[dado5]

I noticed a slight change in the Ear+ newer(Purist, etc.) designs.  Namely the input is now capacitor coupled to the grid of the 5751.  Why the change? Is it a sonic improvement? Do you recommend it as an upgrade for the original Ear+?

Also will removing the balance control on the older Ear + increase the gain?  If so would a higher value pot serve to lower the gain  somewhat?

I am lovin' the amp... just lookig to get that much more out of it.

Thanks much in advance,
Rob

[Dr. Lloyd]

Very observant of you Rob. The input coupling caps were added when I was offering the Chinese "Alps" stepped attenuators which seemed to generate pops when moved from step to step (like the switching was break before make at some points). The coupling cap seemed to minimize this--although theory says the transients should be transmitted right through the cap. Anyway, the latest versions using the Alpha, Alps, or Noble pots do not use these caps or the grid resistors. Adding a cap should never be considered a sonic upgrade but you never know what might sound good to the ears.

The old balance control did reduce gain by about 6 dB. The increase resulting from its removal is not really needed in most cases except with low output portable CD players. You can get about 3 dB more gain using a 12AX7 type in the first stage in place of the 5751.

As for upgrades, the premium Purist HD definitely has a transparent, silvery sonic presentation but I can't pinpoint the critical components. The one I auditioned used Black Gates in the power supply, Caddock metal film resistors, and Hoveland caps bypassing the electrolytic output coupling caps (Black Gate). I am now offering this model with Auricaps instead of the Hovelands. I think that increasing the filter capacitance in the Ear+ by parallelling, say 100uF/350 V caps, across the first two filter caps would be a worthwhile upgrade experiment. (You might try a JJ cap dual 100 uF/500V attached under the chassis with a clamp).

Regards,

Lloyd

[dado5]

Thanks for all the information!   That answered most all my questions.  

I think need to clarifiy the gain issue a bit more though.  I am looking to reduce the gain from the stock version, or at the very least keep it the same while at the same time removing the balance pot if possible (I never use it).  I am rarely able to listen to anything beyond the 9 o'clock position.  Could this be accomplised with a higher value volume pot (say 250K). Or maybe higher series resistance at the line input.  

Thanks again,
Rob

[Dr. Lloyd]

Rob-

Some sources these days put out a very high level signal—2 V or more, which is a problem with a lot of preamps both in terms of excessive gain (volume control at very low position) and/or overloading of the first stage (distortion). You can eliminate the balance control in your Ear+ by wiring the input jacks directly to the volume control and removing all the balance control wires. To keep the gain the same, you can insert 100K resistors in each channel right at the input jacks in place of the 47K ones already there. You can add higher values to attenuate the signal but eventually, the series resistance my cause high frequency loss due to the input capacitance of the first stage. However, it would be safe to add enough resistance so that the volume control was close to mid-position for normal listening. Let you ears be the judge(s).

Going to individual channel level controls in addition to the volume control in the MAD preamps turned out to be a good solution to both the balance function (for those times when you might need it) and to reduce the overall gain on both channels to better center the volume control. However, the single volume control is in keeping with the new "Purist" name for the Ear+. Let us know if the series resistance solves your problem.

Regards,

Lloyd