Solid state preamp grain compared to valves

[hifinutt]

Indeed, not. Let's make it clear, though: I'm not saying that all passives suck the life out of the music, because *in the right system* fundamentally they don't, simply that they sound a LITTLE that way ('soft'), in comparison with the best (much more expensive) actives.

That is my position on the matter, based upon considerable experience of using both. It's the reason why I've kept my modded Croft (owned now for 12 years) and no longer entertained passives, which I can assure you, I wouldn't have done otherwise, as I can afford to buy pretty much what I want.

Marco.

next time i get a MFA baby ref passive , i am going to do a tour and see how much bass and slam and dynamics it brings to a system , its extraordinary [oh and i don`t work for jonathan !!]

[Macca]

. The gain stage could be valves, op-amps, discrete transistors etc. It doesn't really matter for the purpose of this argument.
So with this type of design the active preamp could be seen as a passive preamp plus gain stage. BTW, this is opposite to how Macca thinks the design works, ie gain stage plus passive device, as mentioned here:

So an active pre-amp first attenuates the signal then adds gain? That's the opposite of what I said but that doesn't make any sense?

[Marco]

Yes, but I'm not sure how a phase shift at ultrasonic frequencies would affect dynamics or "suck the life out of music".

I think 'sucking the life out of music' is a tad strong; the best passives, used in a favourable context, certainly don't do that. It could be quite the opposite!

However, in my experience (read what I posted yesterday on the matter), they *can*, when coupled to partnering equipment and/or cables that somehow inhibit their efficacy, soften the sound, so that there is a perceived lack 'punch' and 'guts' with music, compared with a good active design.

Like I said, I can only report what I hear.

For me, conventional 'pots in a box' are best used when they've been designed, from the ground up, to partner a suitable power amp and cables (a single-manufacturer solution), so that synergy is achieved and the whole 'package' works together as intended.

That isn't the case, IME, and harder to get right, when you simply insert (any old) passive into an 'alien' system, which it hasn't been designed to work properly in.

Just my view

Marco.

[Marco]

next time i get a MFA baby ref passive , i am going to do a tour and see how much bass and slam and dynamics it brings to a system , its extraordinary [oh and i don`t work for jonathan !!]

Nice one, but that'll only happen if the test system used allows it.

Marco.

[Barry]

In Douglas Self's book Small Signal Audio Design he has two rules:
1) don't attenuate and then amplify.
2) don't amplify and then attenuate.
Ok, he has an odd sense of humour but the point he's trying to make (I think) is that both do harm, either to the signal-to-noise ratio or the distortion.
Anyway, attenuating with a passive volume control and then amplifying is the way most active preamps are designed. Yes, a fully active volume control as part of a feedback network is more sophisticated and technically better but for some reason isn't often used.

I believe one of the first people to put the volume control in the feedback network was Stan Curtis with the Cambridge P60 amplifier.

[Macca]

In Douglas Self's book Small Signal Audio Design he has two rules:
1) don't attenuate and then amplify.
2) don't amplify and then attenuate.
Ok, he has an odd sense of humour but the point he's trying to make (I think) is that both do harm, either to the signal-to-noise ratio or the distortion.
Anyway, attenuating with a passive volume control and then amplifying is the way most active preamps are designed. Yes, a fully active volume control as part of a feedback network is more sophisticated and technically better but for some reason isn't often used.

Thanks, I understand now.

[Bigman80]

next time i get a MFA baby ref passive , i am going to do a tour and see how much bass and slam and dynamics it brings to a system , its extraordinary [oh and i don`t work for jonathan !!]

Visit here first Phil, I accept the challenge

[Bigman80]

In my limited experience of preamps,

Passives don't suck the life out, but can at times lack drive.

The Slagle AVC, was something which didn't lack drive but is still a passive device. It worked well on anything I put it with. I always felt it didn't grip the bass as well as the active units though which lead to the change.

SS or Valve based active preamps like the KIN, Croft 25 etc, always felt livelier and more exciting, for whatever reason

The Unity gain DCB1 I have here seems to have that same lively drive as the SS & Valve pre but does the delicate stuff as well as the passive and AVC pres. Is ideal? Probably not and that will show over time.

As far as I can see there isn't a perfect pre except for no pre. I would like to try a good LDR just to see what it does although is suspect it will a similar situation.

[Marco]

The Slagle AVC, was something which didn't lack drive but is still a passive device. It worked well on anything I put it with. I always felt it didn't grip the bass as well as the active units...

Yes, I've also found the same with transformer-based passives, in that they can't quite shake off a slight thick, tubby quality and lack of grip, in the bass. I also find them to be, tonally, on the warm side of neutral. Lovely in other areas, though

Marco.

[walpurgis]

Yes, I've also found the same with transformer-based passives, in that they can't quite shake off a slight bloated, tubby quality and lack of grip, in the bass. Lovely in other areas, though

Marco.

You wouldn't say that If you heard my MingDa MC-9 Marco. It has none of those issues.