D
Deleted member 13074
Guest
Artist Edition head purchased new around 12mo ago
Worked fine and not huge hours
Stopped giving sound, but remained lit up
Was running the master at 5 and loop level at half - very loud into iso cab
Lamp on rear indicated power tube fuse blown
4 individual power tube fast blow fuses F160mA under chassis
3 had blown
Ordered direct replacements, and MT160mA version as manual says 'medium blo'
Replaced all 4 like-for-like with F160mA, and one quickly went again (#2) but amp still giving sound
Replaced fuse again
Took out tubes 2&3
Halved speaker ohms
Ran okay
Moved that pair of tubes to sockets 2&3
Ran okay
Went to a new set of JJ EL34 IIs
All four put in for bias
All 4 in, power off standby, bias was 67mV(!)
Reduced to minimum bias on dial - around 25mV
After a few seconds, fuse #3 blew
Replaced that fuse, swapped tubes 3 & 4
Ran okay
Decided it must be the fuses as there was no consistent failure
Put in MT160mA in all slots
Biased up to 30mV
Sounded a bit flat, lower gain (obvs)
Upped it to 34mV, and much better gain structure
Still not convinced there was any issue with the power tubes
Can’t understand why the manual would say medium and the amp be loaded with fast
Never seen a medium blo fuse in this position in an amp
Sent a message to Engl's online cust service, then another to different email
No responses after many weeks
It has run fine for a good while since, but I have to wonder what was blowing the fuses and whether a medium blo is going to set me up for a bigger failure in future
Worked fine and not huge hours
Stopped giving sound, but remained lit up
Was running the master at 5 and loop level at half - very loud into iso cab
Lamp on rear indicated power tube fuse blown
4 individual power tube fast blow fuses F160mA under chassis
3 had blown
Ordered direct replacements, and MT160mA version as manual says 'medium blo'
Replaced all 4 like-for-like with F160mA, and one quickly went again (#2) but amp still giving sound
Replaced fuse again
Took out tubes 2&3
Halved speaker ohms
Ran okay
Moved that pair of tubes to sockets 2&3
Ran okay
Went to a new set of JJ EL34 IIs
All four put in for bias
All 4 in, power off standby, bias was 67mV(!)
Reduced to minimum bias on dial - around 25mV
After a few seconds, fuse #3 blew
Replaced that fuse, swapped tubes 3 & 4
Ran okay
Decided it must be the fuses as there was no consistent failure
Put in MT160mA in all slots
Biased up to 30mV
Sounded a bit flat, lower gain (obvs)
Upped it to 34mV, and much better gain structure
Still not convinced there was any issue with the power tubes
Can’t understand why the manual would say medium and the amp be loaded with fast
Never seen a medium blo fuse in this position in an amp
Sent a message to Engl's online cust service, then another to different email
No responses after many weeks
It has run fine for a good while since, but I have to wonder what was blowing the fuses and whether a medium blo is going to set me up for a bigger failure in future