martin1970 361 Posted February 23, 2014 Posted February 23, 2014 There is a member using a C-1 to drive 2 stereo amplifiers. One output goes to the amp he has driving his speakers' built-in woofer inputs. The other goes to his speakers' built-in mid/tweeter inputs. He's happy using the crossovers that are built into the speakers for this setup. His only issue is that he needs to dial back the gain on one of the amps to level-match with the other one. Ideally, he'd like a component that he can simply plug RCAs (unbalanced setup) into to accomplish this. He doesn't need a full-on set of active crossovers. Anyone know of a decent quality component to do this with that will introduce the least noise into the chain? Given how little this thing has to do, is there a cheap solution?
dennismiller55 4,824 Posted February 23, 2014 Posted February 23, 2014 Here is a product that should work: These are fixed and he may have to experiment with different amounts of attenuation. 1 db > Parts Express Part # 266-230 3 db > Parts Express Part # 266-232 6 db > Parts Express Part # 266-234 1
TNRabbit 371 Posted February 23, 2014 Posted February 23, 2014 your easiest solution is to take a 10k audio taper pot (low wattage...1/2watt or 1/4watt) and put it inline.... about $3.00...
Nahash5150 10,984 Posted February 23, 2014 Posted February 23, 2014 That or if we knew the amps involved, we could calculate the difference between the gains and find the right fixed attenuator.
Zoom 373 Posted February 23, 2014 Posted February 23, 2014 There is a member using a C-1 to drive 2 stereo amplifiers. One output goes to the amp he has driving his speakers' built-in woofer inputs. The other goes to his speakers' built-in mid/tweeter inputs. He's happy using the crossovers that are built into the speakers for this setup. His only issue is that he needs to dial back the gain on one of the amps to level-match with the other one. Ideally, he'd like a component that he can simply plug RCAs (unbalanced setup) into to accomplish this. He doesn't need a full-on set of active crossovers. Anyone know of a decent quality component to do this with that will introduce the least noise into the chain? Given how little this thing has to do, is there a cheap solution? Geez I have this problem to the nth degree. Driving multiple amplifiers, half without gain control, it's is an absolute nightmare to get them to balance and all peak at the same time. My C-11 obviously has 2 outputs. I split them four times. I'll bet a repair team member could dedicate a whole thread to what amps like what input voltage. I didn't know the attenuators existed in this form. But, the issue remains. And those attenuators or a pot should do the trick.
Zoom 373 Posted February 23, 2014 Posted February 23, 2014 That or if we knew the amps involved, we could calculate the difference between the gains and find the right fixed attenuator. You can really do that, Greg?
Nahash5150 10,984 Posted February 23, 2014 Posted February 23, 2014 With respect to voltage levels, yes. An M500 has an input sensitivity of 1.414V, or 30dB An M500t has an input sensitivity of 2V, or 27dB Put a 3dB attenuator on the M500 and you get a 3dB cut to the input signal, which will give you 27dB (1.414V / .707 = 2) 1
B-Man 4,784 Posted February 23, 2014 Posted February 23, 2014 Or, if he can figure out how much cut he needs, he could reduce the output of the main out on his C-1 by swapping out resistors R258, R259, R358 & R359. Doing this affects only the main output - the secondary output is not affected. The part #'s in the list below are from Mouser for 1% MF resistors. No additional parts in the signal path and no extra mechanical connections. 1
Zoom 373 Posted February 23, 2014 Posted February 23, 2014 With respect to voltage levels, yes. An M500 has an input sensitivity of 1.414V, or 30dB An M500t has an input sensitivity of 2V, or 27dB Put a 3dB attenuator on the M500 and you get a 3dB cut to the input signal, which will give you 27dB (1.414V / .707 = 2) Geez I feel like a dumbass....
zumbini 6,153 Posted February 23, 2014 Posted February 23, 2014 If you are looking for adjustability an active balance or DI (direct interface) box might be a better choice. They are designed to adapt a single-ended source to a balanced input but can be configured to pass either. I use an Aphex 124A ($50 used) but ART, BBE, Behringer, Boss, DBX, Nady and others make them too. (Make sure the balance box you choose has variable gain controls 1
cwad8505 148 Posted February 23, 2014 Posted February 23, 2014 With respect to voltage levels, yes. An M500 has an input sensitivity of 1.414V, or 30dB An M500t has an input sensitivity of 2V, or 27dB Put a 3dB attenuator on the M500 and you get a 3dB cut to the input signal, which will give you 27dB (1.414V / .707 = 2) Greg.. How about a small DIY pre-amp like the one you sent to me?? (Of which.. I still haven't gotten around to finishing!) Chris
Nahash5150 10,984 Posted February 23, 2014 Posted February 23, 2014 That tube buffer is unity gain, but yes, it would be fairly easy to make it into an attenuator too.
danowood 2,167 Posted February 23, 2014 Posted February 23, 2014 I have a c-1 and drive two M 1.0T's MKII's Opt2. I use Main 1 out for 1 amp and Main 2 out for the other. When Bi amping I use one amp for left out to left bass, and right out for right mids and tweeters (using existing passive xovers in the speakers, but were split the bass from mid and uppers ), Then on the other amp I put right out to right bass and left out to left mid and uppers. They seem to pretty damned ballanced as far as load and as far as sound. Could be your hook up needs to be more ballanced if all the load on one am is doing the bass and the other amp the mid and highs one is working much harder than the other. Just MHO.
TNRabbit 371 Posted February 23, 2014 Posted February 23, 2014 I have a c-1 and drive two M 1.0T's MKII's Opt2. I use Main 1 out for 1 amp and Main 2 out for the other. When Bi amping I use one amp for left out to left bass, and right out for right mids and tweeters (using existing passive xovers in the speakers, but were split the bass from mid and uppers ), Then on the other amp I put right out to right bass and left out to left mid and uppers. They seem to pretty damned ballanced as far as load and as far as sound. Could be your hook up needs to be more ballanced if all the load on one am is doing the bass and the other amp the mid and highs one is working much harder than the other. Just MHO. I see your thought process, but the issue is different input sensitivity between the amps.
martin1970 361 Posted February 23, 2014 Author Posted February 23, 2014 Thanks for all the great answers guys. Lots of options for sure. That or if we knew the amps involved, we could calculate the difference between the gains and find the right fixed attenuator. It looks like he's got an M1.0t MK2 Opt 2 and ab M-500t MK2 in this setup.
Nahash5150 10,984 Posted February 23, 2014 Posted February 23, 2014 The M1.0t inverting version has the same gain as the M-500t. The NON-inverting version of the M1.0t is 30dB gain, which is +3dB more than the M-500t. The mkII mods do not change the gain.
danowood 2,167 Posted February 23, 2014 Posted February 23, 2014 The M1.0t inverting version has the same gain as the M-500t. The NON-inverting version of the M1.0t is 30dB gain, which is +3dB more than the M-500t. The mkII mods do not change the gain. So if you have 1 m1.0t mkII inverting and 1 m1.0tmkII non inverting what needs to be done between the pre amp and the amps respectively?
Nahash5150 10,984 Posted February 23, 2014 Posted February 23, 2014 I didn't know you were using those to bi-amp Dano... I thought you had two non-inverting right? Anyway, the best solution is to use two of the same type. Other than that, putting a 3dB attenuator on each of the inputs of the non-inverting will balance those amps out. 1
danowood 2,167 Posted February 23, 2014 Posted February 23, 2014 I didn't know you were using those to bi-amp Dano... I thought you had two non-inverting right? Anyway, the best solution is to use two of the same type. Other than that, putting a 3dB attenuator on each of the inputs of the non-inverting will balance those amps out. You did 3 rebuilds Hashy two of 1 and 1 of the other. I did a quick check and luckily I kept the two that were the same and gave the other to my daughter so all is good. You da best!!!
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