Boutique 3-way 115 and 215 on a budget: Part II

[MichaelVee]

Originally Posted by lbwdog

I'd hate to try to sell you a car!

Laughing!

Glad to hear you DO like the 1503, Pedro! You had us worried there for a bit..

It really is a fine cabinet.

[pedro]

LOL!!

[jnewmark]

Originally Posted by lbwdog

I'd hate to try to sell you a car!

Eric, did you ever put the round grills on your 1503?

Pedro, I thought you would like it. I have'nt had much time to use it as I have been out of town for a week, but I'm getting ready to experiment a bit, perhaps trying out one of my JBL E140's or my K140, just to see how it sounds.

[pedro]

I had begun to believe that the cabinet would show its best side in a live setting.

[lbwdog]

Originally Posted by jnewmark

Eric, did you ever put the round grills on your 1503?

Not yet.
I ordered new grills and casters last Friday and for some reason they haven't arrived yet. I need to call Bernie tomorrow and see what's up. I'm hoping he didn't forget to ship 'em as he was actually back in the warehouse when I called in the order.

[edgerunner]

Well - my son's LS1503 came in yesterday and we hooked it up as follows:

1. MIM Jazz Bass into the SansAmp RBI

2. XLR Out of RBI into the Channel 1 input of the Crown xti1000 set to Bridged Mono (1000w into 8 ohm)

3. Speakon Channel 1 out to LS1503 Full Range

So far he is very happy, however, this set up has brought to light that his bass needs works becuase now we hear every single fret buzz and we've discovered that the front pickup on his Jass bass is not functioning correctly (low hiss and some buzz but very little or no signal). YES - it's been awhile since I've played around with his bass and he seems to use mostly the bridge pickup and never noticed it. So now I need to look into opening the pick guard up to see if there is a broken or bad solder connection, and or replace the the pickups.

Anyway - I haven't tried biamping the xti1000 into the LS1503 yet. But - into 8 ohms this amp only puts out 275 watts per channel and the cab is rated at 400 watts program into 8 ohms. I was told that you ideally want the amp to have double the rating of the cab. So to effectively biamp does this mean that I need a more powerful amp?

Greenboy - I know we spoke about this, but I was told the above by a bass player/engineer at the AES show in NYC today. Does this sound right to you?

Well, that's it from here for now.
Chuck

[A9X]

Originally Posted by edgerunner

Anyway - I haven't tried biamping the xti1000 into the LS1503 yet. But - into 8 ohms this amp only puts out 275 watts per channel and the cab is rated at 400 watts program into 8 ohms. I was told that you ideally want the amp to have double the rating of the cab. So to effectively biamp does this mean that I need a more powerful amp?

Biamping won't make much of a difference in terms of SPL output in this case. The breakpoint for the energy in the bass guitar spectrum is somewhere around 300Hz. That means that 50% is above that freq and 50% below. The 15 crosees to the 6 at 500Hz so it's already doing 80% of the work.

Re the double the rating thing. If your poweramp has twice the RMS rating of the cab, then you should be able to wring all the SPL out of the cab, as most cabs are rated for a peak of double the RMS, so theoretically, you'll be able to put the max output of the map into the cab without it clipping. Whether you need to or want to in the real world is another thing, and whether the cab will actually take it and sound acceptable doing it is another. You will not damage the 1503 running your amp as it is, providing you don't spend a large qualntity of time with it clipping hard.
Can you bridge your amp for more power?

[lbwdog]

Originally Posted by edgerunner

we've discovered that the front pickup on his Jass bass is not functioning correctly (low hiss and some buzz but very little or no signal). So now I need to look into opening the pick guard up to see if there is a broken or bad solder connection, and or replace the the pickups.

But - into 8 ohms this amp only puts out 275 watts per channel and the cab is rated at 400 watts program into 8 ohms. I was told that you ideally want the amp to have double the rating of the cab. So to effectively biamp does this mean that I need a more powerful amp?

Pickup problem is most likely bad wiring or solder joint although it could be a bad pickup. I replaced my MIM pickups with Dimarzio model Js (DP123) and love 'em.

As far as power concerns, I've been using a similar wattage GK head and the results are fine even for outdoor gigs. It never hurts to have more headroom but you should have enough power for that cab as long as it's not distorting. Crown is good quality equipment and the power ratings are not overinflated. It probably has as much real power as some manufacturers' 500 watts.

[edgerunner]

Thanks for the input guys. Yes - I am running the amp in Bridged Mono mode which Crowns spec says puts 1000w into 8ohms. 1400 into 4 ohms. So if I add a second cab at some point we'd be able to wring every bit of power out of the amp.

Also - I am wondering where to set the Limiter on the Crown. The options are 3db, 6db, 12db. Now, if I understand correctly, this means that this is the db level before the clip point where the limiter will kick in. Is that correct? What determines where to set this limit point?

As far as SPL - I think this thing get's plenty loud. He has yet to try it with the band in rehearsal or live, but I think based on all the reports here it'll be dandy.

I'll be looking into the pickup problem today and hopefully I can find a bad solder point and quickly repair it. So far I haven't detected too much problem with noise, but at some point I may want to shield it too.

Chuck

[greenboy]

There's not much point in buying 2x the power for a given cab unless one knows not only the thermal limits of a driver, but also the excursion limits in that cab. A lot of next-level operators repeat that 2x thing BY ROTE and may not even be aware of the driver excursion issues so much. Why? Because they tend to use systems that protect the Mains woofers by dint of active crossover, and use subwoofers for the lows - ones with big xmax and limiting, and maybe even cabinet-specific processors to do that more effectively.

My take FOR BASS GUITAR USE is

1) Learn to use gain structure effectively so that all watts any amp may make are available when needed

2) Think more of excursion limits if you can find them out, and bases the 2x wattage thing on THAT. In many cases that's going to be more than 50% lower than the thermal/"RMS" rating.

In the case of the stock driver, I'd say that if gain structure is pretty well used, anything above 500 watts is excess. The same cab and driver for PA use over subwoofers, then I'd say the 800 watt figure is valid.

EDIT: IF you are willing to EQ out a lot between say 60 and 150 Hz you can then use more wattage, but to my ears this often eviscerates the bass guitar. This is somewhat like usng a mild high-pass filter or active crossover.

[greenboy]

Edgerunner,

For awhile, just to be safe I think when bridging (make sure Speakon cable is right for that!) I'd use the -6 dB limiter setting on the XTi. I think they are probably factoring a 3 dB overshoot for the limiter, so this would probably keep more than maybe 500 watts from hitting the cab for any duration.

If that works out with your son's style of music and playing, then try the -3dB setting.

[greenboy]

Originally Posted by A9X

Biamping won't make much of a difference in terms of SPL output in this case. The breakpoint for the energy in the bass guitar spectrum is somewhere around 300Hz. That means that 50% is above that freq and 50% below. The 15 crosees to the 6 at 500Hz so it's already doing 80% of the work.

I think the half-power point with bass guitar is highly variable depending on one's tonal ideals and use of onboard and outboard EQ it may fall anywhere between 200 Hz (if one really likes it bass-heavy) and 400 Hz.

The main benefit of biamping this cab occurs when you have a little more two-channel power on tap, so that a bridged potential cannot be fully used anyway. Then, you end up getting more power into the system on either side of the active crossover point with very good protection due to steeper slope of crossover, and will have less distortion, and less passive crossover loss, and strain on the passive crossover components are minimized since its 500 Hz crossover point is bypassed.

[Crockettnj]

FYI-

I recently contacted Carvin regarding availability of the active components sans cab. I thought this might be a way to get into an inexpensive active 3 way for DIY use. Due to the rock-star-like popularity of this thread, I figured I could save someone else's time by posting this as an FYI. Here is my edited email & their response:


-----Original Message-----
Sent: Tuesday, October 02, 2007 12:19 PM
To: ProductInfo
Subject: LS 1503 active

I am curious as to whether you would be willing to offer the internal
active amplification section of the active amp for sale separately? <snip>...

I have followed the talkbass ls1503 thread ...<snip>...

Thanks for your consideration in this, as I know one customer with an
odd request is certainly not a major important part of your day.

Again, thank you for your help.

PS- I would also be interested, as a second possibility, of a very
heavily scratch&dented active cabinet that you otherwise would not be
able to sell retail.

---------------------------------------


the FAST reply:

Unfortunately not. Sorry about that. You might find a scratch and dent
on our ebay store though.

----------------------------------------------------------------

[pedro]

A lot of next-level operators repeat that 2x thing BY ROTE and may not even be aware of the driver excursion issues so much. Why? Because they tend to use systems that protect the Mains woofers by dint of active crossover, and use subwoofers for the lows - ones with big xmax and limiting, and maybe even cabinet-specific processors to do that more effectively.

(pedro's reaction shown here) - http://youtube.com/watch?v=U74ddrnHyio

[lbwdog]

My simplistic view of power requirements:

Let's say I'm at the gig and I require a lot of volume.
If I have to turn my amp way up and it produces detectable distortion and sounds like the amp is straining, I know that it's underpowered.

Conversely, if I can achieve a high SPL with my amp at a reletively low setting, I figure I've got enough power no matter what the manufacturer rates this amp in watts.

Case in point, my two GK amps, 800RB & 700RB, are rated at 200w & 325w @8ohms respectively. This by comparison to some doesn't seem like much but I have done many high SPL gigs with both and never have felt the need for more, even on loud transients such as slap and pop. So my ears tell me I don't require more power and I seem to have sufficient headroom. On the other hand, I've done gigs (recently) with amps rated at 700/800 watts that sounded anemic by comparison.

Now I don't use any processing to speak of or synth patches which naturally will demand more power but for my normal bass playing gigs I've been more than happy with these particular amps. I just don't get hung up on wattage specs. That's my simplistic view.
:

[edgerunner]

re: the power question. Ok - cool. So I am sticking with whats I gots then.

Now I need to solve this pu problem. So I posted this over in the Pickups forum but have gotten no responses. So I hope I am you'll forgive a temporary thread hijack.

----------------------------
My son's bass seems to have a problem with the neck pu. When I turn the bridge p/u all the way down and turn the neck p/u all the way up - there is VERY little sound coming through. If I crank the amp up more, keep the bridge pu off, and turn the Tone knob all the way off - the volume drops way down, turn the tone all the way up - it comes up BUT - the overall volume is WAY lower than the bridge pu. If I hit the strings really hard - the neck pu sounds distorted (crackly noisy distorted).

I have the control cavity opened up and it seems to be wired correctly (as compared to the schematic off the Fender site). I though I was going to find a loose solder connection but it all looks clean and solid.

Does this sound like a bad pu or a bad pot or some other issue?

I was thinking about replacing the stock pu's anyway at some point with the DiMarzio DP123s, but my son is recording a demo on Monday and I'd like to get this straightened up before then if possible. He can always just avoid the neck pu for now I suppose.
------------------------------------------

Any ideas?

Chuck

[pedro]

Case in point, my two GK amps, 800RB & 700RB, are rated at 200w & 325w @8ohms respectively. This by comparison to some doesn't seem like much but I have done many high SPL gigs with both and never have felt the need for more, even on loud transients such as slap and pop. So my ears tell me I don't require more power and I seem to have sufficient headroom. On the other hand, I've done gigs (recently) with amps rated at 700/800 watts that sounded anemic by comparison.

I bought my 700 this past April. Of all the amps I tried it seemed crazy loud compared to the others. FWIW, in an interview I read with Gallien Krueger he says that bass players who want the GK growl need to figure out how much volume they need because (as I understand him) the amp requires to reach a certain level of stress to produce that growl. If you're in a loud band you might need the 1001 but if not, then the 700 is a better choice.

[unclekebm]

i just received my LS1503...love it! sounds better than my golliathIII,
GB 212neo and eden 410xlt. using a sansamp paradriver & half of my plx2402 to drive it.

[greenboy]

edgerunner,

I find this kind of problem frustrating to diagnose over the internet, especially without control cavity photo[s]. But you could narrow it down by disconnecting final leads to the bass's output jacks, and then connecting the pickup in question directly to the jack. If that works fine, you have a faulty wiring scheme or pot.

[lbwdog]

Originally Posted by edgerunner

re: the power question. Ok - cool. So I am sticking with whats I gots then.

Now I need to solve this pu problem. So I posted this over in the Pickups forum but have gotten no responses. So I hope I am you'll forgive a temporary thread hijack.

----------------------------
If I hit the strings really hard - the neck pu sounds distorted (crackly noisy distorted).

I have the control cavity opened up and it seems to be wired correctly (as compared to the schematic off the Fender site). I though I was going to find a loose solder connection but it all looks clean and solid.

Does this sound like a bad pu or a bad pot or some other issue?

I was thinking about replacing the stock pu's anyway at some point with the DiMarzio DP123s, but my son is recording a demo on Monday and I'd like to get this straightened up before then if possible. He can always just avoid the neck pu for now I suppose.
------------------------------------------

Any ideas?

Chuck

It sounds like a bad pickup or pot.
First thing I would do would be to unsolder the leads to that pickup then connect them with alligator clips or tape to a cable and plug in to the amp. Tap on the pole pieces and see if you get a good strong whump on each. If so the pickup is probably OK in which case I'd replace both pots and maybe the jack while I was at it. The MIMs weren't known to use the best pots. Mine ('95) had cheap mini pots.