Tweaking a plate amp - PE 300-794 (1 Viewer)

[Peter Jessee]

After an e-mail conversation with John Kreskovsky about high-pass filtering the line output of the Parts Express 300-794 250 watt plate amp, I'm preparing to change some resisters to provide a 12 dB/octave high-pass at around 90 Hz.

Now I'm wondering if it would be worthwhile to upgrade the components in the HP circuitry, since all the signal for the front left/right speakers will be passing through these components. Replacing the stock ceramic capacitors would require 4 ea. 0.1 uF/100 volt and 2 ea. 0.7 uF/50 volt capacitors, presumably polypropylene, or at least good NPE's. Would it be necessary to upgrade the capacitors in the LP section as well? How about the Op-Amps?

My system includes a Denon AVR3300, 5 NHT SuperOnes and an Adire Rava. I'll have to add separate amps now, and am considering a Signature 2.1 (cheaper) or a Parasound HCA-855A or -1205A (better sound). With equipment of this quality, would upgrading these components provide noticably better sound?

I've never gotten to this level of tweaking before, but I'd hate to spend $500-1000 on a new amp and have cheap parts holding back the sound quality. Do I need to worry about this?

Peter

 

[Mike_A]

why not just let your denon handle the bass management and just use the sub out to your plate amp? then the amp's high pass filter won't be a factor at all.

 

[Peter Jessee]

why not just let your denon handle the bass management and just use the sub out to your plate amp? then the amp's high pass filter won't be a factor at all.

I have been doing that since I got the Rava, and the system sounds pretty good. But after listening to better systems with full-range surround speakers, I've decided that the common wisdom that bass is omni-directional and one sub for all the bass is enough, is not completely true. I'm planning to have one sub (the RAVA) for the front three channels and LFE, and a second sub (my homebuilt DVC 12") for the rear channels. This will also allow me to add a SACD and/or DVD-A player and still hear all the music.
To accomplish this, I will need to use either the crossovers in the subs to split the signals between the S1's and the subs, or additional active crossovers before the subs. Obviously I would prefer to use the sub crossover's I've already paid for if the sound quality won't suffer. Since the AVR3300 (and most other receivers) doesn't have pre-out/main in connections, I will also have to add at least 4 channels of amplification.
I haven't tried to explain all this to my wife yet, so if anyone has a good sales pitch, I could use that advise as well.
Peter