Nash 400 pre & post -- why?

Greg Vincent · From: Folsom, CA USA

Hi folks,

I've been playing a Nash 400 for years but I don't really understand the relationship between the "pre" and "post" gain controls.

I remember back in my rock days that I could get an overdriven sound at a relatively low level by cranking an amp's pre gain while keeping the post gain low. But I'm sure that's not the reason a Nash 400 has a pre & post gain!

So why does it have both? How should I be treating these controls? How will they affect my tone?

I usually have the pre at about 3-4 and the post at about 7 for gigs, but that's just something I arrived at arbitrarily. I don't really know the "why" behind it.

Any input would be appreciated.

-GV

Nicholas Dedring · From: Beacon, New York, USA

The trick of cranking up the pre and lowering the post or master volume only has a benefit on tubes... you get preamp distortion when you wind up the pre gain. On solid state, the whole thing just cuts out and clips (solid state "distortion" just sounds like garbage.)

I find that I like the sound with the pre and post at about the same clock position. It makes a little more warm and round than with a higher post-gain setting. Just personal preference, and it's a subtle difference in any case. Pre should typically be lower than post to avoid clipping, though.

Greg Vincent · From: Folsom, CA USA

Thanks Nicholas.

Since solid state distortion sounds so lousy, why do solid state amps bother with a pre & post gain in the first place? Why not just have a single, "master" volume?

-GV

[This message was edited by Greg Vincent on 12 November 2004 at 10:54 AM.]

Dave Grafe · From: Hudson River Valley NY

Hi Greg,

As far as I can tell, while the pre and post controls on your amp do to some extent operate like your old tube amp (with the exception that the solid state overdrive is none to warm!) they primarily serve to help with the gain staging (that's getting the proper levels into and out of each device in an audio chain) of any external effects, EQ, etc. that you may insert into the amp's external patching jacks.

Note that the Nashville 400 has a loop on the fron and one on the back as well, one of those I believe is pre-EQ and the other is post. I don't have one on hand anymore to confirm, maybe somebody else can elaborate?

Hope this helps --

Dave

------------------
Strung Out on Great Sounds

pdxaudio.com/dgbio

Greg Vincent · From: Folsom, CA USA

Good point, Dave.

I do notice that if I have the "pre" set real low, the reverb gobbles the signal up and I have to reduce the reverb setting or I sound like I'm playing at the end of a tunnel!

Any other insights or preferences regarding pre & post settings out there?

-GV

Mike Brown · From: Meridian, Mississippi USA

Here's simple explanation; the PRE GAIN control helps in setting the incoming instrument signal, then it is routed through the equalization section to the POST GAIN control. The POST GAIN then sends that signal to the input of the internal power amplifier. NOTE: the lower the setting of the POST GAIN control, the less that the power amp is being driven, hence the less clean output power. A general rule of thumb is to keep the POST GAIN control at a higher level than the PRE GAIN.

Another benefit of this configuration is that when using the PRE EQ PATCH with a volume pedal, the PRE GAIN control sets a constant level(instead of a varying level direct from the volume pedal pot), when inserting your pedal into the PRE EQ PATCH. This eliminates the degradation of the signal through the pedal pot and eliminates any tone change.

Mike Brown
Peavey Electronics Corporation

Greg Vincent · From: Folsom, CA USA

Cool Mike --thanks for that info.

What does all that mean to me in terms of sound?

Mike Brown · From: Meridian, Mississippi USA

Tonewise, the PRE/POST configuration doesn't effect the signal at all...............unless you use the PRE EQ PATCH for your volume pedal. See this article from our website; http://www.peavey.com/media/pdf/steelguitar/pre_eqpatch.pdf

An amplifier with a single volume control determines how much input signal is fed to the remainder of the circuit and also determines how much signal is fed to the input of the power amp, which most likely has a pre set input sensitivity.

So, the bottom line is that the Pre Gain determines how much signal is fed through the circuit and the Post Gain determines how much signal is fed to the power amp.

Greg Vincent · From: Folsom, CA USA

Thank you Mike! -GV

Mike Brown · From: Meridian, Mississippi USA

You are welcome.

Tim Bridges · From: Hoover, Alabama, USA

Mike, or anyone in the know, why is it not recommended to use a Hilton volume pedal through the pre EQ patch?

Donny Hinson · From: Glen Burnie, Md. U.S.A.

Tim, I wouldn't say it's "not recommended", I'd just say it's "not necessary". Using a powered pedal through the PRE-EQ patch just isn't beneficial...so why do it at all?

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