no gain on sub amp

[420247]

Hello,

I attempted to install an adcom amp to the LFE channel of an Onkyo receiver. The adcom amp doesn't have a gain control. .......I think the amp expects a 10V input, I can't get the sub loud enough to blend with the mains.......is there a reccomended line driver used for people with DIY subs??

Thanks

[brucek]

The adcom amp doesn't have a gain control. .......I think the amp expects a 10V input

That would be considered a fairly high voltage level for a spec on maximum input. Can you tell us the model of adcom amp you're referring to?

Generally the input 'gain' control to an amplifier is simply an attenuator that lowers the input level to the amplifier.

brucek

[420247]

unfourtunatly I don't have the model number handy............I thought this may of been a common problem. When attempting to install the sub we tried 3 different amps with the same result (they too had fixed gains) I used REW to send a 60hz sine wave to the Onkyo receiver and measured 100mV AC on the LFE channel with a multimeter.

From my reading on this site the output should be around 2V....the amps manuel had an input range of "x"V-10V, I assumed that 10V would be required to drive the amp to full output............the onkyo must have a bad LFE out?????

[brucek]

From my reading on this site the output should be around 2V....the amps manuel had an input range of "x"V-10V, I assumed that 10V would be required to drive the amp to full output............the onkyo must have a bad LFE out?????

Well, you're not making this easy by not supplying the model number of the Onkyo receiver, but a random sample on their site reveals most seem to supply about a volt from the sub out jack. This would be considered standard (but slightly on the low side). The standard is +2dBV, which translates to 1.26rms volts. The one volt that your receiver should be able to supply is close enough to drive any consumer amp into fits.

An amp that requires 10volts for maximum out would be a PRO amp. I don't have the specs, so I can't really comment.

If your Onkyo outputs 100mvolts at full output, then that is indeed low.

Most people here use a line amp if they don't have the level required to supply a Pro level amp.

brucek

[Wayne A. Pflughaupt]

Can you itemize what your filter settings are?

Regards,
Wayne