RedPlating JVM after retube with FX loop "on"
Posted: 15 Mar 2015, 07:17
Hi All
I am looking for some advice/opinions. I bought a USED Marshall JVM 410H (2008 MY) and decided to retube it to get it to "good tone"
I went V1-5 TAD 12AX7 WA/TAD 12AX7-C/TAD 7025S/TAD7025S/JJ ECC803S
In the power section I installed 4 JJ EL34L (tubedepot 38 hardness) matched quad with 24 hour burn in (Just like my trusty DSL 100 JCM 2000) Great luck
Let the amp run 2-3 hours and set BIAS to 70% with my dual BIAS PROBES. I ran it at home at 1 MV and yesterday was the first day I used it at band practice after "tone hunting on the amp" overall I really like the amp
Sad to say, I did encounter a problem
I run a BOSS DD3 delay, I tried "the loop" not the power amp loop but the other loop. I set the stitch to recommended -10 dB and started to play with it. The volume started to drop in the amp and I then went to the tubes to see.
The pair closest the power transformer (looking through the grille) were REDPLATING!!!! I immediately shut off the amp and pulled the loop cables and took it out 110%
Waited 3 minutes, refired back up and all 4 tubes were the nice usual colour. I ran it for 3 hours jamming on MV 3-4 and didn't have a problem after that.
Whats the deal? I checked the plate voltage and adjusted off 70% of that This method has worked for every other amp I've owned (I don't believe this to be a BIAS issue)
Could it be the V3/4 preamp tubes that control the loop????
The amp came back no worries and sounded great however I DID NOT USE THE FX LOOP AFTER THAT
I'm just scared now, I was contemplating getting a BOSS NS-2 for the gate as well, I really love OD1/2 on orange and the gain set to 2 on the dial and the channel volumes at 5 or higher and I've read a noise suppressor can cure those "squealies" however I am very reluctant now to put anything ever again into the loop
Could the loop be the issue or could it be something totally different....
Thanks In Advance
Dan
I am looking for some advice/opinions. I bought a USED Marshall JVM 410H (2008 MY) and decided to retube it to get it to "good tone"
I went V1-5 TAD 12AX7 WA/TAD 12AX7-C/TAD 7025S/TAD7025S/JJ ECC803S
In the power section I installed 4 JJ EL34L (tubedepot 38 hardness) matched quad with 24 hour burn in (Just like my trusty DSL 100 JCM 2000) Great luck
Let the amp run 2-3 hours and set BIAS to 70% with my dual BIAS PROBES. I ran it at home at 1 MV and yesterday was the first day I used it at band practice after "tone hunting on the amp" overall I really like the amp
Sad to say, I did encounter a problem
I run a BOSS DD3 delay, I tried "the loop" not the power amp loop but the other loop. I set the stitch to recommended -10 dB and started to play with it. The volume started to drop in the amp and I then went to the tubes to see.
The pair closest the power transformer (looking through the grille) were REDPLATING!!!! I immediately shut off the amp and pulled the loop cables and took it out 110%
Waited 3 minutes, refired back up and all 4 tubes were the nice usual colour. I ran it for 3 hours jamming on MV 3-4 and didn't have a problem after that.
Whats the deal? I checked the plate voltage and adjusted off 70% of that This method has worked for every other amp I've owned (I don't believe this to be a BIAS issue)
Could it be the V3/4 preamp tubes that control the loop????
The amp came back no worries and sounded great however I DID NOT USE THE FX LOOP AFTER THAT
I'm just scared now, I was contemplating getting a BOSS NS-2 for the gate as well, I really love OD1/2 on orange and the gain set to 2 on the dial and the channel volumes at 5 or higher and I've read a noise suppressor can cure those "squealies" however I am very reluctant now to put anything ever again into the loop
Could the loop be the issue or could it be something totally different....
Thanks In Advance
Dan