Switched attenuators, what's all the fuss about?

[anubisgrau]

I think this sums up my approach as well, although I have recently spent on TT upgrades that are larger than 'tweaks'.

Now the AD attenuator has been in for a few days all the usual favourite albums have been played, plus a couple of others.

The improvement has been amazing, I am even hearing a better sound from DAB radio at 128kbps, insane.
(Not much but an improvement given the source).

One of the most notable changes has been to the lower registers, they are palpably more distinct. The effect is to underpin the sound with what you could describe as better foundations to a building.
The bass and midbass is now an integrated part of the sound, not drawing any adverse attention, no bloat but tremendous impact when there should be. Kick drums come over with a solidity and power that wasn't apparent before.

The rest of the spectrum has opened out as well, cymbals tinkle more, individual instruments are placed more distinctly. Multiple voices are now all individual such that you can enjoy the performance more due to hearing everyone's contribution.
The power and rasp of brass instruments has come to the fore, I even heard greater nuances on the Yello Toy album, which has been played a lot.

Another big bonus is that CD reproduction has taken a leap forward, now instead of wishing the CD was a vinyl record, I can enjoy the medium without thinking it needs a big upgrade to compete.
Now that's a very pleasant surprise

In conclusion the best single upgrade I have made................

I have been counting up the upgrades over the last 12 months and they total 7. I'll put these into a new thread.

ever tried a good AVC like slagle in place of the these fancy new attenuators?

i'm asking because people keep on telling me that the new stuff (KIN, DCB1) sounds better than slagle AVC which is technically speaking wrong comparison - active device vs passive volume controller. yes it can be done but we should be clear that we don't listen to differences between fixed and variable output impedance.

[pankon]

Maybe I will ask Glenn which he thinks give the biggest bang for bucks!
...

Yes, James, it would be great to have Glenn's opinion about the best value-for-money upgrades. Being an owner of Croft great since 1989, and having had various Croft amps upgraded by Glenn, I know for a fact that Glenn is very cautious with words. Improvements that me and you would describe as "magnificent", "unbelievable", etc., Glenn would say "it works well". Understatement is a built-in characteristic of Glenn.

Your thinking is definitely in the right direction, which I've taken to where I am now. My Croft preamp (Micro 25RSLS, line stage only, with external power supply), is theoretically top-of-the-line for Croft. It is obvious though, that more is to be had... Croft gear seems to have no end in improvement potential.

I will definitely report my impressions, as soon as I have finished with the new pots. But no, I do not do such upgrades myself. I prefer to have them done by experts.

[Jimbo]

Hi Panos,

any news on the khozmo attenuators in the Croft yet? I look forward to hearing your thoughts on this.

[pankon]

Hi Panos,

any news on the khozmo attenuators in the Croft yet? I look forward to hearing your thoughts on this.

Hi James,

as a matter of fact, my Croft preamp reached Poland a couple of days ago. Arek (of Khozmo/Hattor) is going to fit dual mono attenuators in the Croft, plus an upgraded input selector and a remote control. We have been discussing with Arek which attenuator type is the most appropriate. I mentioned that most forum members, who've used Khozmo attenuators, seem to prefer the series type. But those -according to Arek- cannot be provided with a remote control. Therefore, Arek suggests wither shunt type (which I have tested in the Hattor passive preamp and is very good) or the ladder type (which has been used in high-end, rather expensive implementations).

Regardless which attenuator type we'll eventually choose, it's not a simple pots replacement. Arek will have to shift the tubes to the right to make some space for the new attenuators and the input selector. I hope that the upgrade is finished in a couple of weeks or so (depending on Arek's workload) and I should receive the Croft preamp by the end of January. Fingers crossed!

(Patience is a virtue! ??)

[Bigman80]

Hi James,

as a matter of fact, my Croft preamp reached Poland a couple of days ago. Arek (of Khozmo/Hattor) is going to fit dual mono attenuators in the Croft, plus an upgraded input selector and a remote control. We have been discussing with Arek which attenuator type is the most appropriate. I mentioned that most forum members, who've used Khozmo attenuators, seem to prefer the series type. But those -according to Arek- cannot be provided with a remote control. Therefore, Arek suggests wither shunt type (which I have tested in the Hattor passive preamp and is very good) or the ladder type (which has been used in high-end, rather expensive implementations).

Regardless which attenuator type we'll eventually choose, it's not a simple pots replacement. Arek will have to shift the tubes to the right to make some space for the new attenuators and the input selector. I hope that the upgrade is finished in a couple of weeks or so (depending on Arek's workload) and I should receive the Croft preamp by the end of January. Fingers crossed!

(Patience is a virtue! ??)

Yes, good point. To mod the Croft for Stepped Attenuators you will need a small alteration to the guts to fit them in. That said, Alan is very local and overqualified to do the mod.

James, go for it!

[montesquieu]

Just a word of caution before you start modding kit in a major/potentially irreversible way, some of us have tried stepped attenuators including high quality ones, and gone back to film pots.

Sonic improvement are NOT a given, but a matter of opinion. Many top manufacturers use film pots, not on cost grounds but in the belief that there is no sonic penalty while at the same time, the convenience of a film pot and its infinite adjustability outweighs any notional benefit from ladder attenuators.

Personally I've never warmed to stepped attenuators at all. One thing they do do is make correct gain structure even more critical, making too much gain in a system even more of a no-no.

Sorry to be a dissenting voice here but it's too easy to get carried away with a one-sided view of things.

[pankon]

Just a word of caution before you start modding kit in a major/potentially irreversible way, some of us have tried stepped attenuators including high quality ones, and gone back to film pots.

...Sonic improvement are NOT a given, but a matter of opinion...

I've personally decided to proceed to the replacement of the carbon pots in the Croft, after I had tried the Hattor passive preamp (bypassing the pots in the Croft). The difference was far from minute. The result was one order of magnitude (whatever this may mean) more transparency, more detail, more realism. Yes, I agree, the cost of the Khozmo attenuators are two orders of magnitude more expensive than the carbon pots in the Croft, but in hi-fi terms we know that much more money is usually spent for far smaller improvements.

Hence my decision to proceed with the replacement of the carbon pots. Let's hope that this trial of mine will not be followed by an error. And if that is the case, I am open enough to admit it. -))

[montesquieu]

I've personally decided to proceed to the replacement of the carbon pots in the Croft, after I had tried the Hattor passive preamp (bypassing the pots in the Croft). The difference was far from minute. The result was one order of magnitude (whatever this may mean) more transparency, more detail, more realism. Yes, I agree, the cost of the Khozmo attenuators are two orders of magnitude more expensive than the carbon pots in the Croft, but in hi-fi terms we know that much more money is usually spent for far smaller improvements.

Hence my decision to proceed with the replacement of the carbon pots. Let's hope that this trial of mine will not be followed by an error. And if that is the case, I am open enough to admit it. -))

Well at a minimum, you need to be able to get along with jumps in volume that may or may not delivery the sound level you want to listen at.

That's where the main issue is for me. Even relays with 99 steps can fail the acceptability test in my book, never mind your typical 24 or 32 step device.

[pankon]

Well at a minimum, you need to be able to get along with jumps in volume that may or may not delivery the sound level you want to listen at.

That's where the main issue is for me. Even relays with 99 steps can fail the acceptability test in my book, never mind your typical 24 or 32 step device.

Tom,

The Hattor dual-mono passive preamp, when used on its own (i.e. without any active preamplification) has 64 steps. IME the useful range (in my system and room) is between 36 and 54 (with 63 or 64 being the maximum on the display, IIRC), i.e. from very quiet up to quite loud.
When combined with the active Croft preamp, the useful range became wider. Not once did I find that there was not enough resolution between two consecutive steps.
So, for me, that's to a concern. You obviously have different experiences, hence your sensitivity on the subject. It's absolutely understandable to pay attention on points that may have displeased us in the past.

[Jimbo]

I hope your attenuators work out Panos, I will await the verdict at the end of January!

Happy New Year