The *entire* recording chain, from mike preamp to disc cutter or ADC input, is full of "volume controls". All (most of) those knobs you knobs you see on recording consoles and in mastering rooms.
Helios console used to record “Stairway to Heaven”
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I don't know why you started a new thread when the schematic is in this thread.
You bought one of the cheapest line-amps available. To hold down cost it runs obscenely low supply voltage, near 1/10th of any "good" line-amp. The plate resistor drop is a mere 24V. This is worse than a $9.95 AM table radio. "Compromise" is going to happen.
A volume pot, despite all the yay-sayers on this forum, is about the least compromise part of any active circuit. (And does not care about supply voltage.)
If you must tinker the amplifier gain, do this.
You bought one of the cheapest line-amps available. To hold down cost it runs obscenely low supply voltage, near 1/10th of any "good" line-amp. The plate resistor drop is a mere 24V. This is worse than a $9.95 AM table radio. "Compromise" is going to happen.
A volume pot, despite all the yay-sayers on this forum, is about the least compromise part of any active circuit. (And does not care about supply voltage.)
If you must tinker the amplifier gain, do this.
Attachments
If the schematic in Post 42 is correct the gain at the plate is about X1.5. By eyeball the cct reduces to an unbalanced phase inverter.
The common line could be pushed to the bottom of the dwg, the complicated PS reduced to a single supply of total the +ve & -ve supplies.
Am I missing something? This preamp looks to be mostly PS, not much else.
The common line could be pushed to the bottom of the dwg, the complicated PS reduced to a single supply of total the +ve & -ve supplies.
Am I missing something? This preamp looks to be mostly PS, not much else.
For a temporary measure I have bought an inexpensive ready made inline RCA volume controller to put on the input. It was only £4 so I'll have a play with this to see if I can at least get a desired level which prevents it from going near clipping.
Car Home Audio Amplifier Bass RCA Gain Level Volume Control Knob.vi | eBay
Although a lot more expensive than £4 the other solution I was thinking about was something like a miniDSP. I actually owned one of the cheapest miniDSPs before and was less than impressed with it. The uses and functionality of it was phenomenal yet regardless of all this I felt it did take something away from the sound and it wasn't completely transparent in the chain, but I did have the cheapest version.
However I have also just discovered another fairly inexpensive one which is apparently very transparent and maybe a step ahead of the one I owned last time. The 'better one' I have been looking at is the Dayton Audio DSP-408. Bit of a extreme measure to get a £60 Chinese tube buffer/pre amp sounding better But the graphic eq functionally is a great thing to own in itself. Great for shaping frequencies and making the sound more pleasing in any system anyway. No plans on buying one quite yet though.
Dayton Audio DSP-408 4x8 DSP Digital Signal Processor for Home and Car Audio: Amazon.co.uk: Musical Instruments
Car Home Audio Amplifier Bass RCA Gain Level Volume Control Knob.vi | eBay
Although a lot more expensive than £4 the other solution I was thinking about was something like a miniDSP. I actually owned one of the cheapest miniDSPs before and was less than impressed with it. The uses and functionality of it was phenomenal yet regardless of all this I felt it did take something away from the sound and it wasn't completely transparent in the chain, but I did have the cheapest version.
However I have also just discovered another fairly inexpensive one which is apparently very transparent and maybe a step ahead of the one I owned last time. The 'better one' I have been looking at is the Dayton Audio DSP-408. Bit of a extreme measure to get a £60 Chinese tube buffer/pre amp sounding better
But the graphic eq functionally is a great thing to own in itself. Great for shaping frequencies and making the sound more pleasing in any system anyway. No plans on buying one quite yet though. Dayton Audio DSP-408 4x8 DSP Digital Signal Processor for Home and Car Audio: Amazon.co.uk: Musical Instruments
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