2SC1000GR low noise equivalant?

[wavley]

Hey,

I was playing around with my space echo last night trying to get some noise down and echo volume up.  Has anybody replaced a 2SC1000GR with something a little more modern and less noisy?  I'm looking to bump up the gain on the last gain stage of the echo path (post feedback, I can boost it stock pre feedback to the point of distortion) just a little to widen the useful range of the blend knob a bit.  this is already a pretty noisy circuit that I've actually cleaned up A LOT by recapping and ditching the really low input impedance bandpass thing and replacing it with a Mini-booster, and adding a nice op-amp based output buffer.

[Mark Hammer]

2N5089 or 2N5210 ?

[wavley]

2N5089 or 2N5210 ?

Awesome, I think I have some 2N5089's around.

[Paul Marossy]

2N5089s are hard to beat for quiet high gain type transistors.

[PRR]

> something a little more modern and less noisy?

The proposed 2N5089 is no more "modern" than 2SC1000; anyhow clean Silicon has been around since the late 1960s and low-hiss became more a matter of fitting basic physics to the application than sorting for non-crappy material.

Agree the '5089 is a fine pick. But the '1000 should be no hissier than a '5089. The datasheet actually shows it a bit better in most likely conditions, though the '5089 sheet's data is quite old and they still put some CYA margin on the noise specs.

http://i.imgur.com/q1yrQcT.gif

[wavley]

> something a little more modern and less noisy?

The proposed 2N5089 is no more "modern" than 2SC1000; anyhow clean Silicon has been around since the late 1960s and low-hiss became more a matter of fitting basic physics to the application than sorting for non-crappy material.

Agree the '5089 is a fine pick. But the '1000 should be no hissier than a '5089. The datasheet actually shows it a bit better in most likely conditions, though the '5089 sheet's data is quite old and they still put some CYA margin on the noise specs.

http://i.imgur.com/q1yrQcT.gif

I ended up upping the gain a bit with an acceptable amount of noise.  Honestly, after doing so much work to it over the years it's the quietest of the 101, 201, 301 series I've ever had my hands on, and I've worked on quite a few.  My 501 had everything I needed to make a pseudo FA-1 at the preamp and it's actually much quieter/better sounding now too.

So Paul, is there something that actually is significantly lower noise I can use for this?  I'm thinking of replacing the input amp, the last echo amp after the mix, and the output buffer.  The output buffer I'm seriously thinking about going with a lower gain transistor 1. because it has more output than I need 2. If I need more output I can change the clean op amp based buffer I added to a gain stage.  I know there are a lot of other factors here and it's not going to be a sea change in noise figure, but I'll take what I can get.

I'm also thinking of adding a relay to kill the wet signal when I bypass, because currently it just disengages the solenoid and leaves all the noise of the wet signal path.  The 501/555 has tails, the bypass just kills the input to the circuit.  Both have their advantages, but the 101 is fun for stop/start stuff... run the rate really fast, stop it, set the rate really low, kick it back on for a special kind of pitch shifting fun.

I'm going to leave the head amp stuff because some noise in the head amp/feedback path is part of the sound that makes these good.  The compander circuit in the 501/555 kills some of the fun of a space echo in exchange for much less noise.  So for me, the 501 gets fed by an SVC-350 vocoder, and gate/comp/de-esser for vocals and the 101 is pure guitar.

[PRR]

As I know you know from work: Noise usually needs a system-analysis approach, not a silver bullet.

What is this, a tape-loop? Good luck.