Paintpot System Notes

Paintpot System Notes

Here's some more detail about our Paintpot 2 channel microphone preamplifier. It was a brand new design in 1992 and it has stood the test of time, requiring minimal tweaking over the years to keep it at the peak of it's game

We've been making remote controlled audio devices since 1992 and have got quiet good at them. The key to making a great audio device is the choice of circuit elements to do the remote bit. We chose relays from day one, which while expensive and bulky, are the perfect device - no distortions, delays, frequency or level limitations (within reason!). We use relays for all switches and gain elements. The gain circuits in particular act as stepped, switched attenuators, giving perfect repeatable control.

One of the benefits of remote control is that you can place the relays exactly where you want them on the circuit board. Normally with a conventional design, you have got to lay out the front panel first, and then squeeze the electronics around the front panel knobs and switches. Or use lots of wire to join the front panel to the electronics. Now by being able to design the way you want, the whole circuit becomes much smaller and linear - a definite boost for sound quality!

The other unusual feature is our addiction to fully balanced circuitry. Normally designers just put balancing circuits on the inputs and outputs of a box. We keep our circuits fully balanced from input to output, making the design completely symmetrical. This advanced symmetry means that any distortion generated by the design on the hot phase, is matched by an identical distortion, generated in anti-phase on the cold phase. This approach removes the distortions by simple subtraction. Some 15 years after we pioneered this approach, it's suddenly become todays buzzword. Nice to know we were ahead of the game...

What other design features have we got?

Every element of the design has been thought about in depth, but here's a few other details:

• Noise performance at real levels. The circuits have been designed to give a low noise floor at all gain levels. People often talk about how quiet the Paintpot is, and this is why.
• Wide frequency response. In order to get good HF distortion figures, you need a high frequency response. However too wide allows RFI to enter the pre. We use a wide frequency response, tailored by passive rolloff filters for RFI protection.
• Local Power Supply. Each active device has it's own power regulators, spreading the load across several devices for better heat management. The local regulators also provide better power performance compared with one big regulator powering the whole device, as is common in most other pre amps.
• Intelligent control. There are 2 processors in the Paintpot, a central one, and a smaller local one on the Pre amp card. This processing power lets us do lots of little clever things, like muting the pre outputs when you turn the phantom power on/off (stops big thumps), and memorising front panel settings on controlled power down.
• Wide AC power range. The Paintpot has been designed to work of a wide range of power supply variations. So wherever you are, you can be sure the Paintpot will keep working, compared with other pre's.
• AC Power filter. An expensive power filter is used on the power input to stop spikes and noise on the mains from getting into the audio.
• Anodised Panels. The Paintpot metalwork is made out of light Aluminium, giving it a low weight of just 3.5Kg (7llbs). The aluminium panels are anodised (chemically coloured), giving them a stronger, more robust finish than just painting.
• Modular design. The whole electronics are based on modules, making them easy to upgrade, repair, fault find and exchange.