Passive & Tubed pre-amps to power amp at same time?

Al, Zd - THANK YOU both very much.

Al, I was concerned about a potential interaction and absolutely hadn't a clue what the nature of that interaction might be. Appreciate your explanation.

Zd - I think you have given me a good alternative. I'm thinking about getting the Schiit SYS. This does have 2 inputs. What I've read so far seems to indicate the Schiit is pretty transparent so might be OK even if it's in the tubed pre signal path all the time. BUT given what Al has said, not sure what effect if any the passive might have on the tubed pre-amp. If I got it, would have couple of weeks to figure out if it's OK given Schiit's return policy; maybe more if I got it through Amazon.

Al - I'd certainly appreciate your comments about Zd's alternative.

Al - That's a lot for a non-EE to digest. Thank you for the detailed additional input. Much to ponder. Might be simpler to just live with things as they are; i.e., limited usable volume control range on pre-amp with CDP (but things do sound great).

Al - Yes. Looking to extend the range (and "fineness") of volume control which most of the time now is limited to between 7 & 9 o'clock on my pre-amp with TEAC CD3000 as input. I was aware of the Rothwell attenuators. They were my first inclination but I was put off by reports of negative effects on sonics. The fact you found them satisfactory carries some weight with me. I understand the product option you are suggesting. The attenuators would certainly seem to be a more elegant solution than another box or two and more interconnects. As others have stated, you are a real asset to this "community". Thanks once again.

Zd...no volume control on the CDP. It's 2.6 Vms out unbalanced and 4.6 Vms balanced. That's why I had been thinking to skip the tubed pre-amp and go passive with the Schiit SYS.

Thanks for the idea George. What I am trying to do is introduce volume control
for the CDP without any addition boost in gain while leaving other sources
unaffected that run through the tubed pre-amp. Your idea does seems like
something to explore. No tape out...but sub out. However, I am going with Al's
suggestion of attenuators. Ordered a couple of Harrison Labs -12dB RCA plugs
from Parts Express. Much less expensive than those from Rothwell and Parts
Express allows returns if they don't work out. Others on A'gon do report
satisfactory results using these. Thanks again to all for the suggestions.

Al - Have multimeter. Will measure.

Atmasphere - Good one. That would allow me to do what Zd suggested 6 posts above yours. He was thinking my CDP had a volume control (at least, that's how I read it). Re passives' sensitivity to ICs, I assume this would be to ICs on the output side of the pre-amp?

Everyone - thanks. Lots of stuff to try.

Al - Harrison Labs -12dB attenuators arrived today. Running them at the input to my tube pre-amp with CDP as source. They seem to work as advertised. I've picked up (depending on how loud the CD is) 30-60 degrees of additional volume knob rotation to get to my preferred listening level; almost 90 on an older CD that has always seemed "lower volume" to me. So far, I don't notice any negative sonic effects. Thanks very much for the suggestion. I haven't yet made the resistance measurements but will.

Al - Results (all as read) of the measurements you suggested making for the Harrison Labs 12dB attenuators:
Across input/output pins
#1 attenuator 6.77 ohms
#2 attenuator 6.75 ohms
Across ground sleeve & output pin
#1 2.19
#2 2.18
all measurements made using 20K scale setting
FWIW - resistance across input pin to ground sleeve is ~9 (as read, 8.97 & 8.95 respectively).

Al - not sure what multiplier to use for this scale...x10K or x20K?. Let me know if you will. Thanks for your time.

Al - thanks for the reply. I meant to specify the meter used in my earlier note but it slipped my mind. It is a Craftsman Model 82015. I'm thinking the 20K setting I used is good for measuring resistances in the range of 20-200K ohms. The next lower setting is for 2000 ohms. The next higher for 200K. Not sure why things are "denominated" in 2s vs 1s. Sorry if I introduced some confusion - there is no 'x' symbol associated with the scale labels for the meter dial. What multiplier to use was my question only. Let me know if you find something helpful - or other thoughts. Thanks as always. (I well might repeat the measurements taking care not to hold the leads while doing so...I hadn't taken this precaution earlier - but am hopeful they won't change things significantly if current values are sort of "as expected).

Al - thanks for the follow up. I did some on-line reading after posting and found similar info as in your explanations for interpreting the measured impedance values and scale upper limits being multiples of 2. I can indeed take some further readings using the 200K scale setting. As noted previously, putting the Harrison Lab attenuators on the TEAC CDP outputs did give more usable volume control "range" on my pre-amp. None of my sources are tubed so if those low resistance numbers aren't likely to harm the TEAC, I'll continue to use them.

A follow up on use of the -12 dB attenuators. The Harrison Labs attenuators have indeed been beneficial in the system. They provided extra control range on the pre-amp volume control when the CDP was in use as noted earlier. I did NOT think I heard a sonic benefit in this application however, just easier fine control of volume...but no negative effects, either. Recently, I had been bothered by what seemed like upper frequency distortion when playing at higher volumes (mid to upper 80 dB at the listening position) CDs ripped to hard drive. ICs from CDP to pre are Cardas Parsecs. ICs from the Gungnir DAC to pre are Morrow Audio MA-4s. Today after switching the attenuators to the DAC ICs at the pre-amp, I enjoyed a very satisfying listening session with no trace of harshness or distortion at sound levels similar to what had been annoying 2 days ago. I'm wondering if the attenuators are doing a little "tone control" - rolling off the top end just a very little bit (by increasing the impedance of the MA-4s?). Not 100% certain the cause but did order another pair of the attenuators from Parts Express so I won't have to swap them out between CDP & DAC. We'll see if listening continues to be as pleasant and free of harshness going forward. (BTW - Al, I did come across similar values as what I measured being reported on Amazon for the Harrison Labs attenuators).