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Quality passive preamp?

Still interested to hear your experience as I would have loved to have ended up with one fully working as they are extremely well built and transparent. Thats how I ended up with my Rothwell Indus which has proved a really excellent alternative.

I documented it on the Audio Synthesis thread in the classic room, but basically I noticed it looked just a little grubby in there, I suspect from a 20 year old lubricant drying out, so I cleaned all the contacts and wiper with cotton buds and Deoxit Gold. Both are certainly working perfectly and I can’t imagine ever wanting another passive attenuator. They’ll definitely see me out as they are so well made. As I say, there is zero magic in here, it is just exceptionally high quality mechanical/electrical engineering. Really nothing to go wrong!
 
I documented it on the Audio Synthesis thread in the classic room, but basically I noticed it looked just a little grubby in there, I suspect from a 20 year old lubricant drying out, so I cleaned all the contacts and wiper with cotton buds and Deoxit Gold. Both are certainly working perfectly and I can’t imagine ever wanting another passive attenuator. They’ll definitely see me out as they are so well made. As I say, there is zero magic in here, it is just exceptionally high quality mechanical/electrical engineering. Really nothing to go wrong!

Interesting; I have the last PAS-02 I bought sitting in a cupboard unused. I tried to open it up to see if anything could be fixed. However I cannot get the black control knobe off the front so that the faceplate and case can be removed. They appear to be the pull off type not screw secured but they seem to be almost welded on! I'm loath to force them too much in case I break them or damage the facia so it just sits there.
 
Interesting; I have the last PAS-02 I bought sitting in a cupboard unused. I tried to open it up to see if anything could be fixed. However I cannot get the black control knobe off the front so that the faceplate and case can be removed. They appear to be the pull off type not screw secured but they seem to be almost welded on! I'm loath to force them too much in case I break them or damage the facia so it just sits there.

There is a very thin clip-on ‘cap’ to top of the knobs, remove that (you should be able to hook a fingernail under it) and you will see a nut that can be loosened with a socket wrench. Once the knobs are off undo the four bolts at the rear of the chassis and the whole assembly slides out backwards. The PAS-02 attenuator is huge!
 
There is a very thin clip-on ‘cap’ to top of the knobs, remove that (you should be able to hook a fingernail under it) and you will see a nut that can be loosened with a socket wrench. Once the knobs are off undo the four bolts at the rear of the chassis and the whole assembly slides out backwards. The PAS-02 attenuator is huge!

Thanks I would never have worked that out!
I have taken it apapart now and as you say the attenuator is huge.
However, the gold plated contacts at the front are encased in hard plastic shields with bots that appear to run the whole length of the attenuator. Therefore it looks like to clean and service the contacts you have to take them apart and assume the front contact come apart for cleaning? So a fairly intracate job.
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I’d just spray some Hosa Deoxit G5 into the gaps and give it a good workout. Should be fine. I assume its not cutting out in use? I can’t see how that could be possible given the quality. If you are just hearing a very slight crackle when moving between steps that could easily be indicative of an issue elsewhere e.g. a small amount of DC offset on the source, grounding or whatever. I’d not overly worry about it anyway, I bet it will still see off any new passive under £600 or so.
 
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I’d just spray some Hosa Deoxit G5 into the gaps and give it a good workout. Should be fine. I assume its not cutting out in use? I can’t see how that could be possible given the quality. If you are just hearing a very slight crackle when moving between steps that could easily be indicative of an issue elsewhere e.g. a small amount of DC offset on the source, grounding or whatever. I’d not overly worry about it anyway, I bet it will still see off any new passive under £600 or so.

No it does not cut out and the problem only occurs when its volume control is between -3 to -10 DB and its a crack when moving up/down the volume step but only in those few steps. My concern is it might take a tweeter out as its around the normal listening volume. As I said previously i've had several convesations with David Heaton about it and have already been down the DC offset issue route. It has been tried with several different power amps, sources, inteconnect types and lengths so its consistent no matter what and therefore was thought to be a mechanical issue.
I have looked more closely at the construction and the gold contacts are sealed inside a plastic case sandwitched with the other components, so it would need to be dismantled to get any cleaner or lubricant on them.
 
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I’m pretty sure the clear covers on those Elma switches are just clipped on. Yes the resistor ladders will restrict them but you should be able to open one of them enough to get some cleaning fluid in each section. The things aren’t air tight anyway so like Tony says some fluid should get in there.
 
I’m pretty sure the clear covers on those Elma switches are just clipped on. Yes the resistor ladders will restrict them but you should be able to open one of them enough to get some cleaning fluid in each section. The things aren’t air tight anyway so like Tony says some fluid should get in there.

Yes you are absolutely correct having investigated further. Just goes to show you learn something new every day :)
 
I haven't abandoned the idea of a passive pre such as a Wavac TT-S or a Rothwell Indus, but for now I have installed new EH 6922 goldpins in my Herron preamp. It seems that the valves were in fact on their last legs and after I had taken them out and reinserted them, I lost sound in most of the inputs. Perhaps, I did not insert them properly, but since I had already ordered the EH goldpins, I was not concerned. And now music has been restored.
 
I’ll be very interested to see what you think of the Allegri, it is a product I’d love to try.
 
I’ll be very interested to see what you think of the Allegri, it is a product I’d love to try.

I had one on an extended home dem about (?) 12 years ago when they first came out, running into my NVA monoblocks.

It really was superb, way more transparent than the NVA passive I was using at the time, and much less of what to my inexperienced ears sounded like an impedance mismatch with my phono stage. It was hellishly expensive for a passive though - £1800 IIRC.
 
Well, that was interesting!

The Allegri replaced my EAR868pl giving:

Linn Klimax DS/1 Renew > Allegri > EAR534 > Naim SBL

Now, I love the 868, I can listen to all my music all day long and enjoy the detail and dynamics. The Allegri stepped up the clarity, macro and micro dynamics AND the resolution; that is there was more to hear and you could hear better into the recording. So, a slam dunk for the Allegri?

Well, no. The 868 does not miss detail, it is just not quiet to readily apparent, and in gaining that detail it can occasionally move a tad into the uncomfortable; now that may just be being honest to the recording. Interestingly the uncomfortable was far more apparent on Qobuz than it is on locally streamed files. There is also one thing that the 868 does better - the human voice, it just sounds more real to me on the EAR, and this is critical for me.

So, where did this leave me? Well, if I was to buy the Allegri then I suspect I would need to tune the rest of the system by perhaps getting my Audio Note 2.1 back into the system. From a pragmatic POV I need a phono stage AND a remote control for those playlists, so I will very happily remain with the 868pl; but, the Allegri is one hell of a pre-amp and in MANY aspects is better than the EAR.

As always, if you are thinking of a piece of gear you owe it to yourself to demo it in your system, but I can't imagine you would take much of a hit to buy and then move it on. Bloody good day and my thanks to George47 from The Wam. And no, I am not at all convinced that the Allegri won't play on my mind!

M
 
Well, that was interesting!

The Allegri replaced my EAR868pl giving:

Linn Klimax DS/1 Renew > Allegri > EAR534 > Naim SBL

Now, I love the 868, I can listen to all my music all day long and enjoy the detail and dynamics. The Allegri stepped up the clarity, macro and micro dynamics AND the resolution; that is there was more to hear and you could hear better into the recording. So, a slam dunk for the Allegri?

Well, no. The 868 does not miss detail, it is just not quiet to readily apparent, and in gaining that detail it can occasionally move a tad into the uncomfortable; now that may just be being honest to the recording. Interestingly the uncomfortable was far more apparent on Qobuz than it is on locally streamed files. There is also one thing that the 868 does better - the human voice, it just sounds more real to me on the EAR, and this is critical for me.

So, where did this leave me? Well, if I was to buy the Allegri then I suspect I would need to tune the rest of the system by perhaps getting my Audio Note 2.1 back into the system. From a pragmatic POV I need a phono stage AND a remote control for those playlists, so I will very happily remain with the 868pl; but, the Allegri is one hell of a pre-amp and in MANY aspects is better than the EAR.

As always, if you are thinking of a piece of gear you owe it to yourself to demo it in your system, but I can't imagine you would take much of a hit to buy and then move it on. Bloody good day and my thanks to George47 from The Wam. And no, I am not at all convinced that the Allegri won't play on my mind!

M

Mine certainly opened my eyes/ears! Second hand bargain and can't see me being able to afford anything considerably better.
 
Agree it was a very interesting day and glad you liked what it did. I like what it does with my Naim 250DR and there are a few fans of Allegri + Naim including some famous ones. But as always, your ears are the final arbiter.
 
Has anyone on this side of the Atlantic Ocean had the opportunity to listen to music through a "The Truth" preamp from the Horne Shoppe? Could be something rather special.
 


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