Bass Culture Posted August 5, 2009 Share Posted August 5, 2009 Dear all, Just acquired an AH300SMX head off ebay. It's in very good condition and looks as though it's been well looked after. There's a bit of crackling on most of the pots but nothing a bit of judicious know twiddling or carefully applied contact cleaner can't remedy, and nothing that seems out of the ordinary for a 10 year old amp. When it first arrived I didn't have a cab so tried it through a monitor speaker and then the internal speaker on my combo. On both occasions it broke up very badly when playing anything below A on the E string. That said, both speakers were under powered compared to the amp output so I put it down to a mismatch. Yesterday my new Barefaced Compact arrived, just in time for my band rehearsal last night and even with what should be an ideal match in terms of power there was some distortion in the same range of bass notes - though not to the same extent. I'll be honest and say it's a good few years since I've used an amp with a graphic rather than parametric (or semi-parametric) EQ and I'm wondering if I'm overloading by incorrect use of the EQ. I've set it up in favour of the valve preamp slightly, a bit of bass and slightly less treble compression and a bit of bias towards the bass EQ. The graphic is set up in a rather nice looking wave shape (if i do say so myself!) with a peak in the low mids and trough in the low treble, and flat at each end of the spectrum. So, I suppose the question is this - am I being heavy handed with the EQ (no more than 6db cut or boost on any wave band though) or is this distortion sympomatic of a problem with the amp. It's worth mentioning that the signal is lot cleaner if I switch the EQ out completely though I didn't have a lot of time in rehearsal to establish exactly where and how the distortion occurs. Any comments / experiences would be welcome. Cheers, Mark Quote Link to comment Share on other sites More sharing options...
Mr.T Posted August 5, 2009 Share Posted August 5, 2009 (edited) Hi Mark, With no more than 6db of boost or cut at any of the sliders, this amp should not be distorting. Do you have the input gain stage set correctly? i.e: The red should barely (if ever) ever illuminate. p.s. Do not boost the red sliders on the graphic.... cut only! Edited August 5, 2009 by Mr.T Quote Link to comment Share on other sites More sharing options...
Bass Culture Posted August 5, 2009 Author Share Posted August 5, 2009 [quote name='Mr.T' post='560923' date='Aug 5 2009, 09:51 AM']Hi Mark, With no more than 6db of boost or cut at any of the sliders, this amp should not be distorting. Do you have the input gain stage set correctly? i.e: The red should barely (if ever) ever illuminate. p.s. Do not boost the red sliders on the graphic.... cut only![/quote] Hi Mr T, Yeah I downloaded a manual and followed the procedure for setting the input gain, and checked when playing last night that it was only going into red occasionally, so I think that was okay. I think the red slider was cut slightly too. I'll be able to have a more conscientious play this evening, I think. Pip pip! Quote Link to comment Share on other sites More sharing options...
Mr.T Posted August 5, 2009 Share Posted August 5, 2009 Stick with it, a great amp (IMO). Might just need a service.... 10 years of dust, etc. Quote Link to comment Share on other sites More sharing options...
Bass Culture Posted August 5, 2009 Author Share Posted August 5, 2009 Well that's as fair a comment as I've heard for a while. I love the basic tone and combined with the Compact (although, being brand new, the cab will take a little while top completely settle down I guess) I thin it's going to do for me for the kind of small/medium pubs gigs I do. So, sage words, perhaps a service is in order! Quote Link to comment Share on other sites More sharing options...
Tengu Posted August 5, 2009 Share Posted August 5, 2009 I just re-soldered a load of joints where the input jack and all the pots connect to the circuit board on mine. The mute switch had been acting a bit funny and I was getting some noise. Since the solder job it has worked lovely with no noise and certainly no distortion. Looks like you just need the service. Quote Link to comment Share on other sites More sharing options...
Stingray Posted August 27, 2009 Share Posted August 27, 2009 Hi If you boost the eq but keep the pre amp level down so the led does not go into the red area, there should be no distortion at all. However, this depends on your output level and speaker cab. If you boost a lot of bass with maximum power on our amp, it is likely your speakers will complain. I seems like the eq section of the amp would need a service. I hope this helps. Quote Link to comment Share on other sites More sharing options...
KineticX49 Posted August 28, 2009 Share Posted August 28, 2009 Trace are very good with servicing and support, just get in touch with them. Quote Link to comment Share on other sites More sharing options...
Bass Culture Posted September 1, 2009 Author Share Posted September 1, 2009 Thanks all for your comments and advice. I think the service os the way to go. 'Incidentally, what is a service likely to consist of? Are there any/many parts within the head that can be expected to deteriorate over time and therefore affect different aspects of the amp's performance? I ask this out of complete ignorance and would be genuinely interested to know. Mark Quote Link to comment Share on other sites More sharing options...
alexclaber Posted September 1, 2009 Share Posted September 1, 2009 The main thing I know of is electrolytic capacitors drying out. Alex Quote Link to comment Share on other sites More sharing options...
littleal Posted September 1, 2009 Share Posted September 1, 2009 (edited) Might it be the little preamp valve ? Edited September 1, 2009 by littleal Quote Link to comment Share on other sites More sharing options...
KineticX49 Posted September 4, 2009 Share Posted September 4, 2009 Trace will take it apart and check it all over, so if it was something like the above two mentioned I should think they'll find it Quote Link to comment Share on other sites More sharing options...
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