Quoth'd

I replaced with different speakers that had more power (200w per cone instead of the 100w that the GK stock came with) and got the same symptoms for my troubles Hopefully trying out a new rehearsal venue in Derby this week, so fingers crossed I'll be able to run the amp through a selection of external cabs to see if I get the same problem or not.

Thanks for pointers. I'm going to see about getting my hands on a larger cab to test (usual practice venue doesn't have anything big enough) and have a play. I don't think I know anyone I can borrow a dummy load from though. Would an Ashdown MAG 115 provide enough headroom to test with?

PS will get a pic of the bass through the scope

[quote name='MarkBassChat' post='1354752' date='Aug 28 2011, 09:18 PM']I doubt it. A symmetrical sinewave sounds like cheap keyboard. Can you scope it and post a photo? The proper way to check the amp is to use a tone generator and a dummy load. The signal looks like this because the input is not sinusoidal wave and maybe tone controls are not set to the middle position. The contour filter has to be disabled. Before you start replacing speakers you have to verify the amp. If it's OK, you can verify the amp with external cab (you can borrow it instead of buying new speakers). Mark[/quote] Hi Mark, I have already replaced the speakers (last post was a follow up from a month or two ago) and am having the same problem. Contour is off & all tone controls are set mid way. Running a tone generator into it produces a clean wave at 100hz & 1khz. The sine wave from the bass is good both at low and high frequencies. The problem only seems to occur when playing low frequencies (bottom string) through the amp. Can you help? Cheers Simon

**BUMP** Anyone?

Update . . . . Belated OK. I've finally got round to running it through the scope. Higher frequencies come through OK, the problem only manifests it's self with the low frequencies. The output sinewave to the speaker is unbalanced - no DC bias but for every full wave e.g. positive +5 volts, negative -10 volts. As I turn up the gain it increases it averages a 2:1 / 3:1 ratio of positive to negative as you look at the sinewave. [attachment=88043:photo.JPG] The output from my bass has a symmetrical sinewave so I know it's being induced somewhere in the amp. It gets tricky as if I use a tone generator then I get a symmetrical sinewave coming out of the amp. But if I use the bass, it's symmetrical at the higher frequencies and messed up at the lower. Has anyone else experienced this (or anything similar)?

[quote name='ThomBassmonkey' post='1301753' date='Jul 12 2011, 11:37 PM']What head are you using? As someone already mentioned, the GK RB series heads' controls are aren't as intuitive as you might want. Also if you're using a GK head, they're far louder than the wattage rating would have you believe.[/quote] It's the backline 210 combo (300w built in head) - which is why I was expecting it to be able to deliver more before breaking up... I had no idea that GK worked backwards though i.e. master up then turn up the level to get the volume you want

Thanks for the comments I've only had it at practice in the last couple of weeks so has been the first time I've been able to turn it up that loud so can say it's been happening since got it. Passive jazz bass Passive level pedals The input is about 50% Gain is about 40% Trying to turn master above 50% I'm going to take the scope to practice tomorrow & see what the signwave has to say. (If I remember) That should shed some light on if it's an amp / speaker problem.

[quote name='chris_b' post='1299514' date='Jul 11 2011, 01:13 AM']Sounds like User error to me! Turn the gain down. Raise the strings. Lower the pickups. Stop hitting the strings so hard.[/quote] No! I bought it for it's power / volume & my bass is set up fine thanks.

PS I should add that the existing speakers are GK 10" 100Watt 16Ohms [url="http://www.beyerdynamiconline.com/Product.asp?Prd=082-0016-D"]http://www.beyerdynamiconline.com/Product.asp?Prd=082-0016-D[/url] For what it's worth

I have a Gallien Krueger Backline 210 combo (bought late last year when I downsized my full rig to something more transportable)... It's rated at 300w into 4Ohms, has built in 2 x 10" speakers (total 8 Ohm load) and a spare jack on the back for an extension cab. My problem is that whenever I play it at half volume (or more) the speakers start popping when I pluck the strings. It's fine at lower volumes - just the attack when turned up. So I'm wondering what to do as in my opinion, the built in speakers should be easily powerful enough to handle the 180watts the amp is advertised to deliver into 8Ohms at just about any volume + when plugging in an extra cab (1x15 or 2x10) to take the load down to 4Ohms, the amp should then be capable of delivering it's full 300watts. If the existing speakers are breaking up at half volume, what route should I take:- a. Add an extension cab (not sure if I want to add an extra cab at this stage as the amp should be capable of delivering more power before the speakers start breaking up as it is) + it's heavy enough as it is. b. Replace the existing speakers (have seen some Eminence LEGEND BP102-4 (4Ohm 200w) which look like would make good replacements and still leave room for an extension cab later on if I wanted. c. Replace the existing speakers (Eminence LEGEND BP102 (8Ohm 200w) wired in parallel to drop the total load to 4Ohms. Which would allow me to run the full 300w of the amp into the combo speakers. Any pointers welcome, replace the speakers + leave room for an extension cab in the future or is it not worth it & should I replace the speakers and forgo the option of an extension cab in the future. If anyone has similar configuration - I'd welcome your comments on which way to go. Thanks Simon

Evening It's a similar layout to my 3500 head. The DI Out has 2 buttons - one for ground life and the other selects if the DI is pre or post EQ (I think). Either way the buttons only affect the DI output. The Impedance info is simply telling you how many watts output you can have for either 8 or 4 ohm speaker combinations (ie if you plug in 8 ohm then you get this many watts & if you plug in 4 ohms then you get that many). Hope it helps

That looks an absolute beaut After all that hard work to get her naked . . . . It'd be a sin to cover up with paint again Have you decided what finish your going with?

Simple me but I'm really glad someone started this thread as I was thinking it was only me that had a wonky arsed jazz