CCY Engineering F7 Power Amp Part 2 - The Listening Sessions

For these listening sessions, I moved the CCY Engineering F7 power amp (more details of the amp can be found here) into my main listening room. Initially, the set up for source and pre-amp was the same as the one I used in my last post, i.e., the Marantz DV7001 universal player as source and a no-name passive pre-amp for volume control. The one big change, in addition to the listening space change, was the loudspeakers - I switched to the TAD TSM-2201 monitor loudspeakers, rather than sticking with the dinky Missions.

The setup went through the normal adjustment process, with experimentation in loudspeaker positioning and cable swapping. A few days later, I thought I have wrung most of the performance that I could get from this system, but the end result was unsatisfactory to me. The positive side to the sound that I noted in my past post was there, i.e., the qualities of purity and smoothness, but I felt that the music replay was a little flat and loose, lacking somewhat the verve essential for music to sound interesting and, um, musical. Time and again I found my attention drifted mid-track when listening. If the CCY F7 could talk, I think it would say "come on man, please give me something more, something that I could work with". I thought something upstream was throttling the CCY F7. 

On a hunch I decided to ditch the passive pre-amp and pressed my Musical Fidelity A1 integrated amp (2008 version) into service. The MF A1 has a pre-amp output and that was what I was looking for. This change turned out to be the one that finally made the entire system clicked.

The Musical Fidelity A1 (ver.2008) sitting on top of the Marantz DV7001 player. It is not an audiophile best practice to stack equipment on top of each other of course, but I ran out of wooden board, and I found that putting the MF A1 directly on the floor made the sound worse, so compromise, compromise.

Now, the sound through the CCY F7 amp bloomed, the soundstage opened up, and the music took on greater extensions. The sound coming out of the CCY F7 was tonally rich and dense, it was an oil painting now vs water colour from before the pre-amp swap. 

This shows that the CCY F7 has a good level of transparency, being able to reflect changes made upstream. It deserves good quality partners for it to give its best. Don't be fooled by the CCY F7's price, it punches above its price class. 

The CCY F7, with its class A pedigree, did not sound analytical like some solid state amps could, and it was also did not sound warm and fuzzy like some olden day tube amps. Its sound was rather "meaty" and not threadbare, so its music presentation was more natural than hifi-ish.

The CCY F7 had a lively presentation, with excellent dynamic expression and transient attack. Of course this was also subject to the CCY F7's power rating (20w into 8ohms, and 30w into 4ohm) and the sensitivity of the loudspeakers it was used with. With the TAD TSM2201 loudspeakers in my listening room, I could sense a little bit of stress occasionally with big orchestral crescendos, nothing that could not be solved by backing down on the volume control a notch or two, nothing catastrophic happened.  

Soundstaging was pretty good. This was of course also subject to the room and the loudspeakers' capability too. Through the CCY F7, the TAD TSM-2201 conjured up a soundstage size close to what I heard when they were driven by my reference system, despite the huge gulf in price between the two systems (the no-name passive pre-amp shrunk the soundstage quite significantly though, again showing how important it was to pair the CCY F7 with good partners). Imaging has good specificity and focus, with good delineation and space in-between images. 

The star in CCY F7's sound, especially when the price was taken into account, was definitely its purity in the mid and high frequency ranges, which also have an appealing thin layer of warmth added throughout. Further down at the bass region, bass notes were well delineated and quite agile, as opposed to being ponderous. 

Overall, the CCY F7 served music very well in my system. Let me share a few video recordings of this system made with my iPhone SE with you:

For a start, a solo piano piece. Piano has wide frequency range and dynamic range. It has transient attack aplenty being a percussive instrument. Its sound is harmonically rich. So a piano album can be a challenge to systems that are a one-trick-pony, i.e., one that excels in one particular department only. The track used was from George Winston's album "Autumn", track 2 "Woods". With the CCY F7 in the chain, George Winston's piano sounded one piece and came with the requisite tonality, speed, and attack that I was looking for:

  

Looking to have the CCY F7 play something more bombastic? How about Rimsky-Korsakov's Scheherazade? This next recording is a 6-minute excerpt of Scheherazade 4th movement from Fritz Reiner's version on Living Stereo. That this 20-watter could take on this challenge without turning the sound into a complete mush was impressive. Though I could wish for better control at occasional spots in the music, it was nitpicking at this price point. The presentation was exciting and articulated, which were the most important factors for me for the listening enjoyment of this music:

Lastly, the obligatory female vocal test. This is from 2V1G's debut album, track 8 "Don't want to be alone 不愿一个人", the overall musicality in the vocal and guitar was very well expressed:

The CCY F7 power amp truly impressed. At an introductory price of RM1,688, the performance-to-cost ratio is very high. Check it out if you are stepping up from an integrated amp, or are planning to put together a system with budget of say, up to RM20k-RM30k. Suitably matched the CCY F7 power amp will save you a ton of budget in the amplifier department. Highly recommended. 

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Postscript:

I asked Mr. Chong CY, the founder of CCY Engineering about his background and the genesis of the F7, this is what he told me:

"I am a full-time electronic engineer dealing with high power half bridge designs, the applications included LLC switching power supplies and transformerless 100V PA industries Class D power amplifiers. I like dealing with circuits related to audio and have been lurking in the DIYAUDIO forum since my studying time till now.

The whole idea started in the beginning of the COVID-19 pandemic, when everyone was forced to stay at home and do nothing. I told myself why not make something crazy and put it on the market? What if I made the cheapest class A amplifier in the world that everyone would buy without any hesitation? With a price tag of RM888 for a 25w dual mono class A push pull power amp, which was cheaper and better than anything on Aliexpress, that was how my first power amp (the A2540) was born. But the sad thing was that the sales response was not going to the way I was expecting at all.

On the bright side, I met quite a lot of really nice people throughout this journey, Wilson Teoh from My Hifi News, Matthew Ong from AFC Top Hi-Fi, Mr. Hassan from RayaMusicWorld, YF Fong from AudioTech Service Network, and many others.

I was reading on the F7 topology one day - applying positive feedback right after the speaker impedance load and distorting the input signal intentionally? It sounded very unique! I dug out my old F5 (with a chassis very alike the F7) that I built during 2010, put two resistors on it, one 0.33R in series to the ground and one 33.9k back to the input. And wow! That’s a very different sound compared to the original F5! From there, I quickly work on my first F7 prototype and asked my friends to drop by for a listen. The sound was so warm and tubey that they requested me to make a few more for them. That’s where the first F7 Clone pre-order started."

CCY Engineering contact - https://web.facebook.com/CcyEngineering-109995560498110