Progress on the new amp
We’re right in the middle of our discussion on jitter and how, in 1994, we built a product called the Digital Lens that reduced jitter of anything we plugged into it to almost nothing. We’ll continue this tomorrow as I wanted to give my readers an update on the new power amplifier.
As many will recall we have been working on a new power amplifier for some time now. In fact, way too long. The amp was supposed to come out in January but we halted the project because it didn’t sound right. The top end of the amplifier was somewhat missing and there was a scrunched up quality to the sound. Nothing we wanted to have out there as a product.
These things happen because we design products on paper first, based on our best experience and guesses as to what’s going to work. Then we prototype that circuit up on a PC board and listen and tweak the results. That’s a long process and many times we get it right. Sometimes we don’t. This time we didn’t. So we scrapped the PCB and started over with a clean slate.
The overwhelming desire is to create a world-class power amplifier that is about as open and musical as it can be. To do this we decided to really move in a different direction than we’ve done in the past: a zero negative feedback loop. Now, typically in a power amplifier, if you have no negative feedback from input to output you suffer from poor control over the loudspeakers because your output impedance is relatively high. But if you break up the power amplifier into sections, as we have with this design, then you can have your cake and eat it to. This new design breaks up the power amp into two completely separate and isolated sections: the power output stage and the analog input stage. Both have separate power supplies, both are designed entirely differently. This design topology of breaking the amp into two distinctly separate sections is nothing new: we first introduced the idea to high-end audio nearly a decade ago in the Classic 250. But today’s design is quite unique for a number of reasons.
I will get more into depth on this topology and the reasons for it, but let this short note bring you up to date on what we’re doing. A redesign of the analog input stage, from what it was to this new design seems to have solved most of the issues I was hearing and to my ears is a revelation. The input stage is now a high voltage, class A, all MOSFET design with zero feedback.
So far I have only compared it to our last efforts. It blows away what we had and music is coming forth from the Infinity IRS as never before. The next step is to gather a collection of other manufacturer’s power amplifiers to compare those to what we have. That’ll tell the true tale.
But from a music standpoint, the standpoint that really matters, I think we have something extraordinary; a device that lets the instruments sound like themselves, where music sounds like music. In the end, what else matters?
If you want to see a picture of the new PCB of the input stage, you can go to our Instagram page http://instagram.com/psaudio1 . If you click on the follow button on Instagram, I’ll be posting more pictures this weekend of the amp, our DSD sessions in the listening room and other fun things…