Passive or active preamp

[DaveC (David Cressy)]

My dealer is advising me to use a preamp with my Rossini player. Right now I am driving the power amp direct and using the Rossini volume control. I would prefer a passive preamp such as the Townsend Allegri Reference which seems highly regarded and keeps things simple. However, this device does not offer true balanced output. So does the gain in SQ with a passive preamp offset the loss in SQ using RCA connectors. Or do people on here prefer an active preamp option? I would be very interested if anyone has come across the same conundrum. Thanks!

[PAR (Pete)]

I have always taken the position that a preamp is preferable to direct connection. Whether one should go the passive or active route is not something I would decide in theory but in practice listening in real life to alternatives.

Given your predilection for the Townsend Allegri Reference I would point out that though it does not offer fully balanced operation it does offer quasi-balanced operation. This means that you can still use XLR cabling from Rossini to Allegri ( check out Max Townsend’s white paper on his cables, you may be persuaded to use them). Frankly this does have a sonic advantage over using RCA for, as good as the Rossini RCA output stage is, the fully discrete XLR balanced output I think would be judged a little superior by most people.

Technically using quasi-balanced would cause little if any audible penalty in a normal home environment. The advantage of balanced is rejection of noise through common -mode rejection. This can be important in e.g. studio settings with masses of equipment spewing out EMI/RFI but this type of situation is not commonly met domestically.

[Ermos (Erno)]

Hi David,

Your question has been discussed here in lenght, and over and over again.

The results you can find here:
https://dcs.community/search?q=preamp

dCS do not recommend passive attenuators:

[FAQ] Can I omit the preamplifier and drive the power amplifiers directly from a dCS DAC?

Yes, in many cases this unveils extra detail. Note that the DAC’s 6V setting may be too high, forcing you to set the DAC’s volume control too low. Vivaldi’s volume control works well down to around -40dB, while the other products start to lose detail with the volume below -26dB. Changing to the 2V setting allows the volume to be raised by 10dB. The acceptable loudness will be different for each system and listener. The Vivaldi DAC v2.00, the Rossini DAC and the Rossini Player feature two lower …

For other products, if you find you have to set the volume too low, we can only suggest that you resort to passive attenuators (not recommended) or a good preamplifier. Please consult your dealer for help.

[Ermos (Erno)]

@PAR

Technically using quasi-balanced would cause little if any audible penalty in a normal home environment. The advantage of balanced is rejection of noise through common -mode rejection.

[FAQ] Which DAC output is better – balanced or unbalanced?

The balanced output uses complex class-A stages, they give noticeably better sound quality than the much simpler unbalanced output stages. The balanced outputs behave like coupling transformers so they can drive an unbalanced input provided that XLR connector pin 3 is connected to pin 1 at the end of the cable farthest from the DAC. Used like this, you may find that muting clicks are more noticeable. We recommend using the unbalanced outputs to drive an unbalanced input.

[Katzky]

I’d be inclined to get one of each. Unfortunately that’s exactly the kind of thinking that’s going to necessitate a conversation re “the benefits of community college”.

[Katzky]

Do you own a balance power amp?

[DaveC (David Cressy)]

Yes, a Constellation Stereo 1 fully balanced inputs. So it seems a Townsend Allegri Reference using XLR connectors from the Rossini and to the Constellation is the way to go for best SQ?

[Katzky]

Why don’t you try it straight to the amp for a bit? My Rossini is 10 days old and sounds absolutely amazing compared to my previous Bartok. Doubt I’d miss the 1% improvement a preamp might provide. After you get accustomed to the sound you’d be in a better position to demo preamps. Some prefer no pre but most, from my limited experience, insist a pre is necessary.

One guy here uses a Benchmark preamp which is apparently a reference level solution at a ridiculously reasonable price. If you only have one source a $10k preamp might be overkill.

[Katzky]

@Ermos

dCS do not recommend passive attenuators:

They don’t recommend passive attenuators for other products.

[Ermos (Erno)]

Vivaldi’s volume control works well down to around -40dB, while the other products start to lose detail with the volume below -26dB.
For other products, if you find you have to set the volume too low, we can only suggest that you resort to passive attenuators (not recommended) or a good preamplifier. Please consult your dealer for help.

So, other than Vivaldi products.

[Ermos (Erno)]

@Katzky

One guy here uses a Benchmark preamp which is apparently a reference level solution at a ridiculously reasonable price. If you only have one source a $10k preamp might be overkill.

JA found that the Benchmark LA4 ($2499)/ HPA4 ($2999) had a more upfront presentation than the MBL N11 ($14,600) or Pass Labs XP-32 ($17,500), with less soundstage depth apparent on his own recordings.

While the LA4 is considerably less expensive than the Pass XP-32 and MBL N11, its measured performance is on par with that of those two technical high-fliers.

From:

https://www.stereophile.com/content/pass-laboratories-xp-32-line-preamplifier-page-2

[PAR (Pete)]

Just a reminder thread in part from actual users here of the Allegri Reference :

Shortlist of Pre-amps for Bartok into Active ATC System Please

So having started this thread in Dec 2020 here is what has happened: I contacted about 4 retailers who looked as if they could supply the Benchmark LA4 and then asked them if they could also obtain a Townshend Allegri Reference. The former element was good, the latter part resulted in comments along the lines of “ummm”, “maybe”, “not straightforward”, “not sure”, “they may or may not be able to get us a unit”. These were all on the basis of buy both units, trial them and return the unit I did n…

[DaveC (David Cressy)]

Thanks Pete - I did read all those threads. And the conclusion seems to be (plus from what you said about balanced vs unbalanced o/p stages in the Rossini) that a Townsend Allegri Reference using XLR connectors from Rossini and to power amp is the way to go for optimal SQ if choosing a passive preamp. Obviously for active preamps there’s much more choice out there but many cost a lot more. Does that make sense?

[SeanSullivan]

Hello…as I am the original poster of the thread mentioned just a few entries above by PAR (Shortlist of Pre-amps etc), I came to the conclusion that…
I would be better off spending an additional £9k to £10k odd on trading-in and upgrading my Bartok to a new Rossini DAC rather than fussing over differing fairly similar performing preamps.
…so when funds allow I will do this, especially as the trade-in value of my low use Bartok (headphone model) seems strong.

My thinking is that I would rather have the benefit of superior source sound to play around with and pre-amp or not etc etc.
The fly in the ointment of all this is however, I do rather believe that DACS do seem to run best when running at full output which does rather need a pre-amp or ear defenders in my active setup…

[DaveC (David Cressy)]

Thanks Sean - I think I would like to go the preamp route with my Rossini but I’d prefer to go passive to keep things simple and the Townsend seems to have quite a few fans on here. However, it is not a fully balanced design so I expected to use RCA connectors. However, a number pf people have indicated that will not offer optimal SQ so best to use XLR connectors in “quasi balanced” mode. That is what I have understood anyhow. Would be helpful to hear from anyone who is already running Rossini with the Townsend what they are doing and how they have found the results compared with running direct into the power amp.

[wdw (Warren)]

Just a data point…recently added the Constellation Preamp 1 (the partner to your Stereo 1) to a Bartok system. Had been running the Bartok directly to a Pass Lab and was not expecting much, if any, improvement but the preamp is extraordinary. System went to a new level.
Perhaps a passive preamp may be an improvement, but more a sideways step, and not the evolution expected.

[DaveC (David Cressy)]

Thanks for responding Warren - that is really helpful! I am going to borrow the Constellation preamp from my dealer next week so will report back.

[Katzky]

@Ermos Wondering if you’re still happy with the benchmark preamp. Need to get a headphone amp. I can get a nimbus easily since it’s in stock. Did you ever demo it?

[Ermos (Erno)]

I am still very happy with my Benchmark HPA4, but will have to see how it holds up if I get a Abyss (currently a Focal Utopia).

I could not demo a Niimbus yet.

[wdw (Warren)]

Remember to toggle the input (assuming XLR in….only way for Connies) to the one specifically for a Constellation preamp.
BTW: The Stereo 1 is my next upgrade……had one home for an A/B and our Pass Lab held its own in a head to head comparison but the Stereo 1 had a delicacy and level of detail that our (very hot Class A) amp couldn’t quite reproduce.