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.
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.
- ...
- 28 posts total
- 28 posts total