Bottlehead Forum

Bottlehead Kits => S.E.X. Kit => Topic started by: Geographer on December 30, 2013, 03:31:43 PM

Title: Sex volume very low
Post by: Geographer on December 30, 2013, 03:31:43 PM
So my father and I just put together the S.E.X amp (WOOOT) and we set it to the lower impudence since I have Grado RS2's and Grado SR120s.

To test the unit we plugged in an iPhone and the volume levels were very loud.

But then I plugged in my Project Debut II original turntable and the volume is very low. Did I set something improperly? Is it the turntable? Is there anything I can do to get the output louder?

Thanks!
Title: Re: Sex volume very low
Post by: galyons on December 30, 2013, 03:39:04 PM
The turntable output needs to be preamplified and equalized via a phono stage.  There is not enough output signal strength to go directly to the amp.  Additionally vinyl records are pre-equalized via a RIAA curve. The phono stage de-equalizes the signal to a normal listening curve.

Cheers,
Geary
Title: Re: Sex volume very low
Post by: Geographer on December 30, 2013, 03:41:01 PM
I see, can you provide an example link of something I can purchase that will take care of this?

I'm pretty new to record players and hardware.

Thanks much for your reply!
Title: Re: Sex volume very low
Post by: Paul Birkeland on December 30, 2013, 04:04:45 PM
Reduction Phono Preamp (http://www.bottlehead.com/store.php/products/reduction-phono-preamplifier-kit)
Good easy reading (http://en.wikipedia.org/wiki/RIAA_equalization)

The output of a moving magnet cartridge is ~3-6mV (this is 0.003 to 0.006V), the output of your iPhone will be at least 1.5V, if not more.
Title: Re: Sex volume very low
Post by: galyons on December 30, 2013, 04:11:29 PM
I see, can you provide an example link of something I can purchase that will take care of this?...

That is pretty much a "How long is a piece of string?" request.  I take it that you have not played the turntable in your system before or were you using a receiver or integrated amp with a phono stage?  There are a multitude of phono stages available from $25 to OMG hide the checkbook. 

Do a google search for phonostges.  I am assuming that your table has a moving magnet cartridge, so the choices are pretty vast. But you first need to determine the overall system gain that you will need.

If you want a very good one, at a reasonable price, look no further than the Bottlehead  Reduction:
http://www.bottlehead.com/store.php/products/reduction-phono-preamplifier-kit (http://www.bottlehead.com/store.php/products/reduction-phono-preamplifier-kit)

You need to spend some time researching and learning about vinyl playback.  Evaluate how large your vinyl library is, how much you will listen and set a reasonable budget based on those parameters.  You will have a long way to go before you outgrow the SEX amp. 

Cheers,
Geary