Hi-Fi tweaks and modifications, worth or not?

I was always very skeptical regarding tweaks and mods in Hi-Fi equipment. This was due to my understanding that the emotional and psychological state affects a subject’s judgment and objectivity. Most choices we make are actually emotional driven choices that we try to defend them with our logic by seeking reasonable explanations. That is why the Hi-Fi battlefield is prosperous for selling snake oil; people selling snake oil are actually selling pretty, reasonable looking explanations, occasionally packed in heavy, thick aluminum faceplates.

Most people will strive to differentiate in a conscious or unconscious manner. If they expect that with an X tweak the sound system will play better, chances are that they will believe that they can hear the difference. If something looks pretty and is expensive it has to play good, especially after you have spent some money buying it. Accepting that you made a wrong choice hurts your ego.



Panos is modifing his Parasound HCA-2200II power amp. At the upper part the factory components, at the bottom the same (yes, the same) modified board.

Apart from all that, I didn’t like the idea of someone messing with my beloved equipment.

However, quite a few persons that I do not consider them being Hi-Fi victims were insisting that there is this one man (Mr. C.T., the tech guru I have already mentioned at some of my posts) that tweaks the equipment and they sound much much better.

So, I thought to give it a try. I  did not have to spend much – just a couple of tenths of Euros – and the tweak would be reversible, meaning that if for any reason I wanted to return the equipment to the factory standard, I could do.

The first equipment I chose to become "The Cascadeur Of All Mods To Follow" was my Parasound D/AC-1000. The tech guru was insisting that he could transform it and somehow I preferred experimenting with the DAC than with my pre or power amp.



My Parasound D/AC-1000. Till today my favorite source for listening to CDs and DAT.

So, after a few days I got the DAC back and I started listening. Yes, it seemed that it performed better, but was it really performing better or I thought so because it was supposed to perform better?

I had this question in my mind for quite a long time, until my friend Panos decided to get a same generation but a bit superior designed DAC: the Parasound D/AC-1500. Any differences should be against the D/AC1000 so if a tweaked D/AC1000 was playing better than his bigger brother D/AC1500 then we would have a definite conclusion.



Pano's Parasound D/AC-1500.

Here was my opportunity for an objective, blind A/B listening test. A tweaked DAC Vs. a factory DAC which is also theoretically tougher to beat, since it is a better model.

A few words about the test procedure. We daisy chained the DACs through their digital out connection. So, the CD transport was feeding one DAC, this DAC was feeding through its digital out the other DAC. Both DACs were connected with the same type of analogue interconnection cables to two different but equivalent inputs of a Parasound preamp. Of course, we (also) double checked with (also) blind tests that it doesn’t matter which DAC is connected to which preamplifier input and most importantly, the daisy chain digital connection was indeed perfect: it didn’t matter which DAC was connected to the CD transport and which DAC was connected to the digital out of the first DAC. This was possible by changing the connection of the “winner” DAC, meaning after we got our winner, we changed his position to the digital daisy chain connection and/or the preamp input and perform the blind test from the beginning. Last but not least, since the DACs had different output levels, with the aid of a multimeter we carefully marked at the preamp volume control two points were the DACs were causing the same voltage at the output of the power amplifier.

As usual, our blind test had three listening cycles where the listener had to choose all three times the same winner in order for his opinion to be valid. The test was strictly blind, meaning the one of us would listen and the other would change the input and volume on the preamp, blocking with his appearance any possible indication LEDs that would allow to the listener to know what he is listening to. As I already said, the tests were repeated several times in order to make sure that the digital or analogue connection of the DACs was not influencing the test results.

The tweaked D/AC-1000 was a clear winner. The soundstage was much bigger, dimensional and was hugging the listener. The emotions of the music were flowing much easier, harmonically passing from the performer to the listener. I remember that after a short while, Panos told me to fix an appointment and get his DAC moded “tomorrow”. Yes, I still remember this tomorrow thing.

Out of curiosity, we performed the same blind A/B test with both the DACs modified. The result was that we couldn’t distinguish the sound of the one or the other.

Unfortunately, since this happened a long time ago, I do not remember what exactly the mod was. As far as I remember, it had to do with optimizing caps at the audio signal path and bypassing some filtering after the DAC chip output.

A long time has passed since then and we have got moded a lot of equipment. We have also got for review guru's own designed pre, power, phono stage, EMU moded USB interface (till today my favorite computer audio source) and power supply for the EMU. Many of them ended as a happy purchase.


This is a... factory perception of tweaking; initially the component of this well respected American Hi-End manufacturer was not heavy enough, so he thought to increase the confidence of his customers by adding some extra Hi-End weight under the top cover. If it is heavy, it is good, right?

So, to sum up: yes, tweaks and mods can work. They do worth a listening. However, you absolutely got to know the right person to advise you wisely, charge you fairly and perform the mod, or perform it yourself if you can. But please don't get electrocuted, my readers are so few that I can't afford to loose you and you can't afford to see how it looks like when a Hi-Fi equipment explodes. Except if it is not your Hi-Fi equipment or your mother-in-law is sitting right on top of it. Or even better, it is not your equipment and your mother in law is sitting on top of it. But enough about that.

I would like also to share another experience I had. Maybe you already know my opinion regarding cables, if not you can read it here. Being already skeptical about interconnect and speaker cables, you may just imagine what my opinion is regarding Hi-Fi power strips.

I am not talking about active line conditioners which as I have found out that they limit the performance of the system unless if you have such a bad power grid that you can not do without them.

I am talking about simple, plain power strips. With only passive filters inside them and a fancy looking, thick power cable. I almost started a fight with my friend George who was insisting that they do work. He was so sure about it that he lent me his.

So, I plugged my stereo on this heavy Audio Agile Line power grid with a dedicated socket for digital equipment like the CD player. And I listened. And it felt like the damn thing worked. And I listened again. And the damn thing kept insisting working.

Unfortunately I could not perform a blind A/B test for this device – how could I plug and unplug everything in no time? So I did the next best thing, invite a friend. She agreed, there was a difference. I told her to choose the sound she liked without her knowing if the Audio Agile was plugged in or not. She choose the sound with the Audio Agile plugged in. As a last test, I brought the Audio Agile at another house. We plugged it and unplugged it quite some times and the Hi-Fi owner agreed that it did work. (Update Oct. 2018: I tried the Audio Agile at Pano's system, the results were again positive (more airy sound-stage, better controlled base) - so Panos also bought one).



Yes, I got two of them. Yes, there is some cable mess but it is hidden.

George that lent me his Audio Agile was laughing. I got two Audio Agile power strips. I can’t fully understand how and why, but they have a positive effect on the sound without any negative one.

Happy listening as always!

Chris