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Stacked Quad 57s, Auckland


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ESL lovers - any users Quad 57 users in Auckland who would care to share their 57 wisdom with me?

 

I have unexpectedly received a set of stacked 57s (still stunned by my good fortune) and would like to start a process of checking and/or rehabilitating them. I have the power leads (a bit shabby) and Bulgin plugs but I also have lots of questions.

 

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Your man to seek out is our Mr. Gary Jacobson....THE man for stacked lovelies ! (he has not long joined us here as a member)

 

Green does not cover my thoughts at this stage ........SOOO envious, they look fantastic. You are about to enjoy a journey that very few can experience....lucky lucky man,...

ENJOY !! :popcorn:

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Gary's on here? Under his own name, perchance?

 

I'm hoping to get some introductory play on them, before launching down the refurbishment route. These seem to have been in place for some time so I gather they will need attention before long. (The rivets in some of the bass panels appear to have corroded/show some superficial 'white bloom').

 

From what I can see, no alterations have been made since they were first adapted to this rig. The front grills appear to have been removed. But there are no clamping boards or any kind of updates that one might expect.

 

It looks like the rigs would have to be completely disassembled to allow access to the panels, or even to inspect the treble panels. - but hey! They were a gift. No 'dental inspections' of this gift-horse for now!

 

There seem to be several ways to wire these for use with mono amps (PP EL34 in my case - until I can afford more valve power). Anyone have any thoughts on the wiring matter?

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Look'n good.

 

Thanks. I've got to rearrange and tidy up though. We just moved here and still have boxes everywhere! Some speakers will have to find new homes in the wake of these obelisks.

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G'Day Justin,

 

PM'd you a lot of preliminary stuff on the room, but there's more, if you're game :)

 

I'll post this here if anyone has an interest in hearing me bang on about rooms and stacked Quads ... again and again and again .... :)

 

Regards,

Gary Jacobosn

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In for a penny,... besides, this gift has pushed me headlong into the world of 57s. Definitely game.

 

Got to grab some decent/modern/safe power flex to donate to the Bulgin plug cause. Are the Bulgins easy to take apart? Mine look a bit fragile - like they might crack apart at any moment.

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G'Day All,

 

The ROOM... you foolishly asked :)   [Quick! Someone SHUT HIM UP, he's going to talk about room acoustics and stuff!!]

 

I was once a complete non-believer on the subject of room treatments, which, for someone trained in physical science is an unforgivable transgression.  I put it in the category of Americanisher Schwinhund propaganda and sales talk.

 

About eight years ago, I started experimenting with cheap DIY stuff, then professional acoustic panels (properly tested at Monash uni).

 

In short, I was wrong about room treatments.  You cannot hear half of the stuff that your system is doing without them.  I've attached pictures of my listening room as evidence of my conversion.

 

My remarks refer to a room devoid of anything but the listener, system and perhaps a floor covering.  The other necessities of life have to be compensated for by measurement, and I'll get to that later. maybe not tonight though :)

 

OK, let's take Justin's room in Auckland for an example.  He tells me it is 26 feet by 14 feet by 10 feet high.  I thought they'd metricated across the ditch?  That's around 7.9 metres by 4.2 metres by 3.0 metres with a diagonal dimension of 29.5 feet (9.0 metres).

 

These dimensions give us eigentones and possible standing waves at: 38 Hz (length), 71Hz (width), 100Hz (ceiling to floor mode) and 33Hz (diagonal)

 

Most speakers will excite all of these modes.  Quads will tend to excite them all but less so the side to side mode and ceiling to floor mode (cosinusoidal radiation pattern).  The Quads will, being di-polar excite the longitudinal and longitudinal modes more than a box speaker might.

 

Get your stacked Quads 2 metres off the back wall, btw, Justin.

 

Whatever speaker(s) you are using, the bass frequencies in your room will "accumulate" in the corners of the room.  Easy to check. Put on a record or CD with some reasonable bass program content.  No need to go mad though.  Go and stand in the corner!  Put your head right back against the walls. Listen!  Move out of the corner and listen.  Try every corner.  It's the same.

 

Psssttt!!  Make sure that no "normal" person sees you doing this :))

 

All the room modes "focus" in the corners. This is why you hear the emphasis that you hear in those spots.  This is smearing every single sound you hear in the room.  Slap echoes and all the other stuff that you can possibly hear are relatively minor matters if you do not deal with this issue first and foremost.

 

For stacked Quads in a room of this size you need bass traps, floor to ceiling in every corner for best performance, but absolutely behind the speakers.  I suggest bass traps from Sound Acoustics (Melbourne) [James Bellew.  On eBay too, as I recall.  Good products and as noted above, properly tested.  They work for the right reasons, not by accident.

 

I also use mass loaded vinyl sheet behind the corner bass traps in my room to get down to the lowest frequencies (<40Hz) as the Soudn Acostics panels only work to about 50Hz with significant attenuation.  Figures for this on the Sound Acoustics site, btw.

 

I'll attach a few pics of what I'm on about and take the subject up again tomorrow night if anyone is left alive after this effort :)  You will note that even the door in my listening room has been "dealt with" to stop it vibrating like a drum at 70Hz or so.  Behind those door panels is a layer of mass-loaded vinyl sheet (4kg/sq.m.)

 

Regards,

Gary Jacobson

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Edited by garyjac
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Thanks, Gary, very interesting. I have Quad 2905s at work , in a smallish room (in metres, 5L x 4W x 3.2H). Detail has always been less than it should be.

At home, stacked Quads (currently smoke and soot damaged from a fire).

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Gary, I hear your message about bass traps but I think if I tried to smuggle those panels into the house, I'd be ushered straight through it and into the garden! Perhaps I can find alternatives that are more in keeping with our decor - or maybe I will have to fashion some myself for a custom fit.

 

Anyone else got room treatments to share?

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My room treatments include Sound Acoustics bass traps floor to ceiling, augmented by hanging them off 140mm thick acoustic insulation polyester panels in the corners and lots of dispersion panels on the front wall, the 1st reflection point behind and in front of the speakers. +absorbing panels along side and rear walls. I still need to treat the ceiling

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Sent from my iPhone using Tapatalk

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G'Day All,

 

Back to the ROOM to wrap up the basics then....

 

@frankn  :  Some serious ME hardware there and Soundlabs M1s ?

 

@Justin :  To your better half, argue like this -- but, dear, these bass traps are smaller than the speakers and they can be sprayed in designer colours...

 

Anyhow, after you trap the corners, there's the ceiling over your head, any doors that you can feel vibrating and where solid shelf sides and supporting beams meet the walls and ceiling you can trap with broad band absorbers.

 

Please note that putting blanket-like coverings everywhere doesn't work.  You end up absorbing HF only and the whole system (includes room) sounds muddy and dull.  Do it right and you hear more controlled bass than you ever heard before and more detail than you ever heard before.

 

OK, after those basic points you need to get a sound pressure level meter.  Surprise!  The Radioshack Sound Level meter will do the job.  Not expensive.  Then go to Real Traps and read the info there and download the files needed to build a white noise CD source for testing.  The Radioshack meter is good up to 1kHz, so setting your room up in the bass modes can be done with this meter quite accurately.  Anyhow, read up on this at the Real Traps site.  It's very comprehensive.

 

It's possible to "tune" a room to within 2dB of "flat" response at the listening position.  I have mine close to that below 15kHz and above 50Hz, so it's not too bad at all.

 

You "tune" the room by adding more damping and diffusion to the walls at what seem to be "intuitive" spots until the measurements and your ears tell you that things sound clearer all around.  This takes a while, maybe 6 months to get it all tuned in nicely, but it's worth it :)

 

All said and done though, Justin, you've got a bit of work ahead to get those units back in top running order.  Best of British luck and remember that it is worth it.

 

Regards,

Gary Jacobson

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No problem John.  Wayne is just "back" after heart surgery, but he tells me he's ready to rock and roll.  I used to do my own panels, but I've used Wayne's for years now and I'd back him in against any in the world.  Best sonics and best cosmetics.  Plus I have deliberately tried to arc his panels and haven't managed it :)

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Hi @ "aechmea" they are Vicoustic 2D diffusers / 6 (or 8?)per box. About $770/box

@ "garyjac" Yes, ME850HC & ME1400. The valve amps are locally hand built. See

www.westonacoustics.com

I'd recommend Earl's products & service to anyone.

These are the Topaz Duo KT150 monoblocks and this is the model info ;

Due to the recent release of the Tung-sol KT150 output tube, the Topaz Duo now runs KT150's

They sound very nice and are very easy to listen to and they provide good low-down power.

KT150 Class A self biasing push-pull monoblocks.

The Topaz Duo is built on two mirrored chassis.

Uses modified Pi wound output transformers for fully balanced DC resistance, and AC impedance, which equals very low distortion and exceptional frequency response. Secondary windings are made up of 18 layers of 0.25mm wire interleaved within the primary windings.

Runs separate over sized high voltage (600VA) and heater (125VA) power transformers.

CMC Teflon valve sockets, paper in oil coupling capacitors, CDM (Cornell Dubilier Mallory) & Philips cathode capacitors, Vishay thick film bias resistors,

English high voltage copper hook up wire and solid copper core signal wire, CMC speaker binding posts.

Transformers manufactured using Australian magnet wire, Australian and Japanese laminations, English and New Zealand bobbins, Australian made covers.

Chassis tops are Australian laser cut 2mm stainless steel (1.2mm SS bottom plates).

SPECIFICATIONS

Power Output - over 45 watts per channel pure class A

Frequency response -3db - 6hz to >75khz

Signal to Noise - >90db A Weighted

Signal to Hum - >80db

Distortion - <0.1% at 1 watt rms (Typically 0.05%)

Hum Level - <3.0 millivolt

Sensitivity - 500mV

Input impedance - 100K

Inputs 1

Speaker output 8 ohm (6 to 12 ohm is fine) Earle told me the amps are okay for the Quads after reviewing the speakers freq/phase/impedance specs. Earle's specs are very conservative I think

Damping Factor >6 (20hz to 20khz 8 ohm)

Weight ~20kg (~44lb) per monoblock.

Dimensions 440mm x 370mm x 220mm (width x depth x height) per monobloc[

Sent from my iPad using Tapatalk

Edited by frankn
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