Amp for Manger drivers
I am considering using the Manger MSW drivers in a speaker system and swill need an amp to drive them. I have heard that to get the best from them you need an amp with really high frequency response (upwards of 150KHz) and high slew rate (or are those the same as you need high slew rate to get HF extension??) It also needs to be pretty high power delivering 400watts into 4Ohms.
Anyway that excludes quite a lot of amps already.
Currently the Ground Sound PA3CC http://www.groundsound.com/pa3cc.html looks good, but it seems like a lot of money at 195Euro for a simple amp module. Doesn't it? They charge a lot for a simple bridge rectifier and a bank of caps anyway!
Can you suggest any other amp modules, or very simple designs I could use to good effect?
Probably what people are saying is actually "code".
I think they mean that an amp with a bit of extra HF "zing" will sound better on the Mangers. My own experience with them is that they do not do well off axis on the highs above 10kHz., where they are incredibly beamy... dunno if they have changed their "receipe" since I tried playing with them.
Since they don't have hyper extended HF response, I see no reason that one would need a "high slew rate" or "extended HF response" power amp with them... other than the above comment.
My own experience with them is that they are very "not loud" sounding (no matter what the SPL meter said), and pretty "smooth" sounding - but my amp and system is very clean and free of grain to begin with.
So having some power behind them seems to make sense. (within limits, of course) I think you want an amp with some headroom, since you're likely to be running higher than average power levels to make apparent SPL in the room...
Something like a used Hafler Transnova prosound power amp might make a good match at not very much cost?
Guess it depends on your budget and building ability as to what the range of DIY projects might encompass.
The things I read say they need the HF response and fast slew rate because they are such fast drivers. They are about 10 times faster than even a dome tweeter, right across the range! they extend to 35KHz on-axis.
I heard them at Brighton Hi-Fi the other day and the HF response didn't sound too rolled-off, but it was a reverberant room. I think they have a slightly lumpy off-axis response when in the nearfield but 2m away and more it smoothes out. This is because the sound is produced in 'rings' from the centre outwards.
When turned up they sounded loud, but only in the way real music sounds loud. You can be in front of a drum kit and it is forking loud but it doesn't hurt you. This is what the Manger's were like and is what my current system is like too.
Manger recommend ASR amps. Does anyone know what stuff they use inside?
No idea what an "ASR" amplifier is... sorry no info there.
If the Mangers reach out to 35kHz. I would be very surprised. They certainly did not when I had them here some years back. It is possible that they have altered the design some... but I would still be quite surprised.
Perhaps someone here has independently tested them?
Also, explain why you need an amplifier that is "faster" than "35kHz." equivalent "speed" (rise time & bandwidth) to reproduce 35kHz.??
And, what source material will you have that has any information out at 35kHz.?
Where do your ears stop?
I'm not saying it is a bad thing to have a speaker that goes out past 20kHz., I'm merely questioning the logic behind the apparent need for a "fast" amplifier for these speakers.
Almost every solid state amplifier out there today is "fast" compared to any speaker, no matter which ones you chose to consider.
My suspicion remains that they are in practical terms rolled at the top, so a so-called "fast amp" - one with some overshoot on a squarewave - that actually has a slight bit of extra "zing" will sound more "normal" to the average listener on the Mangers.
I could well be wrong. But it seems like hype.
I think that at 2m from the speakers in a small room, they'd be nice to listen to. I think I'd toe them in so that they are more or less on axis to my ears... my experience with them says that they are a pleasurable listening experience in general... not much bass, so subs or LF woofers seem manditory?
If I owned them, I'd build my own little amps, and give some serious consideration to a 35watt class A PP triode amp to run them... or a simple class A Mosfet solid state design. Maybe one of Susan's amps would be very cool for this - the thread is on this forum... they're easy, simple and will work nicely.
quickly above that.
Theoretically, you could extend the response of a Manger driver with as simple 6dB/octave boost to cancel the mass rolloff. This would demand a very fast amplifier, to keep out of the SID region. Also, a fast rolloff would imply either a measurement problem, or some sort of extra cancellation/rolloff in the driver. Nelson, do you have any idea what it would be?
> Manger recommend ASR amps. Does anyone know what stuff they use inside?
ASR is German hand built stuff. AD845 frontend (though they say in their broschure 3 stage design; I wonder how many stages we can find inside the opamp itself), Toshiba driver, 2SK1530 /2SJ201 Power Stage. Class AB.
Mangers do need high bandwidth amps. We tried them with 50kHz vs 350kHz (-3dB), both Class A MOSFET power amps. The difference is not subtle. (So of course we are now using 350kHz.)
I have never seen or heard a Manger, but this website had impdeance(7-25 ohns) and frequency graphs. There are a few impedance bumps between 200 and 2K Hz, but the treble impedance looks flat. Voice coil inductance reported at 18 µH is as low as many tweeters.
From my experience, I would try connecting a low impedance amp directly to the Manger and using an active crossover to the bass. Yep, I'm a control freak when it comes to speaker motors.
"The Manger Sound Transducer, with its fast rise time or even high cut-off frequency (these values can be mathematically converted internally) of 35 kHz (-3 dB), and 60 kHz (-20 dB) respectively"
EUVL, what amp is it you are using that goes to 350KHz?
For those interested, here are some off-axis measurements of the Manger provided by Manger. www.audiosmile.co.uk/msw-off-axis.pdf
I would be using them in an open baffle above about 400Hz so they should become more directive which I hope will help with the off-axis lumpiness. Manger also say that the response smoothes out a fair bit past 1m distance.
> what amp is it you are using that goes to 350KHz?
A higher power version of the following :
There is also a BJT version at the JLH Class A thread, which sounds also very nice.
But of course we are totally biased.
> I would be using them in an open baffle above about 400Hz
So do we, but at about 100Hz, with a sub woofer for anything below.
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