Welcome! Need support, you got it. Or share you ideas and experiences.
Ron, Ultrapath's gain is set at 10 dB. Is there anyway it can be increased, at least for one of the inputs? The problem is with my vinyl playback. For my preferred loudness level I need to set the volume level at almost the maximum. The phono stage has also lowish output but with my other preamp it is less of a problem as its gain is 28dB. I've no problem with CD playback. Or does the problem lie elsewhere?
Ok. I got it. This is a neat-looking preamp. I've been experimenting with battery supplies on my Ultrapath-converted Moondogs, too.If the volume control is a 50K pot, perhaps try a control with a value of 100k or 250K. The issue, too, is if the preamp circuitry is optimized for a 50K potentiometer...which it may be. It also appears that there is a grid-stopper between the wiper of the volume control and the grid of the input tube. What is the value of that resistor, and could it be decreased without compromising the performance? Is the circuit unstable without it?
If the volume controls were expensive, replacing them for higher value pots may not be the most prudent way to deal with the problem. How far away from the Ultrapath preamp is the phono stage?
I'm curious about this, mainly because I think battery power has some serious potential for quiet, great sounding amplifiers. All the old tube radios I've restored use them, and I am doing continuing research on the availability and variety of battery-based power supplies. I've learned that quite a few others have used this rather old technology with great success.
Erik
Sorry, but there is no way to increase the gain of the Ultrapath. Sounds like the problem is with your phonostage not having enough gain. You could either replace your phonostage or consider adding a step up transformer to it.Ron
Perhaps the gain can't be increased on the Ultrapath, Ron. But what about increasing the input sensivity by way of a higher impedance volume control? I have never seen a schematic of the circuit, so I don't know about this. In theory, replacing a lower value pot with one of greater value could increase the percieved loudness. However, if the preamp is also used for other sources this could pose a problem -- making those way too loud. On the other hand, one could off set this with series resistance from the inputs of the jacks to the selector switch....this is just a thought on something that might be tried.
...Or get a preamp with higher gain.
Erik
The volume control for the Ultrapath needs to be kept below 50K because of possible grid leakage from the 6GM8.Besides, increasing the value of the volume control at best might provide a 3dB increase. From the tone of his post I'm guessing he's looking for more than a 3dB boost.
Ron
Of course you know more about this than I, Ron. I just wanted to offer something that might be helpful in his case. Sounds like a phono stage with a little more oomph might be in order.
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