INT 30A how loud should it play?

alexIG · 5th May 2013, 01:46 AM

Hi,
I bought Int 30A and it seems to me that there is something wrong with it. First of all when I crank it to max level it still can’t drive my 4ohm ML Spires (91 db) loud enough and max reading that I can get on display is 63. I would expect that the max reading should be 100. Second when I compare its max output to the output of my XA 30.5 I get LKFS reading of 0.4 for INT30A while I get 1.4 reading for XA30.5 for the same input signal. I suppose I drive 30.5 with pre that has higher gain that the one of INT30 but still I would not expect such a big difference. Any ideas?
Thank you,
Alex

Nelson Pass · 5th May 2013, 02:53 AM

No, they only go to 63, as the volume control has 8 bit resolution (0 to 63 dB).

The specified gain is 26 dB, but examination of the schematic shows that it
should have about 33 dB, which has proven adequate historically.

A definitive answer will have to wait until Wayne pops his head up. I will
drop him an email.

alexIG · 5th May 2013, 03:15 AM

Nelson, thank you for quick response. What is output impedance and max gain of the pre in INT 30A? I drive X30.5 with the pre with 1.0 kΩ ipmpedance and 20 db max gain.

Nelson Pass · 5th May 2013, 04:53 PM

There is no preamp in the INT30A. There is only an input switch and a
volume control. The gain is provided by the power amplifier.

alexIG · 5th May 2013, 08:02 PM

Now I got it.

wayne · 6th May 2013, 12:12 AM

The Int 30 has a bit more than 30 dB gain. Should be no problem if the speakers are really 91 dB. Most preamps in reality function in attenuators mode. My 85 DB speakers the pre never gets into gain mode. Of course this is source dependent.

AudioSan · 6th May 2013, 05:33 AM

ML spires is 91db at 2.83V so 88db 1w/1m

Andersonix · 6th May 2013, 06:22 PM

Maybe the Spire's built-in "200W @ 4Ohms" bass amp is not sufficient?

5th May 2013, 01:46 AM	#1
alexIG diyAudio Member Join Date: Aug 2008	INT 30A how loud should it play? Hi, I bought Int 30A and it seems to me that there is something wrong with it. First of all when I crank it to max level it still can’t drive my 4ohm ML Spires (91 db) loud enough and max reading that I can get on display is 63. I would expect that the max reading should be 100. Second when I compare its max output to the output of my XA 30.5 I get LKFS reading of 0.4 for INT30A while I get 1.4 reading for XA30.5 for the same input signal. I suppose I drive 30.5 with pre that has higher gain that the one of INT30 but still I would not expect such a big difference. Any ideas? Thank you, Alex

6th May 2013, 12:12 AM	#6
wayne In the hills diyAudio Member Join Date: Jan 2002 Location: Northern California	The Int 30 has a bit more than 30 dB gain. Should be no problem if the speakers are really 91 dB. Most preamps in reality function in attenuators mode. My 85 DB speakers the pre never gets into gain mode. Of course this is source dependent. __________________ wizards assistant

6th May 2013, 05:33 AM	#7
AudioSan diyAudio Member Join Date: Feb 2009 Location: Trondheim	ML spires is 91db at 2.83V so 88db 1w/1m __________________ aleph P1.7 pre. F5 power amp. CDpro2(need DAC). Vivaldi8 speakers

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5th May 2013, 02:53 AM	#2
Nelson Pass The one and only Join Date: Mar 2001	No, they only go to 63, as the volume control has 8 bit resolution (0 to 63 dB). The specified gain is 26 dB, but examination of the schematic shows that it should have about 33 dB, which has proven adequate historically. A definitive answer will have to wait until Wayne pops his head up. I will drop him an email.

5th May 2013, 03:15 AM	#3
alexIG diyAudio Member Join Date: Aug 2008	Nelson, thank you for quick response. What is output impedance and max gain of the pre in INT 30A? I drive X30.5 with the pre with 1.0 kΩ ipmpedance and 20 db max gain.

5th May 2013, 04:53 PM	#4
Nelson Pass The one and only Join Date: Mar 2001	There is no preamp in the INT30A. There is only an input switch and a volume control. The gain is provided by the power amplifier.

5th May 2013, 08:02 PM	#5
alexIG diyAudio Member Join Date: Aug 2008	Now I got it.

6th May 2013, 06:22 PM	#8
Andersonix diyAudio Member Join Date: Jan 2004 Location: Silicon Valley	Maybe the Spire's built-in "200W @ 4Ohms" bass amp is not sufficient?

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