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Xiderpunk · 10-30-2008, 06:48 AM

Recently at rehersal ran into a new problem occuring with my DSL 50 or Jackson DK2, I am not entirely sure which is the cause as yet, hence asking for opinions based on others experience.

First the DSL 50 is tubed with 1 original ECC83 in 1, JJ ECC83S in 2,3,4 and two JJ E34L for power tubes. I had all JJ's but the first 1 died within hours in position 1 so put the original back in. All the remaining JJ tubes probably have around 10 hours of play time on them.

The settings I tend to use are Lead 2 with gain at around 7-8 and volume at around 4.5 (earth trembling loud). EQ wise, deep switch in, pres 4, treble 3, mid 6, bass 7, tone shift out. Basically a real Megadeth heavy type tone.

Prior to retubing had no particular feedback problems with these settings, other than the usual, damping strings would stop it immediately. However now with these settings I am getting a mid-range howling (imagine a large dog howl), strings dampened or not, only reducing the guitar volume or playing stops it. Even from 15 feet away from the amp.

My initial thoughts was OK this is probably yet another JJ tube problem, with one of them going microphonic. However I checked all tubes using the pencil tap method.. no difference between tubes.. no sound generated through the speaker with guitar unplugged using very high volume/gain settings.

On the guitar I mainly use the bridge pickup.. a Seymour Duncan TB4 which is a very hot pickup. Using the two single coils (SD STK1's) I have found the howling doesn't start till around vol 6-7 (ears bleeding level), however it is the same howl.. starting at the same pitch and gradually increasing.

Reducing the gain or volume on the amp eliminates the issue, however naturally this is not desirable.

In trying to diagnose this I have tried several different cables to no avail also and also going straight to amp with nothing in the effects loop.

So I still suspect that 1 or more tube is responsible, however after failing with the pencil technique I am questioning whether my guitar could be the cause. Anyone seen these symptoms before?

10-30-2008, 06:48 AM	#1 (permalink)
Xiderpunk Senior Member Join Date: Apr 2008 Location: Farnborough, UK Posts: 122	DSL or Pickup howl? Recently at rehersal ran into a new problem occuring with my DSL 50 or Jackson DK2, I am not entirely sure which is the cause as yet, hence asking for opinions based on others experience. First the DSL 50 is tubed with 1 original ECC83 in 1, JJ ECC83S in 2,3,4 and two JJ E34L for power tubes. I had all JJ's but the first 1 died within hours in position 1 so put the original back in. All the remaining JJ tubes probably have around 10 hours of play time on them. The settings I tend to use are Lead 2 with gain at around 7-8 and volume at around 4.5 (earth trembling loud). EQ wise, deep switch in, pres 4, treble 3, mid 6, bass 7, tone shift out. Basically a real Megadeth heavy type tone. Prior to retubing had no particular feedback problems with these settings, other than the usual, damping strings would stop it immediately. However now with these settings I am getting a mid-range howling (imagine a large dog howl), strings dampened or not, only reducing the guitar volume or playing stops it. Even from 15 feet away from the amp. My initial thoughts was OK this is probably yet another JJ tube problem, with one of them going microphonic. However I checked all tubes using the pencil tap method.. no difference between tubes.. no sound generated through the speaker with guitar unplugged using very high volume/gain settings. On the guitar I mainly use the bridge pickup.. a Seymour Duncan TB4 which is a very hot pickup. Using the two single coils (SD STK1's) I have found the howling doesn't start till around vol 6-7 (ears bleeding level), however it is the same howl.. starting at the same pitch and gradually increasing. Reducing the gain or volume on the amp eliminates the issue, however naturally this is not desirable. In trying to diagnose this I have tried several different cables to no avail also and also going straight to amp with nothing in the effects loop. So I still suspect that 1 or more tube is responsible, however after failing with the pencil technique I am questioning whether my guitar could be the cause. Anyone seen these symptoms before? __________________ Marshall JCM2000 DSL-50 with 1960A 4x12 (2 x GT-75's + 2 x Vintage 30's) V1: NOS Mullard 12AX7 V2: Sovtek 12AX7-EH V3: JJ ECC83S V4: JJ ECC83S Power: JJ KT77 or JJ EL34L http://www.myspace.com/taintedgraceband