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DB359: The Saga Continues . . .

A

ajb

Mar 20, 2005
219
7
#1
Hi everyone. As some of you know, I've posted before about a cut-out problem I've been having with my DB 359 (I would post a link to my previous threads but I don't know how -- computer idiot). The folks at Aguilar requested that I ship the amp to them for inspection and I did. I recently got it back from them, and they told me they could find nothing wrong with it. Because I suspected that the problem I experienced might have been caused by my Aguilar GS212 (for reasons that I've discussed on here as well), I've been running the DB359 through my SWR 2X10 cab. This past weekend the cut-out problem happened again, with the SWR cab. Volume completely dropped out. Put it on standby, took it off standby, and still no volume. When I powered down and powered back up again though, it worked.

The reason I am writing is not to get it into an extensive discussion about what might be causing this problem, because I'm just about at the point where I don't care anymore. I've been dealing with this problem for over a year and half now, since I got the amp. Instead, I would like some opinions as to what I should do next. Ideally I would like my money back since the DB359 has been discontinued and I can't get a replacement. The problem, though, is that the cut-out problem is intermittent and the folks at Aguilar weren't able to reproduce the problem. I understand why they would be hesitant to refund my money when they could find nothing wrong with the amp. At the same time, I don't want to shell out over a hundred bucks in shipping costs again to have them take a lok at it again.

This is a huge headache. I spent a lot of money on that amp and I need it to record a cd next month. It sounds great, but this weird cut-out problem is obviously unacceptable. How should I deal with this problem? I've been sort of a jerk in the past about this with them and blown my top a little, and I don't want to go there again. They seem like good guys to me and were genuinely interested in solving the problem. But they did make a warranty on the amp, and I think I'm justified in expecting the warranty to be honored (either via repair at their expense or a refund).

Help!!!!
 
#2
I may be a knuckle head for asking this,,, but have you tried swapping out the speaker cable? Just for the fun of it.
I suspect that the preamp tubes are seated well. I am not a tech, so I say it almost sounds like it may be a heat related problem or something caused by vibration or sudden movement of the head.
As far as a definite answer I have none at all. But I would look for loose parts or wires connections and at the speaker jacks on the internal side of the amp if anything may be loose or touching. As far as heat goes you may have a cold solder joint somewhere that only becomes a problem as the amp heats up over time or is vibrated by bass frequencies.
Just my uneducated guess..
 
#3
Yeah, I've used different speaker cables, and I've pretty much eliminated every other part of the signal chain (I also own a GK 700RB head). I even had an electrician come to my house to make sure my outlets are okay! (even though the porblem first happened at my rehearsal space) I'm pretty much done investing any more time trying to figure out what the problem is. Aguilar tried and couldn't find the problem. If they want to try again at their own expense, great. But I'm not going out of my way anymore.

As you can tell I'm pretty annoyed at this point. I do not want to sell the amp at a loss. Ideally I want my money back, but I don't know how that's going to happen when the porblem's intermittent and can't be reliably reproduced.
 
#6
Bummer. Is there a way you can get them to sell it for you as a 'factory warranteed second' on their website or through one of their dealers? If they can't find anything wrong, then they should stand by the product and help you out IMO. I know you wouldn't want to dump your problem onto somebody else, and this way it would be the company's responsibility to make sure everything is cool before and after the sale.

The other thing to talk to them about is a trade-in on an AG500.... of course, you'd take a beating on the price, but at least you wouldn't be stuck with a faulty unit and wouldn't have to put out any cash (and the AG500 is A LOT louder than your 359).

Just some ideas... might be bad ideas, but you seem kind of stuck with that thing... time to cut your losses and get something that works for you.

Good luck.

K

Edit: I'm sure you thought of this... but that head is not known for pumping out volume.... are you pushing it a little and is there a 'safety shutdown' that is kicking in?
 
#7
Sorry to hear that. I have a 359 and have had no problems with it. Are the 1/4 jacks mounted correctly? ... could be loose? Check the DI. If I remember correctly, you changed all the tubes and they also checked the fuses. The problem is baffling.

Instead of trading on a AG500 see if they can help you get into a DB750. The 750 will be closer in tone to the 359 than the AG500.
 
#8
Pickebass said:
Instead of trading on a AG500 see if they can help you get into a DB750. The 750 will be closer in tone to the 359 than the AG500.
Click to expand...

+1 on the 750 also.... the 500 is closer in size and weight... just depends what's the most important. If playing at relatively low volumes with a small cab, the 500 might actually sound better IMO, and weigh about 30% as much.
 
#9
Thanks Kjung, these are the kind of responses I'm looking for. It really is a bummer. The AG500 idea is interesting, but I don't see any reason to accept anything less than a DB750 on a trade (since it's only slightly less expensive than the DB359). It would be way more amp than I need (which is why I didn't buy it in the first place), but I think it would come closer in terms of sound than the AG500.

Having Agular sell the amp as "factory warrantied second" is also interesting. Some things to talk about with them, I guess.
 
#12
Wow. I think this is the first time i've ever heard of someone having a problem with an Aguilar head.

I know you're frustrated, but the fact of the matter is, there has to be some way of isolating the problem. At the very least, if you can't figure out what it is, you can figure out how to reproduce it.

First thing to do with a tube amp is always to replace all the tubes with trusted ones. I'm assuming this was done...They have the 6550's mounted horizontally in that amp, and it's not completely out of the question that one of them could possibly be partially shorted. The screen grid(s) could possibly be sagging a bit only when the conditions are right (heat, and the right amount of vibration, or a certain frequency that vibrates them enough to short them against the plate).

I'd trust Aguilar to troubleshoot the amp, as they're build it. But you don't know for sure how much time they put into something like that. If they can't reproduce the problem, how much time do they really spend playing that amp in the shop? If it's heat related, maybe not long enough. But if you can pinpoint when it happens, you can give them more specific instructions on how to reproduce it.

Another option you may have is asking them to call around to their dealers to see if anyone still has a new 359 in stock that they can get you.

But i'd try and get the amp to reproduce the problem. When you turn it on and start playing, start a stopwatch or take note of the time. Take note of how long it takes to happen. If you hear it drop out, remember what note you were playing when it happened. Maybe you can determine a pattern of events that leads up to it happenning. Stress the amp as much as possible...turn it up real loud, turn the low end up all the way...put it right on top of the cab without it being in a road case. While you're playing, tap the chassis...bump the cab. I'd even pick up each corner of the amp slightly and let it drop (not hard obviously) back down onto the cab to see if that aggravates it.

Sooner or later the issue should rear its head enough for you to pin it down more specifically.

Hope that helps. Good luck.

-Nick
 
#14
Thanks for the suggestions fiveightandten (and to all of you who have responded). Thing is, I have spent the better part of a year and a half trying to isolate this problem. This issue was the subject of extensive e-mails between me and Aguilar (including all kinds of details about how the problem manifests, under what circumstances, etc.) Ultimately, they asked me to send it to them so that they could inspect the amp. I would hope, given the amount of time we spent discussing this issue, that they did a thorough job going over the amp (and actually I have no doubt that they did -- Dave Boonshoft discussed with me in some detail the various stress tests they ran on the amp to try and locate a cold solder joint or any other issue that might be causing this problem). They had the amp for nearly a month, and they could not locate a problem. And I believe them! I have been to several rehearsals where the amp worked perfectly. This is not something that happens on a consistent basis, but it does happen often enough to have caused me to lose confidence in the amp.

I hope I'm not coming off like a whiny little bitch here. I understand that problems with any piece of electrical equipment can and do happen. But when more than a year goes by and the problem still hasn't been identified and resolved, I think I have fulfilled my obligations to investigate and correct. Am I way off base here?
 
#15
ajb said:
Thanks for the suggestions fiveightandten (and to all of you who have responded). Thing is, I have spent the better part of a year and a half trying to isolate this problem. This issue was the subject of extensive e-mails between me and Aguilar (including all kinds of details about how the problem manifests, under what circumstances, etc.) Ultimately, they asked me to send it to them so that they could inspect the amp. I would hope, given the amount of time we spent discussing this issue, that they did a thorough job going over the amp (and actually I have no doubt that they did -- Dave Boonshoft discussed with me in some detail the various stress tests they ran on the amp to try and locate a cold solder joint or any other issue that might be causing this problem). They had the amp for nearly a month, and they could not locate a problem. And I believe them! I have been to several rehearsals where the amp worked perfectly. This is not something that happens on a consistent basis, but it does happen often enough to have caused me to lose confidence in the amp.

I hope I'm not coming off like a whiny little bitch here. I understand that problems with any piece of electrical equipment can and do happen. But when more than a year goes by and the problem still hasn't been identified and resolved, I think I have fulfilled my obligations to investigate and correct. Am I way off base here?
Click to expand...

No, I think you have every right to be frustrated. That's a LOT of money to dump into an amp and not be completely happy with it, let alone confident it will perform devoid of relability issues.

I know it's been a long time coming for this to get resolved...but FWIW, I was getting at something with my first post. All Aguilar needs to do is make the amp do what's it's doing to you. If they can do that while they have it hooked up to their test equipment, they can at least isolate it enough to know what they have to replace. If they have it hooked up to a scope and see that the volume drop is in the pre-amp...they can just replace the pre-amp board and be done with it. If the pre-amp seems to function fine, but they see the power supply dipping...replace the power supply board, ect. This is, of course, assuming that they still have parts around for that amp, which...with all their products having a 10 year warantee, i'm sure is the case.

But it sounds to me like you just don't want to deal with any more headaches with the amp...and for very good reason. I'd suugest again, that you call Aguilar and ask them if they could located an unsold unit in the hands of one of their dealers.

Something else that may be a little off the mark...but i'd talk with them about it if I was in your situation; I'd ask about getting a refund, and using the money to buy a used DB359. ...Under the stipulation that they would look it over at the factory, refurbish any parts that needed it, put new tubes in it for you, and provide a warantee as if it were new. I think in the unique situation you have, that wouldn't be completely out of the question. It's an option i'd bring up with them if I were in the same position.

-Nick
 
#16
Something else just occured to me.

What are your usual EQ settings, and do you use the tweeter on your cab(s)?

That amp may be osscilating above the hearing range. I had an old Vox that did this but ONLY when it was on top of a cab. It was aggravated by the magnetic field from the speakers in the cab. I couldn't figure it out at first, and the tech I sent the amp to couldn't get it to osscilate...because they don't normally put amps on top of cabs when they're troubleshooting in a shop. They put them on the workbench. The amp was stable if it was a few feet away from the cab.

I'd suggest using the amp with the tweeter turned off in your cab, and the treble low, and the bright switch off. It can't hurt...

Also, play it with your normal settings...but keep it away from the cab. Of course, if that makes the problem go away, it could also be due to mechanical vibrations, but it's a start...


Adversly...if you can catch it (and have a see-through grille)...try and take a look at your speakers while the volume drops out. If you see the cones moving in and out a ton and don't hear any noise, you have an osscillation BELOW the hearing range. I've seen that as well, in an old Ampeg I was working on. Turned out to be a bad cap in the negative feedback loop...which tested out fine otherwise.

Osscilations are real tough to troubleshoot, as often you're not even aware that's the problem. They're also intermittant very often, and only happen in certain situations (with one cab and not another, one guitar but not another...).

Hope that helps.

-Nick
 
#17
I have the DB359 too, I've had the same problem. These amps have a smart card in them, and somehow, you and I are tripping the smartcard and it thinks it needs to protect the amp. The AG500 and DB750 also have them, and they can be tripped too. I have the AG500 and it's happened once or twice there, too. Frankly, I don't think the smartcard works right, but better than having an expensive amp get messed up.

Here are some solutions that worked for me. First, are you using effects, in particular an envelope filter? If you are, the peaks caused by the filter can clip the amp, causing the card to trip. Try running a compressor right after your filter, and adjust the output so it's not so hot. If you're running a particularly hot bass, that can be the problem too. Combined with effects, you're doubling your chances of tripping the smartcard.

What kind of rack do you have for the DB359? Are the tubes getting ventilation? If they stay cool, they will run more efficiently, especially at high volumes. One thing that really worked well for me was bringing a small personal fan to gigs, and pointing it at the power tubes. This keeps them cool longer and they run more efficiently, less likely to trip the smartcard. The internal fan doesn't pull much air, and having another fan helps. According to Aguilar, the heat doesn't trip the smartcard. However, tubes running inefficiently can. If you're playing a loud gig for a long time, then chances are your amp is getting really hot. Mine gets so hot you can fry an egg on it. Keeping it cool helps tube efficiency on long loud gigs.

Any time my AG500 was clipping for an extended period of time, the same thing happened. Sometimes it was caused by my MXR M-188 envelope filter. Adjusting all the levels just right has helped to eliminate the problem.

I suspect using better tubes might help as well, and having the amp properly biased would improve things. About the smartcard, when you shut off the power and turn it back on, it resets. Flipping the standby switch won't do it. You have to turn it off and on. FYI, the XLR will continue to work, even if the smartcard trips.

Personally, I love the sound of my Aguilar amps. But, I'm disappointed this has happened. I don't think it's fair that they let us down, cause they are really good guys. I know that in older model DB359s, they didn't have the smartcard. Instead there was an internal fuse. If that blew, you had to take the amp all apart and replace it. At least with the smartcard you won't have to do that. For me though, mine shut down on more than one occasion on the last tune of a really great set, and ruined the finale song. It is so distracting when all the sudden you have no sound. There has to be a way around this.

Aguilar, if you're listening, you know I love you guys. You are MY tone! But we can't have this go on any more. I've done my best to resolve the problems with both my DB359 and AG500 to the best of my ability, and for the most part, it's worked. However, there is still the occasional shut down. If the amp can't give any more, just let it be that, not get any louder, no clipping. Shutting down during a song is not an option. I think that if more people knew about this, you'd have less customers, and I don't want that. Nonetheless, let's find a new solution, and give me and the original poster a call so we can have our amps upgraded so that won't happen anymore.

Lastly, I suspect that the AG500 doesn't do it as much because it has a wee bit more headroom than the DB359. Also, it doesn't get hot. The DB750 is probably the least likely to trip the smartcard due to its massive headroom.
 
#18
Dave, that was a great post!!!

But, seeing how this thread is a month old, maybe you should PM the original poster. Dave B. would chime in as well if he sees this thread, i'm sure.

FWIW, I owned the AG500 and the DB359 and never had that problem you both speak of. But, I wasn't gigging with them either.

Great post.
Great amps.
Unfortunate problem that deserves to be solved.
I love Aguilar:bassist: :bassist:
 
#19
rayzak said:
Dave, that was a great post!!!

But, seeing how this thread is a month old, maybe you should PM the original poster. Dave B. would chime in as well if he sees this thread, i'm sure.

FWIW, I owned the AG500 and the DB359 and never had that problem you both speak of. But, I wasn't gigging with them either.

Great post.
Great amps.
Unfortunate problem that deserves to be solved.
I love Aguilar:bassist: :bassist:
Click to expand...

Already PM'd the OP. And I directed an email to tech support at Aguilar to catch their attention to this thread. Maybe DB or Dave Avenius or Jeff Lipman will chime in.

FYI, these amps never did this at home. Only at a loud-ish gig.
 

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