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In the Forum: Melquiades Amplifier
In the Thread: The Shielding Condoms on those tubes....
Post Subject: The Shielding Condoms on those tubes....Posted by Romy the Cat on: 9/21/2009

I got home today, power up the payback and played some bootlegs of Australian festivals that Kostas Metaxas sent me another day. I paid attention that the sound was strange it was too hard atop.  That was something new. I put in my player the CDs that I knew very well and it was the same as I heard on the Kostas' recordings – it was hard and punchy HF.

My tweeter is very precisely calibrated for minus 4.75dB to work along with my YO186/S2 channel (that run at +3.25dB). I spent a LOT of time for this configuration and I know all minute characters of this sound but now it was way off sonically. I switch the playback in calibration mode and the MF/HF channels were stop on: -4.75dB and + 3.25dB. Sonically however it was absolutely fucked up and MF sound absolutely separate from MF with very hard HF temperament. I reduced the HF channel for 1dB. The sound completely got destroyed  and now only the very ugly FM were auditable. Taking about how the “great” sound of YO186!  There was nothing remotely acceptable about it! The sound was like breast of 95 year old women…

Something was very wrong as last night the playback was great and there was nothing changed since then.  Of course I might blame electricity but I did not. Since the last December the PP2000 runs my whole playback, and I am knocking on the wood – I have no single bad electricity day and PP2000 worked flawlessly (to my own surprise!). So, I kind of not accustomed to have bad electricity sound. Also, with bad electricity the LF change texture and now the LF were fine. So, something or somebody changed my FH and I have no idea what it might be.

I was walking about my room, thinking what the hell it might be and I had no idea… I reboot the amps a few times sand  made all imaginable adjustments on the amps and speakers – nothing helped  - the HF and MF behave SUDDENLY  like two alien sound sources. What the bloody hell has happened?

Then it came to me.  The last night I found a set of very cool tubes shields.  They are taken off from measurement equipment and provide very good tube cooling and shielding. They have inside the very fine spider that holds the tube very firm. I figured last night the since the 6E6P is very fast tube (a few hundred megahertz) then an extra shielding would not heart. So, I put the shield on my 6E6P-DR that driver HF channel – I did even forget that I did it.

As soon I took the shields off it was stunning how HF changed – they become super extended super soft and absolutely free from any annoyance.  I put everything back to the default configuration mode and the sound was exactly where it had to be. I was VERY surprised with the enormous magnitude of sonic change that those simple shielding condoms might do.


I did not use any shields on my equipment before. The only price with shields that I have that used and that I knew very well it was Lamm ML2 phonostage, it used 4 WE417A. I hated the sound of that phonostage. In the MC mode it was horrible and even in MM mode it was very much sub-acceptable. I wonder - might it be that the 4 shield that Lamm used did fuck up the sound in there? I changed a lot of tube in there but I think I always put the shields on.

I do not claim the shields are bad. They were horrible with Milq’s HF channel.  It is possible that different tubes react to shields differently. In my case the 6E6P-DR was VERY fastidious….  Anyhow, it is what it is I think it would be worth warning and to remind that best intentions are not always lead to better sound…

The Cat

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