Class D or AB? To repair or replace ...

nobo

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Jul 25, 2007
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Hi
For powering my various speakers, I'm wondering whether to stick with what I have that works, repair what I have (see below) or replace amps (with class D or s/h class A/B). But repairs are often (sadly) uneconomical, and it seems Chinese made class D is now so good (e.g. Aiyima A08 Pro or Fosi V3 or ZA3) , there may be little point. Thoughts welcome! (Including on decent repairs in England - ideally in SE London)

Background

The main use case is for some PMC FB1 floor standers (nominally 90dB/W - 8 ohms) in a room c. 5.7m x 4.4m x 2.4m high. They're currently powered by an Arcam Solo Minis integrated CD/amp/radio, which I doubt is getting the best out of them (probably under powered).

Sources in all cases is be streaming via Wiim Mini (sometimes into an SMSL DAC), but I may keep the Arcam Solo Minis for CD playback (if I don't sell them).

I've put approx date of original release, approx RRP and watts into 8 ohms in brackets for each.

Amps needing repair:

- Marantz PM66SE KI sig (1996, RRP on release £400, 50W) - no output to speakers. Otherwise supposedly in decent health.

- Pioneer A400 (1990, £300, 50W) - working but has an earthing/grounding issue (only solved by disconnecting the earth, which doesn't seem safe/sensible!); dusty and might need re-capping given age.
I recall it sounding good - fast, clean, detailed, perhaps lacking in bass weight so maybe not a brilliant match for my PMCs, which can be quite neutral and detailed and might benefit from some warmth (which the Marantz offered more of).

- Denon CEOL RCD-N7 integrated CD/amp/radio (c. 2011, £500, 60-65w)) - flashing red power light, no output.

- 6 x Flying Mole DAD M100 monoblocks (4 UK models from c. 2007/8 and 2 US ones) - distortion on outputs and/or noise. They've all been repaired at least once already. So far:
a) I can't find anyone to repair them in the UK (Jon Snell has retired)
b) I'm concerned they'll only fail again
c) Repair is probably uneconomical, given the low cost of Fosi / Aiyima etc these days.
d) Even if repaired, I'm guessing Fosi / Aiyima might out perform them (if not, the likes of Hypex and ICEpower presumably would) ... ?

I guess there might be sense in putting Hypex modules in the Mole boxes, but I've never DIY'd an amp and hate soldering, so would likely need help.
FWIW, I used to use these with PMC TB2s and the BX2 and they sounded great (better, to my ears, than the Marantz IIRC)

Working

- Aiyima A07 Pro with Aiyima's 36v 6a psu. Arriving soon, but I'm planning to use this to power some Tannoy Revolution DC4T small floorstanders (nominally 88 db/W - 8 ohms) - living room system (which also has a BK Electronics XL200 FF mkii sub).

- Fosi audio BT30 Pro. Arriving soon. Planning to power all 2:1 speakers of the kitchen system, being 2 x Monitor Audio Bronze BX2 + 1 x Apart SUBLIME 6.5" passive thin sub. This is more of a "fun" system than critical listening - given lots of reflective surfaces, bracket wall mounting of speakers, etc. It's currently powered by an Arcam Solo Mini.

- Cambridge Audio A1 (mk ii or iii) (c. £80, 25W). Probably best sold since it'd presumably the weakest point in any of these systems.

- 2 x Arcam Solo Minis integrated CD/amp/radio (2008, £600-800, 25w). Again, probably best sold.

Many thanks in advance.
 
Last edited:

njprrogers

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Aug 12, 2015
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@Rodolfo any examples or links on good Chinese class A? Seen some cheap tube hybrids as well recently!

You can get Hypex integrated + DAC for around 600 euros these days at Audiophonics. No need to dig out the soldering iron. Check out here. Another 100 euros gets you twice the power here. Obviously a bigger investment than the cheaper class D but you are getting similar tech to e.g. Nad amps costing 5 times as much.
 

Gray

Well-known member
Amps needing repair:

- Marantz PM66SE KI sig
I wouldn't give up on that one nobo. Great amp.
I repaired my one....regretted eventually selling it.
I'm not in SE London, but SE Essex - if you fancy a couple of days out to Southend, you're welcome to leave it with me for a week or two.
No repair, no charge.....working again for £45 (y)
 

James105

Well-known member
Hi
For powering my various speakers, I'm wondering whether to stick with what I have that works, repair what I have (see below) or replace amps (with class D or s/h class A/B). But repairs are often (sadly) uneconomical, and it seems Chinese made class D is now so good (e.g. Aiyima A08 Pro or Fosi V3 or ZA3) , there may be little point. Thoughts welcome! (Including on decent repairs in England - ideally in SE London)

Background

The main use case is for some PMC FB1 floor standers (nominally 90dB/W - 8 ohms) in a room c. 5.7m x 4.4m x 2.4m high. They're currently powered by an Arcam Solo Minis integrated CD/amp/radio, which I doubt is getting the best out of them (probably under powered).

Sources in all cases is be streaming via Wiim Mini (sometimes into an SMSL DAC), but I may keep the Arcam Solo Minis for CD playback (if I don't sell them).

I've put approx date of original release, approx RRP and watts into 8 ohms in brackets for each.

Amps needing repair:

- Marantz PM66SE KI sig (1996, RRP on release £400, 50W) - no output to speakers. Otherwise supposedly in decent health.

- Pioneer A400 (1990, £300, 50W) - working but has an earthing/grounding issue (only solved by disconnecting the earth, which doesn't seem safe/sensible!); dusty and might need re-capping given age.
I recall it sounding good - fast, clean, detailed, perhaps lacking in bass weight so maybe not a brilliant match for my PMCs, which can be quite neutral and detailed and might benefit from some warmth (which the Marantz offered more of).

- Denon CEOL RCD-N7 integrated CD/amp/radio (c. 2011, £500, 60-65w)) - flashing red power light, no output.

- 6 x Flying Mole DAD M100 monoblocks (4 UK models from c. 2007/8 and 2 US ones) - distortion on outputs and/or noise. They've all been repaired at least once already. So far:
a) I can't find anyone to repair them in the UK (Jon Snell has retired)
b) I'm concerned they'll only fail again
c) Repair is probably uneconomical, given the low cost of Fosi / Aiyima etc these days.
d) Even if repaired, I'm guessing Fosi / Aiyima might out perform them (if not, the likes of Hypex and ICEpower presumably would) ... ?

I guess there might be sense in putting Hypex modules in the Mole boxes, but I've never DIY'd an amp and hate soldering, so would likely need help.
FWIW, I used to use these with PMC TB2s and the BX2 and they sounded great (better, to my ears, than the Marantz IIRC)

Working

- Aiyima A07 Pro with Aiyima's 36v 6a psu. Arriving soon, but I'm planning to use this to power some Tannoy Revolution DC4T small floorstanders (nominally 88 db/W - 8 ohms) - living room system (which also has a BK Electronics XL200 FF mkii sub).

- Fosi audio BT30 Pro. Arriving soon. Planning to power all 2:1 speakers of the kitchen system, being 2 x Monitor Audio Bronze BX2 + 1 x Apart SUBLIME 6.5" passive thin sub. This is more of a "fun" system than critical listening - given lots of reflective surfaces, bracket wall mounting of speakers, etc. It's currently powered by an Arcam Solo Mini.

- Cambridge Audio A1 (mk ii or iii) (c. £80, 25W). Probably best sold since it'd presumably the weakest point in any of these systems.

- 2 x Arcam Solo Minis integrated CD/amp/radio (2008, £600-800, 25w). Again, probably best sold.

Many thanks in advance.
I have a Denon CEOL dran5 (I think the same unit but w/o a cd) same issue cleared it with a factory reset.


Hope that helps with one of them.
 

Rodolfo

Well-known member
Jul 31, 2023
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@Rodolfo any examples or links on good Chinese class A? Seen some cheap tube hybrids as well recently!

You can get Hypex integrated + DAC for around 600 euros these days at Audiophonics. No need to dig out the soldering iron. Check out here. Another 100 euros gets you twice the power here. Obviously a bigger investment than the cheaper class D but you are getting similar tech to e.g. Nad amps costing 5 times as much.
I envision it as work in progress. I've only shopped digital audio players recently and HiBy's best offerings are class A. Class A is more demanding and the units do get warm, but the company does consider it superior and proper for "making music more musical" which is their motto. I consider the HiBy R4 Class A DAP released this year at $249 in the US to be the best buy in audio. I own two earlier HiBy units, but I'm sure I'll be at least trialing an R4 model as soon as I see a nice sale on them.

Otherwise, I've seen only some class A tube amps offered at amazondotcom, or amp brands I know nothing about at aliexpressdotus.
 

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