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JGR's 1200 watt micro - let the madness begin!!!!!

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#341
I have a Crest CA9 also, it is what people refer to as old iron, or a lead sled. Heavy torroidal transformer in the center, big heatsinks on each side, class H, about 50 lbs IIRC. Class H is something like Class A/B with infinitely variable rail voltage, supposedly more efficient than A/B alone. Some people used to refer to the CA9 as the "gold standard".
 
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#342
Smeet, I have a Pro Lite 2.0. I also have a Demeter HBP-1 800D. Take this with salt, pepper, and a little cilantro: At home, I tried the HBP through the 2.0 and through its own internal power section. I preferred it with its internal power. It seemed just a little tighter and quicker to me. While trying cabs at Mike A's, I played a few different pres through Jonathan's poweramp (upon which the amp this thread is dedicated to is based). I tried the HBP with its own internal power and through Jonathan's amp. I preferred it through Jonathan's amp. The low end had more authority, the midrange more detail, and that top end more openness. These were not radical differences, but they were noticeable. Caveat: This was done at low-to-moderate volume.

The Pro Lite is a capable amp, especially for the price, but I don't think it's in the league of something like a CA9. I didn't push JGR's amp, but, at the volume I tried it at, it's the first class D that I thought felt as good as (had the authority/quickness/slam of) a good lead-sled. I've played one or two that came close, but this was the first one that I felt did it. I can't say how it holds up under pressure, but based on what I've heard so far -- and considerations of cost aside -- for use in a bass rig I'd take it before the Pro Lite.
 
#343
Interesting. I wonder if the differences are more obvious at high volumes, or less obvious.
Well, hopefully these are subtle enough differences that they won't matter on the gig (and obviously it only matters if I'm not going through FOH anyway).

JGR and anyone else with technical knowledge on these matters: What makes one power amp sound (for example) more "solid" in the low end? They all amplify the same waveform, and at low levels there should be no audible distortion. I believe there is a difference, but what is it?

I owned an Eden WT400 (USA). I also had an 80's Trace Elliot AH500X. The Eden sounded good, but next to the Trace it sounded like it had no bass response. Even with the bass boosted, it sounded fake, like the real lows weren't there. The Trace sounded solid and big in the lows, even when you rolled off the lows. The difference was NOT subtle. Is that from the power amps? Preamps?

Geez, I feel like I'm back in the 70's where I would walk into a stereo store and they would regale me with tales of which power amp, receiver, preamp, speaker etc. had the most detail and heft to the sound. After a while my eyes would glaze over and everything sounded the same...
 
#345
JGR -

I have been following this thread with great interest. I have a couple of questions based on the discussion here:

1) What is inductor based eq? What makes it better than active eq systems found in other hi-end amps? Is there a web site that describes this?

2) Based on some of your responses I get the sense that this type of eq is not designed for precision work, i.e. fix a standing wave issue, but is more for general tone shaping. Is this correct? Would I need to use a precision, i.e. parametric, eq in addition to this unit if I need a more corrective solution?

3) I am not accustomed to the concept of using an EQ circuit as an overdrive device. Is this technique more common with this type of EQ?

4) I mostly play hard rock. I am getting the feeling that I might need an overdrive in front of this amp to get the level of distortion I need. Have you tried overdrives in front of the amp? What has worked for you? Have you tried using higher gain tubes to get a more burly sound?
 
#346
monkeyfinger said:
4) I mostly play hard rock. I am getting the feeling that I might need an overdrive in front of this amp to get the level of distortion I need. Have you tried overdrives in front of the amp? What has worked for you? Have you tried using higher gain tubes to get a more burly sound?
Click to expand...

I'm not JGR but I have been using his 6SL7 pre for awhile now and love it to death. I've stuck with Jonathan's choice if tubes since I'm sure he would know better than I would which to use.

I wouldn't describe the eq as surgical at all, but with my cabs and basses I've had no trouble at all getting dialed in anywhere I've played, and that pre has been in many situations since I've owned it.

I tend to run my pre fairly clean. It'll only get a bit hairy if I lean into it. Distortion boxes are really personal things. I've had really good success with a Mesa Flux Drive, though I really love the Fairfield Barbershop and the Brimstone XD-1(?) looks extremely cool.
 
#347
monkeyfinger said:
JGR -

2) Based on some of your responses I get the sense that this type of eq is not designed for precision work, i.e. fix a standing wave issue, but is more for general tone shaping. Is this correct? Would I need to use a precision, i.e. parametric, eq in addition to this unit if I need a more corrective solution?
Click to expand...

For evereyone's benefit here, full parametric has three variable controls:
Frequency
Q (width of frequencies affected)
Level of boost or cut

It's a great tool for defect control, such as eliminating a standing wave, a room resonance, feedback, howl, or other defects you may want to slice, or "notch" out.
Most folks don't know how to use them properly, so one rarely sees them on amps. They're really to awkward for general tone shaping and interfere too much with the signal to be as clean and free from noise as an amp designer would like. Lots of rack style ones available, but just a couple of pedal ones.
 
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#348
monkeyfinger said:
JGR -

I have been following this thread with great interest. I have a couple of questions based on the discussion here:

1) What is inductor based eq? What makes it better than active eq systems found in other hi-end amps? Is there a web site that describes this?

2) Based on some of your responses I get the sense that this type of eq is not designed for precision work, i.e. fix a standing wave issue, but is more for general tone shaping. Is this correct? Would I need to use a precision, i.e. parametric, eq in addition to this unit if I need a more corrective solution?

3) I am not accustomed to the concept of using an EQ circuit as an overdrive device. Is this technique more common with this type of EQ?

4) I mostly play hard rock. I am getting the feeling that I might need an overdrive in front of this amp to get the level of distortion I need. Have you tried overdrives in front of the amp? What has worked for you? Have you tried using higher gain tubes to get a more burly sound?
Click to expand...


Hi BFunk,

1) It's just an active EQ that uses inductors and caps in the circuit for boost and cut. It was common back when tubes were more prevalent - a lot of the now famous studio EQ's use them, as well as the SVT mid range among others. It's not necessarily better, just different. Like tubes, it has some nice character to it, and it's easy to dial in.

2) Yes, but I'd say most amp EQ's fall into that category as well. I am of the opinion that any instrument/amp/speaker combination (talking electric bass, not upright) should not require additional outboard EQ - if it does, there is something else in your signal chain that should be addressed, and the onus is not on the amp to fix it. That said, there's more EQ capability/flexibility than you will find in a lot of amps, and folks have been happy running flat right off the bat and adjusting gain to taste - so plenty of range on the EQ to dial in/correct.

3) I don't think so - I was just demonstrating the extreme end of the spectrum to show how the overall circuit reacts in what I feel is a pretty cool and musical manner.

4) Hard to say - depends on how much you want. If you want Big Muff saturation, then yeah - if you want a subtle, pushed SVT vibe, then you should be good to go. I used to put a lot more gain in my preamps, but I've found folks always run them a lot cleaner than I would have expected, so I find it's better to err on the side of clean/headroom, and use pedals for extreme stuff. It also allows more flexibility for folks that use high output active electronics/EQ in their instruments. Overdrives work great in front of all my stuff if that is the route you want to go, no problem there. I know Eyeballkid has quite an assortment of OD's he runs in front of his first gen 12ax7 preamp. I've experimented with 12au7, 12ax7, and 6SL7 for the front end of this design and preferred the 12au7 for this particular application, though the others were great as well. You could swap a 12ax7 in the first slot if you wanted which would give you more grit, but I always prefer to use things for how they have been optimized. This amp is on the cleaner side but not by any means sterile, and I voice the gain structure to have warmth/character/grit/punch in the right places - that is the fun part! It comes through pretty aggressive using my rock cabs for instance, so the amp is only one part of the chain to be considered.
 
#350
JGR said:
Love the additional mid now that I have it in - kids, we're going five band. Do not be afraid, when in doubt, just keep them all at noon and all will be well.
Click to expand...

Excellent!

I understand where the fear comes from. I owned a fully parametric EQ for awhile, and tweaking could be like cocaine: "ok, sounds great now, but just a little more and it'll be perfect!" Of course the fault there lay with the operator, not the EQ.

I'm now at the point where for each gig I usually set it and forget it, regardless of how much EQ I have at my disposal. But I like having some EQ to adjust for room acoustics, and my odd collection of basses. I also like to use a variety of tones for each particular bass: f'r instance sometimes I want my P-bass with rounds to sound vintage Motown, sometimes I want it grindy/aggressive for hard rock. Technique helps adjust from one tone to another, but EQ + technique provides more versatility than either technique or EQ alone.

No, I'm not suggesting adding more EQ to the micro. ;) Fact is I'm happy with the 4 band on my JGR 12ax pre, but every so often I've wished for a band around 800Hz. So, band #5 makes it perfect for me.
 
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#356
wow. i just picked a Bearfoot BBJOD and it gets me some of the rock flavor of the amp demo, plus some dirty gain. i'm running it into a Genz Shuttle 9.0. sometimes i wish i could line things like this up side by side and figure out what the differences are. i'm sure if i worked in the industry, i'd nerd out at the bench all day every day.
 
#358
JGR said:
Bass and treble are shelving at 50Hz and 4kHz, and their slopes (and the mid's Q's) are such that there is great separation between all the controls yet no gaps. The low mid is 230 Hz, high mid is 1.6 kHz.
Click to expand...


This is just excellent. Very key points for our instrument.

I especially like that the treble (and it's downward spillover) is set for great effect on our actual topend instead of just acting as a "tweeter knob" of sorts.
 
#359
will33 said:
This is just excellent. Very key points for our instrument.

I especially like that the treble (and it's downward spillover) is set for great effect on our actual topend instead of just acting as a "tweeter knob" of sorts.
Click to expand...


And of course, I post this while reading through the thread, only to discover a fifth band is born. :)
 
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