Can a preamp's gain be lowered?

AES has been tough to communicate with. Most of my questions have gone unanswered. I'd rather not deal with that (whether it's attitude or being too busy I don't know). I can easily build my own attenuators. According to Goldpoint's website, I need 68.1K and 46.4K resistors to reduce the gain by -10 dB when dealing with an input impedance of 100K. I'll use Texas Components TX2575 resistors. I don't think there's anything more transparent available.

Thanks for all your replies. I appreciate your help.

I appreciate the suggestions.

The manufacturer or a modifier can do it internally/elegantly.

I like this idea. I sent a message to Cary and AES to find out what they recommend. I'm waiting to hear from them.

A switch and a few resisters at the power amp input is the fix which the manufacturer should provide.

When preamps offer switchable gain, is it usually a voltage divider design?

Along with Rothwell and Endler, I found Harrison Labs. The Endlers use Yaego metal film resistors which are about the cheapest resistors you can get. This doesn't instill confidence that they're transparent. Rothwell and Harrison don't say what they use.

I'll wait to hear from Cary to find out what they say. The gain of the AE-3 DJH is 20 dB which is definitely high... especially for me since I've been using passive preamps the past year.

07-25-08: Mboldda1
in the case of tube preamps, what about using lower gain tubes?

Is there such a thing as low gain 6SN7's?

Bob, I completely agree with you, but Kevin at Upscale assured me that he's never had a problem mating an AE-3 DJH with amps that have less than 1v input sensitivity. My DAC has an output of 1.8v which is less than your average 2v. My speakers are 87 dB inefficient, so that may help tame the gain as well. I don't have the AE-3 in my possession, so this may be a moot exercise, but I'm preparing myself for the worse case scenario.

Thanks again.

Thanks for your suggestions.

07-26-08: Mitch2
I built my own balanced attenuators for the input side of a tube preamp using Vishay resistors

Is it better to put the attenuators on the input rather than the output to the amp? I'd really like to see your circuit and the values you used. I'm comfortable with diy.

Ait, I appreciate you pointing this out to me. Your mod sounds very intriguing. You know a lot more about tubes and circuits than I do. After reading your description, I see there's very little in the way of actual changes (just two wires if I'm not mistaken), but I have to wonder if your instructions translate to the AE-3. I'm a bit leery of changing the circuit. I might revisit this another day, but for now I'd like to try something less risky.

Mitch2, thanks for those links. I figured it was a voltage divider. I'll email you for pics and values you used.

Thanks again to everyone.

Hi Mjcmt, I've been emailing with Gerald Walsh at AES. He said they can reduce the gain to 10 dB. I'm considering it. It's only $125. But I know I could build attenuators for a fraction of that price (probably using better resistors), so that's my dilemma.

Mjcmt, I appreciate your info. I've been emailing with Gerald at AES, but his replies have been intermittent and sparse. I haven't tried to call. Maybe I should have done that, but he seems either too busy to answer my questions or not interested in supplying information that doesn't directly lead to a service fee. From my perspective, I think it's a fair question to ask if resistors will be added to the signal path to reduce the gain or if the original circuit will be modified. If I sell the unit, I need to disclose any changes to the buyer.

At this point, I think my best option is to use in-line attenuators and keep the unit in stock form. I have a hunch Cary's mod would be the same thing, but tucked inside the chassis. If I use attenuators, I can change them at any point in time. A mod will be permanent.

I just bought a pair of Rothwell attenuators with -10 dB which is perfect for my situation. I think it's the right thing to do given that I can change the attenuation myself at any point in time. Thanks again, Mark