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Are there any other EAR 834P modders lately?

I had to beg David Schulte of Upgrade Company to mod my EAR 834P because there are so many detractors. There are also loads of DIY people who have tweaked the circuit in custom ways. The changes I had made include V-cap coupling caps and RFI shileding. Switching from using the 12AX7 tubes to 5751 or 12AT7 tubes if you can handle the lower gain also is highly beneficial. I use Valvo 6201 blue print in the one spot, Brimar and Siemen Halske 12AT7's in the gain stages 2 & 3. 2 is not left and 3 is not right- it sums the tubes for the gain stage left and right. My results are stunning. Because the 12AT7's only have 70% of the gain or the 12AX7, I changed out my Bent Audio step up tranny's for Bob's Devices Cinemag 1131 with a 1:40 or 1:20, ratio which is adjusted at the flip of a toggle switch.
zenbret
slaw's avatar
slaw
20,405 posts
 
Information overload. The other two posts I made aren't up yet, I've made one more tube change. I put the two Tele's in V2 @ V3, (still have the Seimens in V1). It's obvious that the Tele smooth plates are more sonically neutral than any of the other tubes I own. I feel the Seimens have an edge in bass power/extension,... maybe slightly unrealistic in the treble region. If I had 1 more, I'd try them in all 3 positions.
slaw's avatar
slaw
20,405 posts
 
OK, I switched to the Bugle Boy in V2. Less open, only a hint of the bass the Mullard had, (soft sounding). Put the Mullard back in.

I'm working too hard, party people. Time to sign off and enjoy.
slaw's avatar
slaw
20,405 posts
 
This thread got me wondering about my tube compliment. In the context of my system, these are the changes I made today while listening to Elvis Presley "Live From Memphis" Speakers Corner,. The tube orientation I previously mentioned had a little "spotlight" effect. I had previously used (2) 60's Seimens in V2 @ V3, then went for the Mullard in V2. The Mullards are warm with nice bass, however they are not the greatest for transparency/dynamics. This was a nice compliment to the other tubes, but too much of a good thing. Trying another Mullard in V3 produced a even warmer sound that I'm not very happy with. I then left one Mullard in V2, @ switched the others so the Tele is in V3 and the Seimens is in V1. Things are pretty nice now. Somehow I get the feeling of trying a Bugle Boy in V2 to replace the Mullard. Maybe later, will report back.
zenbret OP
18 posts
 
Slaw- glad your having fun with it. Read my simple post above again about SUT ( step up transformers) - the coil of wire that increases the voltage passively- without any active gain stage like an amplifier does.

MC cartridges are such low voltages that they have to be boosted before you put them into the phono preamplifier's gain stage in order to get a decent signal for the preamplifier. Or you can try some of Frogman's MM cartridge recommendations because they have a high voltage to start with.
zenbret OP
18 posts
 
Found some good info Audio Assylum thread and Joe's Tube lore. Many agree ( Joe- and other tube experts that tell me Joe is pretty much right on on most of his analysis) that the 12AX7 is a hazy, cloudy, non-detailed tube in most circuits. IMO it is better to change to something else for V1 (toward the back of the unit). Tim DiP does say you can use a 12AU7 instead, but he recommends only 12AX7 in the other 2 spots. Apparently RIAA is handled mainly by V2. V3 is actually a cathode follower tube and some have used non matching alternatives in V2 and V3 against Tim DiP's advice with good results. I am buying a Brimar CV4004 (it better be worth the high price) for V2 and will leave the Telefuncan Fisher in the cathode follower V3, and my Valvo 6201 blue print in V1.
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