JLM AUDIO

BTW since converting to active I've got a low level buzzy hum - seems to be in all 3 drivers, tho most noticable in the tweeter.

the passive one is dead silent.

here's the same thing a different way, this time I used SignalScope Pro for osx, and a naiant very small diaphragm omni condenser thru the BAN and fireface. i put the mic only 75cm away because room asymmetry and clutter were likely to have an effect. similar result active http://www.greenmanhumming...

heres a quick and dirty comparison using the freq analyser on my iphone. I fed each speaker pink noise, and held the phone 1m in front level with the tweeter. a crossover dip at 2k in the active version? i wouldnt believe the lack of signal below 125hz thats probably just the iphone... active http:/...

thanks again! RMAA is windows only i think, I'm on OSX, i can boot into windows, but its a pain, and i don't know my way round or have anything configured right, so it might be a while. know of a similar program for mac? I'll have a look, but let me know if there's one you recommend, I've got a freq...

well I've changed one channel to active it works, it sounds good, but i'm not yet sure if it actually sounds better than the passive version. certainly it is different. very hard to describe the difference, other than the tweeter level. theres actually maybe subjectively a little less deep bass. but...

great to see someone else building these, keep us posted on how it goes! my caps for the crossovers arrived today so Joe - a few more questions: * should i leave a passive zobel on the tweeter or is that not now needed with the active setup? * any thoughts on tweeter protection with active? I though...

thanks! its great to have all this help! what are the consequences of getting out of line with the tweeter when using symmetrical drivers? phase cancellation between mid drivers i guess? comb filter effect? aside from the simplicity, whats the advantage of going 2 way rather than the original 2 1/2 ...

I built a opa2604 buffer, works great, and fixed my low level hum problem with the passive volume before it too. not many places here sell 82nF caps or 82 anything really. everything jumps from 68 to 100. i guess a 68 and a 15 in parallel would be ok? looking for decent mkp caps. any recommendations...

The 2 x 1k and 82nF could be shared by both amps with only a small change to its load by the 2 amps but it may change the woofer level a bit as well. but putting it on both won't change the freq response? do the 1k resistors separate the 82nF enough that fitting to both is OK, ie not like putting 1...

brilliant thanks! looks easy enough. does the woofer amp stuff need to be done to both woofer amps? or does some of it interact? the stuff on the input would be paralleled with 2 amps and both fitted like this. how low impedance does it need to be driven by? I'm thinking of making a balanced input b...

link to the schem not working for me...

wow those curves look pretty close, what component did you put where to achieve that? my vol control is a 4 gang stepped attenuator, so matching shouldn't be too much of an issue. the hum thing though i suspect will be a problem, and if the passive is incompatible with the crossover system you've wo...

bump! I'd love some input on some of the issues above * humming volume control inline, whats the best way to do a remote inloine balanced volume control? * mixing 18db and 12 db slopes doesnt this cause phase issues? * any more input at all on the best way to build a active crossover for these speak...

the output is loaded with 10k resistors, but i imagine the actual output impedance of the opamp is very low,like 25ohms or something. i wired the 5402 series-parallel for 1:1 same as the datasheet but without the feedback drive circuit. I had earlier tried it 2:1 in a valve pre, but it was a bit ton...

I have some LL5402 output transformers, are they suitable as a 1:1 OT for a BA with 99v? www.lundahl.se/pdfs/datash/5402.pdf it seems to work OK. any thoughts? what is the output impedance of the BA with single 99v? should I adjust some output resistors? the LL5402 seems to like low z operation, it ...