Class D amp and integrated recommendations

[Raphaz]

The two v3 mono blocks, the ZP3 and switch arrived from Fosi.
A pair of Tekton Uruz speakers are in the making (sold my Kefs) and I’m waiting for my current sub to sell so I can order the SVS SB-3000 R|E.
Can’t wait to put this all together!

I’ll probably switch between the Fosis and the R-2000 (currently in repair again) to experience the difference for a while and then most likely put the R-2000 away as a backup.

Wanted to share my most current setup plans here before I set this all up.
Does that all make sense? Any suggestions, red flags, tweaks…?

 

[will1960]

I’m aware that there are already threads about Class D amplification here on AK and elsewhere, but I was wondering if folks here have experience with some of the latest D class gear they’d be willing to share.

I’m transitioning from a vintage R-2000 that was recently serviced and repaired, but already has issues again. I really like its sound signature and the headroom, the clear, clean, powerful sound when it works properly. But it just failed one too many times on me now. What’s the joy in that when you’re not a tech tinkerer? Besides, some parts become increasingly hard to find.

So I started looking into D Class. Measurements and reviews seem to suggest that, with some of the latest GaN, Nilai, Hypex, NCore X and Purifi based offerings, I may get the performance I’m looking for with a moderate budget. But I’m neither super tech savvy nor do I have experience with D class.
I was hoping to get more insight here as to what to look for and how to make sound (pun intended) decisions.

It’s a bit early in the game for me but I was hoping to keep the budget for amplification plus pre below $ 1,400.
Not sure yet how much additional dough I need to fork out for periphery on top of that. I’m hoping to integrate streamer, DAC, transmitter, switch box and sources from my current system, but who knows...

Can statements be made already about longevity, maintenance, repairability, and availability of parts… or is D Class still just “go cheap, enjoy and throw away?”

As some of the leading D Class vendors and makers are rather entrepreneurial and boutique (vs big box brands) and the tech still evolving, are lemons rare occurrences or rather common? What are your experiences with customer support and warranty?

Is there already a used market for D Class worth exploring?

Besides the core amplification modules, since these still need to be enclosed and connected, what else do I look for, what are other crucial factors influencing sound quality?

Should I go separates, integrated or are there any good D Class receiver options by now?
Is it worth investing in mono blocks? Is there enough audible difference compared to dual mono or even “conventional stereo?”

Generally, are there differences when driving speakers with D vs good old AB class? What do I need to consider for a good match. Does impedance still matter when driving speakers with Class D power?

And of course, I don’t know what I don’t know, so I’m all ears for any tips and suggestions.

Thanks in advance.

I'm late to the thread, but I'm very happy with my PS Audio S-300. Class D output into my Focal Chora 826 speakers. More than enough power, and a very detailed sound. New, it may be outside your budget, but $1k seems to be the going price on the used market. I purchased mine used two years ago, and the only change I may make is trading in for the M-700 mono blocks.

 

[Raphaz]

That sounds like a nice setup, will1960.
I looked into PS Audio as well, they give you lot more headroom; and the Chora 826 was one of my top contenders, great speakers, great design.
But you’re correct, I’m on a budget. I want to first experience current D-class technology and performance (with less foot print) before I invest heavily into an endgame system (if there will ever be such a thing for me). One of the things I compromised on for now is aesthetics and high-end brand pedigree.

I am looking for as much as possible accurate, neutral, almost clinical and room-filling clarity, even at lower volume. I hope my “budget picks” will give me that for now.

Going back to my question above:
Do my most current setup plans make sense? Does anyone have any concerns or suggestions? See attached.

 

[Raphaz]

I wanted to add:
My only concern now is heat with the Fosi V3 mono blocks. On the one hand, the more I read it, the more it concerns me; on the other hand, I suspect most of the failing units were from early batches and/or powered with the split-PSU.
I wonder if there are any more recent buyers of V3 mono blocks here that experienced failures based on overheating.
I often have misc on all day, at moderate volumes.
I ordered heat sinks with thermal-condusive adhesive from Amazon, to stick to the top of the units (and I may consider the Fosi fans for underneath as well). It may help.
To be fair: I also read reviews for Aiyima and other brand amps that had similar issues.

Either way, to me it is a disappointment that heat is even still an issue with Class-D amplification — it was one of the issues that made me consider to go the D route in the first place.

 

[ernieS]

I’ve invested quite a bit into class d from Rotel. They use highly regarded ICE power. The RB-1092 is a beast at 500 wpc. I’ve a 250 wpc x five, a 250 wpc x two channel. I’m so impressed, I built two 1000 wpc sub amps using the same ICE modules. I’ve also built
Very large multichannel amps using Pascal modules. Top quality.

 

[OldJBL]

I wanted to add:
My only concern now is heat with the Fosi V3 mono blocks. On the one hand, the more I read it, the more it concerns me; on the other hand, I suspect most of the failing units were from early batches and/or powered with the split-PSU.
I wonder if there are any more recent buyers of V3 mono blocks here that experienced failures based on overheating.
I often have misc on all day, at moderate volumes.
I ordered heat sinks with thermal-condusive adhesive from Amazon, to stick to the top of the units (and I may consider the Fosi fans for underneath as well). It may help.
To be fair: I also read reviews for Aiyima and other brand amps that had similar issues.

Either way, to me it is a disappointment that heat is even still an issue with Class-D amplification — it was one of the issues that made me consider to go the D route in the first place.

There are a lot of people here that are using V3 Monos and I can't recall anyone saying heat generation was a deal breaker. I could have missed a post saying this though but the general overwhelming consensus I have seen is that heat is not a huge issue if any at all. If someone plans to run them over 90db for hours on end or has very inefficient speakers then other amp options might be a better fit. If I had a pair, I would stand them on their sides using silicone feet attached to the side elevating the holes away from the surface it is standing on to promote better airflow.

 

[mrehorst]

There are a lot of people here that are using V3 Monos and I can't recall anyone saying heat generation was a deal breaker. I could have missed a post saying this though but the general overwhelming consensus I have seen is that heat is not a huge issue if any at all. If someone plans to run them over 90db for hours on end or has very inefficient speakers then other amp options might be a better fit. If I had a pair, I would stand them on their sides using silicone feet attached to the side elevating the holes away from the surface it is standing on to promote better airflow.

The amp design design includes thermal considerations. They are usually designed to be sitting on their feet, so if I wanted more air flow, I'd raise the amp up a bit. If you turn it sideways you don't know what might get cooked inside the box.

Wiim Amp Ultra, top and bottom after about an hour of operation driving Quad ESL-63s at moderate volume level- ambient temp was about 20C:

 

[kyle]

There are a lot of people here that are using V3 Monos and I can't recall anyone saying heat generation was a deal breaker. I could have missed a post saying this though but the general overwhelming consensus I have seen is that heat is not a huge issue if any at all. If someone plans to run them over 90db for hours on end or has very inefficient speakers then other amp options might be a better fit. If I had a pair, I would stand them on their sides using silicone feet attached to the side elevating the holes away from the surface it is standing on to promote better airflow.

I have the Fosi BT2-A Max which has a top vent as well as the sides and an internal fan. It's supposed to be around 100 watts into 8 ohms and uses the same chip as the V3 monos. It has gone into thermal protection 3 times since I got it. It's hooked up to a pair of Wharfedale Linton 85th anniversary speakers which are relatively efficient and 6 ohms nominal. I was playing music quite loud but I have never had another amp shut down from heat before. I only had to power off and then back on and the amp played as before so it may not be an issue. Still....

 

[Raphaz]

So I take it that heat is produced and the design of the V3 does not allow for enough dissipation of excess heat. So if used without additional measures it will be a gamble.

Two questions:
Any concerns about vibration caused by placing the V3s on top of the fans (sold by Fosi separately)?
Any potential concerns about using the amps vertically (as suggested above)?
Am I wrong assuming that vibration is not normally a good thing for most audio components?

 

[kyle]

So I take it that heat is produced and the design of the V3 does not allow for enough dissipation of excess heat. So if used without additional measures it will be a gamble.

Two questions:
Any concerns about vibration caused by placing the V3s on top of the fans (sold by Fosi separately)?
Any potential concerns about using the amps vertically (as suggested above)?
Am I wrong assuming that vibration is not normally a good thing for most audio components?

I think that mounting vertically with fans blowing through the side vents would be a good idea. I've come to think that the Fosi amp cases are too small for the amount of heat they need to dissipate. That said, many people are happy with their amps and have no issue with over heating. It will depend on your speakers and whether you play them for extended periods at higher levels.

 

[OldJBL]

So I take it that heat is produced and the design of the V3 does not allow for enough dissipation of excess heat. So if used without additional measures it will be a gamble.

Two questions:
Any concerns about vibration caused by placing the V3s on top of the fans (sold by Fosi separately)?
Any potential concerns about using the amps vertically (as suggested above)?
Am I wrong assuming that vibration is not normally a good thing for most audio components?

I don't see where using external fans will cause reliability issues. Especially if the fan is not physically attached to the case. The fan just needs to blow air onto the exterior of the case.

As for placing the case on its side, the reason this would promote more air flow though the case is due to hot air rising like in a hot air balloon. The hot air exits the top holes which causes cool air to be pulled into the bottom holes. With the case lying flat all the holes are at the same height which does not promote the same air flow dynamics of placing it on its side. Less airflow though the case means higher temperatures in the case.

All this said, I don't think there is a systemic problem with temperature regarding the V3 Monos. My ZA3s stay at the same temperature no matter what the volume lever is set at which is just bearly warm to the touch. I have older, very tiny class D amps that ran a good bit warmer than the current TPA3255 amps and they ran for years and years with no issues.

 

[C Hart]

When you buy one of these small class Ds you should not have to worry about heat. That is maybe the most important design engineering consideration for an amp, or really any electronics. If you have to use an external fan it is a poor design.

The TPA3255 is widely used and all the products that use it therefore have broadly similar power output for the same AC power supply. I would be very surprised if any of the mass marketers like Fosi (and Aiyima, Douk, Topping etc.) sold anything that was inherently too hot.

@Raphaz There is nothing really wrong with your design but it does have some limitations due to its complexity. You have 3 Wiim boxes, a sub that isn't fed when you switch to the receiver, two preamps, two switches, six speakers, etc, etc - why not start simply? It just seems like a lot to bite off. My main system has a preamp, power amp, graphic equalizer power meter, amp/speaker switch (which handles up to 4 amps and 4 pairs of speakers), turntable, CD, Bluetooth, and a Mac Mini and it is actually simpler. The ZP3 just doesn't have enough inputs. You may want to take a look at a traditional preamp.

Also, perhaps consider using the high level inputs to the sub. That way you can connect it to your speaker/amp switch output and have it work with both the pre and the receiver.

 

[fredgarvin]

The two v3 mono blocks, the ZP3 and switch arrived from Fosi.
A pair of Tekton Uruz speakers are in the making (sold my Kefs) and I’m waiting for my current sub to sell so I can order the SVS SB-3000 R|E.
Can’t wait to put this all together!

I’ll probably switch between the Fosis and the R-2000 (currently in repair again) to experience the difference for a while and then most likely put the R-2000 away as a backup.

Wanted to share my most current setup plans here before I set this all up.
Does that all make sense? Any suggestions, red flags, tweaks…?

i've seen two versions of the Uruz, one had the nice Fountek ribbon and the other one, later maybe, has an AMT tweeter. Which one are you getting in your new ones?

 

[J English]

I have the Fosi BT2-A Max which has a top vent as well as the sides and an internal fan. It's supposed to be around 100 watts into 8 ohms and uses the same chip as the V3 monos. It has gone into thermal protection 3 times since I got it. It's hooked up to a pair of Wharfedale Linton 85th anniversary speakers which are relatively efficient and 6 ohms nominal. I was playing music quite loud but I have never had another amp shut down from heat before. I only had to power off and then back on and the amp played as before so it may not be an issue. Still....

I also have a new BT20a MAX from Fosi, with the 48v/5a power brick. I've tried it with a couple of speakers now, and feel it's definitely better suited to playing at moderate volumes rather than "loud loud." Despite the specs, it seems to run much warmer than the other 3255 amps I own. You may find that switching to Fosi V3 monos or Aiyima A07 MAX amps in mono mode will work better for you. Alternatively, you could try adding in a Fosi P4 preamp in the chain, to boost the signal coming into the amp.

 

[OldJBL]

PFFB can make class D amps run warmer than without it. My two ZA3s get barely warm to the touch without PFFB.

 

[BOSEblows115]

I have been very interested in this one....and will most likely purchase it real soon... the impressed with the LED screen to a Douk A5

I have been very interested in this one....and will most likely purchase it real soon... the Aiyima A80....

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I have been very interested in this one....and will most likely purchase it real soon... the Aiyima A80....

View attachment 3616493​

found the older Aiymia A80 to be a mediocre DAC—very generic-sounding except for its strong Bluetooth. Audio from my Panasonic CD player via optical was almost indistinguishable from my old setup: a $100 SMSL DAC + $89 Douk A5 class-D amp

 

[BOSEblows115]

I m not a fan of class D amplifiers. I don't care if its Crown, Mcintosh, Carver and a lot of others. It's just like there are great tube amps but most don't cut the mustard for me . I had my share before transistors came along that were dependable. Knight, Scott, Fisher and Mcintosh, but didn't always sound great. Oh! I had a Dynaco or two and the only one worth its salt was the MK III 60 watt mono amp.

Just like anything else when it comes to integrated amps it's who makes them. I really liked Pioneer back in the 70's and 80's. Sansui at the time was special. Back in th days of tubes, Sherwood didn't always measure that well, but I found the sound to be enjoyable. Even more than my Scott and Fisher stuff. I have always liked the sound of the 6000 series Mcintosh integrated amps with out autoformers. The 9000 Mcintosh and the 8900 sound great with most speakers, but not so much with others. They are good with Magico for instance even if a 275 in mono is better. It's about the midbass sound in this case. The big Macs sound great with Magnepan as those speakers are inefficient. Accuphase Class A integrated are super if you have semi efficient speakers and a lot of spare coin. I would say 95+ db 1 watt 1 meter at 8 ohms. I have always been suspicious of Yamaha. I prefer Marantz most of the time. Denon can be good with one model and the next even better or worse. I can't explain that as it's just the way the cookie crumbles for me. I wouldn't have a Sony if you paid me. I basically gave up on integrateds after my MA 230 Mcintosh when I changed from very efficient speakers, 98 db 1 watt 4 feet, to 94 db 1 watt 4 feet. Finding a Great integrated with over 40 watts per channel both channels operating with less the .5% distortion was impossible back in the 60's. So I have used separates ever since. That also applies to modern HT stuff where a lot of folks use AVR's. They are not for me. There have been a lot of new Brands that have come along that I haven't auditioned. It seems thru ought that past 60+ years a lot of brands have come and gone. Some I miss others are a faint memory. B&K is one, Haffler, Dynaco, Sansui, and Onkyo is here one day and gone the next. I worry with Mcintosh being sold to Bose just like I did when they were sold to Clarion. What ever you buy make sure it can be serviced by a local dealer with a great reputation for service after the sale. 10 to 20 years can fly by pretty fast and that is when you can start having issues with some pieces. Stay away from tubes unless you have money in the bank.

Have you ever had any knowledge or insight on the Sherwood Newcastle R-771 2ch stereo receiver the face plate looks identical and shares similar specs to the sherwood RX-4109 I liked the sound of the 4109 and I wanted to upgrade to the R-771 but is it different parts inside or is it just rebranding(I have a pair of Altec Lansing 83 speakers btw)

 

[kyle]

I also have a new BT20a MAX from Fosi, with the 48v/5a power brick. I've tried it with a couple of speakers now, and feel it's definitely better suited to playing at moderate volumes rather than "loud loud." Despite the specs, it seems to run much warmer than the other 3255 amps I own. You may find that switching to Fosi V3 monos or Aiyima A07 MAX amps in mono mode will work better for you. Alternatively, you could try adding in a Fosi P4 preamp in the chain, to boost the signal coming into the amp.

I think that if I change amps, I'll get an AB amp instead. Class D was just an experiment and Fosi has been non-responsive when I've contacted them. I have enough amps sitting around here to move on to something more reliable and better sounding.
Thanks for your time though. It is appreciated.

 

[justin_r_23]

Have you ever had any knowledge or insight on the Sherwood Newcastle R-771 2ch stereo receiver the face plate looks identical and shares similar specs to the sherwood RX-4109 I liked the sound of the 4109 and I wanted to upgrade to the R-771 but is it different parts inside or is it just rebranding(I have a pair of Altec Lansing 83 speakers btw)

The R-771 is an AVR and supports digital surround sound (DTS and Dolby Digital) and has a subwoofer pre-out and five speaker outputs (Main L/R, Center, Surround L/R), so it's not a 2-channel.

Sherwood Newcastle R-771 user manual : Free Download, Borrow, and Streaming : Internet Archive

archive.org

So you might be thinking of something else?

 

[mrehorst]

I think that if I change amps, I'll get an AB amp instead. Class D was just an experiment and Fosi has been non-responsive when I've contacted them. I have enough amps sitting around here to move on to something more reliable and better sounding.
Thanks for your time though. It is appreciated.

Have you tried WiiM? Very good product support, and very good products.