Passive preamp to a power amp?

stuff_jones
I was reading reviews on the Schiit Saga and people were having a hard time differentiating between active and passive mode. In that case, why not just get the Schiit Sys passive and save 300 dollars?

There is quite a difference between the two in passive mode. The Saga and Freya have a far better quality relay switched volume control, with better contact points between wiper (relay contacts) and resistive component in this case fixed resistors.
Where the Sys even though it’s very good for the money, has inferior wiper contact and resistive track component called a potentiometer, which most active preamps use.

When matched to source/amp I believe passives have superior transparency and dynamics to any active preamp, they have far less but still have sonic differences between them though, as I just pointed out above being what what passive system was used E.G:

1: Potentiometers like the Sys (wiper contacts in the signal path)
2: Switched relay/resistor like the Saga and Freya (relay contacts in the signal path)
3: Transformer volume control (TVC) (rotary switch contacts in the signal path)
4: My Lightspeed Attenuator passive pre (no contacts in the signal path)

To me nothing sound as transparent and dynamic as going source direct to poweramp, using the source’s digital domain volume control if it has one. One caveat though, if a digital domain volume control is used below 75% you run the risk of "bit stripping" (resolution reduction)

BTW: Your Shiit Vidar is a little low input impedance at 22kohm for 10kohm passives, but if your Bluesound Node 2i is less than say <200ohms output impedance all should be fine.  


Cheers George

@georgehifi

To me nothing sound as transparent and dynamic as going source direct to poweramp, using the source’s digital domain volume control if it has one.

An interesting twist to the last stage of assembling my system. Paul from PS Audio talks about this too and agrees with you.

https://www.youtube.com/watch?v=HdytsbrzjCA

Why then does anyone use a preamp?

One caveat though, if a digital domain volume control is used below 75% you run the risk of "bit stripping" (resolution reduction)

How then does one control the volume at lower levels?

This is all new information to me and means may I should pool my pre-amp + dac budget and get a nicer dac with a volume control (If I’m understanding right).

Thanks for the eye opening post!

stuff_jones OP
Paul from PS Audio talks about this too and agrees with you.

https://www.youtube.com/watch?v=HdytsbrzjCA

Great video more should watch the first half and take it on board. (Not the promoting of the BHK preamp, as it just adds gain/coloration/distortion into the system that not needed.)

stuff_jones OP
Why then does anyone use a preamp?

Active Preamps, (pre-amplifiers) were needed in the old days when extra gain was needed, but today sources
have far higher gain 2v and over output, and most poweramps today only need 1v in to give their full power. some only need 0.5v!!!!! So as you can see there is no need to "pre-amplify"

Nelson Pass quote:
"We’ve got lots of gain in our electronics. More gain than some of us need or want. At least 10 db more.

Think of it this way: If you are running your volume control down around 9 o’clock, you are actually throwing away signal level so that a subsequent gain stage can make it back up.

Routinely DIYers opt to make themselves a “passive preamp” - just an input selector and a volume control.

What could be better? Hardly any noise or distortion added by these simple passive parts. No feedback, no worrying about what type of capacitors – just musical perfection.

And yet there are guys out there who don’t care for the result. “It sucks the life out of the music”, is a commonly heard refrain (really - I’m being serious here!). Maybe they are reacting psychologically to the need to turn the volume control up compared to an active preamp."

One caveat though, if a digital domain volume control is used below 75% you run the risk of "bit stripping" (resolution reduction)

stuff_jones OP How then does one control the volume at lower levels?

Now this is more tricky, if your system allows you to use the digital volume above 75% your good to go.

Wadia and Mark Levinson realized this also, and inside so inside their top cdp’s and dacs, they had a few different output buffer gain setting switches, so if you were below 75% on the digital volume on your system, you selected a lower gain setting on the buffer so you could use the digital volume control above 75% Bricasti do the same on the M1 but via the remote programming.

stuff_jones OP

This is all new information to me and means may I should pool my pre-amp + dac budget and get a nicer dac with a volume control (If I’m understanding right).

If your dac or cdp doesn’t have this above, then the next best is to leave the digital up full or use the fixed outputs and use a passive volume control, it the closest you’ll get to going direct.

Cheers George

Here we go again....same old selective and mostly out of context quotes pushing a passive preamp from a maker of one.

To the OP: Sorry but this topic has been discussed ad nauseam in multiple threads each with multiple pages. Bottom line is you need to try a passive in your system and hear it for yourself. Majority of the folks, including me, and yes I’ve used a Node2 via Schiit Sys as well, agree the music will sound lifeless, especially over a short time. The initial perceived transparency quickly wears out and becomes dry and soulless. Try one that you can return so you don’t get stuck.

Sorry but this topic has been discussed ad nauseam in multiple threads

There's a simple answer for you, DON"T READ THEM!

Majority of the folks

You wish!