Amp Basics: Tube Preamp w/Solid State Power Amp.


Hi, need some basic information. How does one ensure a proper matching of a solid state power amp w/a tube preamp? The tube preamp I am considering has "low" 12db gain (PrimaLuna Prologue 3).

Does one have to be concerned with the wattage of the power amp (being too much)?

As well, what is a "class A" power amp?

Any good suggestions on a SS Power amp in the $1000-2000 price range.

Thanks, any help would be appreciated.
elf73
Do a search for tube preamps, there's been quite a bit of discussion on them.

I run a TAD150sig tube pre into a McCormack DNA1 power amp. This has been a very good combo in many folks systems...including mine. I run power-hungry 4 ohm speakers & the gain-volume control issue hasn't been an issue in my system.

McCormack power amps have a great reputation & can easily be had for 1-2K, depending on the power you need & it's upgrade status. Steve McCormack will do upgrades on the amp if you want..this gives you some upgrade headroom down the road without switching to another amp.

If you're looking ofr an overall primer on audio system basics...Robert Harley has a Guide to High End Audio book that is useful.
I agree with Jmcgrogan2. One thing to add is if your preamp does not have a cathode follower, then you'll want to keep your cabling between the pre and power pretty short. Depending on the cable, longer runs could roll off the high frequencies.

If the pre does have a cathode follower in the ouput stage, then longer cable runs should be OK.

best
John
Thinking of this combo....(of course, I'm a newbie and am entirely open to suggestion and criticism)... just been reading various reviews on the internet. I'll have to pick up that primer on Hi-Fi.

Clayton S40 Power Amp:

* Rated power output: 50-watts continuous RMS into 8 ohms, pure Class-A, 100-watts continuous RMS into 4 ohms, pure Class-A
*Voltage gain: 26dB
*Input impedance: 47K
*Negative feedback: Virtually zero

PrimaLuna Prologue 3:

Specifications
Freq. Response: 4Hz-85kHz +/- 3dB
Gain: 11.5dB
THD: Less than 1% at full power
S/N Ratio: 109dB unweighted
Input Sensitivity: 200mV
Input Impedance: 100k Ohms
Output Impedance: 3.5k Ohms
Power Consumption: 48 watts
Tube Compliment: 2 - 12AX7, 2 - 12AU7, 2 - 5AR4
Dimensions: 11" x 7.5 " x 15.5" (WxHxD)
Weight: 23.5 lbs
Inputs: 4 pair RCA
Outputs: 2 pairs of pre-amp outputs + tape monitor out
Elf73,

Apart from compatible sensitivity and output impedance of the linestage vs. input impedance of the amp, there are other "mystery" compatibility issues that can only be figured out by trying the components together. I have heard quite a number of combinations that looked respectable on paper that sounded really bad, even when the individual components were expensive and respectable.

In particular, some tube linestages seem unpredictable in how they match with amps, particularly solidstate amps. If you can, give the combination a trial.

I liked the Clayton amp I heard (don't know the model). That should be a promising choice with almost any linestage you select. The output impedance of the Prologue, as you have shown above, is fairly high, but it should still be compatible with the 47k ohm input impedance of the Clayton. I don't know how to convert the voltage gain specification of the Clayton to a sensitivity figure, but, 12 db of gain from a linestage is usually way more than enough unless you are also juggling other considerations, such as a low output phono cartridge and a low gain phonostage.

Good luck with your search.