Bottlehead Forum
Bottlehead Kits => Eros Phono => Topic started by: BNAL on September 07, 2016, 11:46:24 AM
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I just got the email notification that my Eros is in the mail and will be to me by Friday. I can't wail to start the build and replace my cheap ebay phono that has served me well, but it runs on two 9v batteries and I always forget to turn it off so the batteries rundown. It will be good not having to worry about that anymore.
My plan is to build it mostly with the stock parts, the only changes I'm thinking about making during the build are to replace the EF86 tubes and run the 6BR7s. I searched the forum and found that the 6BR7 appears to be a nice alternative that sounds at least as good as the EF86 and are quieter. I also, have some Reflector 6N23P-EV tubes that I plan to use. I used them in an amp and like how they sounded in that implementation, so I'm hoping that they will work as well in the Eros.
I don't think that I will change any of the caps in the initial build, though I do have pairs of Russian Teflon FT3s in .1uFs that I may try in the shunt regulator.
The other change I'm thinking about doing sometime after the initial build would be to remove the servo circuit. I have read two slightly different ways to do it and I'm not sure which is the correct method. The first is removing the 2700uF 4v cap and replacing it with a HLMP-6000 LED and removing the 2N222 transistor. The other adds the removal R3(174 ohm resistor) with a jumper. Not sure which is the correct method, so any help would be appreciated.
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Thanks for posting this Brad. I too would be interested in the right way to remove this servo circuit.
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What's the benefit to being rid of the servo circuit? What's it do for ya?
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The servo circuit was developed by PJ when we found that different brands of tubes were sometimes running quite different plate voltages in the circuit. The servo compensates for this. If you have tubes that run at the proper plate voltage with LEDs on the cathodes, you don't need the servo setup. I tend to use that setup as I think it sounds every so slightly better. But if you change to LEDs and the tubes won't run at the right plate voltages, either go back to the servo or try different tubes.
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PJ, PB or Doc, when you have time, would you mind posting on the correct way to remove this servo circuit? Thank you.
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Just got the kit yesterday and it came with a nice set of tubes. The EF86s and 6922 are the Russian equivalents (6J23P and 6N23P) and a NOS U.S. 12BH7 black plate.
Can't wait to start the build. I'm going to have to wait a couple of weeks, because of travel for work and family visiting.
Brad
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Replace the 174 Ohm resistor on each board with a piece of wire (seems optional upon second glance).
Clip out each 2N2222
Remove the 2700uF cap
Replace the 2700uF cap with an HLMP6000 LED, striped side of the LED to -reg.
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Thank you PB!
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PB thanks. That help