Too Loud

I'm looking for a little bit of advise .

I have just replaced my amp ( icon stereo 40 ) , and I love the sound it makes , it just makes too much sound too quickly ( especially with CD ) .

I've been doing a bit of research and it looks like I need to lower the output voltage from the CD .

I'm toying with the idea of putting resistors into the interconnects ,but thats as far as I have got .

Has anyone any idea's or info ?

Thanks in advance , e .

 

u can either go for attenuated interconnects e.g. russ andrews does the pbj i/c (if i remember correctly) complete with built in attenutation, or do the same diy, as you've considered.
or get a set of rothwell attenutators
http://www.rothwellaudioproducts.co.uk/html/attenuators.html
which i guess u can diy too

 

Hello, unless it's actually clipping the input of the amp, I would try and learn to live with it. In my experience any cable attenuation is likely to lead to a loss of sound quality.

Graham.

 

Thanks for the answers ,

I'm using kimbers at the moment , thats what started me to think about resistors . The cheapskate in me thinks I can mod my cables
cheaper than Mr Andrews .

The amp isn't causing any cliping , but it would be nice to have
some control over the volume .

anyone got any ideas for resistor values ?

Cheers , e .

 

Its any easy fix ...just two resistors one in the signal the other to ground ....I'll look up some values but off the top of my head its about 10k on the signal and 1k to ground ..will give you about 8db cut ...its very easy to build into an rca plug with a socket to stick infront of the ic from the cdp.

 

Thanks Zanash ,

I'll try those values , they will give me a good starting point .

I will hopefully do it this week and will post the results .


Cheers , e .

 

Hi,

Assuming an input impedance on the amp of 20k Ohm and you want to attenuate by -6dB (half the volume) you need a series resistor of about 10K Ohm and a parallel resistor of about 20K Ohm. This will keep the input impedance of the amp (load presented to the CD player) as 20K Ohm.

On the other hand you can try simply putting a 20K Ohm (or a bit less) resistor in series and forget the parallel resistor. However, this will present almost double the input impedance to the CD player. Not necessarily a bad thing, it can give you a flatter frequency response. Just try it.

A 1K parallel resistor would likely present the CD player with a load way too low for it to drive nicely.

 

Actually, I'd go with Zanash's approach, a 10:1 divider. This means the power amp input 'sees' a 900ohm source impedance (10K+1K in parallel, assuming the cdplayer has negligable output impedance). The cd player sees a load of 10K +(10K+1K in parallel), about 10K9, assuming 10K input for the power amp - not a problem load.

Adding 10 k in series as Tenson suggests does drop the level 6dB, but the power amp input 'sees' a 10K source impedance, which is effectively doubles its equivalent input noise (assuming 10K input for the power amp); a subtle but important difference. HTH

 

Ahh you changed what you wrote lol. Wouldn't the CD player see pretty much the load presented by the parallel resistor?

 

No - think of it as an L-pad; the power amp is driven by only the voltage appearing across the lower resistor, but the cd player primarily 'sees' the 10K+1K series as its load.

 

I'll trust you on this as you seem to know more than I, but my calculations for L-Pads nearly always have a parallel resistor value of pretty much the value you want the source to 'see'. In my example, 20K.

 

I've not got round to doing the sums .....

I was just looking at a pair of attenuators I'd got floating about....but they were about 6db attenuation

There are several ways to do this depending on the impeadance ...of which I've not the foggiess for the original units ...so not add to much seems a reasonable idea....

try this

http://www.troester.org/ls/lpad.html

for 6db and 50k series res 24k para res50k ....

I'd just transposed the values in my original [off the top of my head ]

 

I can't get the second calculator on the page to work if I fill anything into the parallel resistor value....

Still, if you use the top calculator and fill in a value of 20K impedance and 6dB attenuation it gives pretty much the same results I got so I guess it uses the same formula.

 

Update .

I've put some 10k and 1k resistors in some old interconnects
as an experiment , and it gives me an extra two " hours " on
the volume pot , but there's a trade off , the music has lost some of it's " sparkle " .

However it's not all bad news , a guitarist friend of mine suggested
swaping the first stage valves for something with a lower gain ,
( apparently guitar players do this all time ) .

Said friend lent me a couple of 12at7's to replace original 12ax7's
and it did exactly what I wanted and more , in fact i'm sure the sound has improved , music seems to have more " air " .

Thanks for all the suggestions .

Cheer's , e .

 

Thats great ......

the loss of sparkle ..could be because all resistors are not the same. What type did you use ?

but if the 12at7 have sorted things that a good result....could be there just better valves ?

 

Hi Zanash ,

Resistors were 0.25w metal film all bought new from rs components ,
I could try larger wattage resistors maybe that would make a difference ? .

But I'm very happy with the valve change , swappd Electro
Harmonix for JJ's , both Russian .

Once again , thanks for the advice .

 

Both nice sounding valves ....

I bet they were stock metal film resistors.....

pm your address and I'll post some Dale vishay of the same value [if I can find them] they may sound nicer !

Of course the Ic may well have affected the sound too !