Best op amps for original Bugle?

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majerjack

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Best op amps for original Bugle?
« on: 22 Jun 2014, 04:32 pm »
I have an original Bugle pcb which was never populated with components.  I want to use it in a new preamp I am building for my home audio system.  I noticed from the schematics of the original Bugle and the newer Bugle 2 that the suggested op amps for the original were OPA2134 while the op amps for the newer version are LM4562 (LME49720).

I plan to use the Bugle at the standard moving magnet cartridge gain of 40dB, with moving magnet  cartridges ranging in impedance from about 1500 ohms to about 3000 ohms, and a standard regulated power supply of +/-15V.  Of the two op amps listed above, which would give me the lowest noise in this application?  Are there other audible benefits from using one op amp or the other, and can anyone share experiences of using other dual op amps in the original Bugle?

Thanks to all who respond.   

bregez

Re: Best op amps for original Bugle?
« Reply #1 on: 22 Jun 2014, 11:19 pm »
One alternative is discussed in this thread
http://www.audiocircle.com/index.php?topic=121496.0

majerjack

  • Jr. Member
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Re: Best op amps for original Bugle?
« Reply #2 on: 23 Jun 2014, 12:02 pm »
Thanks, bregez.  After my original post I discovered the Search feature of the forum and found some personal experiences and suggestions relating to my questions.

My main point of uncertainty has to do with the input amplifier.  My understanding is that FET input op amps are more resistant to radio frequency interference than bipolar input op amps and have a higher input impedance (useful for high source impedances).  Bipolar inputs, on the other hand, generally have less voltage noise but higher current noise.  I am not knowledgeable enough to predict the relative performance of the OPA2134 and the LM4562 in the input position of the original Bugle, thus my questions here.

One of the posts I found in my search said that Jim Hagerman designed the EQ of the circuit around the OPA2134 characteristics, so is it best to use that specific amplifier?  Perhaps Jim could comment on this question and the relative merits of of the two op amps in the original Bugle circuit, and if anyone else can offer some useful information, I would appreciate that also.

hagtech

Re: Best op amps for original Bugle?
« Reply #3 on: 27 Jun 2014, 09:26 pm »
The EQ is not dependent on which type of opamp you use.  The LM4562 will be noticeably quieter.

jh

majerjack

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Re: Best op amps for original Bugle?
« Reply #4 on: 29 Jun 2014, 05:47 pm »
Thanks, Jim.