MI Audio Blue Boy IC

Hi guys,

I've been mucking around with a bunch of different ICs in the Blue Boy, and I think I found a favourite,...

I tried:
- JRC4558D (stock)
- RC4558P
- LM833N
- TL072
- LM358
- LM1458

My favourite was the LM1458! Even I was surprised. VERY VERY VERY smooth. The ones I had were marked 'TESLA',... very strange,...

 

I will be making more of them. It will probably be about 3 months before they start to roll of the production line again.

I'm not too sure if I should put that IC in there or not. It's not a popular one, and not often used in the guitar community. The reality of the matter is that many guitarists have already made up their minds about what the best IC is, namely the JRC4558D. If I shipped the Blue Boy without the JRC4558D, I'm sure I'd receive at least a few emails per day asking for a 'custom' order with the JRC4558D IC.

Having said that, 95% of the tone comes from the pedal design, with the IC contributing 5%. Changing ICs does make a difference, but won't cover up for a bad pedal design. It also won't change the tone of the pedal dramatically,... for example, changing the IC in the Blue Boy won't turn the pedal into a high gain monster, or anything like that. It's a lot more subtle.

I found the LM1458 to be very similar to the LM833, but it's a bit smoother. The strange thing is that I also found it to be very very low noise, which is strange, because the LM1458 is just meant to be an ordinary IC, not a low noise deisgn or anything like that. Perhaps it's the batch that I have,...

 

Hey 58,... working on that,...

Also, I've thought about the idea of an IC pack, but you guys get the ICs much cheaper in the US. It's not worth it from your perspective, and shipping is expensive (it costs the same to ship one IC as it does a whole pedal )

on a completely different note, I've resurrected the Tube pedal idea. I'm working on a prototype at the moment. It's going by the working title of 'Gainius Maximus',... Here's a picture of the protos guts,....



It's a 2 channel pedal, with independant Gain, low, mid, high and volume per channel. There are also 2 master volume controls, and a global presence and resonance control. You have 4 footswitches:
1) Bypass
2) Channel Select
3) Boost (to go from crunch to high gain on either channel)
4) Master Select.

It also has 4 outputs:
1) To guitar Amp
2) To Power Amp
3) To Headphones (Speaker simulator)
4) To Mixing desk (Speaker simulator)

This design gets all its tone 100% from the tubes. No solid state anywhere, and the tubes run at nearly 300V. Even the EQ is the classic passsive tone stack, like a tube amp. The only solid state in there is for driving each of the outputs to get a low impedance output. But it's basically pure tube.

The idea behind this pedal was looking at the stuff available today, you either get lower gain tube pedal, or the high gain stuff is typically hybrid (mostly solid state), and often running the tubes at low voltages. They're also typically quite basic in terms of features. I want to make something which is flexible, real tube at real voltages and full-featured.

I'll hopefully get this up and running within the next few weeks. If this ones doesn't work out (and I've built quite a few prototypes which I wasn't happy with), I'm canning the project!

 

I am trying to keep the cost of the thing under US$400. US$350 would be great, but that might be a stretch. Anyone who's worked with metal knows that the big killer for small production runs is the cost of tooling. I can't use a standard 'hammond' type casing. I need to have custom work done, so that's my big problem at the moment.

 

ohmygodohmygodohmygod,... I just fired up the Gainius Maximus,... heaven,.... I'm so excited, I'm shaking,...

yaaaaaaaaayyyyyyyyy

 

Yeah, it's a neat little PCB.

Tomorrow, I'm going to test the speaker sim outputs.

 

That's not too difficult at all. In fact, that was what I was originally planning, to avoid having lots of plugs.

I decided against that for one reason: Speaker sims suck. Doesn't matter how accurate their frequency response is, or if it's simulated with the world's most powerful computer,... they never work. I believe the reason for this is that you lose the guitar/amp interaction. Part of the cool thing about the sound of a guitar is the way that the guitar pushes the amp, and the amp, in turn, pushes the guitar back. I believe that this is a big factor which gives life to guitar tone.

So one way to get a bit of life back into your speaker sim signal is to have separate outputs. One goes to your guitar amp, and you monitor through the amp (so you have that interaction), and the second output you send to the mixing desk. This way you avoid the hassel of micing, but still get a natural recorded sound with guitar/amp interaction. This is obviously not necessary, but I wanted that option to be there. The reality of the situation of course, is that if you're using a speaker sim, you're doing it to avoid plugging into an amp, probably for noise reasons,...

 

Hey DonneR,

I think even if it were possible to simulate speaker distortion and compression, it still wouldn't sound good. It would still sound fairly 2 dimensional. You really need feedback to make the whole thing sound real. I don't mean long sustaining, singing feedback, but rather some way of the amp signal affecting the way that the guitar strings vibrate.

Erskin, yes, when you bypass the unit, the speaker sim is still active, so you can use it purely like a headphone amp. BUT,... you've brought up an interesting point. What if you want to use reverb AFTER the preamp, and before the speaker sim? In other words, should I put an FX loop on there? Problem is, you'd need to be able to switch that loop on and off, and hence you'd need a fifth footswitch. That's a lot of switches to remember on a dark stage. Also the unit would get quite large.

Well, if you had to limit yourself to 4 footswitches or less, which functions would you like to have at your feet:
- Bypass (can't avoid that one)
- channel select (ditto)
- boost
- Master select ('solo' control for volume boost)
- FX loop
- other functions,....?