Based on Amir’s VTV amplifier teardown, I had posted some reworks on my used Hypex one. @Rottmannash liked what he saw and, after a brief conversation, decided to have me evaluate his VTV Purifi amp. The goal here is to improve build quality and safety - not to alter the any of the Hypex or Purifi modules. I use a Quantasylum QA401 audio analyzer and, while not Amir’s AP, helps identify major flaws and validate that any mods are beneficial rather than harmful.
So, here the first pass. Here is my markup of the BEFORE pic that was posted in Amir’s teardown thread:
First, I should mention that before opening this amp, I ran some quick checks and no major noise issues were identified. At this point, the main focus became improving any identified safety concerns. Please note my use of different colors is more for contrast than any other purpose. Starting with the Red X in the upper right, this is meant to note the lack of a case fuse. Some might say, the EMI filter is an issue too, but not as best as I can tell with my analyzer. So, will just be adding a 250V 15A fast blow fuse. The red circle to the left of the X is some slightly exposed AC wiring and will eliminate that. The yellow arrow points to the case ground that lacks a knurled washer and will add one of those.
Continuing with the AC wiring, there are several improvements planned. One is to shorten it by a bit more than half. This will be done by remounting the power supply so the heat sink is on the left. This also eliminates all the wiring running over the heat sink as identified by the yellow oval. Next will encase the AC wiring in nylon braid to double insulate most of it from the case. Finally will add some wire tires to tidy it up a bit too.
So here is a pic after I remounted the power supply:
As you can see, this left a lot of excess AC wiring and now only the LED wire needs to go over the heatsink. Will add some heat shrink tubing for the LED wire to double insulate. At this point, I reran my tests and found a very marginal improvement in low frequency noise. This may improve more once I shorten the wires. Along with shortening the AC wiring, plan to solder the power wires to the input connectors. This will prevent them from falling off and causing potential loss of power or shorting.
So, here the first pass. Here is my markup of the BEFORE pic that was posted in Amir’s teardown thread:
First, I should mention that before opening this amp, I ran some quick checks and no major noise issues were identified. At this point, the main focus became improving any identified safety concerns. Please note my use of different colors is more for contrast than any other purpose. Starting with the Red X in the upper right, this is meant to note the lack of a case fuse. Some might say, the EMI filter is an issue too, but not as best as I can tell with my analyzer. So, will just be adding a 250V 15A fast blow fuse. The red circle to the left of the X is some slightly exposed AC wiring and will eliminate that. The yellow arrow points to the case ground that lacks a knurled washer and will add one of those.
Continuing with the AC wiring, there are several improvements planned. One is to shorten it by a bit more than half. This will be done by remounting the power supply so the heat sink is on the left. This also eliminates all the wiring running over the heat sink as identified by the yellow oval. Next will encase the AC wiring in nylon braid to double insulate most of it from the case. Finally will add some wire tires to tidy it up a bit too.
So here is a pic after I remounted the power supply:
As you can see, this left a lot of excess AC wiring and now only the LED wire needs to go over the heatsink. Will add some heat shrink tubing for the LED wire to double insulate. At this point, I reran my tests and found a very marginal improvement in low frequency noise. This may improve more once I shorten the wires. Along with shortening the AC wiring, plan to solder the power wires to the input connectors. This will prevent them from falling off and causing potential loss of power or shorting.
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Any idea why?
