Amplifiers known to be reliable for <4ohm speakers

[ex brickie]

Here you go:-

So does that work properly with Linn Saras Andrew?

 

[Funk]

I bought a used XTZ Class A100 D3 to drive Celestion A3s and now Kef Reference 3.2s. Although it can run in pure class A I can't hear any difference with AB mode so leave it in that. It's rated for 180w in 4 ohms and 300w into 2. The only downside is it runs warmish, typically arround 35degC which is fine in winter, not so great in a heatwave! It sounds remarkable for the money; I picked mine up from Heathcote Audio for £495 a few years ago.

I do sometimes think about changing it for something class D but never actually get around to it.

 

[flatpopely]

So does that work properly with Linn Saras Andrew?

Oh yes!

320W into 2ohm

 

[Jim Audiomisc]

Obviously 5WPC would usually be more than enough to reproduce a harpsichord at realistic level whilst worst case would be heavily compressed music close to clipping.

Well, not quite so obvious to some may be the size of the transient peaks that can give sources like a well recorded haprsichord a fairly high peak/mean ratio.

 

[ex brickie]

Oh yes!

320W into 2ohm

What model is it? Picture is fuzzy

 

[flatpopely]

JVX AX-Z1010TN

https://pinkfishmedia.net/forum/threads/jvc-ax-z1010tn-review.168851/

 

[ChrisS]

Aragon made a number of amps that would work. The 2004 mk2 and 4004 mk2 are good candidates. The 2004 is 100w into 8 ohms and 200 into 4. Double for the 4004. It looks like there is a 4004 mk1 at emporium hifi. The difference in the marketing info for the mk2s adds “the continuous output power continues to increase into 2 and 1 ohm loads”. That said the mk1 might be find depending on the specific impedance characteristics of the speakers. Any of them would obviously benefit from service at this point.

 

[Mr Pig]

I had the same problem during the summer months. Feeding a pair of “Old Linn speakers” . Solution……..A pair of 135s

They were twice the price of the 250 for fractionally more power, never saw the attraction. The 105s are cheaper than a 250, about 40% more power and from what I've been told sound better than the 135s!

 

[Paul Hindle]

They were twice the price of the 250 for fractionally more power, never saw the attraction. The 105s are cheaper than a 250, about 40% more power and from what I've been told sound better than the 135s!

To be fair, for twice the price you do get two boxes . But I won’t argue with anyone about what sounds best, it’s subjective and personal to us all. However, I can’t quite work out which of the three amps you have actually heard. Personally I loved my 250, the 135s more but the 105s I’ve never heard. From what I’ve been told though, they do sound very Naimish.

 

[Arkless Electronics]

I've had a few Meridian 105 sets in over the years. Better than a NAP250 but still nothing special.
103 was better.

 

[Mr Pig]

To be fair, for twice the price you do get two boxes

Naim pricing is a fairy tail for grownups. The 135 is basically a 250 with a channel removed. Ok, some other small tweaks but not much. The 180 and 250 are the same except for one small circuit board and the price difference was how much?

Yes, the 105s sound very like Naim. If you like one you'll like the other. I certainly have no regrets. I've never owned 135s but it was a while after I bought the 105s I was talking to a guy who ran a six-pack of four 135s and two 105s and he said the 105s were the better sounding amp. I've since heard the same opinion from a couple of other people.

 

[Beobloke]

I have a Yamaha PC-5002M.

61kg, Two mains leads, 750W per channel into 4 Ohms. it gets tight, deep, punchy bass out of Goodmans Maxim 2s.

I doubt there’s much it’ll struggle with!

 

[Locheeboy]

I have an ATC all in one CD/DAC/amp (SIACD) which runs quite hot with my Boenicke speakers . Boenickes are known to be a trickier load - sometimes dipping below 4ohms.

I’ve only listened at fairly low volumes and the amp hasn’t shown signs of cutting out yet (it has a thermal switch) . But I may want to turn it up occasionally

My understanding was that ATC make amps that are very durable even under a bit of stress? The manual doesn’t specify that only 4-8 ohm speakers can be used

Just in case, what makes/models are out there that are very reliable under a difficult speaker load?

I only know of Linn Klout or LK280 used to drive very difficult Linn Saras

Has to be in a £1k to 1.5k ish second hand price range .

I might be worrying unnecessarily of course! If there are ATC amp users out there they might be able to help!

If ye just have the itch... don't get jealous of other folks equipment. Ye bought your stuff because you like it.
Get a set of spikes, isopod-style supports, vibrapods (use them maself ) any other supports which'll raise yer machine - off the carpet, off the plinth, off the sideboard etc. Make sure ye have plenty air circulation.
If yer itch turns into a scratch and a determination tae replace with new amps...try PrimaLuna. They handle difficult loads superbly.
I'm about tae sell a pair of PL monoblocks, but for twice your budget.
Think about where yer amp is, and where ye can place it, tae best advantage.

 

[Johnjo]

Multiple pairs of output devices, plenty of heatsinking and power into 8R kept reasonably low are the things to look for in an amp to drive low impedance's safely.

That’s an interesting point Jez about 8R power kept reasonably low, never heard of that before. I’ve noticed Mark Levinson amps tend to be rated quite low for their given size, e.g. 100WPC for something reasonably massive but tend to almost most double their power into 4 ohms.

 

[Arkless Electronics]

That’s an interesting point Jez about 8R power kept reasonably low, never heard of that before. I’ve noticed Mark Levinson amps tend to be rated quite low for their given size, e.g. 100WPC for something reasonably massive but tend to almost most double their power into 4 ohms.

IIRC the 25wpc ML2 will do about 100wpc into 2R. The high voltages required to give 200WPC+ into 8R puts the output transistors under a lot of stress when giving the currents required to drive <4R loads, much more so with particularly awkward low impedance loads with big phase angles.

 

[Johnjo]

IIRC the 25wpc ML2 will do about 100wpc into 2R. The high voltages required to give 200WPC+ into 8R puts the output transistors under a lot of stress when giving the currents required to drive <4R loads, much more so with particularly awkward low impedance loads with big phase angles.

Thank you, you’ve taught me something today

 

[ex brickie]

Has it blown up yet?

If an amplifier is working hard it can get hot. It's not a fault, it's a characteristic. My NAP250 used to shut down regularly and get so hot you couldn't keep your hand on the top. My Meridian 105s also get very hot at high volume and shut down occasionally, they're more powerful so much less often. No damage is done, they're designed to do this.

ACT build studio gear, so it's tough. I'd be very surprised if your amp wasn't totally fine with running hot and has a thermal trip to protect it.

And 4ohms is not that bad. Old Linn speakers can drop to two.

It hasn’t blown up, the manual says it has a cut out at 60 degrees C but it has always been played at low volumes. I’d prefer not to have it blow up before I know Imneed something else but I’m reassured by comments that it ought to stand up to a bit of volume

I’ve also emailed ATC for a view but I also appreciate the experiences of others (although I don’t think I’ve heard from any ATC amplifier owners yet?)

If @flatpopely’s JVC is driving Saras it must be a bit of a monster

 

[Arkless Electronics]

Wow 60C is way low! About 80-90C ish is typical of last resort thermal cut out on heatsinks.

 

[ex brickie]

The ATC manual refers to the heatsink at 60 degrees. It says this in the manual. https://atc.audio/wp-content/uploads/2013/08/CDA-2-SIACD-Rev-C.pdf

Excessively high operating temperatures are potentially very damaging. The SIACD heatsink is fitted with a 60°C thermal switch and if the heatsink temperature exceeds this limit, the unit will shut down. Excessive operating temperature is only likely if the load is too great (speaker impedance too low) or, if the ventilation is not adequate. It will only be possible to restart the unit after enough time has passed that the heatsink temperature has fallen well below the 60°C threshold

Hence my question re amps able to operate with a tricky load (low ohms)

Just for info, There is no visible heatsink (ie fins) externally on my ATC unit - must be buried!

 

[Salamander]

Naim pricing is a fairy tail for grownups. The 135 is basically a 250 with a channel removed. Ok, some other small tweaks but not much. The 180 and 250 are the same except for one small circuit board and the price difference was how much?

Yes, the 105s sound very like Naim. If you like one you'll like the other. I certainly have no regrets. I've never owned 135s but it was a while after I bought the 105s I was talking to a guy who ran a six-pack of four 135s and two 105s and he said the 105s were the better sounding amp. I've since heard the same opinion from a couple of other people.

I don't know what 'small tweeks' Naim made, but to my ears 135's were far better sounding than the 250, although I wouldn't recommend them for difficult to drive speakers, they kept cutting out partnered with my Obelisk's if I decided to up the volume a little