Preamps can color sound considerably. Surprising?

Gawd only knows…

Maybe like a power conditioner?
But I am not sure what the meaning was in the poster’s statement, so it is only a guess as to what the meant might have been.

Which is the ultimate reason for not using a pre when the DAC has a decent - and preferably analogue attenuator. DACs produce sufficient output voltage not to use a pre.

Maybe… but if one listens at a low volume, then the attenuator also has a rising output impedance, so the cables start to affect it more and more as the volume goes down. But they seem good in theory if one doesn’t scratch the surface.

And then if one has an RCA DAC and an XLR amp, there needs to be something in between. Or visa versa.

both are relatively rare cases and the majority of pres between attenuated dacs and power amps add distortion and little else

@antigrunge2 
Depends on how quiet it is, but at say -40dB, I think that might be 1/100th, so if the output impedance is high, then it becomes 100x higher… flat out it should work a treat though.

Absolute neutrality shouldn't be the goal (and is unattainable) Musical enjoyment is what we are after - if you can still recognize the voice of your favorite soprano / tenor, it's all good.

OK, I guess for a “stereo” I agree.

But HiFi sort of had “fidelity” buried in there, so that sort of has the idea of neutrality associated with it.

Not to be argumentative, but I don't think that this analogy works.

Maybe a kidney?

I assumed they was referring to the removal of waste and toxins?

It‘s funny how people argue about this subject. Attenuation and amplification are fundamentally different and the simple fact of the matter is that dacs only require the former. So what may be useful in amplifying a phono signal with rare exemptions become distorition when a dac is used.

But one can also just use an amp as a buffer to change impedance.
If the DAC does the volume, and not other things need to be switched, then one does not need the attenuation nor the amp.

One of the rare exceptions is to drive the cables better to the amps, should the output be driven to very low listening levels. If the OP is not using horns and a high gain amplifier, and not listening at a low level, then they have less to consider.

But which arguments were you referring to?

If my two preamps sound similar, and it is not night and day.

Is it because they have the same tube type?
 

@charles1dad it has been some of covered in a few places…

In theory and on paper, the passive approach should be more invisible/transparent, more out of the way.

In theory it starts to barf when the passive is doing more control.
Running “wide open” the passive is essentially a wire.

Remember that the passive pre is attenuating both voltage as well as impedance.

The pros and cons from my list:

• A high output impedance source = con
• Low output impedance source = pro
• High input impedance amp = pro
• Low input impedance amp = con
• High listening levels = pro
• Low listening levels = con
• Low sensitivity speakers = pro
• High sensitivity speakers = con
• High gain amp = con
• Low gain amp = pro

So the worst situation is driving some highly seniors give horns, at low volume through an amp with high gain from a high impedance source.

The volume is then cranked around anticlockwise, and the passive is attenuating the already high output impedance of the source to become tens of hundreds of kohms. 
 

If it is less sensitive speakers listen to at higher volume then the passive does not attenuate nearly as much.

If we add in ICs with high capacitance or inductance then we get a filter.
At that point it is often better to have a preamp than a passive, when the passive is trying to go very low… and it’s better to run a passive if it is doing very little attenuation.

@antigrunge2 Can you find it for your specific DAC?

In the example I gave above, one would likely be better off to adjust the DAC’s output level much lower, and then a passive pre would be cranked around louder.

I suppose those with a passive pre and a DAC with adjustable output level, could do this at home and tell us if there is a difference or not?

A DAC without the output level adjustment should not be as good (if all else was equal)…

That is super low output impedance, compared to a CD player or other sources with 600-1000 ohms.
It is the stuff in ~1k ohms or the 10k ohms range that would then get knocked down 40dB (or maybe it is 20dB in both volts and impedance… so one goes from 1k ohm to 100k ohms, and trying to drive the amp with a 100 k ohm input impedance.

A 112 ohms output impedance going through an attenuation of -40dB should be 11,2 k ohms?
It is probably better to run the knob at -20 and knock down the DAC by -20dB to get to -40dB.
 

Your last sentence only applies to digital attenuation, which is lossy.

I am running an RME, so I knock my DAC down by 10-15dB just to get the DAC and the other sources to be about the same, which are 4 RCA sources and 2 XLR sources. It seems OK, but I could see knocking down 6 bits off of 16 would be a problem. Especially if only 12-13 bits were in action.

We will see what @atmasphere says, but half the reason I post is to get corrected if my thinking is off… but I think/believe I have this right.

My Tortuga passive and has plenty of power, punch, clarity and detail. Width is nicely presented and depth too.

I use a 1/2 meter  Audience IC that goes to a Modwright phono stage from the Tortuga.

I am using 1/2 meter Kimber KCAG IC`s from the Tortuga to my ATI 3002 amp. The ATI feeds a pair of Revel F52`s. 

I use a 1 meter pair of Zu IC`s into a Dayton Audio SA 1000 subwoofer amp which powers a Revel Ultima Sub 15 subwoofer. I have 3 other subs in the mix too.

This is my recipe for a very satisfying, enjoyable sounding system.

This works well and It will play as loud as you would ever want.

Try a Tortuga passive, you might be pleasantly surprised by what you hear 👍 

@scm yes ^that^ is a recipe.
We don’t know your source’s output impedance nor the amp’s input impedance.

So it is a nice story, but doesn’t answer why it seems to sound OK.
But we at least have a combo that is good, and we can say why it is good then that is even better.

I am pretty sure that it the witches brew of cables are good, and they are short, which is also good.

@scm 

holmz ...The source output impedance is VERY low according to what I see listed for my ModWright 9.0X phono stage. Couldn`t find anything showing exactly what it is.

The amp`s input impedance is 28K ohms

The most important here is the listening level, and whether the interconnects to the amp is short or not.

Much easier if the passive to amp is a stereo amp and short ICs, then a long length to mono blocks across the room.

Every amp I own, and have owned, is / has been rated to reach full power with less than 2 volts at the input. If you have a good 2 volts to work with, impedances are well matched, and the system caters to your desired volume level ( s ), when does the preamp’s additional voltage kick in? Most preamps in most systems are still used in attenuation mode, ime.

Actually an amp requiring 5V would be better and the preamp needs to use less attenuation. Basically the lower the amp gain, the better.

Or the closer the preamp runs towards 0dB attenuation, the better.

@jumia (I dunno) … all things equal, and cost not being a consideration, then IME (and in theory) one would want mono blocks are shorter speaker cables… especially for cable capacitance.

Some of the Linz designs (or weaving patterns) are pretty low in inductance.

But I think it is probably mostly lost when one hits the passive crossover, as there is a lot happening there, and the amp should generally be able to overcome capacitance and inductance.
However an active crossover should be a lot easier to damp and control.

How “hearable” it is, is uncertain, as sometimes I can believe I hear it, and at other times then sometimes I do not believe it. So i am not 100% certain.

With respect to ICs, the shorter the better, and especially with cart to phono stage.

If one is pushing a long distance between a preamp and amp(s) then they probably don’t want high capacitance cable and a passive preamp. If they are using a passive preamp, then they probably want to have the volume cranked up it, which means lower amp gain… if it needs to play quiet and loud, depending on the day and time, then a passive is not as ideal as an active preamp (IMO).

In your case, I’d suggest just putting a couple of 3’ pieces of speaker wire and try it. If it works, then sell the 12’ ones. I just got some cotton covered stuff from Jupiter Capacitor to try, but I could not find any bananas, so it’ll have to wait… and I am literally still running the lamp cord that I put in a year ago.
That 12ga cotton covered copper stuff is cheap enough to try.

But I am also trying to sell a couple of tube amps (mono block pair and a stereo amp), and if so I will go to XLR based mono blocks.

Clearly you understand impedance and volts and ohms, with respect to their relationships to all the various pieces of gear.  This is quite a feat to accomplish in my opinion.

Not really… a couple of electronics courses and most gear is designed to work as designed.
But it is not like, say a ski binding with a DIN7880 standard where they all conform.
Ideally all the sources would be some DIN with say 600 ohms output impedance, and all amps using another DIN specifying say 100k ohms input impedance.

However it is more like the Wild West with RCAs, and more standardised with XLRs and pro audio.

Adding in high capacitance cables, and long cables, are ways to coulor the sound… and totally ignoring what is happening inside of the preamp, the input and output impedances make a difference.

But the speakers are usually doing way more in terms of distortion, so I think starting there is generally more wise… and the more things that are lower distortion in the chain, seem to make it easier than trying to correct things with cables and coloured preamps.