geoffbyrne Posted October 26, 2010 Share Posted October 26, 2010 My Shuttle 6 went wonky a couple of weeks ago. I was sitting 'tone-twiddling' (as one does) with the semi-parametric at just barely over conversational levels, and also playing with the valve-gain & pre-output when there was a buzz and the volume dropped about 70%. I thought it was a glitch & turned it off. When I played at the next practice I found it was severely curtailed in the total output volume department. I opened it up & poked around but could find nothing visible. I decided to change the valve on the off-chance. I had an unbranded 5751 in it as it's my tone-generator of choice. The amp was still on at this time and I poked the bracket supporting the end of the valve, and got a big crackle in response - something obviously not right there, then. I switched off, removed the offending valve & have replaced it with a NOS Mullard ECC83. Now volume all returned & sounds magnificent. Putting the 5751 in my Laney valve amp produced much spluttering & background crunch. 5751 binned. So, a valve with a dud side will drop your volume by at least half, but will still work, so don't panic if you get this symptom, just take the top off & replace the valve. G. Quote Link to comment Share on other sites More sharing options...
Pentode Posted October 27, 2010 Share Posted October 27, 2010 Tell you what - that Shuttle will sound sooo much better with the nice new shiny 12AX7 I have here and, AND, just for you, I'll do a straight swap for that nasty old Mullard. Can't say fairer than that can I....? Result on sorting it though! Quote Link to comment Share on other sites More sharing options...
geoffbyrne Posted October 27, 2010 Author Share Posted October 27, 2010 [quote name='Pentode' post='1001977' date='Oct 27 2010, 06:33 AM']Tell you what - that Shuttle will sound sooo much better with the nice new shiny 12AX7 I have here and, AND, just for you, I'll do a straight swap for that nasty old Mullard. Can't say fairer than that can I....? Result on sorting it though! [/quote] Just to make you jealous, I have a NOS 4005 in the drawer also. I assume you've seen this: [url="http://www.guitaramplifierblueprinting.com/Tubeprimerandselection320-2.pdf"]http://www.guitaramplifierblueprinting.com...ection320-2.pdf[/url] G. Quote Link to comment Share on other sites More sharing options...
Pentode Posted October 27, 2010 Share Posted October 27, 2010 [quote name='geoffbyrne' post='1002264' date='Oct 27 2010, 12:06 PM'] Just to make you jealous, I have a NOS 4005 in the drawer also.[/quote] Thanks for the link Geoff! Quote Link to comment Share on other sites More sharing options...
geoffbyrne Posted October 27, 2010 Author Share Posted October 27, 2010 You don't have a genuine (i.e. *not* a failed/downgraded 12AX7) 5751 knocking about, do you? G. Quote Link to comment Share on other sites More sharing options...
Pentode Posted October 27, 2010 Share Posted October 27, 2010 'Fraid not...... Sorry mate... Quote Link to comment Share on other sites More sharing options...
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