Macca's Lash Up 2: Lash Harder

[jandl100]

No I don't think it does. I barely get halfway to zero attenuation for most stuff, just beyond half for really uncompressed recordings. Using a buffer goes against my purist tendencies though It is under consideration though. Thanks for the offer Jerry.

But the buffer is exactly the circuitry that an active pre provides that makes the difference from a passive!

You purists.

[Marco]

Well, aside from anything else, it involves another set of cables!

Marco.

[jandl100]

Yeah you don't like Tan-noise. Odd one out of, ooohhh...

I dunno about that - I've come across many folks who share my aversion to the horrid things.

[User211]

I dunno about that - I've come across many folks who share my aversion to the horrid things.

Well the new ones are a bit shit with the exception of Kingdom Royal (only when driven right) and even some of the Prestige ones can sound OK sometimes when they aren't suffering from a tendency to overdo bass in an uncontrolled way.

[Firebottle]

Well, aside from anything else, it involves another set of cables!

Marco.

Looks like I need to come over with my KIN and show you all how it's done



............... and get the TT connected again to show what you are missing

[User211]

Looks like I need to come over with my KIN and show you all how it's done

I think you should. But what happens if the Croft walks all over the KIN? Runs the risk of an ahem KINshite verdict

Is that a risk you can afford to take?

[Macca]

But the buffer is exactly the circuitry that an active pre provides that makes the difference from a passive!

You purists.

No it isn't, because it doesn't amplify the signal any whereas a pre-amplifier does. I think that buffer you have is designed to provide a better impedance match.

[Marco]

But what happens if the Croft walks all over the KIN? Runs the risk of an ahem KINshite verdict

Lol - you're on form today!!

However, I don't want to deflect attention from the main event (trying to fix the issue in Martin's system), with a 'willy-waving' sideshow between active valve preamps.

Therefore, unless Martin (as it's his gaff) particularly wants to hear the Croft in his system, in which case I'll duly oblige [no problem in shlepping it down], then if Alan wants to bring along the KIN, we can simply use that for active duties, and be done with it

Marco.

[DSJR]

Okay have put in a power amp that is intended to be a perfect match for the pre-amp. Not changed anything else. Going to have a listen to a variety of stuff before I comment further on SQ.

Re the compatibility of the Krell to a passive Duncan may have a point and Justin already advised me some months ago that I would not get the best out of the Krell with a passive. Problem is I am a bit short on active pre amps. I can use the pre amp stage of an old Harmon Kardon receiver or the pre amp stage of an XTZ A100 integrated, although the latter is hooked to the TV at the moment since it has a DAC with optical input but I do have another amp with a DAC in so I could swap that in and free up the XTZ.

But neither the XTZ or the HK have particularly impressive pre-amp stages.

Marco if you could bring your Croft that would be great. I know it is a pain to shlepp it with the power supply box and that. Oliver says he will bring the Slagle autoformer passive that impressed me at NEBO. So a bit of a bake off developing...probably have room for one more if anyone else fancies dropping over for a couple of hours.

Really appreciate all the help and contributions here folks. You're a bunch of stars.

The ONLY reason a passive preamp would possibly compromise your Krell is the sensitivity issue if used with old sources with say 500mV output not going loud enough - the KSA 50S needs 1.3V for full output. NOT AN ISSUE WITH CD sources or most other digital ones I believe - some phono stages have good gain as well Even with my old tuners, I never ran out of volume travel, but head-bangers might possibly and it's on these low-output sources a line buffer would be needed possibly, but not particularly a digital source with a 2V maximum output, which would give some headroom.


One reason I sold the Krell to you (the main ones were financial and the potential overheating issue where I needed to site it) is the trap you're falling into here due to what I feel may be incorrect advice. the Krell carries a certain cachet and reverence about it, meaning a cheaper 'twin-pot-in-a-box' isn't going to be judged 'good enough' for the almighty Krell power amp, which because of its ability to drive itself up the side of a bloody house if needs be (oh alright, a 2 ohm loading) and the main reason for its size and considerable cost when new (even your baby one was four grand at least) - large power supply and beefed-up casework to accommodate it, means it can be used with all sorts of over complex expensive speakers and the current output helped with low impedance US-made panels too. To keep with the 'image,' a matching active preamp would be regarded as mandatory by these people to get the 'best' out of it, despite most older Krell or usual ARC preamps having a 'sound' to them (the ones I heard do, although it doesn't necessarily make them 'worse' as such).

Then of course 'ordinary cables' wouldn't be good enough, so a few more grand on these is deemed necessary to bring the best out from this amp as ordinary cables aren't expensive enough or good enough looking... - See where I'm going here?

Apologies for diving in too soon possibly, but the Krell amp is an AMP, not bloody audio royalty, and it's main function was to drive complex speaker loads of the time that many other amps would limit themselves with and to provide heaps of current into low impedance loads. Your speakers needed this ability far more than mine, and I have no money to get on the cachet bandwagon of a 'matching' preamp, whatever expensive brand that should be, let alone foo cables of the right price tag....

The only way your *particular* power amp really *could* be improved - and this following the Stereophile review - is by possibly using a fully balanced preamp (I'm thinking the Levinson ML28 as Barry here uses as a start, as I believe it's circuit is fully balanced from input to output, needing very careful component matching I remember and you can get the odd one for under a grand now I think). I follow a path that tells me that 'balanced' isn't really needed for domestic setups requiring shorter interconnect runs, but if the Krell is positioned in between the speakers and fed by several metres of interconnect, then *in this particular instance* it might give a better sound than a 'pot-in-a-box,' which is potentially better than anything else otherwise - you do know that transformer 'preamps' have hundreds of feet of wiring in and across the signal path and they 'will' add distortion of sorts, even if it's benign... A precision attenuator such as you have is but one high quality resistor ONLY in the signal path, the others just 'shunting away' not-needed voltage (I'm hoping that's correct enough to save censure from Rothwell and others).

If I've got it all wrong then I apologies. Krell is one of those brands build like an outhouse and designed for a particular market, as was Mark Levinson of old and other juggernaut amps on the domestic market. This particular market is a kind of 'club' which I used to hang on the fringes of and the chap who passed it to me originally was very much of this band of loyal followers, raving about the 'cheap' mains cable he'd just sold at a mere £760! (his was from further up the range as were his 'Transparent Audio Reference' signal leads). Last I heard, he had a D'Agostino amp and twenty grand ML panels used with his freshly restored once £20k Krell CD/Digital preamp. The KSA 50S was a temporary standby amp while his FPB 400 was being serviced...

[Marco]

The ONLY reason a passive preamp would possibly compromise your Krell is the sensitivity issue if used with old sources with say 500mV output not going loud enough - the KSA 50S needs 1.3V for full output. NOT AN ISSUE WITH CD sources or most other digital ones I believe...

So are you disputing the figures that Duncan posted earlier then Dave, in terms of the low input sensitivity of the Krell? Also, to your knowledge, has the Krell ever been serviced/re-capped?

Marco.