GR Bass AT800 Cube issue

[tauzero]

On Saturday night, my AT800 uttered a few horrible noises (even more horrible than my normal playing) and then ceased to emit any noise whatsoever.

 

Yesterday was diagnosis day. The combo has an amp in a sleeve at the back, with a jack plug connecting speaker and one output. With the jack plug unplugged and a speakon cable connecting the amp to a known good cab, I got sound. Reversing the experiment and connecting the jack plug from the speaker to a known good amp, I got a little sound from the tweeter. I extracted the main driver and checked for continuity - open circuit. The driver is a Sica, custom made for GR Bass. Considering this amp has only done about 50 hours of gigging, keeping up with a medium loudness drummer, this is rather disappointing, and I'm trying to get a replacement driver from GR Bass as a warranty issue. Fortunately I have a spare amp and cab which I was intending to give a run out to anyway, so I'll be using those until I get a replacement speaker.

[tauzero]

No warranty replacement - a) I opened the amp up to diagnose the problem, voiding the warranty, and b) warranty for woofer is only one year. They've offered to sell me a replacement at a discount, just waiting to find out how much that will be.

[Chienmortbb]

Prepare yourself for a shock. OEM driver are notoriously expensive.

[tauzero]

Not too shocking (not cheap though) at 160€. Top tip: TransferWise is very useful to do bank transfers to banks in forn parts.

[DGBass]

Will the replacement driver be covered by warranty if you install it yourself? Just saying, as some manufacturers will sell OEM spare parts but insist an "authorised" repairer fit the part to maintain any future warranty claims.  

[Royaly T]

On 19/08/2024 at 13:20, tauzero said:

On Saturday night, my AT800 uttered a few horrible noises (even more horrible than my normal playing) and then ceased to emit any noise whatsoever.

 

Yesterday was diagnosis day. The combo has an amp in a sleeve at the back, with a jack plug connecting speaker and one output. With the jack plug unplugged and a speakon cable connecting the amp to a known good cab, I got sound. Reversing the experiment and connecting the jack plug from the speaker to a known good amp, I got a little sound from the tweeter. I extracted the main driver and checked for continuity - open circuit. The driver is a Sica, custom made for GR Bass. Considering this amp has only done about 50 hours of gigging, keeping up with a medium loudness drummer, this is rather disappointing, and I'm trying to get a replacement driver from GR Bass as a warranty issue. Fortunately I have a spare amp and cab which I was intending to give a run out to anyway, so I'll be using those until I get a replacement speaker.

Sorry to hear about the amp, I've got the same one, how old is yours, I didn't know the speaker was only covered for year.

Edited August 26, 2024 by Royaly T

[tauzero]

1 hour ago, Royaly T said:

Sorry to hear about the amp, I've got the same one, how old is yours, I didn't know the speaker was only covered for year.

 

About four years old - first used it somewhere round this time in 2020, used it at maybe 20 gigs since then.

[Royaly T]

4 minutes ago, tauzero said:

 

About four years old - first used it somewhere round this time in 2020, used it at maybe 20 gigs since then.

Not alot of use then, I've PM'd you

[tauzero]

I don't know for certain what may have caused this - however, using a Tecamp Puma 900 and a Basschat 112 at the gig I did on Saturday night, when using a particular dirty patch on my Helix I found the speaker making unpleasant noises when I played anything from bottom G or so downwards (unpleasant enough for one guitarist to comment on it). I kept away from that patch, only using clean patches, and didn't have any further problem.

 

So I suspect it was using a patch that caused too much speaker excursion or some other physical damage to the speaker, but I don't know for sure. However, that patch is getting deleted to avoid anything similar happening, either to the BC cab or to the GR Bass once I get it back. I didn't hear any bad noises at the gig when the speaker failed, but the room we were in had a very bad resonance at low frequencies and I couldn't make out exactly what was happening on the low notes. When I put the bass into the PA, I left the Helix out completely.

[tauzero]

Driver now winging its way from Italy.

[Royaly T]

15 hours ago, tauzero said:

Driver now winging its way from Italy.

Keep us updated 

[tauzero]

Driver arrived a few days ago. Took the old driver out (I'd reinstalled it loosely so as not to lose the screws and so I wasn't creating more clutter than necessary), put the replacement in, using my veterinary training to slide my hand in to connect the spade terminals. The speaker leads are gathered together with a zip tie, hence not having much slack in the cable. Having put a few cylinder heads on in my time, I tightened the screws evenly, and as they go into T-nuts (and after a previous traumatic experience), I avoided pushing down while I was tightening the screws.

 

All that done, I did a test which showed it was all working fine again. I shall be very careful of dirty in my patches and nasty resonances in future.

[Royaly T]

Thanks for the update