AQVOX DAC - The Modification Thread

🤣🤣

May I suggest a through hole plating repair kit Oli, its a great getout of shite card

Hi Oli

This what I use

www.circuitmedic.com/products/201-2100.html

Anyway..... repair kits aside, I decided on my way home from work that I was going to put some juice into the DAC and see what happened.

I double...no, triple checked the cap that had removed a pad from the bottom of the PCB and all seemed fine.

So, in went the juice..



We have lights!!!!

Not only that, we also have the correct voltages on all of the umpteen test points on the PCB!

The one thing I'm not sure of is why the input LED stopped flashing, as though it had a connection, when it clearly doesn't. I may not be recalling correctly as to whether the dac keeps blinking until lock is achieved, or if it only blinks while everything gets going.

I may not be out of the woods yet, so I am still a little apprehensive about how well I've done UNTILL I get sound out of it...which will be tomorrow, all being well.

However, I am over the moon that no caps blew electrolytes across the PCB, or a new regulator went up in magic smoke 😂

@bigman80 Good luck.

Itching to hear your impressions Oli! Do you have an unmodded Aqvox to compare with still?

Oli if you do organise a DAC off would it be possible for me to attend and bring by Mutec along ? Mine has been worked on by Tony and is powered by an Sbooster LPSU and would really like to hear it against an unmolested Mutec with LPSU input .

Sounds a good plan. I’m sure the owner of the Aqvox would be very happy to oblige 😁👍

Well, five hours of play has been very beneficial for the Aqvox. Originally, for the first few minutes, it sound extraordinary. Extremely ethereal, floaty and the soundstage was monstrous vs the previous incarnation. However, it quickly turned into a lean sound with a HF emphasis.

5hrs later and it is now sounding a lot better.

The LF has returned, there are now improvements to that too, particularly the rez.

It is now showing signs of great promise. I'll update further when it's had some serious play time

Officially 36hrs in and I'm not happy. The DAC has opened up with an extremely transparent and all encompassing soundstage, which is amazing, but it's WAY to thin.

The bass is appearing almost in the very centre of the image, which is extremely weird to hear.

However, the detail is unbelievable.

I know it's extremely early to be hitting the panic button, so I have mildly prodded it and bought some of these:



Yes, they are older caps and no you haven't heard of them, but they were WIMAs top cap for audio, and they were only released in Asia. They are the only other cap I can see that will fit and not just be a generic cap.

They will take at least a month to get here, so the Amtrans have until they arrive to fill out a bit. If they don't, the WIMA will be going straight in when they get here.

Yeah, quite possibly.

I sincerely hope not, but my experience is that caps are usually fattening up by 30hrs and these have, but nowhere near what's required.

It's always a lottery with caps.

If I ever design a DAC it's going to have enough space for PROPER caps.

The fact the LF is still in the middle of the soundstage, like a central point, suggests the Amtrans aren't burned in yet.

Well, I'm at least 50hrs in and the Amtrans aren't getting to where I want them to be. The next logical step was to see if ANY caps sound different in that position.

I had these WEET Metalised PP caps anyway, so bunged them in.



Instant tonal gratification.

They sound so much richer and human than the Amtrans. I can't lie, the Amtrans are transparent and detailed in the extreme and I can think of a hundred different devices that they would instantly improve, but not this Aqvox.

The WEETS sound a bit shut in at the moment, but LF is there already, but a bit loose. The LF is low down in the soundstage too, rather than in the middle, like a bullseye on a dart board.

I haven't given up on the Amtrans yet. I'm going to whack some volts through them for another 100hrs while these WEET are burning in and the WIMA are on the way. Then I'll give them all a listen....

However, I am now starting to think I may just risk it and go with no coupling caps. I wasn't keen before, but now I face the very real issue of not being able to use any caps I really want due to space issues.

If only there was space for some Film and Foil.

Oli, I have some 10uF 25V Silmics you can try.

They won't fit Tony.