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Old 'green' Solo

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FritzS View Drop Down
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    Posted: 07 Feb 2018 at 12:11pm
Hi,
I have an old 'green' Solo (buy'd 2007). 
I use an LME49720HA as OPA
As far as I know the output impedance of this Solo is about 33 OHM.
But this are a bit to high vor some of headphones I use (sometimes I get headphones to test them).
On other side the peak output voltages are to small (so as for AKG K1000).

Which peak current or voltage level, which output impedance have your actual Solo?
Which OPAs did you use actually?

Gives a way to test your actual Solo top model? I live in Austria.

AKG K812, K872, K712, Q701, K701, K501, K550, K271, Denon AH-D 7000
"Green" SOLO (with LME49720HA), WNA MKII
Marantz SA7001 KI, Philips CD650
Revox B790, G1042, Reflex
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Graham Slee View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 07 Feb 2018 at 12:52pm
Hi Friedrich, you are asking me to divulge the Solo Ultra Linear DE design in public?

The OPAs are contained in the ultra-linear module which modifies their open loop gain thus widening their open-loop flat frequency response. When negative feedback is applied it is purely 180 degree much higher up the frequency scale - well into the midrange - very much like valves. Normally the op-amp open loop gain turns over at a few 10s of Hertz, meaning that negative feedback is on the 90 degree slope which leads to the "all leading edge" sound which typifies solid state, and the LME49720 is no different in this respect.

The output impedance is set by 15 Ohm resistors.

Hope this helps.
There are only two things to stop you being a success in life and they're both called Google - Notions are not solutions!
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FritzS View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote FritzS Quote  Post ReplyReply Direct Link To This Post Posted: 07 Feb 2018 at 1:04pm
Hi Graham,
in the old 'green' Solo (buy'd 2007) there are 33 Ohm instead now 15 Ohm resistors used.

Are the peak current or voltage levels are now higher?

Gives a way to test your actual Solo top model? I live in Austria.

If you remember, past years ago, I was a Solo, Novo, Reflex protagonist and send you some hints to.


Edited by FritzS - 07 Feb 2018 at 1:05pm
AKG K812, K872, K712, Q701, K701, K501, K550, K271, Denon AH-D 7000
"Green" SOLO (with LME49720HA), WNA MKII
Marantz SA7001 KI, Philips CD650
Revox B790, G1042, Reflex
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Ash View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ash Quote  Post ReplyReply Direct Link To This Post Posted: 07 Feb 2018 at 2:24pm
The AKG K1000 seems to need a lot of current for full drive so Graham's Proprius are more suitable than the Solo for powering them, especially if the K1000 "wings" are as far out as possible and you also really want to crank up the volume. In this scenario, I used a Majestic into a Solo UL and I was able to reach the "ceiling" of the maximum power that could be delivered (right before clipping, distortion etc). With Majestic into Proprius monoblocks, there was much more current or available power in reserve that I never reached a "ceiling" as it was much beyond what would damage the device.

Edited by Ash - 07 Feb 2018 at 2:27pm
Bitzie, Majestic, 4x Proprius, Lautus USB, Lautus coaxial, Lautus phono-XLR, Lautus-R3 TRS-XLR, Mark Audio Alpair 10P/12P/12PW
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FritzS View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote FritzS Quote  Post ReplyReply Direct Link To This Post Posted: 07 Feb 2018 at 5:14pm
K1000 need voltage not current - but he have low sensitivity 
Sensitivity 74 dB/mW
Impedance 120 Ohm

I had one for same month to test, with my Solo no chance, but with my own build HA it works, only his sound level are not high. K1000 needs an amp with more than +-19V peak to peak, better bridged amps each stereo channel.

Past days I test the follower of K1000 Mysphere 3.2 http://mysphere.at/ with 100 Ohm impedance.
Mysphere 3,2 needs 5,4V RMS for 122db SPL.



Mysphere 3.2 http://mysphere.at/  is developed from the same people who developed the K1000
AKG K812, K872, K712, Q701, K701, K501, K550, K271, Denon AH-D 7000
"Green" SOLO (with LME49720HA), WNA MKII
Marantz SA7001 KI, Philips CD650
Revox B790, G1042, Reflex
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Post Options Post Options   Thanks (0) Thanks(0)   Quote FritzS Quote  Post ReplyReply Direct Link To This Post Posted: 07 Feb 2018 at 5:30pm
An other topic.
In my RG time (Graham know what I mean) I build an HA DIY project too.
This HA is in pure Class A and use a main voltage of +-10V. Mine have an output impedance of 15 Ohm.
Now I use 2x OPA627 in pre stage.

My AKG K812 is an headphone who don't forgive sharpness in recording or signal path.
For some music he need an warmer tuned amp.

I compared my Class A HA with Solo - my old Solo ist a bit sharpened as my Class A DIY amp.
Because both are near 10 years old, so I search for an follower and a chance to test before buy.
AKG K812, K872, K712, Q701, K701, K501, K550, K271, Denon AH-D 7000
"Green" SOLO (with LME49720HA), WNA MKII
Marantz SA7001 KI, Philips CD650
Revox B790, G1042, Reflex
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Graham Slee View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 07 Feb 2018 at 7:20pm
Originally posted by FritzS FritzS wrote:

...so I search for an follower and a chance to test before buy.


You have Suggs. He will send you one if you pick up the postage bill both ways (mainland Europe).

Suggs doesn't get paid by me, he is a volunteer. I ask no questions - the loaner program is conducted without my knowledge.

If you like it tell us all.

Please use the private messenger to talk with Suggs.

Graham
There are only two things to stop you being a success in life and they're both called Google - Notions are not solutions!
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