For tube/ss lovers: Where do you feel tubes should be

[trh8654]

In my experience, tube amps provide the magic.

Thats always been my findings too. i use all tubes right now, but have preferred SS preamp and tube amps when mixing the two.

 

[MarinJim]

I use a Musical Fidelity tube buffer because of the input impedence mismatching between my Lamm amps and the amps in the JL Audio Gotham subs

Too bad you cannot tube roll or change the wall wart.

 

[MarinJim]

What (as far a impedance match) do you guys think about my Burmester 911 MK3 and Concert Fidelity CF-080 LX?

CF -080 LX:
Input Impedance: 100kohms
Outputs: 1-Line Level Output (RCA)
Gain: Selectable between 6dB and 12dB
Tube Complement: 12AU7 (2) for gain (tube-swapping possible), 6CA4 (1) for rectification

Burmester 911 MK3:
23K unbalanced
2K balanced

 

[MylesBAstor]

What (as far a impedance match) do you guys think about my Burmester 911 MK3 and Concert Fidelity CF-080 LX?

CF -080 LX:
Input Impedance: 100kohms
Outputs: 1-Line Level Output (RCA)
Gain: Selectable between 6dB and 12dB
Tube Complement: 12AU7 (2) for gain (tube-swapping possible), 6CA4 (1) for rectification

Burmester 911 MK3:
23K unbalanced
2K balanced

You can probably get away with that but don't have the equation at my fingertips. You should watch out when the tube preamps output impedance is around 500 K or greater (like my old ART).

 

[MarinJim]

^ Thanks Miles, much appreciated.

 

[MylesBAstor]

^ Thanks Miles, much appreciated.

Although in looking at it again, I don't know what the story is if using balanced. Also, I assume when you said input impedance on the CF, you meant output impedance?

 

[MarinJim]

Although in looking at it again, I don't know what the story is if using balanced. Also, I assume when you said input impedance on the CF, you meant output impedance?

No, input impedance is what the CF website publishes.

 

[KeithR]

The ratio is 10:1 that you want at minimum.

As a former pass amp owner, i can safely say there arent many tube preamps with low output impedance.

 

[microstrip]

The ratio is 10:1 that you want at minimum.

As a former pass amp owner, i can safely say there arent many tube preamps with low output impedance.

I have posted it in another thread, but when using tube preamplfiers the situation is more complicated then just 10:1. The tube preamplifiers usually have a capacitor output that will cut bass frequencies when used with low impedance amplifiers and most tube stages will have much higher distortion in loads bellow 50 kohms. There are exceptions to this - the Atma-sphere preamplfiers are prepared to drive a 600 ohm load.
Although there are no rules, from my experience with a limited number of preamplifiers I got the impression that tube preamplifier prefer a load around 100 kohms.

And yes, I prefer tubes - lots of them if possible!

 

[puroagave]

the Joule Electra (tube) has an output impedance of just 400 ohms and could easily drive the aleph's low input impedance of 23k without roll off of the high freq. it also has two gain settings to optimize for for best s/n with the widest range of amps, speakers, etc.

 

[Gregadd]

How about tube pre and hybrid amp?

 

[MarinJim]

^ My Concert Fidelity CF-080 LX also has two gain settings.