passive pre with seca

chrisb

Asked this on the signing in thread. I apologise.
Been looking at the goldpoint passives they seem reasonably priced just to try. My amp has 47k input I think,so which value volume pot would be best to use . They have several values, and does anyone have experience with the goldpoints.
Regards Chris.

Brain_Dead

Hi Chris,

Is it the 20W SECA from Paul?

I will check records but I think it's input impedance is 10K Ohm.

Best Col

chrisb

Yes Colin that's the one cheers

quickie

Hi Chris,

I've used 10 and 22k pots with no problems.

Not tried the Goldpoints, but should be good.

Paul.

Brain_Dead

Hi Paul and Chris

That will be OK, did you use a ALPS Paul or a Penny and Giles?

Col

chrisb

Hi Paul, hope your ok the seca is still great . Not tried passive before , you think it's the way to go.
Cheers Chris

quickie

Have used Alps Col, but prefer Sfernice p11 cemet track or the Panasonic pots. Never tried a P & G

The transparancy with a passive pot will be outstanding Chris. I still prefer to use it with my Inca Designs ID1P, but then it depends on which pre you are using i suppose.

Tried a very well regarded Conrad Johnson pre a while back and didnt like it all all......totally killed the music.

Paul.

 

chrisb

No pre at all at the moment, laptop young straight to power. I'm relatively new to computer audio and just wondered if a passive pre would be better than the volume control on the laptop.
Chris.

uglymusic

Beware! I ran laptop into Young into monoblocks. It sounded great, and ran without problems for months.

Then, one day, the software crashed and a full-power electronic scream blew two loudspeakers. Bang!

Brain_Dead

I would think the other trouble with lap top/pc volume the noise ratio would increase as the volume was reduced.

Dave does this happen?

Brain_Dead

Paul have you tried step attenuation type with fixed resistors?

Did Alan have a LDR volume type I wonder how that performed?

I wonder if a lower impedance type would give a better top end response I suspect it should.

 

Alan

I do have an LDR, it is very good - better than a twin mono cermet pot passive.

Dave and I both had a cheaper LDR a year or more ago which was also good, but they both failed. This could have been because we were using aftermarket power supplies though.

I got a lightspeed which I really like, but have also run my system 'pre-less'. It sounds marginally better that way, but a decent LDR pre is almost invisible in the system, so I am happy to have it there as a safeguard, for the reason Dave described. Also, I have more than one digital source going into my DAC, so software volume control won't work for me.

I have my repaired & rebuilt EVA still, its a remote control three input LDR pre - I haven't gotten around to selling it yet. Quite happy to loan it out for a demo if Chris is interested?

chrisb

Hi Alan ,
I would be interested in trying the Eva if that's ok, would like a volume pot for the obvious reasons stated but not if it reduces enjoyment so to speak.I no knowledge of ldrs
Regards Chris

Alan

Sure thing mate - PM me your address details & I'll get something sorted for you. Postage shouldn't be too much. Do you need an extra set of interconnect cables?

LDR is just a another type of passive pre - when I get some time I can explain a bit more - unless someone else wants a go?

chrisb

Hi Alan,
Not shure if Colin checked my amp input impedance which could be as low as 10k ohm. Will it still be suitable to try?

Brain_Dead

Chris,

Sorry I did check it is 10K been a bit busy with hospital etc.

Col

Alan

I don't know mate, I believe the Lightspeed is recommended for use with amps with an input impedance of 47Kohm, I don't know about Eva. I will try to find out this week.

chrisb

Thanks Colin, no problem and cheers Alan

chrisb

Ok chaps,
Anyone tried the akustyk passives they lookwell built and reasonably priced? And also source is a young dac outputing 2.65mvs can't find impedance and amp input 10k . Is the 5k pot best sorry for asking again.
Chris

Alan

I don't even know how one works this out?! Col? Paul?...

I am happy to lend EVA to you, I just don't know how to ascertain if 'she' will work.

Brain_Dead

Hi Chris,

2.65mvs please read spec again, is it 2.65Vrms at full O/P?

Col

Alan

Yup - it's a hot ouput on the Young.

Alan

See product spec here:

Output voltage: 2,65Vrms (7.5Vpp @ 0dBFS) - from spec.

Brain_Dead

Woo hell that is high need to reduce that a wee bit for the SECA

Will find you something.

chrisb

am i struggling with trying to use a passive  . 

Alan

Maybe use some RCA attenuators?  (Not so big in real life!)

Brain_Dead

Hang in there it will work and sound bloody amazing.

I will find a nice POT and a pretty box and work it for you. So hang on it does take time for me, ticker is giving starting problems again. Must be wrong octane fuel.

 

Brain_Dead

OK that will work 

Maybe use some RCA attenuators?

chrisb

I'm prepared to wait col until you have time and get it right. Just let me know cost involved.
Thanks once again Chris

Brain_Dead

PM address Chris

quickie

Ive got the Young dac too.
Not sure if I have tried it with a passive, but i've got a 22k pot in a box here somewhere, so will try it out and let you know what its like.

Paul.

chrisb

Thank you paul,
Is the issue the amount of volume rotation before the amp clips. For example only say 9 o'clock before being to loud because of to much output from the dac. Excuse my ignorance.
Chris

Brain_Dead

Hi Chris,

The amp is set for 1.00VRMS for max power and your DAC is 2.?lot VRMS just a shade to much, but Bob and I can fix it.

8-}

Best Col

chrisb

So am I right in thinking that for the volume control to work correctly it needs to work across its entire range without causing the amp to overload. For a passive to work it needs to be designed specifically for the the source its being fed and the amp receiving the signal, so it can only ever really be a single input device. Or am I an idiot lol.(probably) this is all very interesting for me with no technical knowledge.
Chris

Alan

I think that if the amp is designed for a passive then you'll be alright. Most sources are line - level (2v), so once a volume pot is selected to give a suitable range of attenuation than there won't be much difference between sources.

OK so the Young is a little hot so will be a touch louder than a normal CD player, but it is Italian! Full of excitement!

My lightspeed passive is only a single input device, the Young acts as a digital source selector (HiFi/TV/DVD).