[Otherwillsmith]

Hi AC! This is my first post so apologies if this is addressed elsewhere. My name is Will and I love DIY audio projects. I am that farthest from an electrical engineer, but I have a ton of soldering experience and I can follow clear directions, meaning I will forever be relegated to the beginner realm of the hobby.

I have always been a believer in Class A and while I love the sound of tubes, the cost and calibration of tube amps has been a bit of a blocker for me. One of these days I’m gonna take the plunge and order a Bottlehead, but I haven’t gone down that path yet.

My favorite Amp Designer has been Nelson Pass. Both because his amplifiers sound amazing to my ears and because he is an absolute champion of the DIY audiophile community. I’m also a huge fan of point source and subsequently full range drivers for their imaging and super clean signal path. Not having to calculate time alignment issues is a huge time saver for the DIY enthusiast.

I recently decided to see what all of the hype is about and try out Class D. I picked up an ICEpower 50ASX2se and dropped it into a Ghent Audio case and fired it up. My mind was blown! How could this sound so good?!? The input seemed a little low being fed from the single ended Schiit pre I was using (Saga S) so I dropped a pair of 1:2 step up transformers at the input and for about $350 all in I was listening to one of my favorite amplifiers.

I emailed a little with a gentleman at ICEpower and in doing so, I learned that the ICEpower amp I used is a Class D amp, but it differs from Hypex and Purifi in that it uses mosfets and not GaN. I realized I don’t truly know the difference between an amp running mosfets in a Class D topology and a GaN Class D amplifier so I thought I’d reach out to this community with my first post and ask if you fine people might be able to lay it out for me/the community?

Anyway, I hope it’s not too stupid a question and that I’ve posted it properly. Looking forward to growing in knowledge through this village.

Thank you!

[WGH]

I think the input stage is just as important as the Class D output stage. Some DIY Class D amp kits give the builder a choice of different input stages.

The PS Audio Stellar M1200 amps use a tubed input into a ICE Edge Class D amp. Their Stellar M700 amps use the standard ICE Class D amp (no Edge) with a zero feedback, discrete, Class A MOSFET input stage.

https://www.psaudio.com/collections/amplifiers

I borrowed a pair of the M1200 monoblock amps from a friend. They work very well with his power hungry speakers. I still prefer a well designed Class AB amp in my system.


An Amp Comparison: PS Audio Stellar M1200 and AVA Vision SET 400
https://www.audiocircle.com/index.php?topic=176173.msg1856501#msg1856501


Our audio club borrowed a pair of the original NCore Class D amps back in 2013, we kind of savaged their sound. Class D has improved a lot since the early days.

NCore Listening Impressions
https://www.audiocircle.com/index.php?topic=117854.0

System synergy is the most important factor.

[ArthurDent]

Greetings & Welcome to AC Will    I'm sure some of the more knowledgeable folks on Class D will chime in, but you might also pose the question in the The Lab circle here  -

    https://www.audiocircle.com/index.php?board=20.0

[Phil A]

Welcome!

[Speedskater]

 Bruno Putzeys writes:

Life on the Edge
 – A Personal Perspective on the Past, Present, and Future of Class D Audio Amplifiers

https://hometheaterhifi.com/30th-anniversary/the-now/life-on-the-edge-a-personal-perspective-on-the-past-present-and-future-of-class-d-audio-amplifiers/?utm_source=HTHIFI&utm_medium=HTHIFI&utm_campaign=HTHIFI&utm_id=18776575&utm_term=HTHIFI&utm_content=5

[HAL]

Orchard Audio offers his GaN Class D amps as kits for DIY.  He sells the amp boards and SMPS and chassis.

Excellent sounding amps.

[Otherwillsmith]

Thanks for the welcome and the input guys! Much appreciated.

@WGH - I agree completely. I was blown away by the results of the addition of the 1:2 transformers added to the input of the ICEpower amp I assembled. I would love to learn how to build a tube input stage. If I had a better understanding of electrical engineering, I’d try placing a Korg Nutube at the input. I do however feel that there’s a difference in sound between the other Class D amps I’ve listened to. I thought so before I learned that FETS could be used with Class D topology and differ from GaN. Once I learned that there was a difference, it somewhat confirmed what I thought I was hearing. Now I would love to learn about what the difference is between the two and exactly how they work. Paul Meister at ICEpower shared this article with me which arose from their in-house testing of GaN and its advantages/disadvantages vs their use of MOSFETS. https://icepoweraudio.com/is-gan-worth-it/

@Speedskater - Thanks for the article! I’m going to read it as soon as I finish this reply. I love this kind of intel.

@HAL - I have heard great things about Orchard Audio and have been drooling over their kit, but the cost of their kit is a bit outside my price range. The ICEpower/Ghent build was very accessible as I was able to buy components spread across multiple pay checks. This great helps with significant other and her inability to understand why I need another amplifier On a side note, your avatar looks suspicious familiar and you’re listed as an industry insider. If my suspicions are correct, know that my FREQ is my single favorite build thus far! If I’m mistaken, thank you for the great recommendation!

Thanks again ladies and gents! (You never know)

[FullRangeMan]

Hi,
Gan-FET transistors are hi efficiency devices, MosFets have low efficiency.
Check this topic:
https://www.audiocircle.com/index.php?topic=188775.0

[Otherwillsmith]

@FullRangeMan, that was it! That was the piece I was missing. I feel a bit silly now cause it’s such a simple distinction, but it’s surprisingly rare to find it discussed. At least in the knuckle dragging circles that I frequent. Thank you sir! Much appreciated 🙏🏻