aleph 5 and aleph xa100 will it work with dac?

[elviukai]

hi, I have nice parasound d/ac 1500 laying arround. it uses 102 000uf PS filter, 3 trafo, cs 8412 receiver and 4x Burr brown pcm 63P (K) 2 operating in push-pull to every channel ,fully balanced digital operation.
it has folowing outputs
balanced- 6V nominal 1.2Kohm
unbalanced 3V nominal 600 Ohm
manuf recomends minimum 10Kohm suitable load
some rewiewers notice that output even is too strong.

question - is it good iea to put in discrete volume attenuator and run directly to poweramp. this dac will work without any loss in quality feeding one amp? I even thinking feed 2 amps.
poweramp is Pass labs xa100 clone and Aleph 5 clone.

is it posible to attenuate balanced signal and how to do this.? this is the main question.

pass labs power amp aleph 5 has 10kohm unbalanced and balanced probably 25 kOHm. aleph x ???

so will they work together? I dont mean SPL but quality. I have noticed that sometimes even cheap preamp works better that DACT atenuator.greater image and microdynamic at low levels. and how to make discrete atennuator to reduce balanced signal?

thanks for any help.

[Nelson Pass]

The best way to attenuate the input to an X amp is to place
resistance in series. The Alephs generally will prefer a
divider on the input.

[elviukai]

thanks Mr. Nelson again for clearing clouds on sky. that probabaly means that aleph 5 in unBALANCED mode works in best in clasic mode (attenuator + input/output. and ground. 3pins required on attenuator now I am using 20k atenuator hooked this way to it. )

and aleph x in BALANCED mode best will work with two pins atten. only conected + input/output? I suppose Atenuator in balanced mode conacts to + not - or gnd?

if I am wright , so how to conect aleph 5 in BALANCED mode?. not like Aleph x? not only in series like aleph x?

[DFroehlich]

Hello,
i have nearly the same configutation. I have a parasound dac 1600 ( i think it is nearly the same as the dac 1500) and an Aleph 5 clone.
Since now, I run them single ended with a alps black beauty 100 k Ohm pot ( not the best arrengement, I guess).
Now I am wondering if I can make a balanced shund attenuation with 2,5 K Ohm resistors in series with either the positive and the negative output of the balanced dac and 12 switched resistors (24 in the future, but I have a 12 position switch from siemens laying around) between this two lines.
Does someone know if this is possible and are there ideas for the values of the resistors ?

Thanks
Dirk

[Nelson Pass]

If I understand it correctly, the DAC want to see 10Kohm or
more as a load, so I would suggest a 10K series resistor and
a variable shunt whose resistors ad up to 20k to 30K ohms.

[DFroehlich]

Thank you so much for your answer Mr. Pass,
it is unbelievible, that you take time to answer such questions like mine.

I think this is a nice configuration for a balanced attenuation, because it requires only a two deck switch for two chanels. But I'm wondering if there are some contras, because there are not many who uses that configuration.

So the best configuration might be a 5k resistor in the positive signal-line and another 5k resistor in the negative signal-line to get the 10 k ohme output for the dac and between that to lines switchable resistors from zero ohm (for lowest level) and 20k ohm (for highest level) ?

Can I pick up the correct values of the resistors out of the spreadshields for shunt attenuators?

Greetings
Dirk

[DFroehlich]

No replies ?
Is it really such an uninteresting topic/question ?

Nice weekend
Dirk