Taming the JCM 900-Part 2

DC135er · 11-23-2009, 11:46 PM

A couple of weeks ago I wrote in and asked about whether y'all thought it would be a good idea to exchange the 12AX7 P/I tube with a 12AT7. I appreciate everyones response. While checking all the tubes, I found the one in the P/I hole to be, well, I don't know what it is because nothing was stenciled on it. That was definitely the culprit. It looked like no 12AX7 I've ever seen before and I'll try to get an image loaded before long to see if anyone can ID this tube.

That said, yesterday I found another problem. I arrived early at the church as did the sound-man who already had the system warmed up and running. When I turned my amp on I heard a nasty hum coming thru. I turned off the amp and began troubleshooting, assuming it was the tube I had replaced. I tried an AX7 but still had the hum so I put the AT7 back in. I removed everything from the power strip I was plugged into, still had the hum. Finally, in my last attempt to correct the problem, I plugged the power strip into a different outlet and BAM!!! Problem solved. Yesterday I had the pleasure of hearing my guitar sound like tubular bells at times. GEEEEZZZZ, this is fast becoming one of the best amps I've ever used. I cannot believe I used to think Marshall was overated.

So to Jim Marshall and all the rest of the company, I'd just like to say thanks for making one great amp. This 4102 is so versatile I can virtually get any tone I want. Also, I'd like to add a thank you for making such great pedals.

BTW, in the event anyone's interested, I was using my Carvin DC135 guitar with Carvin's twinblade humbuckers and a Carvin C22B bridge H/B pickup running thru a Bad Monkey into the Marshall Regenerator's chorus (lightly of course). This is an absolutely awesome set-up.

11-23-2009, 11:46 PM	#1 (permalink)
DC135er Member Join Date: Aug 2009 Location: S. Texas Posts: 83	Taming the JCM 900-Part 2 A couple of weeks ago I wrote in and asked about whether y'all thought it would be a good idea to exchange the 12AX7 P/I tube with a 12AT7. I appreciate everyones response. While checking all the tubes, I found the one in the P/I hole to be, well, I don't know what it is because nothing was stenciled on it. That was definitely the culprit. It looked like no 12AX7 I've ever seen before and I'll try to get an image loaded before long to see if anyone can ID this tube. That said, yesterday I found another problem. I arrived early at the church as did the sound-man who already had the system warmed up and running. When I turned my amp on I heard a nasty hum coming thru. I turned off the amp and began troubleshooting, assuming it was the tube I had replaced. I tried an AX7 but still had the hum so I put the AT7 back in. I removed everything from the power strip I was plugged into, still had the hum. Finally, in my last attempt to correct the problem, I plugged the power strip into a different outlet and BAM!!! Problem solved. Yesterday I had the pleasure of hearing my guitar sound like tubular bells at times. GEEEEZZZZ, this is fast becoming one of the best amps I've ever used. I cannot believe I used to think Marshall was overated. So to Jim Marshall and all the rest of the company, I'd just like to say thanks for making one great amp. This 4102 is so versatile I can virtually get any tone I want. Also, I'd like to add a thank you for making such great pedals. BTW, in the event anyone's interested, I was using my Carvin DC135 guitar with Carvin's twinblade humbuckers and a Carvin C22B bridge H/B pickup running thru a Bad Monkey into the Marshall Regenerator's chorus (lightly of course). This is an absolutely awesome set-up. __________________ One man's ear is totally different from another man's. Some are tone deaf, others have perfect pitch, and yes, some just don't give a s**t.

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