SS or Tube line stage Buffers

Hi Manek,

I guess Siva is a prime candidate to offer and post, even though he is not based in Mumbai. However, he is on a holiday...

Viren you have something to offer ?

Try this link :
http://www.headwize.com/ubb/showpage.php?fnum=3&tid=6413


Also, my THEORITICAL fav :

http://www.borbelyaudio.com/eb804421.asp

I ordered the kit ( Euro 100 ) it came thru no duty or problems. Made it, but seems rather warm sounding and ( maybe ? ) lacks details. U are welcome to audition at my place.

Cheers

Hi Manek,

Since you already have a valve preamp, I doubt if an input buffer stage will add anything more. The input impedance of a line stage of a valve preamp is very high, of the order of 100k to 1M, so loads the connected source (CD player) minimally.

Problems of loading can arise with solid-state preamps, which have low input impedances, 10k or less. However, the good ones will have buffered input stages anyway.

Viren.

Viren,thanks for the clarification. I was curious about these small boxes. Yes my tube pre has a 100K input impedance and should pose no problems with any cdp I should think.

BTW I did notice that the jolida cdp 100A has an output impedance of 47Kohms. I wrote to jolida to verify thinking it would be a typo but they confirmed the number ! Wonder what kind of pre would do good with this player then ?
They said any pre with a 100K input impedance would work...
I wonder !

I ask this question becuase the general ratio of 1:10 for input to output impedance is considered just adequate for the source to be able to drive the device it connects to. People say 1:20 is the minimum.

What do you guys say ?

Manek.

Manek schrieb:

Viren,thanks for the clarification. I was curious about these small boxes. Yes my tube pre has a 100K input impedance and should pose no problems with any cdp I should think. BTW I did notice that the jolida cdp 100A has an output impedance of 47Kohms. I wrote to jolida to verify thinking it would be a typo but they confirmed the number ! Wonder what kind of pre would do good with this player then ? They said any pre with a 100K input impedance would work... I wonder ! I ask this question becuase the general ratio of 1:10 for input to output impedance is considered just adequate for the source to be able to drive the device it connects to. People say 1:20 is the minimum. What do you guys say ? Manek.

1:10 is exactly the number i was quoted ib a DIY forum as well for imedance matching. but again as confirmed by viren, you need not really need a tube buffer. i have an MF one and use it only between my ipod and int am when i want to playt from that. now am p;aning to migrate it into my PC setup spomehow with a SI T amp..

maybe that could be my DIY, project an all in one PSU, SI t am and tube buffer

yes but 1:10 is supposd to be the minimum norm but i wonder if there is a big sonic difference in sound if a pre of 1000ohms is connected to two amps,one with 10kohms and one with 20kohms all other specs being equal ?The one with 20kohms just may play a bit louder at a particular volume settingbut other than that ?

manek.

I have been exploring High Impedance terminations, for sometime now, with particular reference to Sound staging

MOst forums that I have posed this query on, seem to post a 'dont care' reaction to a preference for high impedance terminations.

A few points that I would like to ventilate :

1. The tube buffer is usually added to add tube's euphonic sound ( Distortion ? ).

Maybe something like changing the sound by 'matching cables'

I must add that currently I am a valve guy and much prefer the valve sound... despite its short-commings.

2. Mark Levinson has, a couple of years ago, launched the VIOLA range of Amps and Pre amps. The Pre is priced at US $ 14,00 MRP... so a serious product.

The product was reviewed by Stereophile with a brief tech backgrounder. The VIOLA line has been designed with PARTICULR emphasis on maintaining a VERY High Input impedance throughout ... 500 K ohms to 1000 K ohms.

3. My Prima Luna Integrated has an input pot ( Volume control ) of 250K Ohms... that is HIGH. i suspect this contributes atleast in some way to the excellent sound stage depth I have at home.

4. My Denon 2900 Universal Player has 2 Audio outputs, wired simply in duplicate ( in parallel ).

I have heard the sound change for the worse even if I connect a second pair of Interconnects, WHICH ARE NOT CONNECTED TO ANYTHING AT THE OTHER END.

The second cable's capacitance is enough to spoil the sound. Hence the load on the CD player will CERTAINLY change the sound quality, even for a properly engineered Solid State CDP.


4.

Id like to address this matter as a separate post :

HOW IS OUTPUT IMPEDANCE DETERMINED

The text book methord calls for the output to be loaded with reducing values of resistors, till the output voltage falls to 50% of the no load value.

This is the Output impedance.


Clearly, the measurement is NOT done with an eye on distortion or optimum distortion performance. When the output level has fallen by 50%, you can almost be assured that the distortion will be MUCH worse than on no load ( ie a Very High Load Impedance value )


Hence it would seem prudent to keep the load at atleast 10x the output impedance.... a factor not always considered in Solid State designs......

Amp Nut,
you have compiled a lot of valuable info on i/p o/p impedances. My question is what does all this info lead us to?

I belive this is the loose standard of impedancefollowed by audio equip manufacturers. When will they formulate a standard? May be they will never do that fearing the wrath of Hi End cable industry !

Warm regards

Anil

Manek schrieb:

BTW I did notice that the jolida cdp 100A has an output impedance of 47Kohms. I wrote to jolida to verify thinking it would be a typo but they confirmed the number ! Wonder what kind of pre would do good with this player then ? They said any pre with a 100K input impedance would work... I wonder !

my friend here owns the JoLida CDP 100A & he has used atleast 2 preamps w/ this CDP - JJ Electronics 243 & his present passive transformer volume control (TVC). Yes, a passive preamp! According to him, the passive TVC is the very best that he has ever heard. His list of preamps is quite large (tho' they were not used with the JoLida CDP 100A).
So, the JoLida is quite compatible with mnay preamps - more than what the numbers would indicate.