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Amplifier for passive monitors - PMC TB2s

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Amplifier for passive monitors - PMC TB2s

Postby Jez Corbett » Sat Dec 28, 2019 5:20 pm

For as long as I can remember, I've been powering my PMC TB2s with - gasp - AV receivers. Awful, hateful things, but they do the job.

Now my current one, after my old one died, I realise actually belongs to someone else, and they want it back. So now I should get a proper one.

Any recommendations? I'm adverse to spending too much as at some point in the not too distant future the speakers will be getting replaced with an active surround set up.

Having a volume control would be highly preferable (I can control from the device, but dont want any nasty surprises), and a headphone out and switchable inputs would be a bonus but not essential. Also something not as gigantic as an AV receiver would be nice too.

EDIT: been offered a NuForce STA200 for €400 but no idea if this is good or not.
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Re: Amplifier for passive monitors - PMC TB2s

Postby ef37a » Sat Dec 28, 2019 6:00 pm

Cannot find a figure for the power rating of the TB2 but their brochure says "good results from modest amplifiers so perhaps the 80W per channel from that amplifier will be enough?

From a review I don't like the acceptance of a crazy response to 900kHz but one takes these things with a grain of salt!

The VC is an easy fix, get a Monitor Controller.

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Re: Amplifier for passive monitors - PMC TB2s

Postby jimjazzdad » Sat Dec 28, 2019 8:57 pm

The ART SLA-1 has been around for ages, with a good rep as a cheap & cheerful little amp (2 x 100W). They had a bit of a 'budget audiophile' following too. I have three of them, used for everything from driving studio monitors to a small PA set up and as a power amp for my bass guitar preamp. I can generally find them used for as little as $125 on my side of the pond.
https://www.thomann.de/gb/art_sla1.htm
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Re: Amplifier for passive monitors - PMC TB2s

Postby James Perrett » Sat Dec 28, 2019 9:33 pm

I don't know if you've still got your old amp kicking around but, when my Quad 405's became too annoying I made one good one out of the two bad ones and then used the case of the other to house a pair of Hypex amplifier modules and their associated power supply. Hypex can also supply much of the wiring so it is a fairly easy job (although there's a little bit of mains wiring involved so this isn't recommended for someone with no electronics experience). The whole thing came to around £250 including VAT and postage and I ended up with a very high quality power amp for not too much money.
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Re: Amplifier for passive monitors - PMC TB2s

Postby Hugh Robjohns » Sun Dec 29, 2019 12:46 pm

TB2s thrive on power. The more the better.

So I'd be looking for a decent second-hand hifi amp, the chunkier the better.

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Re: Amplifier for passive monitors - PMC TB2s

Postby Zukan » Sun Dec 29, 2019 1:07 pm

Jez, I bought a used Bryston 4B to power my TB2S+. I bought it in Canada and it worked out quite cheap. The delivery cost more than the taxes but it was worth it. Brystons come with a 20 year warranty and mine was around 17 years old.
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Re: Amplifier for passive monitors - PMC TB2s

Postby Jez Corbett » Sun Dec 29, 2019 2:19 pm

Thanks for the replies. I should say there's some urgency to this with me needing to do it as an end of year cost, and also that the owner of my current amp wants it back asap, so this sadly precludes spending some time searching around for something second hand.

The ART one looks fine, although I kinda associate the brand with low quality budget gear. Only annoying thing is the hefty rack ears would not fit so well into my current set up (my current amp is mounted vertically) but thats a minor niggle.

Did anyone have any thoughts on the NuForce?

EDIT: Should also add I can push up to €1k ex VAT if its really worth it.
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Re: Amplifier for passive monitors - PMC TB2s

Postby ef37a » Sun Dec 29, 2019 2:38 pm

https://www.richersounds.com/denon-dra-800h-black.html

That ^ is around £500 if it meets Hugh's criterion of "lots of power" at 100W pch into 8 Ohms?

Why Denon? Well, I had a superb Denon cassette deck and their spares were readily available and low cost. (the deck had been dropped, refused repair cost) They have been around forever and I have never read a bad word?
Of course, Sony, Marantz and many other names make decent gear.

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Re: Amplifier for passive monitors - PMC TB2s

Postby Jez Corbett » Sun Dec 29, 2019 2:48 pm

I'd really like to avoid ever touching an AV receiver again if I can help it!
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Re: Amplifier for passive monitors - PMC TB2s

Postby ef37a » Sun Dec 29, 2019 2:58 pm

Jez Corbett wrote:I'd really like to avoid ever touching an AV receiver again if I can help it!

Ok but I think finding a 'plain ole hi fi amp' new these days is going to be tricky?

I thought you meant " AV amplifier" as in 5.1 kit? They ARE technically challenged unless you pay a huge amount of money and as you say, are big lumps. That Denon looks to be about standard size? Then, the
network electronics of a 100W amp are a trifling part of the final cost.

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Re: Amplifier for passive monitors - PMC TB2s

Postby Hugh Robjohns » Sun Dec 29, 2019 3:27 pm

I'd second James' suggestion for Hypex amps. If the DIY approach is not appropriate, check out www.nordacoustics.co.uk/. Pick one of the MP NC models to suit. They do monobloc and stereo amps with a range of powers. I'd suggest the 250W model would be best.

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Re: Amplifier for passive monitors - PMC TB2s

Postby ef37a » Sun Dec 29, 2019 3:37 pm

Hugh Robjohns wrote:I'd second James' suggestion for Hypex amps. If the DIY approach is not appropriate, check out http://www.nordacoustics.co.uk/. Pick one of the MP NC models to suit. They do monobloc and stereo amps with a range of powers. I'd suggest the 250W model would be best.

H

Wow! THAT much of lots and lots! By my reckoning that would produce 114dB SPL at 1mtr.

Headroom indeed!

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Re: Amplifier for passive monitors - PMC TB2s

Postby Hugh Robjohns » Sun Dec 29, 2019 3:55 pm

Headroom - when used with care -- is good! :-)

Like Eddie, I used to run my old passive TB2s on a Bryston 4B which was similar power-wise, to these Hypex amps, and they sounded really good. Running on a Quad 405 with less than half the power was disappointing... And it really didn't allow the speakers to shine.
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Re: Amplifier for passive monitors - PMC TB2s

Postby Jez Corbett » Sun Dec 29, 2019 4:05 pm

Tangential question - I'll be running an out direct from an RME Fireface or Babyface. The babyface kinda is a monitor controller, and the fireface has a master out knob, but should I invest in something between the two anyway to avoid accidental face explosion?
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Re: Amplifier for passive monitors - PMC TB2s

Postby Jez Corbett » Sun Dec 29, 2019 4:27 pm

Hugh Robjohns wrote:I'd second James' suggestion for Hypex amps. If the DIY approach is not appropriate, check out http://www.nordacoustics.co.uk/. Pick one of the MP NC models to suit. They do monobloc and stereo amps with a range of powers. I'd suggest the 250W model would be best.
H

I am slightly resentful about having to get something shipped to Finland from the UK when the company calls itself 'Nord' :D

EDIT: Btw, what's the '12v Trigger' option about?
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Re: Amplifier for passive monitors - PMC TB2s

Postby Hugh Robjohns » Sun Dec 29, 2019 4:54 pm

Jez Corbett wrote: Btw, what's the '12v Trigger' option about?

Common facility on high-end hi-fi to turn devices on-off. It's a 12V DC control voltage.

Typically, a preamp would provide a 12V Trigger output when it's powered up, which would be used to turn on a separate power amp. Or the preamp might have a switched 12V trigger output that could be used to activate the curtains when TV input is selected, etc...

And a power amp would typically have a 'soft' powering mode where it's left permanently powered on, but it shuts itself down unless it receives a 12V trigger signal.
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Re: Amplifier for passive monitors - PMC TB2s

Postby Hugh Robjohns » Sun Dec 29, 2019 4:57 pm

Jez Corbett wrote:Tangential question - I'll be running an out direct from an RME Fireface or Babyface. The babyface kinda is a monitor controller, and the fireface has a master out knob, but should I invest in something between the two anyway to avoid accidental face explosion?

Plenty of people use their interfaces as monitor controllers perfectly successfully, and RME interfaces are far less likely to go loco than anyone else's.

...but maybe have the power amp's on-off switch within easy reach just in case! :D
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Re: Amplifier for passive monitors - PMC TB2s

Postby ef37a » Sun Dec 29, 2019 6:50 pm

You could just have a speaker kill switch box as a panic measure?

There are times anyway when you want to silence monitors, using a live mic for example.

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Re: Amplifier for passive monitors - PMC TB2s

Postby Jez Corbett » Mon Dec 30, 2019 3:24 pm

Ok, turns out I need to push the button today due to financial end of year stuff, but having massive procrastination crisis.

Nord One MP NC252 250W, including delivery and VAT will cost me €880.

I can also get a Creek Evolution 50P, as recommended by SOS's power amp article, for €649.

Or I can just get the cheap ART one.

Thing is, how long will I run the PMC TB2s in this way? How long until I get an active surround set and these just become my home HiFi speakers run through a ... spit ... AV receiver?

Basically think I need a reason to justify the (not especially large) cost of the amp when I might only end up using it in its current purpose (driving the TB2s in my studio) for a year.

Or do I just shut up and buy the damn Nord?
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Re: Amplifier for passive monitors - PMC TB2s

Postby Hugh Robjohns » Mon Dec 30, 2019 9:18 pm

I'm afraid I don't know any of those amps, although the Nord is based on familiar Hypex modules so should be fine...

I'm sure the Creek is lovely, and the recommendation counts for a lot, but as a stereo amp it would be very underpowered for the PMCs. It would be okay if you bought two and ran them bridged.

I've always been impressed with ART stuff, but I'm not sure it would be able to help the TB2s deliver their full potential...

Can you buy on a sale or return basis?

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