Post by Kevin on Oct 28, 2008 17:48:30 GMT
From: Marcelo (Original Message) Sent: 11/09/2008 10:55
Hello Charlie!
I have a Jerry Jones Baritone guitar. This one is intonated from A to A with the same intervals of the regular guitar (because its scale must be intonated this way). The strings gauge is 072, 056, 044, 030, 018, 013.
It's not like a Burns Barracuda that has to be intonated from E to E.
I use it through my VOX AC-30 TB. Is it right?
Other question: the Trem Vib pot of the VOX has three positions: one is nule and on the other two I don't perceive the difference. Which is the difference?
Thank you!
Regards!
Marcelo
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From: Charlie Hall Sent: 11/09/2008 15:47
Hello Marcelo,
It shouldn't harm the amp but you should be careful about having too much bass if you use the low notes on the low string. The speakers are not really designed to withstand the low frequencies for very long.
The 3 position switch is usually marked Speed as far as I remember, and should give 3 different speeds of tremolo. The Trem Vibe pot should have 2 positions so maybe it has been replaced with a 3 position switch. The vibrato effect should be very different to the tremolo effect. Have you tried replacing any of the valves for the tremolo/vibrato effect?
Regards,
Charlie
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Recommend Delete Message 3 of 5 in Discussion
From: Marcelo Sent: 11/09/2008 17:28
Hello Charlie!
Thanks for the advice.
No, I never change this valves and I don't know whicb they are as is the first time I do something with this channel. But the Trem and Vib position sound exactly the same in my VOX. Speed yes I can hear the variations.
Thank you!
Regards!
Marcelo.
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Recommend Delete Message 4 of 5 in Discussion
From: Charlie Hall Sent: 11/09/2008 19:11
Hi Marcelo,
I think most of the preamp valves are 12AX7 (ECC83), and there is also one 12AU7 (ECC82) included in the tremolo circuit. Some reissues also had a 12AT7 (ECC81) instead of one of the other two types.
If you don't know which valves to change, you could try replacing one at a time for the same or equivalent type and seeing if the switch then produces the two sounds. If changing one valve makes no difference, then put the original back and try the next one.
Do not change the EL84 output valves unless any are known to be faulty or worn out.
If changing any of the preamp valves makes no difference, it is just possible that the GZ34 rectifier valve (if one is fitted to your amp) is putting out lower voltage than it should.
If trying a different one still makes no difference, there should be two preset pots inside the amp to adjust the tremolo/vibrato.
If none of that helps then it might then be better to have it looked at by a technician unless you feel inclined to try adjusting the presets yourself to see what they do.
Do not work inside your amp chassis unless you know what you are doing as there can be high voltages even when the amp is switched off and unplugged from the mains power.
Regards,
Charlie
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Recommend Delete Message 5 of 5 in Discussion
From: Marcelo Sent: 11/09/2008 22:06
Thanks for the information and for giving me your time!
Probably I'll try with a technician as I'm not so familiar about doing it by myself.
Thanks for all!
Marcelo.
Hello Charlie!
I have a Jerry Jones Baritone guitar. This one is intonated from A to A with the same intervals of the regular guitar (because its scale must be intonated this way). The strings gauge is 072, 056, 044, 030, 018, 013.
It's not like a Burns Barracuda that has to be intonated from E to E.
I use it through my VOX AC-30 TB. Is it right?
Other question: the Trem Vib pot of the VOX has three positions: one is nule and on the other two I don't perceive the difference. Which is the difference?
Thank you!
Regards!
Marcelo
First Previous 2-5 of 5 Next Last Delete Replies
Reply
Recommend Delete Message 2 of 5 in Discussion
From: Charlie Hall Sent: 11/09/2008 15:47
Hello Marcelo,
It shouldn't harm the amp but you should be careful about having too much bass if you use the low notes on the low string. The speakers are not really designed to withstand the low frequencies for very long.
The 3 position switch is usually marked Speed as far as I remember, and should give 3 different speeds of tremolo. The Trem Vibe pot should have 2 positions so maybe it has been replaced with a 3 position switch. The vibrato effect should be very different to the tremolo effect. Have you tried replacing any of the valves for the tremolo/vibrato effect?
Regards,
Charlie
Reply
Recommend Delete Message 3 of 5 in Discussion
From: Marcelo Sent: 11/09/2008 17:28
Hello Charlie!
Thanks for the advice.
No, I never change this valves and I don't know whicb they are as is the first time I do something with this channel. But the Trem and Vib position sound exactly the same in my VOX. Speed yes I can hear the variations.
Thank you!
Regards!
Marcelo.
Reply
Recommend Delete Message 4 of 5 in Discussion
From: Charlie Hall Sent: 11/09/2008 19:11
Hi Marcelo,
I think most of the preamp valves are 12AX7 (ECC83), and there is also one 12AU7 (ECC82) included in the tremolo circuit. Some reissues also had a 12AT7 (ECC81) instead of one of the other two types.
If you don't know which valves to change, you could try replacing one at a time for the same or equivalent type and seeing if the switch then produces the two sounds. If changing one valve makes no difference, then put the original back and try the next one.
Do not change the EL84 output valves unless any are known to be faulty or worn out.
If changing any of the preamp valves makes no difference, it is just possible that the GZ34 rectifier valve (if one is fitted to your amp) is putting out lower voltage than it should.
If trying a different one still makes no difference, there should be two preset pots inside the amp to adjust the tremolo/vibrato.
If none of that helps then it might then be better to have it looked at by a technician unless you feel inclined to try adjusting the presets yourself to see what they do.
Do not work inside your amp chassis unless you know what you are doing as there can be high voltages even when the amp is switched off and unplugged from the mains power.
Regards,
Charlie
Reply
Recommend Delete Message 5 of 5 in Discussion
From: Marcelo Sent: 11/09/2008 22:06
Thanks for the information and for giving me your time!
Probably I'll try with a technician as I'm not so familiar about doing it by myself.
Thanks for all!
Marcelo.