[izerbi]

Hi guys. I'm using the bugle (fantastic machine!) set for 44db of gain with a 1.6mV cartridge and it's just perfect! Shortly i'll change the cartridge for one with 0.37mV output and i would love to have the same final level. Is there any equation to set the gain ?
Help would be fantastic.
Thank you

By the way, changing the third opamp for a lm4562 is an improvement over the stock one? or not really... anyone

Thank you

[jcg0322]

A gain of 44dB tells me that you are using 1k ohm resistors at R5, R3, R23 and R21.
If this assumption is correct, then to obtain the same gain from a .37mV input, a gain of 56.72dB would be required.

Jim can correct me on this, but you would need to change these resistors to 473 ohms with 475 ohms being the closest 1% tolerance standard value.

All of this is assuming you are using stock parts. If you change the opamps to something other than opa2134pa then you would have to recalculate everything from the start.

[Theo]

Hi guys. I'm using the bugle (fantastic machine!) set for 44db of gain with a 1.6mV cartridge and it's just perfect! Shortly i'll change the cartridge for one with 0.37mV output and i would love to have the same final level. Is there any equation to set the gain ?
Help would be fantastic.
Thank you

By the way, changing the third opamp for a lm4562 is an improvement over the stock one? or not really... anyone

Thank you

Use the Hagtech tool to calculate resistor values in the Bugle circuit for the desired gain.  It's near the middle of the tools page under "Calculate Bugle Values" section.  For 0.37mV output from a LOMC cartridge, try 55 to 60dB gain.  For example, I set mine to 60dB when I use Denon DL103 (0.25mV). 

Hagtech tool link:  http://www.hagtech.com/equalization.html

I switched the third opamp to LM4562 and found the gain very much the same to that of the stock OPA2134.  How opamp sounds is subjective.  I found the LM4562 a bit more detailed, while the OPA2134 has better bass though a little muddled.

Adjusting the gain is not all you need to do when using LOMC.  You will have to adjust loading as well for balanced sound.  Most LOMC work well between 100 to 200 Ohm loading.  Add a pair of 1% resistors of the desired loading value to R16 and R34.  I have good result using 150 Ohm for DL103.