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purejazz
11-20-2015, 07:14 AM
I have a Rca 100w tube amp powering a jbl 3110 and 3105 crossover , my issue and question is if I connect the 3110 XO not using the LF connection and connect the HF to the 3105 input and outputs of 3105 LF to jbl2440 and HF to jbl 2405 tweeter . Will not having the LF on the 3110 connected cause issues on my output transformer or the XO , any input that can shed light on this would be great , I have heard that this is a no no and may stress OP transformer , some say not a problem. If there is a almost expert or expert on the subject matter please chime in , thanks . I tried using a dummy load as a means to load the LF of the 3110 , I noticed that there is a blue light emitted from my power tubes each time the bass hits , not sure if this is overworking tubes or XO either way I removed dummy loads . Dose anyone have this configuration used long term without damage to amp or XO ??????

grumpy
11-20-2015, 08:17 AM
Blue glow is not typically a problem. Some circuits do this more than others.
I have a MusicMan amp that runs at >700v on EL34s ... they run blue all day long.

Most tube circuits do not like to be unloaded and played hard.
A dummy load (even 2x the nominal value, e.g., 16ohms vs 8) should be ok, just don't
go lower than nominal.

Crossover operation won't care. (3110 LF and HF circuits are in parallel).

purejazz
11-20-2015, 04:30 PM
thanks for you reply , if I am reading what you are saying , the blue glow when the low frequencies hit is not a problem to amp or crossover ???, the reason why I ask this is because on another exact amp powering a le15a and le85 when the bass hits no glow at all , this leads me to believe that the amp is being overdriven or something along those lines . Ideally I would like to just leave off the LF and only use the HF to drive the 3105 XO , based on what I think I understand by your statement , no LF connection to a woofer will not be a problem to amp or XO ????. Am I on the right page with this ????

grumpy
12-10-2015, 11:04 PM
Sorry, I missed your reply. I'd still load the crossover LF terminals to be safe,
but using a larger value should be ok ( and load the amp less ).