[WireNut]

My preamp line outputs provide more gain then I need. Is there an easy way to lower the line out gain?
I'm not an electronics expert, I can follow easy schematics.

What I'd like to accomplish is to be able to use the preamp volume control at around 12-2 oclock positions rather then 8-9 oclock.
My loudspeakers have an efficiency of 91.5 db, 1 watt/meter. I'd rather not mess with the loudspeakers if possible.

Thanks for any help you can provide.

   

[Davey]

It may be easy, it may be impossible. 
What preamp is it, and do you have a schematic for it?

Dave.

[WireNut]

It may be easy, it may be impossible. 
What preamp is it, and do you have a schematic for it?

Dave.

Hi Dave. It is a Vintage Pioneer SA-8500 MKii integrated amp. I don't have a schematic but I might be able to find one online.

[Davey]

If it ain't broke, don't fix it.    Something like that I would just leave alone if it's working correctly.  Your unit has a preamp-out/poweramp-in loop connection, so simply add a fixed attenuator there to move your volume control to a higher/better position.  Very easy.

They have a service manual (schematic) here:
http://www.hifiengine.com/manual_library/pioneer/sa-8500.shtml
You'll have to register to download it though.
I've downloaded many service manuals from here for equipment that I've repaired.

Back in the day, it was not uncommon for preamp/integrateds to have too much gain in the line-amp section.....relative to today.

Cheers,

Dave.

[gnostalgick]

I'm currently using Rothwell Attenuators between my pre & amp.  Very transparent & also lowered the noise floor of my system (had some hiss before).  I got mine from ebay for about $50.

[WireNut]

I'm currently using Rothwell Attenuators between my pre & amp.  Very transparent & also lowered the noise floor of my system (had some hiss before).  I got mine from ebay for about $50.

Rothwell Attenuators.

Perfect. Thank you.

[Davey]

Those Rothwell attenuators are much too expensive, for what they are.  IMO.

I would find myself a decent two section 5-10k adjustable volume control and insert it in your pre-out/amp-in loop and experiment with the setting over the course of a couple of weeks until you find a preferred position.  The remove it and (without disturbing the setting) measure the results with an ohmeter and then substitute an equivalent fixed-resistor pad to duplicate the attenuation.

Super cheap and easy.

Dave.

[WireNut]

Those Rothwell attenuators are much too expensive, for what they are.  IMO.

I would find myself a decent two section 5-10k adjustable volume control and insert it in your pre-out/amp-in loop and experiment with the setting over the course of a couple of weeks until you find a preferred position.  The remove it and (without disturbing the setting) measure the results with an ohmeter and then substitute an equivalent fixed-resistor pad to duplicate the attenuation.

Super cheap and easy.

Dave.

Dave,

I'd like to try this. Mouser has hundreds to choose from. Not sure what to purchase. Could use your help.

[Davey]

Mouser part # 313-2420F-10K would be fine.
A small box and four cheap RCA connectors and you'll have a device that will come in handy in other situations as well.

Dave.

[G Georgopoulos]

let's leave input dynamics intact, let's concentrate on gain,99% of gain is through a feedback network,changing an inexpensive resistor changes the gain at minimum cost,more complex than a pot?,yes and no,if you know what you're doing input dynamics are not effected...

[Davey]

Wirenut,

Is your interest here a result of bad left/right tracking in the volume control at the lower positions??
And/or maybe a hair-trigger volume increase effect because of the audio taper of the control at the lower positions??
Or some other factor??

Dave.

[rollo]

 Davey just looked in to check out and I must say you are very helpful. Nice to see.
cheers
charles

[Davey]

Charles,

I've always been helpful on AC.  I don't appreciate the snide undertone to your comment because it implies that I haven't been helpful in the past.
Some folks might reside in audiophile la-la-land and not like hearing the objective truth about things, but that's not my fault. 

I've offered an option for the technical issue here (as much as we know regarding it since Wirenut hasn't elaborated on the underlying issue he's experiencing) but there might be a better one.  So, if you have an alternative lab-ish type of suggestion for Wirenut, please offer it up.

I've looked at the schematic for the integrated amp in question here and, unfortunately, the quality of the scan is fairly poor and many of the (control-amp portion) component designations/values are difficult to see.  So, I'm not comfortable with any other suggestions than the one I've already offered.

Dave.

[rollo]

Davey WTF ? You are quite off base. I was being sincere and giving you a compliment for goodness sake. Not very nice.


charles