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Double Bass Amplification question

T

TLATX

Mar 10, 2018
18
7
#1
I am currently running a radial PZ pre into a GK 1001 head and 15” GK cab. My pickup is an oldschool Underwood.

With the gain set at the 11 o’clock position, (found this to work best for tone) on the radial box, the signal going into my head seems insanely hot. I have the gain at 20% on the head and when I adjust the master to achieve desired volume, it seems there is a millimeter of difference between tasteful and insanely loud...
Any suggestions?
 
#2
One more thing, the gain level on the Radial was set running a signal to a board after experimenting at a couple venues. I had the engineer tell me when he was getting an appropriate level to mix
 
#6
No boost. Is there that much of a difference between sending the signal pre or post eq? I do sometimes send it post if I know the soundman isn’t great....but obviously I’m not great at this myself
 
#8
TLATX said:
the signal going into my head seems insanely hot.
Click to expand...

Is the input clip light flashing?

TLATX said:
Is there that much of a difference between sending the signal pre or post eq?
Click to expand...

Frequently yes, especially with no boost dialed in (how I also run my 1001). It'll vary depending on your gain staging between "volume" and "boost" on the GK, but I typically have my volume at -2.5 notches from noon for clean operation, and in order to match the "post" signal to the same level of "pre" I typically need to boost the DI volume by about 90 degrees (from roughly 12:00 to 3:00 as an example).
 
#9
Kro said:
Is the input clip light flashing?

Not clipping. I’ve also been blending a little boost...maybe I need to just use the volume

Too many knobs...


Frequently yes, especially with no boost dialed in (how I also run my 1001). It'll vary depending on your gain staging between "volume" and "boost" on the GK, but I typically have my volume at -2.5 notches from noon for clean operation, and in order to match the "post" signal to the same level of "pre" I typically need to boost the DI volume by about 90 degrees (from roughly 12:00 to 3:00 as an example).
Click to expand...
 
#10
TLATX said:
Not clipping. I’ve also been blending a little boost...maybe I need to just use the volume
Click to expand...

If the clip light isn't flashing, then your signal isn't too hot. That light goes off based purely on the input signal, nothing else on the amp effects it besides the pad, which... if the light isn't flashing, you don't need need. :)

My recommendation: try setting volume at -2.5 clicks from noon (should be roughly 9:30) and then use the woofer for master volume.

-2.5 "volume" is a strategic setting, as I've found that at least with my amp, a signal that is hot enough to light the clip light will begin to distort the first gain stage (just slightly) at roughly that level. Therefore at that setting, your clip light not only can be used as an input clipping indicator, but also a clipping indicator for the first gain stage.

Clipping that initial volume gain stage introduces a lot of high-frequency distortion. Similar levels of distortion from the boost stage emphasizes lower harmonics and appears to filter the higher-frequency distortion - which is why GK seems to recommend it to be used to warm things up over just cranking "volume".

I hope that helps. Good luck!
 
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#13
Kro said:
If the clip light isn't flashing, then your signal isn't too hot. That light goes off based purely on the input signal, nothing else on the amp effects it besides the pad, which... if the light isn't flashing, you don't need need. :)

My recommendation: try setting volume at -2.5 clicks from noon (should be roughly 9:30) and then use the woofer for master volume.

-2.5 "volume" is a strategic setting, as I've found that at least with my amp, a signal that is hot enough to light the clip light will begin to distort the first gain stage (just slightly) at roughly that level. Therefore at that setting, your clip light not only can be used as an input clipping indicator, but also a clipping indicator for the first gain stage.

Clipping that initial volume gain stage introduces a lot of high-frequency distortion. Similar levels of distortion from the boost stage emphasizes lower harmonics and appears to filter the higher-frequency distortion - which is why GK seems to recommend it to be used to warm things up over just cranking "volume".

I hope that helps. Good luck!
Click to expand...
That’s about exactly where the gain is set on the head. I’m maybe assuming it’s the boost in addition to the master(woofer)? I have a gig tonight so I’ll have a chance to play around with it before we start
 
#14
TLATX said:
That’s about exactly where the gain is set on the head. I’m maybe assuming it’s the boost in addition to the master(woofer)? I have a gig tonight so I’ll have a chance to play around with it before we start
Click to expand...

I've had amps that have felt that way, concerning the jump, before. I have no such issue with my 1001RB. Usually my woofer is at 12:00+ though. I frequently play with 0 boost also, so I don't think it's that.

You're using the master as the primary volume control, right?
 
#15
peterpalmieri said:
That’s not really a thing. Loud amps can play quietly without it jumping in volume with small turns of the knob if the gain staging is done correctly.
Click to expand...

I don't know. The OP said that the issue was that "there is a millimeter of difference between tasteful and insanely loud".

My thinking is that a less powerful head would not be capable of getting "insanely loud"...so the issue would become a non-issue..:-)
 
#16
Kro said:
I've had amps that have felt that way, concerning the jump, before. I have no such issue with my 1001RB. Usually my woofer is at 12:00+ though. I frequently play with 0 boost also, so I don't think it's that.

You're using the master as the primary volume control, right?
Click to expand...
Yes. Gain set consistently. Usually the boost and woofer around 9-11 o’clock
 
#17
Zbysek said:
I don't know. The OP said that the issue was that "there is a millimeter of difference between tasteful and insanely loud".

My thinking is that a less powerful head would not be capable of getting "insanely loud"...so the issue would become a non-issue..:)
Click to expand...

I don’t mean to be snarky but I do happen to know controlling volume is quite possible even with really powerful amps. Of course buying another, smaller, amp is a possible solution but it’s absolutely not necessary.

Another way to trouble shoot this is to work backwards with the master volume set to full or up around 3 o’clock.and input gain completely off. Or as I said bypass the preamp on the head since you already have one on the radial. If you get the initial input gain on the radial correct this should solve the problem.
 
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#19
All these suggestions are very good, but in the end it's quite possible that the Underwood, Radial PZ Pre, and GK 1001 into a single 15 cabinet
isn't a good match.

I have lots of experience with the Underwood, since I got one when they first came out (yep I'm older) if you try to turn up with one they "squeal"
that's why the Wilson pickup was so popular for a time, as it solved that issue.

The Radial PZ Preamp is a great unit, so going directly into the power amp should solve a lot of the problems.

The Gallien Krueger RB 1001 had some issues early on with the circuit board design. I remember Gravity Strings having to send some back to GK.
They were great about swapping them out.

A wiser TB friend once explained to me that the effects loop, isn't quite the same, as a input on a power amplfier and is placed so the signal is inserted into one of the
latter stages of the preamp. So it can also boost the signal. Double Midi can explain this better than I can.

Volume controls on different amplifiers have different sensitivies. Just barely touching the controls on some amps ups the volume significantly.

Cleaning the pots could make a huge difference. Just my take.
 
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