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It is currently 13 Aug 2020, 21:23

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PostPosted: 23 Jul 2020, 23:30 
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Joined: 06 Jun 2008, 18:23
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Location: Australia
Only using parts in da lab I’m building another Salt Cellar amp. This time SS rectification and just two stages - drive and power tube. The 6EM7 has two triodes in the one bottle. I’m told they are similar to a 6SL7 and a 45. An attenuator at the front accepts both channels then with two 3.9K resistors mixes the signal down to mono.

This one will use a different external universal Tranni box. Another wine box amp with a stain/lacquer finish. On the blond box comes out a light toffee. I wanted it different than the first and it is, for sure. Again an aged Salt Cellar look about it.

Should have it finished tomorrow
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Projects:“Salt Cellar” - Mono 807 triode integrated amp |
"Rosso" - E88CC SRPP preamp | ”Salt Cellar II” - 6EM7 mono wine box triode amp | “MWH” - 1920s UX-171A preamp |


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PostPosted: 25 Jul 2020, 08:10 
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Joined: 06 Jun 2008, 18:23
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Location: Australia
It lives! Under test here and I’ve only had a 5 minute listen but sounds good so far. Triple Pi filter with 10H 125mA choke. With the music off and 98db speaker it is dead, dead, dead quiet. “Is it on” quiet.

Hope to have a big listen tomorrow. It is complete and in my main system.
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Projects:“Salt Cellar” - Mono 807 triode integrated amp |
"Rosso" - E88CC SRPP preamp | ”Salt Cellar II” - 6EM7 mono wine box triode amp | “MWH” - 1920s UX-171A preamp |


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PostPosted: 25 Jul 2020, 13:07 
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Joined: 06 Apr 2009, 10:08
Posts: 1678
Location: US Pacific Northwest
Looks good Mark!

I look forward to your impressions of how it sounds.

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Matt
It's all about the Glass!
http://www.CascadeTubes.com
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PostPosted: 27 Jul 2020, 19:56 
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For the first few hours, once more, I was wondering if this amp would ever sound good. For some reason I seem to forget this is a brand new amp with all unused new parts, passives and tubes. Initially I felt the 807 triode amp was clearly going to out perform it. But a day or so later the 6EM7 has settled and parts burnt in and now sound very good. I expect it to improve even more over the next week or so of serious listening. My session are generally four hours a day at least five days a week.

In Beethoven’s Mass in C the soprano sounded extremely good but massed voices a little congested. But I have heard similar on my bigger system. Human voice sounds really excellent and violins even better. Bass is good but due to the Beymas fading under 63hZ but bass is there and followable not super deep.

Really enjoying the SC II amp and may try in a week or so to AB with the 807 triode amp. Not sure now which will outshine the other.

_________________
Projects:“Salt Cellar” - Mono 807 triode integrated amp |
"Rosso" - E88CC SRPP preamp | ”Salt Cellar II” - 6EM7 mono wine box triode amp | “MWH” - 1920s UX-171A preamp |


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PostPosted: 27 Jul 2020, 22:44 
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Joined: 06 Jun 2008, 18:23
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Location: Australia
I’m not one to tweak but just added some bipass caps to the Cks - 0.1uf Polies and a bipass on the last cap (10uf) of the triple Pi filtration right at the OPT after the HT limiting resistor. The amps dead quite and there is no noise to suppress but just a matter of course and like all the parts in this build they were on hand begging to be used.

Not a tweak just lazy on the original build and wanted to hear my creation after a couple of long days budding. Added to more holes in the bottom to allow an air flow across the filament limiting resistors (5W of heat). Also put a heat shield on the back of the pot which is near the hot resistors.

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Projects:“Salt Cellar” - Mono 807 triode integrated amp |
"Rosso" - E88CC SRPP preamp | ”Salt Cellar II” - 6EM7 mono wine box triode amp | “MWH” - 1920s UX-171A preamp |


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PostPosted: 07 Aug 2020, 20:57 
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Joined: 06 Jun 2008, 18:23
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Location: Australia
Had a good chance to critically review both amps (807 and 6EM7) and for absolute clarity SC II wins. The 807 amp feels like it has a more solid thicker sound but on the CRO both amps produce 1.5W and roll off at about 60hZ.

If faced with the choice of only able to keep one I’d probably go for this amp - SC II.

_________________
Projects:“Salt Cellar” - Mono 807 triode integrated amp |
"Rosso" - E88CC SRPP preamp | ”Salt Cellar II” - 6EM7 mono wine box triode amp | “MWH” - 1920s UX-171A preamp |


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