2. amps-preamps
  3. 188287-99185

Amp, Preamp, two volume pots, there can be only one!

Hello everybody,

I have a question regarding the two volume knobs in my system and how they

should co-relate.

Here is my gear, both units are tubed:

Amp: Coincident Dynamo 34SE Mk1 (Output power: 8Wpc, Sensitivity: 300mV for full output, Input impedance: 100k ohms, S/N ratio: 92dB)

Preamp: Doge 8 2018 (Output impedance: 600 ohms, Input impedance: 50K ohms, Input sensitivity: 200mV)

Speaker: Proac 140 Mk1 (Sensitivity 91db, Amplifier Power Range 15 - 250 watts)

Now here is the dilemma, Coincident says if Dynamo is used a power amp the volume pot should be left open (heard that some call it a sensitivity pot too) but this introduces noise in the system (albeit when music is not playing) and leaves a very small usable range on the preamp volume knob, and hard to hit the sweet spot as at 9 o clock its already very loud.

So what would be the best way to run things without losing signal quality? And is there any mismatch between my power/pre?

Thanks in advance for any suggestions!

neverlast
neverlast OP
6 posts
 

Thank you all kindly for the ideas and advice, I will give everything a try.

@atmasphere in theory which specs would the amp need to have to play along with my preamp?

atmasphere's avatar
atmasphere
11,632 posts
 

 in theory which specs would the amp need to have to play along with my preamp?

@neverlast Find one that takes 2Volts or more for full output. If the amp is properly designed, that will drop your noise floor about 15 dB and will make your volume control a lot more useful.

neverlast OP
6 posts
 

Thanks @atmasphere will keep this in mind in case I can try something in my system and compare. My Doge preamp has a switch which can drop the gain by -8db, would this be useful in my system and would it have some derogatory effect on the sound?

neverlast OP
6 posts
 

My bad, it appears that the -8db gain reduction works only for the phono stage…

neverlast OP
6 posts
 

Short update: After listening to several positions it seems that there is something lost in the high frequencies when I set the power amp at 3/4 which leaves a useable range on the preamp. Would using an attenuator (cca -11dB) be a better option or would it be the same thing in essence?

More to discover