Fully ballanced valve preamps

RobHolt said:
Look here chaps is all this really necessary?
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Trust me Rob, yes it is.

My life is too short and valuable to waste even five minutes of it in the company of BBV. You are of course cordially invited anytime however.
 
That sounds very civilised Rob. However I doubt SM can put his prejudices to one side. As his comments show.
 
I'm sorry but I'm desperately tryin' to put the topic back....

Anyone familiar with Job passive pre - Job is a Swiss company that used to be somehow related to Goldmund. As far as I can remember, some 7-8 years ago there was great hype around it at some audiophile circles in Germany and around.
 
Yes but Goldmund, Nagra, Reson, Anagram Tech - all Swiss product with global presence and plenty of pieces cropping up for sale on Audio Markt. Nothing on Job in comparison. Why?
 
They were not as big as Goldmund or Nagra and especially they didn't have such a history. It started as a students project but they were good enough to design stuff for Goldmund.
 
Have you settled on a valve pre yet ?

You asked earlier about EAR valve pre's with XLR out.

The EAR has transformer coupled XLR out and gives good performance with XLR or RCA, the BAT is a fully balanced circuit, therefor the XLR is superior to the RCA.

The EAR is very quiet with good depth etc, not that bloomy or warm , and sounds superb with active ATC 20.

It is less fussy with cable , placement etc, has superb valve life and good resale value.
 
Why are some valve preamps phase-inverting?

Can one use them with active speakers? I've just noticed that Cary recommends that users of SLP94 connect their speakers in reverse polarity (- to +, + to -). Does this mean that you can't use these amps with active speakers?
 
Hi,

anubisgrau said:
Why are some valve preamps phase-inverting?
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Because a single valve stage is inverting.

anubisgrau said:
Can one use them with active speakers?
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Sure, why not? Just send the signal into the "cold" XLR pin (inverting input). But few valve preamp's would drive a 10K load easily.

anubisgrau said:
I've just noticed that Cary recommends that users of SLP94 connect their speakers in reverse polarity (- to +, + to -). Does this mean that you can't use these amps with active speakers?
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You cannot easily use the Cary with active speakers because of the low input impedance, not because of the issue of polarity inversion.

Ciao T
 
Well i bit the bullett last night and bought Cary SLP-98L, so we`ll see how it goes. I couldn't get Bent NOH.

I liked the sound of earlier model (94) as well as how it's built. It has a good upgrade potential (either usual parts upgrade or non-DC rework) so I believe I can get eventually what I want.

If I'm wrong, I hope I can sell it without too much money lost. The new one is around 2000 pounds. I paid around a quarter for 7 years old. There was nothing decent on offer for that money and I couldn't wait anymore.
 
funnily, ATC engineer just replied that there is nothing to worry about neither about impedance matching nor about polarity.

what kind of question can wake them up?
 
Dennis Had from Cary also confirmed that 400ohm preamp into 10kohm poweramp is fine.

Next Wednesday we'll have a live test.

Not sure if they've heard about PMC, though.
 
Hi,

anubisgrau said:
Well i bit the bullett last night and bought Cary SLP-98L, so we`ll see how it goes.
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Just one or two comments.

The SLP-98 shows significant LF rolloff into loads much lower than 100K, with 10K load you are looking at -1db @ 30Hz. Also, the fairly current starved output stage may still handle 1V into 10K gracefully (the measurements in SP suggest so), but it will be a borderline case.

See measured performance of the Preamp here:

http://www.stereophile.com/amplificationreviews/204cary/

The Cary preamplifier is not one I would select to drive a lowish impedance Pro-Audio input. It may be desirable (in the light especially of the excessive gain of the line stage) to use an L-pad in the form of a 22K resistor in the XLR Plug which raises the load on the Cary Preamp to 32KOhm and attenuates the noise of the linestage another 10kdb or soand reduces the overall gain to around 11db from the well excessive 21db.

As or polarity inversion, I noted before, simply feed the signal into pin 3 on the XLR instead of pin 2 to invert polarity.

Ciao T
 
3DSonics said:
The SLP-98 shows significant LF rolloff into loads much lower than 100K, with 10K load you are looking at -1db @ 30Hz.
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I hope this would not be too dramatic for speakers with -6dB@45Hz.

this is the consequence of coupling caps - i will be anyway keen on trying a mod that bypasses them, turning the preamp into non-DC one, gaining speed, dynamics and more freq.extremes.


3DSonics said:
The Cary preamplifier is not one I would select to drive a lowish impedance Pro-Audio input. It may be desirable (in the light especially of the excessive gain of the line stage) to use an L-pad in the form of a 22K resistor in the XLR Plug which raises the load on the Cary Preamp to 32KOhm and attenuates the noise of the linestage another 10kdb or soand reduces the overall gain to around 11db from the well excessive 21db.
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you are probably right, T, i've been already thinking about its high gain and i've had pretty similar ideas about putting a resister to raise the load.... although cary has independent L+R gain controls separate from volume, hope this can do some further tuning of the excessive gain

i anyway bought this amp 1) liking a general tone character of older cary preamps such as heavily moded SLP-94 /also meaning that i have someone experienced with cary tweaking near me/ 2) having in mind its great tweaking potential 3) ok i will not mention a low price here

once it is with me, i'll see how it works and then i will try to get the most out of it. i count on your remarks, thanks a lot.

right now i either didn't have a budget and/or access to the preamps that would be a better match out of stock, or just failed to be impressed with these whose numbers seem to be a better match (such as EAR or BAT).

once again, thanks for all these extremely useful remarks!
 
Hi,

anubisgrau said:
I hope this would not be too dramatic for speakers with -6dB@45Hz.
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It all compounds and adds to group delay. I found (perhaps paradoxically, perhaps not) early LF rolloff often more audible with limited bandwidth, early LF rolloff speakers.

anubisgrau said:
this is the consequence of coupling caps
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Yes.

anubisgrau said:
i will be anyway keen on trying a mod that bypasses them,
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This is definitly not advisable, in Valve Preamps such as the Cary the coupling capacitor blocks usually 100V or more, something you do not want to apply to the input of the your active ATC's, at least not if you want to keep enjoying them (maybe blowing them up would give you a reason to upgrade to something better though).

Ciao T
 
this looks like a killer

melody SHW 1688-II

http://www.melody-europe.com/uk/preamplis.htm

anyone had a chance to try it?

very big in japan and germany.

it uses 101D triode, quite seldomly seen in commercial preamps. not sure if they found some decent sounding chinese tubes or got a stock of WE NOS.

and it looks like a bargain at 2400E plus shipping from france.
 
Shame it doesn't have remote control. Would have added it to my shortlist otherwise :-(

Only ever heard fawning praise for this preamp. Not sure how easy it would be to source 101D's though. Quite a difficult tube to find AFAIK.

The 6SN7 & 6SL7 tubes are probably Chinese, and would therefore require immediate replacement. Chinese 6SN7's are the worst modern production valves I've come across so far.

Am I right in thinking Melody are designed & built in Oz? The recent Hi-fi+ SP3 article certainly alluded to this. I thought they were Chinese?!

Lovely looking pre-amp though. Really like Melody's H845W monoblocks too. Very tasty - 88WPC Push-Pull 845's - 50Kg's each!!

DT
 


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