Helderius Posted August 23, 2016 Share Posted August 23, 2016 Hi, I bought a Fender Bassman 59 about 5 years. I think not need to go into detail regarding the quality and tone;), it is a superb amplifier. I play mostly with passive basses with flatwound strings. Unfortunately a few months ago I started to notice that whenever I increase the volume and play an E on the G string, I hear a sound trepidation. Like something shaking inside the amplifier. It only happens in the highest register of the Bass. Also I do plug in a Fender Bass VI and nothing like that happens. I wonder if it will be something not very well tight!!! Anyone has had a similar situation?? Your help will be very welcome. Cheers Hélder Luís Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted August 23, 2016 Share Posted August 23, 2016 Possibly a microphonic tube. To test turn the amp on with no instrument plugged in, volume halfway, gently tap each tube with a pencil. If you have a microphonic tube you'll hear it. Quote Link to comment Share on other sites More sharing options...
Helderius Posted August 23, 2016 Author Share Posted August 23, 2016 [quote name='Bill Fitzmaurice' timestamp='1471954703' post='3117201'] Possibly a microphonic tube. To test turn the amp on with no instrument plugged in, volume halfway, gently tap each tube with a pencil. If you have a microphonic tube you'll hear it. [/quote] Thanks I will do that Cheers Quote Link to comment Share on other sites More sharing options...
Helderius Posted August 25, 2016 Author Share Posted August 25, 2016 [quote name='Bill Fitzmaurice' timestamp='1471954703' post='3117201'] Possibly a microphonic tube. To test turn the amp on with no instrument plugged in, volume halfway, gently tap each tube with a pencil. If you have a microphonic tube you'll hear it. [/quote] Hi[url="http://basschat.co.uk/user/446-bill-fitzmaurice/"] Bill Fitzmaurice[/url], I did it and I heard no sound. ;( Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted August 25, 2016 Share Posted August 25, 2016 In that case it's not a microphonic tube. Is this an open back '59 Bassman reissue? Despite the Bassman name they're guitar amps, useful for bass only at very low volume. Quote Link to comment Share on other sites More sharing options...
Twincam Posted August 25, 2016 Share Posted August 25, 2016 Still probably a tube. But not microphonic as such but rattling all the same. Make sure the retainers are tight and use some tube dampening rings. Tubes hanging upside down and near the speaker. Never understood that design its a recipe for noise. Or why they didn't have a suspension system like the wem amps. Quote Link to comment Share on other sites More sharing options...
Helderius Posted August 25, 2016 Author Share Posted August 25, 2016 [quote name='Bill Fitzmaurice' timestamp='1472127793' post='3118727'] In that case it's not a microphonic tube. Is this an open back '59 Bassman reissue? Despite the Bassman name they're guitar amps, useful for bass only at very low volume. [/quote] Yes, it is open back. Yes I understand they´re more used as guitar amps. I just love the sound of passive basses on this amp rather than on my SWR Super Red Head. Quote Link to comment Share on other sites More sharing options...
Helderius Posted August 25, 2016 Author Share Posted August 25, 2016 [quote name='Twincam' timestamp='1472133398' post='3118776'] Still probably a tube. But not microphonic as such but rattling all the same. Make sure the retainers are tight and use some tube dampening rings. Tubes hanging upside down and near the speaker. Never understood that design its a recipe for noise. Or why they didn't have a suspension system like the wem amps. [/quote] Hi [url="http://basschat.co.uk/user/30982-twincam/"]Twincam, [/url]I will have to learn how to do it. Cheers Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted August 25, 2016 Share Posted August 25, 2016 [quote name='Helderius' timestamp='1472133508' post='3118777'] Yes, it is open back. [/quote]I'd suspect the speakers. Quote Link to comment Share on other sites More sharing options...
Twincam Posted August 25, 2016 Share Posted August 25, 2016 [quote name='Helderius' timestamp='1472133651' post='3118779'] Hi [url="http://basschat.co.uk/user/30982-twincam/"]Twincam, [/url]I will have to learn how to do it. Cheers [/quote] There known for valve noise. And any valve amp I've had that's made noises its nearly always turned out to be the valves in some way. Next something not tight or a wire rattling off something etc And as Bill said it could be the actual speakers. Im all up for using a bassman with a bass and a bass cab but in the combos the drivers and open back design ain't really up to the job. I would check any screws are right yourself. Then if no improvement try the o rings that for on the valves. These dampen the vibration somewhat. If no joy then maybe the speakers, you could try this by disconnecting the speakers and trying the amp portion with a know "good" bass cab if you are ok with wiring and ohms etc. Tracking down these noises can be a pain! Quote Link to comment Share on other sites More sharing options...
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