Author Topic: The Cape Town Hi-Fi Club  (Read 276853 times)

Offline Jozua

Re: The Cape Town Hi-Fi Club
« Reply #255 on: May 09, 2014, 03:12:58 PM »
Chris

The ribbons you heard last night are 5.ohm drivers. Quite easy to drive with my Quad 306.

There must be some other reason why the amp struggled.  Even the 12 watt valve amps coped at low volume.  I suspect that there could have been a naked wire at the back of the speakers connectors.

The .5 ohm versions I am referring to in my previous post are pure ribbon one meter long drivers. Completely different to what was auditioned at the club meeting. 

Regards

J
« Last Edit: May 09, 2014, 03:27:43 PM by Jozua »
A real audiophile will eventually end up with the ARC Ref stuff..

Offline Jozua

Re: The Cape Town Hi-Fi Club
« Reply #256 on: May 09, 2014, 03:24:50 PM »
In hindsight- we never auditioned the amp of Stefan Erasmus !! Wonder how that slipped by?
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Offline Shonver

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Re: The Cape Town Hi-Fi Club
« Reply #257 on: May 09, 2014, 04:41:57 PM »
I do not use transformers with the 0.5 ohm ribbons.

I see. Do understand, though, that you cannot expect an ordinary amplifier to drive them reliably. Amps for driving such low impedances directly have to be designed for purpose.



Pierre wat? He can make you a nice class D amp for this application quite easily.
« Last Edit: May 09, 2014, 04:44:37 PM by Shonver »
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Offline skollie

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Re: The Cape Town Hi-Fi Club
« Reply #258 on: May 09, 2014, 06:37:15 PM »
Found someone's red banana plug attached to one of my cables. Pse advise for return.

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Offline chrisc

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Re: The Cape Town Hi-Fi Club
« Reply #259 on: May 09, 2014, 07:11:54 PM »
Consider it a donation
Music is the shorthand of emotion

Offline Chingy

Re: The Cape Town Hi-Fi Club
« Reply #260 on: May 09, 2014, 08:58:17 PM »
next meeting I'm coming fully loaded

F5, KidNap, Akai 3way Speakers , and something special from the 70's x 2
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Offline Peter Carpenter

Re: The Cape Town Hi-Fi Club
« Reply #261 on: May 09, 2014, 09:16:51 PM »
Fully loaded would have been those Marantz HD66's rigged them up for your visitation, what a glorious sound, unvisited for some time, Akai from the 70's a non contender to that above.

Offline Chingy

Re: The Cape Town Hi-Fi Club
« Reply #262 on: May 09, 2014, 09:28:32 PM »
Fully loaded would have been those Marantz HD66's rigged them up for your visitation, what a glorious sound, unvisited for some time, Akai from the 70's a non contender to that above.
sorry Peter, soon, tomorrow mybe, will call you first, again sorry
Tannoy, HPD/315/8 dual concentric
95 db 35Hz. to 20 KHz. xover at 1.2 KHz.

Offline Jozua

Re: The Cape Town Hi-Fi Club
« Reply #263 on: May 09, 2014, 10:48:28 PM »
next meeting I'm coming fully loaded

F5, KidNap, Akai 3way Speakers , and something special from the 70's x 2

I was actually on the lookout for you...
A real audiophile will eventually end up with the ARC Ref stuff..

Offline Jozua

Re: The Cape Town Hi-Fi Club
« Reply #264 on: May 10, 2014, 12:03:12 AM »
I see. Do understand, though, that you cannot expect an ordinary amplifier to drive them reliably. Amps for driving such low impedances directly have to be designed for purpose.

Pierre wat? He can make you a nice class D amp for this application quite easily.

Shaun

I have sufficient power available.

J
A real audiophile will eventually end up with the ARC Ref stuff..

Offline chrisc

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Re: The Cape Town Hi-Fi Club
« Reply #265 on: May 10, 2014, 08:52:06 AM »
Jozua is using a Quad power amp to drive his ribbons.  Quads are specifically designed to cater for peculiar impedances as they get when driving electrostatics and thus won't get upset when seeing a 0.5 ohm load.  An ordinary direct-coupled MOSFET amp will have its output reduced considerably by such a low impedance and might only provide 20% of the regular power, hence the strange noises we heard.  So it is not just brute power, it is the design of the output stage which counts the most
Music is the shorthand of emotion

Offline Jozua

Re: The Cape Town Hi-Fi Club
« Reply #266 on: May 10, 2014, 09:20:31 AM »
Chris

Some clarification !

The ribbon speaker demo at the club is a 5 ohm speaker and can be driven by a Quad 306.

The 0.5 ohm and quarter ohm ribbons I have designed myself are driven class A amps.

Regards

J
A real audiophile will eventually end up with the ARC Ref stuff..

Offline chrisc

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Re: The Cape Town Hi-Fi Club
« Reply #267 on: May 10, 2014, 09:23:07 AM »
As Alice (in Wonderland) said, "peculiar and most peculiar"
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Offline Shonver

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Re: The Cape Town Hi-Fi Club
« Reply #268 on: May 10, 2014, 10:22:21 AM »
The 0.5 ohm and quarter ohm ribbons I have designed myself are driven class A amps.

Do these amps have a name?
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Offline chrisc

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Re: The Cape Town Hi-Fi Club
« Reply #269 on: May 10, 2014, 01:01:06 PM »
I think they are Krells.  Jozua has one in each room
Music is the shorthand of emotion