Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Planars & Exotics ESL's, planars, and alternative technologies

Driving Quad 57s with First Watt J2 amp?
Driving Quad 57s with First Watt J2 amp?
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 4th December 2016, 10:01 PM   #1
oltos is offline oltos  United States
diyAudio Member
 
Join Date: Mar 2012
Location: Long Island, NY
Default Driving Quad 57s with First Watt J2 amp?

For the few here who are not familiar with the Quad ESLs https://en.wikipedia.org/wiki/Quad_E...ic_Loudspeaker
and the ESL 57 in particular QUAD ESL-57 ONE THING

The 57s were intended to be driven at about 15 wpc. They are somewhat fragile, not so easy to repair and cannot be driven beyond 100db SPL without risk of damage from arcing. But ~ 83.5db SPL at 11 ft is probably a bit loud for me in my room anyway. One 57 owner gets very good results by raising them ~ 18Ē above the floor and using them with a pair of Dynaudio subs. Mine are Rythmik 12" sealed subs.


However, while Iím no kind of expert, success driving the Quads with the J2 seems mostly dependent on two things:

1.) Damping Factor: One Quad 57 owner I know told another one that he tried the Atmasphere S30 OTL tube amp but said it ďsounded terribleĒ with the 57s; ďÖ..nonexistent bassĒ. The S30 might be an otherwise excellent balanced input, very low feedback Class A amp. But notice that thereís no spec for damping factor or output resistance. Atma-Sphere Earlier when discussing this, Ralph Karsten made the invaluable point that high efficiency speakers-like my 97db, 7 to 8 ohms two way mains-donít like amps with high damping factor. The midbass will likely sound lean!

So amps with damping factors over 20 are off my short list to drive my hybrid horns.

Conversely, ESLs in general are at least 10db less sensitive than my hybrid horns. For example, Soundlab recommends a 100 wpc amp for their smallest full range ESL model. The more powerful amps tend to have lower output impedance and thus higher damping factors, like the Pass Labs XA series, with typical DFs of 150. https://en.wikipedia.org/wiki/Damping_factor OTOH, the Quad 57s, though even less sensitive that the Soundlabs, probably canít take much over 50 watts without risk of damage. But, like the Soundlabs, they apparently need an amp with a much higher DF-perhaps at least 20, which is likely at least 5 times higher than the Atmasphere S30.

No wonder that Quad owner go no bass from the S30 driving his 57s.

2.) Stable Output Impedance: The Quad 57ís, like ESLs in general, have wild impedance curves that can play havoc with a lot of amplifiers, regardless of type or output power. Quad ESL & ESL63 Information And so another important point that Ralph made is that ďBass is hard to get with transistors and Quads because many transistor amps will double power as you cut the load impedance in half. The Quad has high impedances in the bass region and low impedances in the treble/HF region. Most transistor amps would likely play the Quad 57s with weak bass and too much highs."

So it looks like the Quads need an amp having both ample damping factor and a high impedance output; not so easy to find in most solid-state amps

But the solid-state J2 has a damping factor of 20. http://www.firstwatt.com/pdf/prod_j2_man.pdf
And according to John Atkinsonís measurements, the J2 not only prefers high impedance loads, but when the 57ís impedance drops to about 3 ohms at ~ 18kHz the J2ís output power drops to perhaps less than half what it is at 8 ohms. Thus, wouldnít that keep the 57s from sounding bright? Check out this report. First Watt J2 power amplifier Measurements | Stereophile.com

Obviously, the big questions are what is the J2ís watts/channel at 30 ohms?

And what are its overall frequency response, distortion and noise with that load?

Has anyone done or may care to make those J2 measurements or estimations at 30 ohms?

If yes, on a scale of 1 to 10, with 10 being best, how might the J2 amp and the Quad 57s sound together?

Would bass response extend down to its 45Hz spec?

And would treble reach up to its usable 18kHz? And sounding sweet-and hopefully airy-but never bright?

Last edited by oltos; 4th December 2016 at 10:06 PM. Reason: Added J2 manual link
  Reply With Quote
Old 5th December 2016, 01:48 PM   #2
anji12305 is offline anji12305  United States
diyAudio Member
 
Join Date: Jan 2006
Many of us pass over the readilym available Quad amps, which are a surprise with Quad ESL.

Before pursuing the First Watt design, please consider a Q606. They're not 'special' or flashy, but competent and musical.

Sent from my Nexus 6 using Tapatalk
  Reply With Quote
Old 5th December 2016, 10:53 PM   #3
stokessd is offline stokessd  United States
diyAudio Member
 
stokessd's Avatar
 
Join Date: Nov 2002
Location: Grantham, NH
I don't know about the J2, but I built a pass Zen when the design first came out and it worked remarkably well with my original quads at the time (that was really surprising to me). I haven't had luck with single ended tubes and any electrostat, but single ended transistors in the case of the zen worked pretty well. That said, I prefer EL84 based amps with the original quads. But I also often use the Quad II's or a ST-70 variant on them.

I generally listen to my 63's these days with either a quad 99 , or a classe 70, or a citation II.

Also if you are going to be trying higher powered amps, you might want to install a set of the treble panel clamp boards just in case.

Sheldon
  Reply With Quote
Old 5th December 2016, 11:04 PM   #4
rayma is offline rayma  United States
diyAudio Member
 
Join Date: Apr 2011
Quote:
Originally Posted by oltos View Post
what is the J2ís watts/channel [B][I][U]at 30 ohms?
The power supply is +/-24V, so the most output voltage possible is (24 / 1.414) = 17Vrms.
Then into 30R, P = (17 x 17 / 30) = 9.63W.
  Reply With Quote
Old 6th December 2016, 11:10 AM   #5
anji12305 is offline anji12305  United States
diyAudio Member
 
Join Date: Jan 2006
Quote:
Originally Posted by rayma View Post
The power supply is +/-24V, so the most output voltage possible is (24 / 1.414) = 17Vrms.
Then into 30R, P = (17 x 17 / 30) = 9.63W.
How much current does that work out to?
My Quads struggled to produce bass with "high power" amps and came to life with a Quad 909, which was built for them.


Sent from my Nexus 6 using Tapatalk
  Reply With Quote
Old 6th December 2016, 05:02 PM   #6
rayma is offline rayma  United States
diyAudio Member
 
Join Date: Apr 2011
Quote:
Originally Posted by anji12305 View Post
How much current does that work out to? My Quads struggled to produce bass
with "high power" amps and came to life with a Quad 909, which was built for them.
Into a 30R resistor, the peak current is 24V/30R = 0.8A peak (0.57A rms).
The peak current into a reactive load will be higher.

Last edited by rayma; 6th December 2016 at 05:07 PM.
  Reply With Quote
Old 6th December 2016, 07:05 PM   #7
anji12305 is offline anji12305  United States
diyAudio Member
 
Join Date: Jan 2006
Quad 909 has available 11amps per channel, peak demand and 'current dumping' topology which relieves the input side of the driving circuit from handling swings in power demand.

It's a cunning implementation of traditional vacuum tube design.

http://www.quad-hifi.co.uk/our-story.php?id=23

Sent from my Nexus 6 using Tapatalk
  Reply With Quote
Old 7th December 2016, 06:25 AM   #8
oltos is offline oltos  United States
diyAudio Member
 
Join Date: Mar 2012
Location: Long Island, NY
Quote:
Originally Posted by stokessd View Post
I haven't had luck with single ended tubes and any electrostat, but single ended transistors in the case of the zen worked pretty well.
What's so strange is how some Quad 57 owners risk dancing around the 57's wild impedance curve. Friday I'll be attending my VERY first Quad 57 session with at the home of long time owner on Long Island. He's actually driving them with a Wavelength Duetto 300B SET amp. He's also got a Wavelength Crimson DAC. Wavelength Audio Duetto Stereo Amplifier by Ian White It only does 8 wpc. But its switchable down to a 4 ohm output. Presumably, that allows the output voltage to be a lot more constant with frequency, compared to the transformer's 8 ohm tap, yes?


But I suppose that my solid-state J2 amp's output couldn't do this? First Watt J2 power amplifier Measurements | Stereophile.com

Quote:
Originally Posted by stokessd View Post
Also, if you are going to be trying higher powered amps, you might want to install a set of the treble panel clamp boards just in case. Sheldon
I hadnít planned on buying higher wpc amps. If I was I would probably pass on getting the Quads and go for this kit.

Acorn Electrostatic Loudspeaker Kit

But Toppsey here said that he actually drove his Acorns with a Yarland 845SE 16 wpc amp! ER audioís US rep said, that amp must have less than 1 ohm output impedance and the highs would be rolled off as the ESLsí impedance drops so low up there. But who wants and amp that draws >600w!?

Meanwhile, the J2 is only 13 wpc into 4 ohms, so forget about that option. I just wish I could find a great sounding Class A transistor amp that wasnít so big and didnít get so hot and that could drive the Acorns to an average of ~ 84db SPL at ~ 11 ft in my 14 ft x 19 room. If not, then maybe a tube amp-IF it didnít get so hot.
  Reply With Quote
Old 7th December 2016, 10:44 AM   #9
anji12305 is offline anji12305  United States
diyAudio Member
 
Join Date: Jan 2006
If you're in the US, it might be worthwhile to contact Kent McCallum about your concerns. He has lots of real World experience refitting electrostatics, and sorting out associated gear.

http://estatsolution.com

Sent from my Nexus 6 using Tapatalk
  Reply With Quote
Old 20th December 2016, 09:15 PM   #10
lafish is offline lafish  United States
diyAudio Member
 
Join Date: Oct 2007
Location: Port Townsend, Washington
Currently driving my ESL 57's (rebuilt by Wayne Piquet) with a First Watt M2. Very sweet and detailed, but not as punchy as with my diytube st35, an el-84 amp. Try to hear them with Rodger Modjeski's RM-10, which was designed using them. They don't tend to like single-ended triodes.
__________________
Pass B-1, Pearl 2, diytube ST35
  Reply With Quote

Reply


Driving Quad 57s with First Watt J2 amp?Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Driving high watt speakers w/lower watt amp? bwolf Chip Amps 15 9th February 2016 11:28 AM
For Sale: First Watt J2 amplifier wyan Swap Meet 0 17th November 2015 01:01 PM
J2 amp driving these HF/MF ESLs? oltos Pass Labs 1 27th December 2014 11:53 PM
First Watt J vs. J2 izzy2 Pass Labs 3 31st March 2012 02:38 PM
1000w amp driving a 1 watt speaker scampo77 Car Audio 24 8th March 2010 10:01 PM


New To Site? Need Help?

All times are GMT. The time now is 06:21 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio
Wiki