FP 33 and XL2

Steve Oakley · June 9th, 2008, 09:11 PM

yes. its not that a switching supply can't make clean power, its that you won't know it until you plug it in :( so a basic transformer type supply is better, with a basic regulator.

Josh Bass · June 9th, 2008, 09:26 PM

Thanks. It's all Greek to me, so I appreciate the guidance. If I didn't mention it before, I'm using the PS21 external power supply so far. . .haven't tried batteries yet . Also, when I do the battery test (again, with external power, but it's supposed to give you a reading on either), which is supposed to tell you whether it's getting adequate power, the needle is right at 0. . .I don't know if Shure means for that to tell me it's too low (technically it's outside the happy power red zone, but just barely).

Josh Bass · June 10th, 2008, 12:08 PM

A friend of mine much more versed in electronics and audio matters took at look at the circuit diagram for the mixer (I guess this ships with the mixer), and tells me that though it can take up to 30 volts, everything is regulated down to 15.

Steve Oakley · June 11th, 2008, 09:49 PM

I for one would love to see a circuit diagram of the FP33. are you sure its a 33 ? and not a 32 which is a different beast. AFAIK they have never put out circuit diagrams, certainly not with the unit, but maybe as a service manual. just because there are 7815 regulators doesn't mean its 15V. while thats what the regulator is putting out, op amps require negative voltage to work correctly so the difference between +15 and -15V is 30. knowing those TL082's that shure used, this would be near their max operational voltage.

Josh Bass · June 12th, 2008, 01:21 AM

I'll pass your circuitry question on to my friend. We tried the mixer with a 19v power supply he had, which based on his thoughts, would have provide plenty of juice. I noticed a few things--the little LED that was blinking red when I turned on the power with the PS21 power supply was now blinking green, and when I did the battery check, it was way in the red, instead of at 0, where it was with the PS21. So I guess that's good. I couldn't hear a huge sound difference, but those other signs seem to indicate that it does want a hotter power supply, even if not quite as hot as you state.

Yes, it is "shurely" (heh) an FP33, says so right on the front. I'm sorry, I can't find a tech diagram anywhere online. I have a hard copy, but this thing unfolds like a map, it's huge! It'd be tough to scan. If you want to seek it out, it's called "FP33 Stereo Mixer Technical Information". Maybe they'd send you one if you called.

Marco Leavitt · June 12th, 2008, 04:20 PM

You probably will get a little better performance using the RCA consumer line inputs, but I don't think it would be worth dealing with an unbalanced signal. I'd put barrel attenuators on the mic inputs and use that, so you can run a true line level signal. It's way safer when working around power cords and other things that can cause interference.

Josh Bass · June 12th, 2008, 04:24 PM

Even using the Beachtek XLR adapter to get the line level? I've tried it, seems to work fine. What kind of pad, for mic level? Where do I get them? How much?

Marco Leavitt · June 12th, 2008, 04:45 PM

I think using a Beachtek would be really awkward with the XL2. You want the ShureA15LA.

http://www.bhphotovideo.com/c/produc...e_Adapter.html

You may need two of them. Pricey, yes, but from what I understand you can't cheap out on an attenuator. The quality of the transformer can have an impact on the sound.

I usually tape the XLR cable to the handle of the tripod in case somebody trips on it. Because the attenuators are so long, it would be a lot of strain on the inputs if somebody were to jerk at the cable at a 90 degree angle.

Josh Bass · June 12th, 2008, 07:17 PM

Can you clarify, awkward how? Thanks.

Marco Leavitt · June 13th, 2008, 09:42 AM

Well, the XL2 is already kind of large and unwieldy. Balancing it on top of one of those Beechtek or other XLR adapter isn't something I'd do.

Josh Bass · June 13th, 2008, 01:34 PM

Ah. Well, I've always left the beachtek ok there, regardless of whether it gets used or not.

Josh Bass · June 13th, 2008, 05:24 PM

So, according to my tests, it seems that if I want to get my cam to max out when the mixer does (according to Ty), I actually need to set the tone higher, not lower. So, equating the 0 tone on the mixer to -20 on the cam causes the cam, no matter how loud I get, to max out at about -6; it simply won't go any higher without turning up the cam's pots. If I set 0 tone to -12, though, then the cam maxes out at -2 or so, about where ty said the peaks should be. I guess if I did it between -20 and -12, it would all work out. Or, if instead of setting the mixer's master pot to 0 for tone, I could set that lower as well.

June 9th, 2008, 09:26 PM	#32
Josh Bass Slash Rules! Join Date: Apr 2002 Location: Houston, Texas Posts: 5,472	Thanks. It's all Greek to me, so I appreciate the guidance. If I didn't mention it before, I'm using the PS21 external power supply so far. . .haven't tried batteries yet . Also, when I do the battery test (again, with external power, but it's supposed to give you a reading on either), which is supposed to tell you whether it's getting adequate power, the needle is right at 0. . .I don't know if Shure means for that to tell me it's too low (technically it's outside the happy power red zone, but just barely). __________________ The Bass' camerawork The Bass on IMDB

June 10th, 2008, 12:08 PM	#33
Josh Bass Slash Rules! Join Date: Apr 2002 Location: Houston, Texas Posts: 5,472	A friend of mine much more versed in electronics and audio matters took at look at the circuit diagram for the mixer (I guess this ships with the mixer), and tells me that though it can take up to 30 volts, everything is regulated down to 15. __________________ The Bass' camerawork The Bass on IMDB

June 12th, 2008, 01:21 AM	#35
Josh Bass Slash Rules! Join Date: Apr 2002 Location: Houston, Texas Posts: 5,472	I'll pass your circuitry question on to my friend. We tried the mixer with a 19v power supply he had, which based on his thoughts, would have provide plenty of juice. I noticed a few things--the little LED that was blinking red when I turned on the power with the PS21 power supply was now blinking green, and when I did the battery check, it was way in the red, instead of at 0, where it was with the PS21. So I guess that's good. I couldn't hear a huge sound difference, but those other signs seem to indicate that it does want a hotter power supply, even if not quite as hot as you state. Yes, it is "shurely" (heh) an FP33, says so right on the front. I'm sorry, I can't find a tech diagram anywhere online. I have a hard copy, but this thing unfolds like a map, it's huge! It'd be tough to scan. If you want to seek it out, it's called "FP33 Stereo Mixer Technical Information". Maybe they'd send you one if you called. __________________ The Bass' camerawork The Bass on IMDB

June 12th, 2008, 04:24 PM	#37
Josh Bass Slash Rules! Join Date: Apr 2002 Location: Houston, Texas Posts: 5,472	Even using the Beachtek XLR adapter to get the line level? I've tried it, seems to work fine. What kind of pad, for mic level? Where do I get them? How much? __________________ The Bass' camerawork The Bass on IMDB

June 12th, 2008, 07:17 PM	#39
Josh Bass Slash Rules! Join Date: Apr 2002 Location: Houston, Texas Posts: 5,472	Can you clarify, awkward how? Thanks. __________________ The Bass' camerawork The Bass on IMDB

June 9th, 2008, 09:11 PM	#31
Steve Oakley Trustee Join Date: Apr 2006 Location: United States Posts: 1,158	yes. its not that a switching supply can't make clean power, its that you won't know it until you plug it in :( so a basic transformer type supply is better, with a basic regulator.

June 11th, 2008, 09:49 PM	#34
Steve Oakley Trustee Join Date: Apr 2006 Location: United States Posts: 1,158	I for one would love to see a circuit diagram of the FP33. are you sure its a 33 ? and not a 32 which is a different beast. AFAIK they have never put out circuit diagrams, certainly not with the unit, but maybe as a service manual. just because there are 7815 regulators doesn't mean its 15V. while thats what the regulator is putting out, op amps require negative voltage to work correctly so the difference between +15 and -15V is 30. knowing those TL082's that shure used, this would be near their max operational voltage.

June 12th, 2008, 04:20 PM	#36
Marco Leavitt Inner Circle Join Date: Jul 2002 Location: Albany, NY 12210 Posts: 2,652	You probably will get a little better performance using the RCA consumer line inputs, but I don't think it would be worth dealing with an unbalanced signal. I'd put barrel attenuators on the mic inputs and use that, so you can run a true line level signal. It's way safer when working around power cords and other things that can cause interference.

June 12th, 2008, 04:45 PM	#38
Marco Leavitt Inner Circle Join Date: Jul 2002 Location: Albany, NY 12210 Posts: 2,652	I think using a Beachtek would be really awkward with the XL2. You want the ShureA15LA. http://www.bhphotovideo.com/c/produc...e_Adapter.html You may need two of them. Pricey, yes, but from what I understand you can't cheap out on an attenuator. The quality of the transformer can have an impact on the sound. I usually tape the XLR cable to the handle of the tripod in case somebody trips on it. Because the attenuators are so long, it would be a lot of strain on the inputs if somebody were to jerk at the cable at a 90 degree angle.

June 13th, 2008, 09:42 AM	#40
Marco Leavitt Inner Circle Join Date: Jul 2002 Location: Albany, NY 12210 Posts: 2,652	Well, the XL2 is already kind of large and unwieldy. Balancing it on top of one of those Beechtek or other XLR adapter isn't something I'd do.

June 13th, 2008, 01:34 PM	#41
Josh Bass Slash Rules! Join Date: Apr 2002 Location: Houston, Texas Posts: 5,472	Ah. Well, I've always left the beachtek ok there, regardless of whether it gets used or not. __________________ The Bass' camerawork The Bass on IMDB

June 13th, 2008, 05:24 PM	#42
Josh Bass Slash Rules! Join Date: Apr 2002 Location: Houston, Texas Posts: 5,472	So, according to my tests, it seems that if I want to get my cam to max out when the mixer does (according to Ty), I actually need to set the tone higher, not lower. So, equating the 0 tone on the mixer to -20 on the cam causes the cam, no matter how loud I get, to max out at about -6; it simply won't go any higher without turning up the cam's pots. If I set 0 tone to -12, though, then the cam maxes out at -2 or so, about where ty said the peaks should be. I guess if I did it between -20 and -12, it would all work out. Or, if instead of setting the mixer's master pot to 0 for tone, I could set that lower as well. __________________ The Bass' camerawork The Bass on IMDB