Or is it my imagination or is it just coincidence? After finishing the MiniTubes and VoxEXP, I've just noticed how much quieter they are compared to other high-gain devices I've tried.
JFETs and MOSFETs are inherently quieter than bipolar tranies.
Doesn't necessarily mean that's ALWAYS the case in a practical circuit though! (sadly) :)
There are at least two practical matters that may need to be considered when making comparisons, in addition to any inherent noise characteristics of JFETs.
JFETs have less gain than comparable BJT circuits. For example, a single JFET at full gain exhibits less gain than a comparable single BJT at full gain. Higer gain generally means noise is also amplified more.
Another possibility is that JFETs are often used without clipping diodes, the inherent distorion characteristics being exploited. Thus the output can swing several volts. Whereas a different circuit may have diode clippers limiting the output to +-.7V. This puts the noise floor much higher, meaning you must crank the output volume higher to get comparable output levels, which will also raise the base noise levels.
You are quite right.
JFETs in well-designed circuits can be audibly quieter (less noisy, better signal-to-noise ratio) than bipolar trannys or op amps IF
1) the input impedance to the JFET stage is above 3K-5K ohms impedance (not just DC resistance)
and
2) you select an appropriate low-noise JFET for the circuit
Got it?
Just don't expect them to make an exceptionally low-noise mic preamp for 150-300 ohm microphones.
Agreed, and JFET's are so musical. Tuning each stage correctly can produce harmonic content that jumps out at you. Doug Hammond's Meteor is a great example. For simplicity the Mini Booster is a winner. Minimal parts, self biasing, and sounds big, still one of my favorites.
JFET's rock! Jered
Even a week or so later, I can't get over how good these things sound. I've NEVER gotten a classic (not 'modern') Marshall sound out of a pedal like I have out of the MiniTubes. IMHO the Vox EXP blows the TBIAC AWAY! The EXP is what I'd hoped the TBIAC would be (but was very disappointed in the TBIAC).
I just really want to build at least one more 'Mini'. I want to try a different tone stack (Mesa?) and use more J201's instead of MPF102's for a more modern/higher gain sound.
Duh, sorry, what / where is this 'MiniTubes', please?
yeah, I wouldn't mind seeing the minitubes.
I have been working on another MOSFET distortion with an interesting opamp feedback loop that has a sound that is taking on the form of Doug Hammond's Sweet Thing sound. I am noticing that much of the tone is dependent on the symmetry and frequency response more than it is the particular FET..
Quoteyeah, I wouldn't mind seeing the minitubes
AMZ CD.
Regards
RDV
Quote from: BucksearsEven a week or so later, I can't get over how good these things sound. I've NEVER gotten a classic (not 'modern') Marshall sound out of a pedal like I have out of the MiniTubes. IMHO the Vox EXP blows the TBIAC AWAY! The EXP is what I'd hoped the TBIAC would be (but was very disappointed in the TBIAC).
.
Wow, interesting...
Any chance you could do a couple sound clips to compare? I've never heard a TBIAC. I never actually built the vox exp, it was just some fun on the breadboard. Maybe I should...
Doug
Unfortunately, I don't have the TBIAC anymore; it was sold within two weeks of getting it. It was just a disappointment because it was just an overdrive and didn't sound anything like I hoped it would; it was just muddy as all get out. I had the same problem with Menatone (Trainwreck copy) pedal I also had very briefly.
I wanted a Voxy-ish DISTORTION and the VoxEXP has it. I'm a little curious about trying it with different guitars/pickup combinations. It's a little dark with my ES135 with '57 Classics, but sounds great with my Ibanez Artstar w/Super 58's.
Played back-to-back with the MiniTubes, you can hear the (respective) Vox and Marshall flavoring. It was just a really nice surprise because these two pedals sound better than almost all of the amp/pedal distortions I've had.
Quote from: BucksearsUnfortunately, I don't have the TBIAC anymore; it was sold within two weeks of getting it. It was just a disappointment because it was just an overdrive and didn't sound anything like I hoped it would; it was just muddy as all get out.
Wow, that's weird. A year or so ago the group over at musictoyz was going nuts over the TBIAC. Now it seems like its popularity has died down somewhat over there.
Quote from: Bucksears
I had the same problem with Menatone (Trainwreck copy) pedal I also had very briefly.
I wanted a Voxy-ish DISTORTION and the VoxEXP has it. I'm a little curious about trying it with different guitars/pickup combinations. It's a little dark with my ES135 with '57 Classics, but sounds great with my Ibanez Artstar w/Super 58's.
Played back-to-back with the MiniTubes, you can hear the (respective) Vox and Marshall flavoring. It was just a really nice surprise because these two pedals sound better than almost all of the amp/pedal distortions I've had.
That's pretty cool. I will have to give the exp a try again.
Thanks! :D
Doug