Any way to increase gain?

[jwags81818]

I built the ANK L3 Phono amp. Actually its a clone but loaded with premium parts. It works great. No noise and sounds good but I need more gain. Is there anything I can do to this circuit to increase the gain a little? I am running a DV20X2 High output cart and it requires I turn my amp up to 3/4-7/8 volume to get listening levels where I like them. My previous phono amp had adjustable gain and was a fair bit louder. I have it loaded with all factory recommended values. Is there any resistor changes or something similiar I can change to get more gain out of it?

 

[rayma]

The second stage could be a 12AX7 also, with higher plate and cathode resistors,
but it would have higher output impedance, and higher grid capacitance.
The RIAA value of C7 would have to be adjusted somewhat.
But this will only give a few dB more output.

 

[ejp]

There’s about 41 dB of gain there, allowing -20 dB for the RIAA. Should be enough. What’s the sensitivity of the next stage? And the cartridge output?

 

[vinylkid58]

I am running a DV20X2 High output cart and it requires I turn my amp up to 3/4-7/8 volume

That's the problem with some high output MC's. They have less output than a typical MM cartridge, and leave you in "no man's land" output wise.

Get the "Low" output version of your cartridge, and a 1:20 SUT. That will be the end of your volume issues.

Or, build one of those Zhili Audio EAR834p clones. They have a lot more gain.

jeff

 

[b_force]

The second stage could be a 12AX7 also, with higher plate and cathode resistors,
but it would have higher output impedance, and higher grid capacitance.
The RIAA value of C7 would have to be adjusted somewhat.
But this will only give a few dB more output.

Depending a bit on the following stage, but in general I find that two 12AX7/ECC83 is kinda mandatory if you want about 1Vrms of output. Or use pentodes instead.

If we want to go a little less purist, we can put the first or 2nd stage in cascode with a NPN or Mosfet.

 

[Citizen124032]

If you dare to lower the plate voltages of the 83 & 88 for higher Ra's and hence a little bit higher gain.
Marginal though, as by #2.

 

[DNic]

You could try installing something like this
https://www.aliexpress.com/item/100....order_list.order_list_main.11.3e1e180242swu7
Using your cart outs as balanced, will give around 2dB of gain.

Cheers

 

[rayma]

I think you must mean 20dB.

 

[Ixnay]

Feast or famine with these phono preamps and carts. I have seen just a few phono preamps, a volume control which made me wonder if that is a good idea. Certainly not to increase gain, but likely only for attenuation.
I am also with the idea of getting the low output model and adding a transformer.

 

[ejp]

Or get a transformer anyway. That 47k loading isn’t correct for an MC cartridge.

 

[TonyTecson]

I built the ANK L3 Phono amp. Actually its a clone but loaded with premium parts. It works great. No noise and sounds good but I need more gain. Is there anything I can do to this circuit to increase the gain a little? I am running a DV20X2 High output cart and it requires I turn my amp up to 3/4-7/8 volume to get listening levels where I like them. My previous phono amp had adjustable gain and was a fair bit louder. I have it loaded with all factory recommended values. Is there any resistor changes or something similiar I can change to get more gain out of it? View attachment 1300747

increase b+ and increase plate load resistors...

 

[vinylkid58]

That 47k loading isn’t correct for an MC cartridge.

Right or wrong, that's what most manufacturers spec for their HOMC cartridges.

jeff

 

[ejp]

I’m also wondering how that ECC83 is going to like 100R in parallel with its grid leak resistor.

 

[ejp]

Right or wrong, that's what most manufacturers spec for their HOMC cartridges.

It’s not what this manufacturer specifies for this cartridge.

 

[vinylkid58]

It’s not what this manufacturer specifies for this cartridge.

I see that, but that won't have any effect on gain, which is the issue here.

I see the OP @jwags81818 has started another thread on this topic anyway?

jeff