For comparison with matched Harris 520/9520 as output transistors:
Here's what 1 watt output looks like on the spectrum analyzer:
.
I listened to the ACA Mini with the Fairchilds in it yesterday...it sounds amazing. I have not compared it to the amp with the Harris outputs side by side...yet. I'm not sure how much of the enjoyment I had listening yesterday was due to the Fairchilds, or I was just stunned by it's sound since I haven't listened to the ACA Mini in a while. I ordered another Meanwell PS so I can keep both amps warm while switching back and forth.
Here's what 1 watt output looks like on the spectrum analyzer:
.I listened to the ACA Mini with the Fairchilds in it yesterday...it sounds amazing. I have not compared it to the amp with the Harris outputs side by side...yet. I'm not sure how much of the enjoyment I had listening yesterday was due to the Fairchilds, or I was just stunned by it's sound since I haven't listened to the ACA Mini in a while. I ordered another Meanwell PS so I can keep both amps warm while switching back and forth.
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I was able to spend some time with both amps today. I thought the difference would be very subtle and I would have to "hot swap" them in order to hear that...I was wrong. To my ears the difference is not subtle and i prefer the ACA mini with the Fairchilds (jumper or no jumper) by a wide margin. It's like everything just snapped into focus.
Anyone else want to give this a try? I have enough matched FQP3P20/FQP2N30 for three more amps. PM if interested.
Anyone else want to give this a try? I have enough matched FQP3P20/FQP2N30 for three more amps. PM if interested.
Hi Kevin,
In your post #1402, the graph on the right seems to be that of for Fairchild jumper-out.
Can you please post the Harris jumper-out one for comparison?
Thanks,
Dennis
In your post #1402, the graph on the right seems to be that of for Fairchild jumper-out.
Can you please post the Harris jumper-out one for comparison?
Thanks,
Dennis
Good catch Dennis...I grabbed the wrong file while attaching in that post.
I'll make a clean post of all four graphs side by side.
Look for the text explaining setup in the lower left hand corner.
Good evening all!
Question regarding the Harris IRF520's.. I purchased the essentials kit from the store and somehow overlooked the fact that there were 2 types of mosfets in this kit! oooops.. Anyway, upon first application of power, I was fortunate enough to see some magic smoke for the first time on a DIYAudio project! Learning! Continuing my glass 1/2 full outlook, I was also afforded the opportunity to also work on my desoldering skills! Arguably, they needed some honing.. After moving the Mosfets where they needed to be, I found one of the 520's to be "Tango Uniform" and was able to verify it with a mega 328 (Thanks 6L6 for the suggestions!)..
All of this is to ask: Does anyone have any recommendations on where to purchase a replacement 520? Digikey wants me to buy 732 pieces and Rochester Electronics needs me to order 900 I think.. Lol.. Thanks for any suggestions, and I hope you all get a laugh out of my stupidity!
Cheers!
Question regarding the Harris IRF520's.. I purchased the essentials kit from the store and somehow overlooked the fact that there were 2 types of mosfets in this kit! oooops.. Anyway, upon first application of power, I was fortunate enough to see some magic smoke for the first time on a DIYAudio project! Learning! Continuing my glass 1/2 full outlook, I was also afforded the opportunity to also work on my desoldering skills! Arguably, they needed some honing.. After moving the Mosfets where they needed to be, I found one of the 520's to be "Tango Uniform" and was able to verify it with a mega 328 (Thanks 6L6 for the suggestions!)..
All of this is to ask: Does anyone have any recommendations on where to purchase a replacement 520? Digikey wants me to buy 732 pieces and Rochester Electronics needs me to order 900 I think.. Lol.. Thanks for any suggestions, and I hope you all get a laugh out of my stupidity!
Cheers!
I added Mark’s filter and modernized the chassis. For those of you with access to The Container Store, this is a $10 6x6x2 acrylic riser.
Attachments
Lovely build @rhthatcher !!
Looks like there's plenty of room under there to install several SMPS filter boards, for those who prefer to kill a mosquito with a bazooka. SMPS --> filter PCB #1 --> filter PCB #2 --> . . . . --> ACA Mini power-in terminals
Looks like there's plenty of room under there to install several SMPS filter boards, for those who prefer to kill a mosquito with a bazooka. SMPS --> filter PCB #1 --> filter PCB #2 --> . . . . --> ACA Mini power-in terminals
Thanks Mark!
I saved the 2nd one I have for the next build. I just ordered more ACA mini goodies from the store today. I’m going to try the FQP test.
I'm trying the REW software for the first time. It's capable of giving information on the phase of the harmonic distortion.
