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

[nobo]

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.

 

[nopiano]

Hi

Flying Moles DAD M100s​

Is there a question here?

 

[Al ears]

Is there a question here?

No is the simple answer....
Although someone with a very similar name asked a question about these amps on another forum..... in 2011!

 

[nobo]

Sorry - premature post! Now edited and completed.

 

[Rodolfo]

@nobo: "...it seems Chinese made class D is now so good..."
True enough; but consider how good Chinese engineers are making class A.

 

[njprrogers]

@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]

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

 

[James105]

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.

Resetting factory settings RCD-N9

manuals.denon.com

Hope that helps with one of them.

 

[Rodolfo]

@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.

 

[nobo]

Thanks James - that's really helpful. I've found it's temporarily fixed by unplugging it for over an hour. It then works again, albeit briefly, but the problem recurs. I'll try the reset. Failing that, since the speaker cables seem fine, etc, I'm guessing it's a power protection issue/failed caps, and may need repair. Shame as it sounds respectable and have more power (something like 60W) than the Arcam Solo Mini I would otherwise use here. I suppose I ought to actually compare them rather than rely on specs!

Thanks Rodolfo - HiBy R4 Class A DAP does look interesting!

 

[good_enough]

If you don't take up the kind offer from @Gray above:

Michael https://www.ebay.co.uk/itm/404205932903 is very good and straightforward - bought my refurbed Nak off him, and he turned around a minor niggle with it toute suite and no delivery charge. I'd certainly approach him if I had a fault with anything else, without hesitation.

Brett is good https://www.hear-audio.co.uk/ - you'd need to combine with a day out in Brighton or walking the Downs I expect, according to taste. I see his website is showing booked out at the moment. He re-capped my MA Studio 20SEs, and returned them having also given them a nice polish! Think he may specialise in 'upmarket' kit but may be worth asking.

Alternatively there seems to be a lot of DIY advice on that Marantz on t'interweb.

 

[Gray]

If you don't take up the kind offer from @Gray above:

Brett is good https://www.hear-audio.co.uk/ - you'd need to combine with a day out in Brighton or walking the Downs

I liked Brighton (worked at the Top Rank there for a year or so).
But, visit Southend and you get a walk, or train ride on the longest pleasure pier in the world 😉

 

[good_enough]

I liked Brighton (worked at the Top Rank there for a year or so).
But, visit Southend and you get a walk, or train ride on the longest pleasure pier in the world 😉

We'll be into a 'best fish and chips' debate next.

 

[nobo]

Interim update:

Pioneer A400

I've cleaned up the A400 and it seems to be working fine (save for a noisy volume control - scratchy pot but generally quiet once in a fixed position). Plugged into the Tannoy Revolution DC4T floorstanders, it sounds (perhaps unsurprisingly) a lot better than I remember the Denon CEOL RCD-N7 sounding on the same speakers, and not at all lacking in low end grunt by comparison.

Aesthetically I could use something smaller in the space, so I'll experiment a bit once the Class D stuff is here and compare.

Denon CEOL RCD-N7

No joy so far following the reset procedure, which sometimes fixes the flashing red light.

Marantz PM66 SE KI sig

Repairs/soldering are likely to be beyond my own DIY ability/appetite, but I'll look into getting it fixed up. Situation is:
- Powers up - red light comes on.
- However, no output from the speakers or the headphone output, whatever input is used/whatever the settings are.
- It was repaired a few years back - the issue was no +24volt supply due to an open circuit feed resistor.
- Photos without the lid here: https://www.amazon.co.uk/photos/share/MXrp7VLL1mw5m6IdfyQunv6HUIDIP6YLafAt9UGYtIJ

 

[gasolin]

Fosi audio v3 monos or the topping B100

A Marantz pm 6006 or 6007 might for 350 euros or less (depending on if the amp is new or used, for 400 euros you might be able to get a marantz pm 8005) sound as good or better than your Marantz PM66SE KI sig

 

[Gray]

Interim update:

Pioneer A400

seems to be working fine (save for a noisy volume control - scratchy pot

A can of Servisol Super 10 is your cure for that.

Marantz PM66 SE KI sig
No output from the speakers or the headphone output,

You might find that your remote will toggle the amp's 'mute' LED, but you don't hear the relay - which should be clicking as the LED goes on and off.
If that's the case, then you've got the same symptom as I had.

 

[Stuart83]

A can of Servisol Super 10 is your cure for that.

You might find that your remote will toggle the amp's 'mute' LED, but you don't hear the relay - which should be clicking as the LED goes on and off.
If that's the case, then you've got the same symptom as I had.

Or a new pot but the replacements don't come with a balance adjustment at the rear part of the dial.