,325
Thanks.
I prefer that it gets evident that it is DIY. 😀
At least it is very robust.

As the amp burns-in, micro and macro-dynamics improve, images are more palpable and textures and tonal depiction are more credible. If you like "girl and guitar" music, go for a SET amp, but if you like classical music, like myself, this is the better amp. As I said before, it simply doesn't care about how large the orchestra or the score is... 😎

I will also experiment with an autoformer based attenuator between amp and speakers.

Cheers,
M.
 
#3,326
As regards using LL1540 as input transformer input, would it be OK to connect the single ended RCA input via the transformer as well, given the strict rule that only RCA or XLR may be connected, and not both?

Please see the attached diagram - I borrowed mackiew's original for connecting the LL1540 from an earlier post - thanks!
 

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#3,329
Gbatokai said:
Thanks for the reply - that's true, and completely fine. I was more worried about the grounding scheme, as the FO will now be floating with no ground connection outside itself.
Click to expand...
Hello!
I realize I ve mixed up something, the smaller signal (RCA) should be connected to the smaller winding , so at pin 2-4 , and not the xlr pin 3 as I mentioned ..

About floating, well, unless one of the element in your system has its gnd connected to earth somewhere, then you are always floating 🙂
but if you question this, then you might question why using a transformer 😀
 
#3,330
maxidcx said:
Hello!
I realize I ve mixed up something, the smaller signal (RCA) should be connected to the smaller winding , so at pin 2-4 , and not the xlr pin 3 as I mentioned ..

About floating, well, unless one of the element in your system has its gnd connected to earth somewhere, then you are always floating 🙂
but if you question this, then you might question why using a transformer 😀
Click to expand...

The transformer provides proper balanced to unbalanced conversion, that's why. 🙂 The single-ended RCA input is there because several friends are interested in the FO M, and unlike me, they don't have a nice, properly balanced front-end - so I need the RCA to let them hear the amp in their own systems. + 6 dB on the XLR is completely fine... it's easy to mess up with these Lundahls as the pin numbering doesn't correspond to the sequence of taps on the windings.

I was just asking to be on the safe side, with the recent stories of burnt zobel networks, improper grounding etc.

I guess as long as the FO has its GND referenced to the power supply, it'll be fine. I also prefer to isolate ground when possible, which is the main reason why I changed the scheme for the LL1540 in the first place.
 
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