2. amps-preamps
  3. 157108-134614

Unsure how to set levels to use tubes and power amp together

Hello to all...

I have a question regarding setting the power amp to work with my preamp:

I have a Wolze Line Level Tube Preamp -2-AX7s and 2-EF86 tubes, playing into a Parasound HCA-750a then to a pair of JBL L25 PRIMA speakers...

In a past forum: it was suggested that I could either play my CD unit directly thru the amp, using its volume controls ( it has independent R&L volume controls on the back of the unit) OR add a preamp, use the volume knob on the preamp, and set the volume controls on the back of the amp, according to how loud ( at what o’clock) I wanted to use the preamp volume.

My confusion relates to a minimal understanding that any electronic device ’amplifying’ a signal introduces distortion in the transmission, and therein lyes my confusion. Do I just set the amps volume control 1/2 way on the back (to minimize the distortion from that piece) and use the preamps volume control, OR do I set the amps volume controls full-on, and just use the preamp volume controls as best I can (even if it means minute adjustments never past about 8:30 on the preamp volume control).

So I’m questioning which piece of equipment’s distortion is better to take a advantage of... And what I should do.


insearchofprat
reubent
6,996 posts
 
Google is your friend......

I Googled "Parasound HCA-750a" and found a link to the Parasound page for this discontinued amp. Right there on the page as the following question:

Q - Where should I set the volume controls on the back of my amp?

A - Under normal conditions you should turn them all the way to allow full power output from your amp. However, if you need to match the volume output of one of our stereo amps with another brand (BiAmping) you could adjust them accordingly.

Set the power amp volume knobs to full. If you feel that you do not have enough granularity when setting your system volume using your pre-amp VC, back off the volume control on the amp until you have useful granularity (steps).
twoleftears's avatar
twoleftears
5,318 posts
 
Volume controls on preamps are reputed to have an optimal range of operation, where the pot operates the best.  So if your volume control goes, say, from 8 o'clock to 4 o'clock, the best range would likely be somewhere between 11 (fairly soft) and 1 (fairly loud).  The recommendation was to set the R+L controls to achieve that range on the preamp.
wolf_garcia
6,696 posts
 
I owned a Parasound HCA 1000 for years (a great amp by the way) and found it sounded best  at the 100% level setting, which is what every other "non volume pot" power amp is by design.
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