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Jim Griffin's JX92S designs
Jim Griffin's JX92S designs
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Old 23rd April 2010, 06:23 AM   #171
mikelm is offline mikelm  England
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Default possible improvement in treble ( for those who don't mind taking risks )

If you take the faceplate off of the Aurum Cantus G2si and make a new faceplate with a suitable sized & shaped cutout so that the rectangular (ish ) body of the ribbon tweeter fits through it and mounts flush with the front, it sounds better - not only clearer but also cleaner - in fact very nice indeed !

There is a slight rise in output in some regions, so some may want to tweek the X-over . . . but to my ears it still sounds just fine with the original published x-over.

Of course this means that the ribbon is not now protected with a grille so each will have to decide if this mod is for them but if you don't mind taking the risk it is possible to reproduce quite sublime, smooth & natural sounding treble.

I'll post pics when I have made mine look a bit more presentable

mike
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Old 23rd April 2010, 07:18 PM   #172
mikelm is offline mikelm  England
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p.s.

I made my new face plate from plastic because from what I could understand of the design a metal face plate done in the way described above could short circuit the ribbon
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Old 22nd March 2011, 09:07 PM   #173
northernsky is offline northernsky  Italy
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Hi,

I intend to build the Griffin's minimonitor. I am not an expert (I can just copy) so forgive me for the basic question.

I have problems in finding some components for the crossover with the exact design value.
In particular I can find for L2 0.33 mH instead of 0.30;
4.7 or 5.6 microF instead of 5.1 for C2 and 3.3 ohm instead of 3 for R2.
Are they OK or should I find exactly the design values?

In addition I realized that there are very expensive capacitor, the Mundorf Mcap supreme for instance are 4 times more expensive than Mundorf mcap standard! Is it worth to go for the more expensive ones?

Thank you for your help

Renato
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Old 22nd March 2011, 09:20 PM   #174
Jim Griffin is offline Jim Griffin  United States
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For my prototypes I purchased components that are in the middle of the price range for each items. Not too cheap yet not too expensive. The merit of expensive parts isn't worthwhile in my opinion.

For alternate part selection I suggest within 10% of the nominal values is OK. While parts within 5% tolerance would be better, your sources may not be able to satisfy this criteria without undue search.

Good luck on your build and I hope that you are pleased with your new speakers.
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Old 22nd March 2011, 09:27 PM   #175
northernsky is offline northernsky  Italy
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Thank you for the suggestion. I hope to get the boxes working as soon as possible, but I'll take some time, I am not very fast.


Renato
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Old 23rd March 2011, 03:06 AM   #176
rlrohlfs is offline rlrohlfs  United States
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I went the inexpensive route with Solen caps for my first build. Later I went with Sonicap. I prefer the Sonicaps.

At the time I built my first set, Parts-Express had all the components listed in Jim's specs available.

-
Rick
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Old 24th July 2017, 07:51 PM   #177
TimA is offline TimA
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Jim

I'm currently building your JX92/Ribbon IB design.
This will be pentagonal 3/4" ply cabinets lined with 7mm ceramic tiles for stiffness - a recipe which has worked quite nicely in the past.

Question please - did you use air or ferrite cored inductors in the bass section (it isn't obvious to me from your design pack)? Previously in listening tests I have preferred ferrite cored inductors in the bass section of two way designs but I'm not necessarily set on that this time.

When they are finished I shall compare them with my rebuilt/modified ESL63s so I'm curious to see how they fair!

Tim
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Old 25th July 2017, 02:11 AM   #178
Jim Griffin is offline Jim Griffin  United States
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Tim,

Great to hear that you are building the JX92s/ribbon speakers. I still use my speakers as daily listeners so I'm still pleased with the results.

I used air cored inductors in my prototype speakers so I really have no baseline for suggesting or using ferrite cored units.

Best of luck on your project and let us know how they sound.

Jim
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Old 4th August 2017, 09:57 AM   #179
TimA is offline TimA
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Jim

The mini monitors are now finished, with laminated steel inductors in the bass section, Ansar supersound polypropylenes everywhere, bypassed in the treble with small film/foil PIO and Teflons. Measured values are spot on. The 0.3mH inductor is air cored but with a slightly higher dcr than is indicated by your 20AWG figure so I have resized the resistor in series correspondingly as I assume it's the total resistance here that matters.

The boxes are sealed. Subwoofers are set for 85Hz.

Listening to them I'm pretty impressed with their speed and apparent precision. Your comments in the design pack with regard to retaining the coherency of the full range Jordan unit are much In evidence too. Ditto for 'lightning in a bottle'!

I lived with the full range Jordan Eikona/VTL for a year before returning to my much loved electrostatics for their effortlessness and openness in the treble, much as I admired the coherency of the Eikonas. These ribbon monitors come closer to the ESLs and sound more polished than the Eikonas.

I'd like to try film/foil capacitors in the treble section at some point but the Ansars will do for now. I have a pair of Fountek Neocd3.0 ribbons which might be interesting to compare. By my reckoning the ribbon and associated resistors present a 10R load to the crossover treble section, so resizing them to account for the change in sensitivity and retain the 10R load to the crossover seems a good place to start. Your thoughts on this would be much appreciated. In the meantime thank you for making this design available. There's definitely a synergy between Jordan/Aurum Cantus!

Tim

Last edited by TimA; 4th August 2017 at 10:00 AM.
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Old 5th August 2017, 09:12 AM   #180
TimA is offline TimA
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Following up on my last post and after more listening...

Highly articulate and resolved, fine burnished detail, wide open and seamless.

The surprise for me is just how well they hold their own against my ESLs. On the listening I've done so far (in a medium sized but not large room)it would be a tough call to choose one over the other.

Tim
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