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Old 6th July 2013, 07:20 PM   #1
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Default Need hekp with how to select a preamp

I just bought 2 QSC 1400 amps to run a pair of Bose series 1 901's and the volume knobs are in the back.

I have an EQ so inputs are not a real issue, but I would like a main volume control for the amps, plus I read that the output volts should be around close to 2. on the preamp for these amps to get full use.

Please help I am lost, and not looking to spend a lot on a preamp jsut need volume control.

Thank you for nay ideas or opinions.
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Old 6th July 2013, 10:57 PM   #2
Zero D is offline Zero D  United Kingdom
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Hi, in their PDF, it says 1 Volt RMS for rated power @ 8 Ohms !

Quote:
2 QSC 1400 amps to run a pair of Bose series 1 901's
1 - The Amps are 2 channel, so why do you need 2 Amps to run 1 pair ? Are you going to bridged the outputs ?

2 - Are you going to use the unbalanced inputs, or balanced on the 1400's ?

3 - Does the EQ have balanced inputs & outputs ?
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Old 6th July 2013, 11:11 PM   #3
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Speaker Power and Performance

  • The Bose 901 Series 1 speakers have a maximum power output of 270 watts per channel RMS at 8 ohms. They can handle a power surge of 400 watts for less than five seconds. The minimum amplifier output necessary to operate the speakers is 25 watts per channel, and the speakers produce a continuous sine wave of 50 watts per channel. Eighty-nine percent of the power is radiated by reflection, and 11 per cent is radiated directly.


Read more: Bose 901 Series 1 Specs | eHow

They will explode with that sort of power!
1100 1200 1400 1700
OUTPUT POWER(per channel)
Both Channels Driven
8 ohms, 20-20 kHz, 0.1% THD 50w 100w 200w 325w
4 ohms, 20-20 kHz, 0.1% THD 70w 150w 300w 500w
Bridged-Mono Operation
8 ohms, 20-20 kHz, 0.1% THD 140w 300w 600w 1000w
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Old 7th July 2013, 10:17 PM   #4
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They will be bridged and they won't be cranked up full volume ever, but the amps will be set at half and I would like a cheap preamp just to control the volume.

I will be using the 1/4 input on the amps with RCA on the other ends.

I know this is more than needed for theses speakers, but I have run them on other people's stereos and they distort real early compared to on my old pioneer receiver with 110 a channel real watts that I use but I might get different speakers eventually so I want more power if buying amps might as well buy something I want.

PS anyone that finds this thread the 901's series1 do not work real well with low powered amps, including fake pa amps with false ratings of 1,000+ watts.
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Old 8th July 2013, 12:41 AM   #5
Zero D is offline Zero D  United Kingdom
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Your EQ should have input & output volume controls, & if so should be fine. What make & model is it ?

If for some reason it hasn't then i can show you how to make a Very simple one. But can you solder & have got a soldering iron ?
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Old 8th July 2013, 03:12 AM   #6
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Um... a preamp for "what"? Guitar?

Are you talking about a hi-fi stereo preamp with switchable input (like, phono, tape, etc)?

Or, more for instruments, like a mixer board?
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Old 8th July 2013, 03:42 AM   #7
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Join Date: Apr 2013
It would have been a hi fi preamp. I found an RCA line level controller all built for a couple bucks, I suppose that is all I need.

I don't think I can build one for that price.
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Old 26th July 2013, 02:03 AM   #8
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Thank you, but I have them hooked up now and they are no where near close to exploding at full volume they run wide open just fine. This is with a out a preamp right now so not sure how much that will improve the power but just direct input to the amp bridged teh speaker has no distortion or no struggle at full gain.

How much more power will there be with a preamp? I hope a lot more at this point I am disappointed since my 110 a channel receiver is close but starts to distort after 3/4 volume.


Quote:
Originally Posted by JonSnell Electronic View Post
Speaker Power and Performance

  • The Bose 901 Series 1 speakers have a maximum power output of 270 watts per channel RMS at 8 ohms. They can handle a power surge of 400 watts for less than five seconds. The minimum amplifier output necessary to operate the speakers is 25 watts per channel, and the speakers produce a continuous sine wave of 50 watts per channel. Eighty-nine percent of the power is radiated by reflection, and 11 per cent is radiated directly.


Read more: Bose 901 Series 1 Specs | eHow

They will explode with that sort of power!
1100 1200 1400 1700
OUTPUT POWER(per channel)
Both Channels Driven
8 ohms, 20-20 kHz, 0.1% THD 50w 100w 200w 325w
4 ohms, 20-20 kHz, 0.1% THD 70w 150w 300w 500w
Bridged-Mono Operation
8 ohms, 20-20 kHz, 0.1% THD 140w 300w 600w 1000w
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