Big valve amp fail. Ashton BV cap explodes..

[VTypeV4]

Happily playing away this afternoon (a bit of Level 42) then all of a sudden I have no sound followed by a 'that' smell and a couple of clouds of smoke. An exploded electrolytic was quickly identified as can be seen in the pix.

[URL=http://s778.photobucket.com/user/VTypeV4/media/AshtonFail1_zps3d1f37bc.jpg.html][IMG]http://i778.photobucket.com/albums/yy70/VTypeV4/AshtonFail1_zps3d1f37bc.jpg[/IMG][/URL]

[URL=http://s778.photobucket.com/user/VTypeV4/media/AshtonFail2_zps5f01846e.jpg.html][IMG]http://i778.photobucket.com/albums/yy70/VTypeV4/AshtonFail2_zps5f01846e.jpg[/IMG][/URL]

[URL=http://s778.photobucket.com/user/VTypeV4/media/AshtonFail3_zps9c81937d.jpg.html][IMG]http://i778.photobucket.com/albums/yy70/VTypeV4/AshtonFail3_zps9c81937d.jpg[/IMG][/URL]

Off to the repair man on friday to replace one if not a number of these bad boys.

[HowieBass]

I'm close to having a go at replacing the smoothing caps in an old WEM valve combo - one of those big twin 50uF + 50uF 500V radial electrolytic capacitor jobs...

[paul_5]

That's a sizeable cap to blow. Best leave it to the professionals...

[VTypeV4]

Those big voltages scare me a bit thats why I've opted to let someone else worry about it. If it was something on the pre-amp board then maybe I'd have a go.. Plus if there's something else that's caused the cap fail, hopefully he'll spot it.

[Dad3353]

This is the size of caps in Hiwatt KT88 amps...

[attachment=162195:Hiwa_Capa.JPG]

...I don't know how those tiddly little ones manage to do the same job.

[VTypeV4]

There's two bigger ones on the end plus there's a choke on the top behind the mains transformer.. I wouldn't mind some greater capacity ones (or two, three etc) in an attempt to circumvent a repeat incident tho.

I should state that this amp has worked faultlessly since purchase and has been used quite a bit probably averaging twice a week for a couple of hours each. Might buy it some new valves when I come back from holiday..

[JapanAxe]

[quote name='VTypeV4' timestamp='1399483225' post='2444702']
I wouldn't mind some greater capacity ones (or two, three etc) in an attempt to circumvent a repeat incident tho.
[/quote]

If you are going to upgrade your caps, don’t go for bigger values, as this can cause your rectifier diodes to fail. By all means go for higher working voltages though, for a wider safety margin.

[VTypeV4]

It's gone to the tech man today so hopefully next time I see it, it'll be sorted. I left him a note asking to replace the faulty cap, any he thought that might be suspect and if he thought they were underspecified to put better ones in..

[quote name='JapanAxe' timestamp='1399665614' post='2446566']
If you are going to upgrade your caps, don’t go for bigger values, as this can cause your rectifier diodes to fail. By all means go for higher working voltages though, for a wider safety margin.
[/quote]


I've learned something today, thanks.

[ahpook]

I feel dumb for asking this...but what blew up ?

Could you tell me where I'm looking...

Edited May 9, 2014 by ahpook

[VTypeV4]

Sadly, it's not quite as exciting as the title makes out.

If you look in the second pic, you'll see on the left that there's three caps next each other and that the middle one has it's top missing with just a little bit of the innards on the outside. The other two still have their black tops intact.

I haven't had a cap fail in a valve amp for a while and forgot how much they stink and smoke. There was a little pool of the electrolyte juice too.

[Roland Rock]

[quote name='ahpook' timestamp='1399677014' post='2446713']
I feel dumb for asking this...but what blew up ?

Could you tell me where I'm looking...


[/quote]

Had you not asked, I would have :-)

[VTypeV4]

Sorry guys, it's not [i]that [/i]exciting..

I had a series of big ones let go in a QSC MX series and they did look great, proper burst open and the electrolyte sputtered all over the inside of the case. Just before it died, it did a great impression of a smoke machine and stunk the room out.

[ahpook]

[quote name='VTypeV4' timestamp='1399716718' post='2446900']
Sorry guys, it's not [i]that [/i]exciting..
[/quote]

It is, it is !

Edited May 10, 2014 by ahpook

[VTypeV4]

[quote name='ahpook' timestamp='1399749262' post='2447333']
It is, it is !
[/quote]

Cheers man!

[VTypeV4]

Amp fixed and cap uprated to 450v vs the old dead one of 350v. I do have a pic, will upload later..

[paul_5]

Cool, glad this has had a happy ending. They stink when they blow though, don't they!

[VTypeV4]

[URL=http://s778.photobucket.com/user/VTypeV4/media/FixedBV1_zps7121a255.jpg.html][IMG]http://i778.photobucket.com/albums/yy70/VTypeV4/FixedBV1_zps7121a255.jpg[/IMG][/URL]

New black cap in place.. Sorry the image is fuzzy, it was tricky trying to balance the chassis and take the pic!

[URL=http://s778.photobucket.com/user/VTypeV4/media/FixedBV2_zps19e3ccb3.jpg.html][IMG]http://i778.photobucket.com/albums/yy70/VTypeV4/FixedBV2_zps19e3ccb3.jpg[/IMG][/URL]

An arty shot..

And yeah, they stink not to mention the smoke! It's cost less than 30 quid for someone else to fix so I'm a happy bunny.

[Billy Apple]

I know nothing about Ashton stuff. Any background to the amp, please?

[Count Bassy]

I'm a bit surprised he didn't swap them all.

Still, glad you're back in action.

[VTypeV4]

Billy, have a look here..

[url="http://basschat.co.uk/topic/176021-ashton-bv300-all-valve-300w-bass-head/page__pid__2454020#entry2454020"]http://basschat.co.uk/topic/176021-ashton-bv300-all-valve-300w-bass-head/page__pid__2454020#entry2454020[/url]

This is my bit of a review, hope it's of interest. This amp is also badged as Fame and Smarvo as well as Ashton. The old Eden 300T is also a version of this albeit with an inverted chassis and a (apparently - I found a few arguments on other forums including Eden's own) modified pre-amp.

Their other ranges of bass amps are 500w micro-amps and a more traditional solid-state line of combos and heads with the same blue-brushed metal front panel as mine although the larger ones also have a graphic EQ and possibly a compressor. The combos start with tiny 20 watt offerings up to the big 400w head. I tried the 200w head and whilst it lacked a little bit of identity, it was quite pokey and with my usual EQ curve gave a pleasing sound.

Count Bassy..

I left him a little note saying if he thought any were suspect that he should replace them but he says it was a simply a bit of bad luck and that the others are fine.