Bottlehead Forum
Bottlehead Kits => Legacy Kit Products => Stereomour => Topic started by: indydieselnut on October 28, 2013, 07:35:08 AM
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Greetings! I truly wish my first post here contributed more to the forums, but I have not been able to search out (definitively) whether or not the EML 2A3-mesh is fully compatible with the Stereomour. These tubes are a bit spendy and I want to make sure I won't be shortening their life at all. I see many people here running them which is encouraging, but I was hoping someone might chime in with a definitive "yes" to put my mind at ease.
Shawn Phelps just finished my Stereomour with Mundorf Supreme gold/silver/oil caps, TKD pot, Goldpoint selector, and Vampire copper-body jacks and posts. It should ship to me tomorrow and I'm awfully excited to hear it for myself. I have so much respect for everyone here that builds their own kits. I'll tackle one of them someday but in the meantime I'm very grateful to learn from all of you. Thank you!
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The EML mesh plates seem to have a problem with direct coupled amps. This is because the grid of the output tube floats to a high voltage at startup.
The Stereomour is not a direct coupled amp. The driver stage is decoupled with a 0.1uF or larger cap (I don't have the schematic). Since Stereomour is an evolution of my Paramours, which have a 0.1uF interstage cap, I know that the Stereomour is not direct coupled.
I'm about to put some Silver/Gold/Oil Mundorfs in my Paramours.
Go for it!
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Grainger49, thanks for the explanation - that makes a lot of sense and certainly helps put my mind at ease.
Congrats on the Mundorfs! When I finally get around to building one of these myself I'll likely build it stock and then have fun experimenting with each upgrade, discovering the best gains in sound quality. Since I had this one built, I wanted to go ahead and put most of the meaningful upgrades in there from the start.
Looking forward to it!
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Grainger, I just noticed your signature as well - I will be running Orcas and a Dungeness sub with my Stereomour. Good to see yet another member of the forums enjoying this combination!
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I'm still waiting on my Dungeness subs. There was a SNAFU at Blumenstein, it happens to everyone! I'm expecting shipment next week or the next. This kind of stuff happens and there is no use in worrying about it.
BTW, I have MQ iron and therefore needed 10uF Parafeed caps. I have been using Obbligato PP/Oil since the conversion. I have some Clarity caps waiting in the aisles for the Parafeed caps.
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Hi and welcome,
The real issues with the EML 2a3 and the stereomour is to make sure (as is already the case) that your coupling cap is not a PIO type, but a film type. Also the filament voltage should be within 5% and the grid resistor approx 500k -- this is what EML specs.
You're in for a real listening treat and there are many BH folks using this combination and loving it. Just be sure to give things a couple hundred hours to settle down before trying any more tweaks, and you'll probably also continue to notice a nice maturing of the sound for a few hundred hours after that -- a lot of that will be the Orcas but the amp itslef also benefits from extended playtime. WWWhich is not to say it won't be very nice all along, just more and more sweet as time goes by.
HTH,
Jim
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Grid to ground resistor is specified as 250k, the Stereomour has 249k so no problem.
http://www.emissionlabs.com/datasheets/EML2A3-mesh.htm
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Yup, he's right -- 250k for the 2a3. I've been reading both the 2a3 and 45 data sheets recently and it's the 45 that specifies 500k. Also filament supply tolerance is 4%, not 5 as I originally said.
-- Jim
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Jim the website says 4% but the sheet that accompanies the tubes says 5% for most EML tubes.