Question about prevalent 6L6GC Screen Grid Voltages

[apehead]

Well, again, it's all a matter of taste, but with my instruments (Jazz basses) I find that roundwounds accentuate an undesireable quality in the timbre of the instrument. Even with flatwounds, the jazz bass is one hell of a spanky sounding instrument, and I think that roundwounds turn it into an insectoid buzz factory (especially when used with active pickups) or give far too much of that "modern" voicing (shudder). Of course with the right amp and studio production, roundwound users like Geddy Lee and Chris Squire come to mind. I think what's more important to what I'm trying to convey, is to not think of my issue as "bass/treble" conflict, but more of a "articulate, clarity/flat, muddy". The butcher sounds so sweet at low volumes, like an angel is farting out every one of the notes. They are so clear and it picks up every nuance of the bass (also, it sounds pretty badass when it just starts to compress/break up ever so slightly on the high octaves after you turn the pre up a bit). The mesa, on the other hand, sounds good, but not "I will gladly shell out $200 to retube power section" good. It really doesn't have the "tube" (how douchey sounding is that?) sound. I could've got some POS Berhinger with just as much power for probably 2/3 the money, and it would sound as decent. So I just want to sweeten it a bit, because if I had the tone and the power, this amp would rule so hard, I'd have to silkscreen Darth Vader's head right on the front. I was thinking of adding a bright cap (240pF) to the master volume, and changing the .1uF C233(?) coupling cap between the second pre stage and the phase inverter to a .047uF. Sound like a good move?

[Enzo]

And did we discuss the most important part - your speakers? Certainly the tone you describe won;t come out of a single 18. Are you using something like a 4x10 with horn?

[apehead]

2x15 open backed cab. I used to use these with the butcher, and it sounded great. I've never met a bass setup with less than 12" speakers I've found sonically pleasing, and even 12" is pushing it.

[Enzo]

Oh well, just a thought. I love a good 410 box.

The Butcher was PV building their version of a Marshall.

[Robert M. Martinelli]

I think most times it is better to just be direct and make a clear point rather than worrying if it is stated gentle enough.

My -60v supply gave me a shock. I better decrease it to -100 for safety.


OK OK I'll stop.

Enzo,
you know what?

You would have been a perfect teacher in any university worth of this name.... and all the students would have loved you!

Discussing/explaining concepts in a humorous/hilarious way increases the chances the concepts are understood and remembered IMHO.

And....a laughter ALWAYS helps to make every day a better day.

( .....Geez, I LOVE this forum! )

Cheers

Bob

[Enzo]

Thank you , Bob, you found my dream. I think of myself as a teacher. I was looking for an opening at the local vocational college in the electronics department for years. You know what they've done? They phased out electronics! They teach computer programming, computer maintenance and repair, but no straight electronics. You need almost no electronics at all to service computers - a voltmeter maybe. They never solder anything. SO much for that dream. And at my age fewer and fewer opportunities will come up. I had wanted to teach digital logic circuits, and troubleshooting classes, of course.

But I have been in industrial training one way or another for the last 35 years.

[Robert M. Martinelli]

......You know what they've done? They phased out electronics! They teach computer programming, computer maintenance and repair, but no straight electronics. You need almost no electronics at all to service computers - a voltmeter maybe. They never solder anything.

Yeah, I can tell.....

That looks like trying to teach how to run to someone who can't even walk.....

Looks like education is going down the drain almost everywhere..

Nowadays everyone calls himself a technician, even the ones who don't have a clue about the basics. They just swap cards, and I bet that's more or less all they can do....

Years ago I called a "technician" to repair my home's heating system; it turned out that the burner's control card was broken, and he asked some 400 Euros for a new one. I asked him to start running ( 'cause I don't like shooting at still targets, it's not fair ) then I put the card on my bench, did some measurements, changed an open 2W resistor ( fifty cents worth ) and had the burner up and running within a few minutes.....

....Back to your dream......I think it has come true, for you can consider this forum as your "classroom"

Cheers

Bob

[Steve Conner]

Amen to that. I always look forward to a post from Enzo, because I know it's going to be something wise, insightful, or just plain funny.

First a vain attempt to stay on topic! Apehead, from this talk of Peavey Butchers, open-backed cabinets and Darth Vader heads, I'm going to guess that you play bass in a somewhat heavy "modern power trio". Maybe you're looking for a sound that's more distorted rhythm guitar than bass, and so maybe the Bass 400+ is just the wrong amp for you.

There's another guy here, David Schwab, who's a bass expert and has owned a 400+, hopefully he'll read this and comment.

Now this talk of "phasing out electronics", I think I agree, and it worries me! Electronic technology used to be on a scale where one person could comfortably deal with it by himself. Now it's snowballed out of control, everything is a system-on-a-chip, nobody repairs anything when it breaks down, and the "straight electronics" is all hiding inside ASICs.

Jim Williams wrote about this, it was him who said that if you want to keep doing analog electronics, the only way to do it is to design special purpose analog ICs, because nobody makes systems with discrete analog electronics any more. He's currently doing just that, as the senior scientist at Linear Technology.

I think the kind of smart kids who would have played with analog electronics in the 60s, 70s and 80s are going into computer programming now. I hang out with some guys like these, and they all ridicule me for my love of tubes. I ridicule them back for their love of Arduinos and odd coloured hair.

I decided to get into DSP and embedded programming, though, because I thought it would make me more employable. I consider myself to be a pretty mediocre programmer, and I'd much rather specialize in pure analog electronics. But sure enough, every job I've had has been programming up the wazoo, with just the odd glimpse of a soldering iron.

Having said that, at the university where I'm based, we still teach our students to solder. I've had the pleasure of taking that lab a few times But yeah, it bothers me that electronics seems to be the preserve of a kind of elite now, rather than a DIY culture.

[apehead]

Oh, Steve! You wound me! Some proof that I'm not in a "modern power trio":

1. The peavey butcher was $270 on Craigslist. After looking at the schematic, I snapped it up a quick as possible. There was no intent besides "wow, what a great deal on a real 100W all tube head!".
2. The opened backed cabinet is a result of necessity. I have two Eminence Kappa 15C's is an old silverface bassman cabinet. There is no venting on this cab, and the travel of the speakers is too great. I had to open the back up so the speakers wouldn't be choked. I plan on getting some scoops built when I can afford it.
3. Darth Vader is the effin' man, and he's been around since 1977, so there's nothing "modern" about his awesomnity.

I'm just gonna swap those caps, and let you know how it goes.

Oh yeah, and I totally agree there's no respect for real technicians anymore, it's all just plugging cards, or attatching wires to terminals.

[Enzo]

Oh I have plenty of respect for guys who know computers inside and out, they just don;t use any electronics in the process.


I on the other hand I know zero about computers. I have never been able to generate an interest. I find them totally boring. I only like the things I do with them, like word processing and email. I don;t play games on them. I spent a couple decades in the coin operated amusements field (arcade games) and believe me, the last thing I want to spend time doing is playing video games.

[tubeswell]

When the amp is already built, it's easy enought to measure, but what about designing from scratch? Just keep pushing until something does melt, or smoke, or catch fire, or blow a fuse? Seems to me like there would be a better way.

I am just a hobbyist and I find this site enormously helpful

How to design valve guitar amplifiers

[apehead]

That website is pretty awesome! Thanks for the link.