Flat settings for 800RB?????

Johnny Atomic · #1 02-20-2007, 12:09 PM

I've recently gotten a GK 800RB.

Would setting all the tone knobs at noon, w/ all the tone switches out (off) be pretty close to flat???? Has anybody done spectral analysis to find out where the flat settings are????

53 Kay bass, Rev Solo 2 PU, K&K dual channel pre, 800RB, Aguilar GS210, Avatar 112, if that matters.

Johnny

Bass · #2 02-20-2007, 02:22 PM

Yes, noon on the dial is flat, with all the voice filters out (off). The manual says basically the same thing except it calls the position five:

http://www.gallien-krueger.com/manuals/800rb.pdf

I find my settings on e-bass quite different than upright. On e-bass, I have the tone leaning towards bass, whereas with upright I'm leaning the tone towards treble. I don't really like the voicing filters with e-bass, whereas I have the low-cut on for upright.

I kind of suck with EQ, and I've only had the upright for 3 1/2 months. But I hope this helps anyways.

I understand the 800RB is designed to sound best flat, and flat is probably the safest place to be for upright or electric. Definitely the right place to start anyway.

bolo · #3 02-20-2007, 08:47 PM

fdeck did a spectral analysis (did I say that ??) on a GK Backline 600 head I think. And w/ that head, the flat settings (which he called "Centered" in his analysis) did not produce a flat EQ curve. But he tells you how to turn the EQ knobs on that head to get close to a flat curve.

Ah, here it is.

P.S. His graphs also include the popular MB150E with the EQ knobs centered. Wild stuff.

Johnny Atomic · #4 02-21-2007, 08:21 AM

Quote:

Originally Posted by bolo

fdeck did a spectral analysis (did I say that ??) on a GK Backline 600 head I think. And w/ that head, the flat settings (which he called "Centered" in his analysis) did not produce a flat EQ curve. But he tells you how to turn the EQ knobs on that head to get close to a flat curve.

Ah, here it is.

P.S. His graphs also include the popular MB150E with the EQ knobs centered. Wild stuff.

I had read that a while back, has anybody done anything similar for the 800RB, are the knobs similarly centered?

The MB150E low end rolloff must be why so may upright bassists love it, takes the wolf out of it.

Johnny

EDIT: After re-reading that article I've concluded that the contour knob on the BL600 is a massive mid scoop. Therefore since the 800RB doesn't have that control, and since the other knobs are similarly centered for the different models would imply that the other suggestions for flat setting would convey.

robgrow · #5 02-21-2007, 11:05 AM

All GK amps are voiced. That's not necessarily a bad thing though: Walter Woods amps, which have long been very popular with double bass players, are also voiced. FWIW I sold my flat and neutral Acoustic Image amp and kept my Walter Woods.

Ric Vice · #6 02-21-2007, 12:15 PM

Quote:

Originally Posted by Johnny Atomic

I've recently gotten a GK 800RB.

Would setting all the tone knobs at noon, w/ all the tone switches out (off) be pretty close to flat???? Has anybody done spectral analysis to find out where the flat settings are????

53 Kay bass, Rev Solo 2 PU, K&K dual channel pre, 800RB, Aguilar GS210, Avatar 112, if that matters.

Johnny

Johnny,
When it comes to GK's the 800 RB is one of their best efforts. In my experience the midrange of all GK's is somewhat voiced but the 200 MB, 400RB and 800RB were voiced in a way that complimented the Double Bass. Mabey I'm just a prude, but I not as fond of the later units especially the MBE, even though it's got way more power than
the 200's did. With my instrument it the midrange "honks" even when it's dialed all the way out.

RIc

robgrow · #7 02-21-2007, 12:35 PM

Quote:

Originally Posted by Ric Vice

...the 200 MB, 400RB and 800RB were voiced in a way that complimented the Double Bass.

+1

Ric Vice · #8 02-21-2007, 02:09 PM

Quote:

Originally Posted by robgrow

+1

Rob,
I did a quick search on used 400RB's and found to
for under $50.00. Kinda the opposite of Walter Woods.
Not near the amplifier, but they sure are reasonable these
days. Provided you trust the source.

Ric

fdeck · #9 02-21-2007, 07:30 PM

Quote:

Originally Posted by Johnny Atomic

I had read that a while back, has anybody done anything similar for the 800RB, are the knobs similarly centered?

The tools that I used are available at my little website. I wrote a program that functions as an easy-to-use real time analyzer. It is freeware. The documentation is not stellar, but hopefully sufficient. You can watch the curve while you twiddle knobs. The only other stuff you need are a couple of 1/8" patch cords and 1/8 to 1/4" adapters.

I would encourage anybody to measure the curve of their amp (just the preamp section is all you need to do), if you are trying to figure out settings for upright bass. At the very least, knowing how to dial a flat curve as a starting point is a possible way to get better results out of amps that were voiced for electric bass.

It's also a useful diagnostic on older amps to make sure the EQ section is functioning as expected if you are having tone problems.

Johnny Atomic · #10 02-22-2007, 08:35 AM

Since the power amp is flat according to your measurements, it would imply that you only only need to hook up the preamp to the spectrum analyzer. So it sounds as if you could simply cable up your amp to your computer using the 1/8 inch adaptors to connect the send of your effects loop to the Mic input on your computer sound card. And the input of your amp to the speaker output of your computer???
then use that freeware program that I downloaded?

By doing it this way you don't have to worry about dummy loads or anything complicated like that.

Furthermore, I bet you could pull the knobs off your amp, adjust the amp to flat response then put the knobs back on at those settings with the pointers straight up. Then you could easily and visually see your flat settings during normal usage.

winston · #11 02-22-2007, 06:34 PM

I have an '87 400RB and an '88 200MB. The 400RB with an EA Wizzy is one of my favorite DB rigs--lots of detail and very loud for its size. Even with all controls set flat the amp has a color of its own--fast, bright, and punchy.

If you have an external preamp you like you can just bypass the GK pre and plug your external one in through the FX return jack. The GK's boost control is an extra gain stage that lets you drive the power amp to full volume with an instrument-level signal. Most FX returns on other amps I've tried (including Mesa, Carvin, Eden, Ampeg, and SWR) need a line-level signal. I've done this on the 400RB(with great results) using Boss EQ pedals and various SansAmp, LR Baggs, and Fishman DIs.