Channel Strip?

[dukeorock]

Note that the shuttle, shuttlemax and GBE series amps are built around the channel strip topology, with input impedance, gain range, and eq points targeted specifically for bass. The Streamliner topology is significantly different and is not based on channel strip topology

My ShuttleMax amps have been my 'channel strips' for recording for a couple years now

 

[Calaverasgrande]

I've toyed with the idea of turning one of my extra PM1000 channel strips into a bass pre. I'd have to fiddle with the input impedance to get it right. Maybe just bypass the input transformer entirely. I'd also have to tweak the eq so it reaches into the "real" midrange. Not sure what Yamaha was thinking with 1k, 2k and 4k?
But the low end on a PM1000 is amazing esp after it is re-capped. I keep several of those channel strips around just for drums.

 

[agedhorse]

The PM-1000 input circuit is kind of a bad candidate for this because of the fairly unique circuit. The transformer feeds a pretty low impedance CE amplifier and even bypassing the head amp stage Q1-Q2 (which is what the attenuator eventually does in the top 3 line level positions) and push-pull buffer Q3-Q4 but it's still awfully low. The best way to adopt this is to add a FET head amp (to buffer the signal, that way it can drive the lower impedance) internal to the strip to a 1/4" switching input that interrupts the signal at the "preamp bypass" position. Look at the schematic and you will see what I mean. You will be adding a switched instrument input.

I've toyed with the idea of turning one of my extra PM1000 channel strips into a bass pre. I'd have to fiddle with the input impedance to get it right. Maybe just bypass the input transformer entirely. I'd also have to tweak the eq so it reaches into the "real" midrange. Not sure what Yamaha was thinking with 1k, 2k and 4k?
But the low end on a PM1000 is amazing esp after it is re-capped. I keep several of those channel strips around just for drums.

 

[HolmeBass]

Note that the shuttle, shuttlemax and GBE series amps are built around the channel strip topology, with input impedance, gain range, and eq points targeted specifically for bass. The Streamliner topology is significantly different and is not based on channel strip topology

So that explains the awesome DI tones I get from the sm 9.2. I've posted a few times about how great the DI signal sounds when recorded, and indeed it's the best bass amp DI sound I've used.

I would love to have the opportunity to compare it to something like the 737. When I did that session a few years ago I was running my Eden Metro as my main rig, and the engineer tracked it along side of the 737. There was no comparison really, the 737 had clarity in spades over the Eden pre, and yet still had warmth and solidity. The top end was really where the 737 crushed the Eden.

 

[Calaverasgrande]

The PM-1000 input circuit is kind of a bad candidate for this because of the fairly unique circuit. The transformer feeds a pretty low impedance CE amplifier and even bypassing the head amp stage Q1-Q2 (which is what the attenuator eventually does in the top 3 line level positions) and push-pull buffer Q3-Q4 but it's still awfully low. The best way to adopt this is to add a FET head amp (to buffer the signal, that way it can drive the lower impedance) internal to the strip to a 1/4" switching input that interrupts the signal at the "preamp bypass" position. Look at the schematic and you will see what I mean. You will be adding a switched instrument input.

Yeah, I was looking at something like that. I have a couple BB op amps left over from another project. I'm also thinking of simply changing the input transformer. It's not anything I'll be getting into right away. I am still working on a step sequencer and some 555 timer nonsense.