SUT - electrical theory and practical experience

I am trying to figure out:

• whether they generated a square wave with the same output impedance as the cart and fed the SUT with that.
• Or if they had a test LP with a square wave
• and then if it is a test LP is that square wave a triangular shape on the track to make an electrical square wave.

?

@holmz 

this one -

• whether they generated a square wave with the same output impedance as the cart and fed the SUT with that

Dear @dover  : Yes I did it during the " thousands " of tests with the prototypes of the phonolinepreamp and through measures and listening tests the only parameter we can been aware was changes in SPL but not in FR but additional to that normally LOMC cartridges come with the " rigth " internal resistance to work very good looking those 100 ohms. Clearaudio is something espcial with those 50 Ohms.

There are plenty of MC's up to 40 ohms ( eg Benz, Dynavector, Sony to name a few ) for which 100 ohms loading in my view is killing the cat.

If your phono linear were stable you would be able to load at any value.

It would seem that any observations or cartridge evaluations posted by you with this phono stage would be jaundiced by improper loading. 

Dear @dover : Yes, is totally stable. Now, till today 7-8 other owners never reported issues about and satisfied with their units.

A " trouble " with the phonolinepreamp is that any load resistor change means to unsolder/solder the new one and to do that we have to open/take out the top plate and make the job carefully because the boards are 4 layers and we have to make 2 changes because is a dual mono design.

During the unit presentation/show in USA I was at around10 different room/systems with different cartridges with no compliant for the system owners.

I was not the designer engeenering in chief but I learned a lot down there and maybe theory not always works as should be depending of the kind of design.

Rigth now I have not a clear explanation why performs so well against the 10x load other than minor SPL changes where noise level is no issue due that the unit has very low noise and distortion levels.

The audio friends at my place with their own cartridges almost always were " impressed " by what their cartridges showed here through this phonolinepreamp.

Jaundiced? you can be sure that’s not that way: theory vs real facts, including measures during prototype tests.

In my vitual system says: " current mode " design ( what José stated. ) that comes from around 15 years ago and perhaps not estrictly " current mode " by today standards or a current mode " variation ". The issue is that works in excellent conditions over any " scenario ".

 

I can remember very clear that when I was showing it in Houston at a top Agoner and today reviewer ( he owns Rockport TT , Acapella Triolon’s, JC-1’s, ) that his Lyra was out of work in the same just time he was showing his system in its dedicated room and when the Lyra " hit " the first LP grooves he took in count that the Lyra was with out stylus : just disappeared and then we chage it by a Clearaudio he owned and we made the set up in his Rockport and he was really " surprised " for what he listened through my unit ( yes 100 ohms resistor ). Here what he posted:

Audiogon Discussion Forum and this the first time down there:

Audiogon Discussion Forum

Audiogon Discussion Forum this gentleman with a Ruby2 in a Triplanar.

 

This the first version of the unit and VDH cartridge:

Audiogon Discussion Forum

another ones:

Audiogon Discussion Forum

Audiogon Discussion Forum

and I can go on andd on. Lewm owns a 3160 and mine is the 3180.

 

Other cartridges as the Magic Diamond in a Walker TT in Phuladelphia with 15-20 listeners including Lloyd Walker him self and other presentation in San Diego with 15-20 listeners at an Audio Salon big audio distributor. Different cartridges same " resistor ".

 

R.

 

 

R.

 

In Georgia with Aolivero he owns the Proteus, Dallas with Albert Porter the 47 Labs, with the group in San Diego Lyra Skala and in the same area a gentleman with all Air Tigth electronics and with Air Tigth cartridge too. Other cartridge Allaerts and over there in a shoo-out vs Dartzeel  with 3 different cartridges the owner of this unit made one load impedance change that in the Dartzeel and in the Essential nothing change and even the owner prefered ( not night and day differences. ) the Essential. In other place Dougdeacon with the Universe II and in Boise the Lyra Olimpos. I can't remember the cartridge at @sbank  place .

Dover, have you an explanation?

 

R.