I am/was mostly a Solid-State kinda guy. Old school Luxman, NAD, B&K preamps and Amps. Later in life added Pro Audio and DJ equipment on the list. But kids came in and had to give most of these things up. So I ventured into headphones and was never satisfied until I got the Fiio E12A and FIIO E12 DIY for my bass head needs. The Guitar guys’ opamp roll all the time to get different sound signatures. So I started swapping opamps in the E12 DIY to figure out what I like. You would think a simple 8 legged opamp would just pass the signal from A to B and that would be it. But it’s how the circuit within is implemented that changes the sound. There wouldn’t be so many varieties of opamps on the market if the circuit was basically the same within and the output always the same. On top of that, the circuit surrounding the opamps effectively alters the sound as well. This is how big name companies can use cheaper opamps and still manage to get their “house” sound out and make a slightly better profit per unit. Soooooo, the hunger for more power came after getting the Hifiman 400i. I started with the NAD 2140 amp and was happy for a while. Then there was the B&K dual mono amp and it sounded nice. The car amp for headphone use adventure began, which were powered by HP server PSU’s. But I wanted to opamp roll, so I ended up with Parasound Z series and opamp roll on the cheap. I installed DIP8 sockets into the Preamps and Amps. I’ve used the same opamps that came in the FIIO kit of mine and some Muses. The Muses in the preamps did great, but I disliked them in the Zamp as they just didn’t sound as good as in the FIIO portable amps. Burson contacted me to try out their opamps in my hardware setup and post the results. It didn’t matter if my findings were positive or negative. I’ve heard the Burson’s V4 in the Gustard’s from two forum members and I really liked what I’ve heard. So I agreed that I would try the Burson’s out in my setup in exchange of me posting my findings. I received the V5 early one morning and within a few hours had some extensions made at work. Two sets where made, with one set containing a small 0.1uf WIMA cap soldered between the positive and negative leg of the dip socket. This was based on the “upgrade” suggested on the Burson’s website. 100 Hours of burn in was required. I rounded up 4 fellow audio enthusiast that are familiar with my audio setup at work. Swapped out the Muses8920 out of the Parasound preamp first. Huge difference right away in output and everybody agreed that the Parasound was on a whole different level now. Everything sounded more detailed, but wasn’t so smooth. So the adapters with the Wima caps went in and BOOM!!!!!......NOW the Parasound was perfect. It’s detailed with every type of music. I was able to remove the sonic maximizer that I was using with my headphones. Acoustics are just might boggling. Next up was the Zamp which had all its caps replaced. I had swapped out the stock JRC for Opa2134 and the sound was too bright. Then I used the Muses02 and I liked it again. But stopped swapping opamps l after the Opa1611’s went in. That was the sound I liked the most. Well that was until the Burson went in. Same scenario again. Initial impression was WOW! The WOW became a WOW WOW when the Wima cap went in. I soldered the Wima cap between the + and – legs as close as possible to the opamp. My fellow audio witnesses all agreed on the WOW factor that the Burson brought to their genre of music taste. So the impact in sound was the greatest in the Preamp vs the Amp. And I say it’s a worthy upgrade for the Preamp. Was it worth the upgrade in the Parasound AMP? If I had spare change, I would purchase it for the Zamp. The Parasound preamp on the hand sounds better than the old school Luxman preamp of mine. But this happened after 3 days of running the Burson’s continuously. I didn’t hear any difference in sound after 3 days of burn in. For giggles the Zamp V.3 went under the knife and got its JRC 072D removed for a Burson upgrade. Short work was made and a machine wrap 8 pin socket went in. The burned-in Burson went in and something new was born. The very good Parasound V.3 amp is now on a different level. I like it way more than the Zamp V1 and it’s a worthy upgrade. Music is very detailed, open and alive. Doesn’t sound clinical at all and you can easily listen to your jams for hours on end.