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Thread: Looking For More Punch From My 2245, 4345 Clone

  1. #91
    Senior Member Ian Mackenzie's Avatar
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    Hi Widget,

    I had a similar situation with audio visitors.

    One guy bought over a $500 rca interconnect. Only he could hear a difference and went red faced when the majority said they could not here a difference with the stock cable my Luxman 105U CD play came with. That was actually very good CD player in its day but not hi end.

    It is one of those things. I made a diy cable once with flat copper ribbon wrapped in Teflon plumbers tape when that style of cable was popular. Of course l thought it sounded great...Lol.

    Making your own interconnect is not difficult btw.

    Hey, l saw a Blow Torch preamp on Audiomart recently. You might use exotic cables with that.

    I am thinking (Only thinking) about getting an Aurender A10. How much should l spend on the power cable and interconnect? Lol.....

    I left all that once l started building discrete class A preamps. The particular transistor, Fet or Jfet used has a much more audible influence on the sound. I serviced a 50 watt Sae power amp years ago. One channel was blown. I ended up replacing all the transistors with modern equivalent parts. According to the owner it sounded way better. It was one of the cleanest most detailed amps l have heard.

  2. #92
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    Quote Originally Posted by Ian Mackenzie View Post

    My opinion on the question of power is it’s relative to your listening distance and just how loud you like to play your system most of the time. That’s the bit you missed. 115 dB is 10 dB louder than 105 dB and requires 10 times the power. 105 dB is 6 dB louder than 99 dB and requires 4 times the power. With that in mind the user can then make a reasonably educated guess on just how much power he proposes to use. Crown has calculators on their website for this purpose. The 6 dB headroom rule is a nice to have if you need it like in a studio environment. Distortion and burnt out drivers is the trade off under those conditions. But will the typical domestic home user be stretching his system in that way day in and day out or just turn it up occasionally to impress his mates and piss of the neighbours?


    Ian Mackenzie
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    These are theoretical values and in practice are under-estimates when dealing with high power levels near the limits of the speakers capabilities. In the real world, when you apply big power you heat up the voice coils and the resistance increases (power compression), requiring even more power to achieve a theoretical increase. In actually, "10X the power" may be more than 20X the power, and that's only for 3 dB of power compression. Actual values/necessary power could be considerably higher.

  3. #93
    Senior Member grumpy's Avatar
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    Hi Ian.

    I was careful to state average 1w vs peak (crest factor ranging from 6-20dB). Understood re typical tone control ranges.
    Regardless, I think the point is made: it's easy to overdo a bass boost it without audibly seeming like it's 'that loud'.

    -dave


    Quote Originally Posted by Ian Mackenzie View Post
    First line yes.
    Second line no.
    A bass tone control typically has +- 10 dB on audiophile equipment but there aren’t many that do these days. The Hafler 101 has tone controls.
    Vintage integrated amp had bass tone controls up to 15 dB.

    Now you know why subs have very powerful class D amps

  4. #94
    Senior Member 1audiohack's Avatar
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    Quote Originally Posted by Ian Mackenzie View Post
    No problem here. No ones asking you to leave.

    But your response is at odds with Roberts observations:

    Quote
    “When I crank it up the clip/limit light on the 550w Crest 2445 amp are my limiting factor. When I was quad amping I used a 25w multi channel McIntosh amp on the top three. I could never make the power guard lights come on.
    Ian Mackenzie
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    I understand no one is trying to run me off and thank you for saying it anyway.

    I just don’t want to waste our collective time.

    If one uses a current monitor and compares the current going through the 2245 and the 2123, as one may expect, considerably more current goes through the 2245. However if one monitors the voltage, I routinely see higher voltage peaks going to the 2123. Peak voltage, not average current.

    I don’t know if his small amps are looking at peak voltage or the collapsing of the power supply to indicate they are approaching their limits but if he can clip a 500+ Watt amp on the 2245 and has no indication that the 50 Watt amp driving the 2123 has reached it’s limits, and there is a lack of “punch”, maybe an amp for the 2123 with the ability to swing higher voltage is in order.

    I can explain my measurement methods and equipment if there is interest. I am a data guy.

    I really need to re run all these measurements, photo document them and take the time to post them in their own thread. If only I could manufacture time!

    Barry.
    If we knew what the hell we were doing, we wouldn't call it research would we.

  5. #95
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    I was having problems with my power conditioner/sequencer and my Krell amp. It didn't want to turn on the Krell for some reason unless something else was plugged in to the same stage. I decided to buy a Furman CN-2400S and the sound difference is amazing. Way more crisp and it has way more snap. Obviously there was something wrong with the old conditioner. I have those tamper proof wall plugs also and it seems like the plug only connects in the last 1/8". It has to be plugged in all the way to work. Maybe there was a bad connection at the plug?

    I can still make the clip lights come on on the 550w Crest amp, but that is only during a long Led Zepplin drum solo and it is extremely loud. On normal music I don't think i could make it clip without hurting myself.

    I also bought a Bedini 250/250 amplifier. I don't have it yet, and I'm not sure what I am gong to do with it. My 50w Krell has enough for now. I have a feeling a 250w Class A might use a lot of power.

  6. #96
    Senior Member grumpy's Avatar
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    Quote Originally Posted by robertg View Post
    ...
    I also bought a Bedini 250/250 amplifier. I don't have it yet, and I'm not sure what I am gong to do with it. My 50w Krell has enough for now. I have a feeling a 250w Class A might use a lot of power.
    Not to worry... probably not as much as you might think. A two channel 250w Class A amp would need heat sinks the size of a small car (Ok, maybe a bit less). Very likely Class A to a point, but not 250w... maybe tens of watts (high-bias Class A/B?).

    Still a nice amp (was well regarded, iirc) and it may very well run warm enough to warrant keeping the local airspace clear, but 2x250w Class A would pull around 8-10A from your wall... continuously.... Like a hair dryer.

    Glad to hear most of your issues have been sorted!

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