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Messages - JonnyDeth

#1
Amplifier Discussion / Another ridiculous deal
April 16, 2024, 09:27:49 PM
I bought a Crate GX1200H and 4x12 cabinet for $150 off Craigslist yesterday evening. I was surfing for used table saws, and I don't know how, but I ended up in their music gear ads.  :o

The stock speakers in the cabinet are definitely lower quality in comparison to those in the GX combo I bought, and it needs some modifications to both the clean and dirty channel tone stacks, but I don't think I've come across a deal this good in a few years.
The main problem with the stock speakers is their low end response is abysmal, mids and treble are crisp and punchy; great for numetal. The more you crank the volume, the more aggressive in reduction on your bass control is required, and even at modest volumes, it has to be significantly cut from the start.

Unfortunately, I remember why I had to mod this head extensively when I bought one 28 years ago which I still have to this day, but fortunately after some proper education, the mods I have for them today are exponentially superior. The lead/rhythm EQ has a shape control which has some great characteristics, but it won't produce a significant scoop as many of us desire. Fortunately, it only involves replacing a 100 ohm resistor to ground with a 500 ohm pot. The clean is great but needs a brightness switch added which will actually be there to shunt some of the highs to ground. The dirty EQ could use a bit larger value cap, but overall, it's primary shortcoming is they opted to save money by excluding the midrange control, adding the shape which is a bandpass sweep, and then reintroduced the mid in some of the models that came quite a few years later, another of which I own.

As far as solid-state goes, the GLX version is identical but with the mid control included and the best solid-state amp I've ever heard for metal. I think because they introduced the Blue Voodoo when these came out, they intentionally shot this model line in the foot by ditching the mid control. These sold new as full stacks for 650 to $800 depending on when you went looking for one, and I think the Blue Voodoo head in itself was 8 to $900. The simple solution back in the day was running an EQ on it's effects loop, but even that they required a stereo Y-adapter to presumably, save more money on mfr. On my original, I scrapped that and converted it to 2 mono jacks on the rear which eliminating the front stereo 1/4" jack gives an odd location but ideal space for adding the dirty midrange.

If I knew near 30 years ago what I did today, I would have made a killing modding these even for solo shredding metalheads, and they wouldn't have such a very checkered reputation like they do to this very day. This model line and those it was reintroduced as with all the same short comings are pretty much considered the worst solid stamp of the 90's onward well into the 2000's lol.
#2
Quote from: RookieRecurve on April 09, 2024, 09:39:06 PMGreat explanation of why tubes are still so popular.  Its also a great reminder that great tones from inexpensive SS stuff can be had with the right piece(s) of equipment in front of it.  Sometimes I like to just plug into my fairly stock Valve Jr. and appreciate its simplicity, but other times I love playing around with different tools.  Your talk about having a tube in the signal path makes a ton of sense.  Thanks!

Crate really screwed themselves going back nearly 30 years ago when they started producing the cheapest solid-state amp line on the market, and because they were releasing the BlueVoodoo soon, they omitted the midrange control from their dirty lead and rhythm shared EQ. For their scale of production, we're talking a 10 cent pot replaced with a 1/20 of a cent 100 ohm resistor. Fundamentally, every reputable amp's midrange control coupled with a "legendary" speaker scoops the midrange deeply, and what they did was remove this control and replace it with the "shape" that is an active band-bandpass that sweeps it's cornered frequency while cutting or boosting while you rotate it.
You hear the amp, and initially they sound amazing, until you hear something that truly does lol. Then you hear the GLX which has the midrange coupled with the shape control, and it's one of the best metal amps you've ever heard, especially when paired to the right pedal. I own a GLX, and 3 GX amps, 2 of which are the same heads.
I scored this insane deal for $150 last night, and will mod the preamp to add the midrange EQ...the deal was only the Crate gear, not the valve-state Carvin V3 lol.

In regards to the science explained in simple language everyone can understand, I would probably churn out 50 paragraphs, but there's a decent redacted version. When a tube is pushed into overdrive and clips, it does 3 specific things. It obviously clips the signal producing distortion, it produces soft clipping so the edges of the wave's knee where the bandwidth cuts off and declines in magnitude is rounded, as are the mini-waves when zoomed in that comprise the entire waveform, and it cuts off bandwidth organically.
In general, a 12AX7 peaks out in typical operational bandwidth at about 20Khz in the audio spectrum, but it's actually more typical that it has a steep cut-off at about 10Khz. The soft clipping also results in an abundance of low, even order harmonics and by order we're regarding bandwidth so you hit a 100 Hz range bass note, and you aren't hearing a "crust" of 10Khz bolding within it let alone 20Khz, 40Khz etc.

What semiconductors do when driven into clipping is usually but not always, produces hard clipping so the waveform reproduction curve has a sharp edge at the bandwidth drop-off point of response and the mini-waves the entire waveform is comprised of also have sharp edges, and the bandwidth response/reproduction curve is massive. It will go out into 50 and 60Khz. If the circuit architecture isn't designed so it produces asymmetrical clipping, you get an abundance of dominant, odd order harmonics. These sound sleazy, sour but oddly very pleasing, and all around harsh. You hit a 100 Hz range bass note and you're hearing 13Khz, 27Khz etc; high, odd order harmonics due to semiconductor's organic bandwidth. It's literally the nature of the material at the quantum level due to speed of it's materials under electrical pressure.
When you design solid-state or for that matter, digital that uses semiconductors to clip asymmetrically, now it's even order harmonic dominant, but it's still high magnitude even order harmonics. So, you hit a 100 Hz range bass note, and you're hearing 10 Khz, 20Khz etc. content in it, which sounds more or less like static, swooshing and white noise.
People will often use an EQ pedal on solid-state gear and run a 12AX7 somewhere in their signal chain, and this greatly improves upon reducing the high even order harmonics because the valve naturally incorporates some low-pass filtering to remove some of that content in the signal, adds low even order harmonics, and some rounded clipping.

I'm here obviously because I love solid-state amps. Overall, I find they have much better modern characteristics than 90% of valve circuits which is why most every player uses a solid-state pedal in front of their tube amps. I prefer the sleaze, raunchy, in your face thrash metal sound, but also despise that high, even order harmonic content so it's the tradeoff you face in tube vs solid-state. At this current time though, I am designing my own gear from the ground up, and only just made my last few purchases because I have a pile of gear in need of minor repairs and some crazy famous b*t** I prefer not to name smashed my Zoom G5 modeler which just happens to have a 12AX7 in it, and sounds great on my tube amps, but significantly better on the solid-state.

(I had to order that all the way from Japan, but even at 12 years old, it sounds better than the 2023 Valeton flagship model I have, the flagship model Headrush I returned after a few weeks which was a 3-legged dog, and I would put it up against the $500 PODs for that matter. That valve at the end of the digital chain makes a massive difference, but even with it switched off, it sounds much better than what was released in the last 5 years from virtually everyone and this is from having tried or temporarily owned their gear.)

The first thing I sat down to do recently was design a transistor-based distortion without diodes by overdriving the transistors into clipping organically and asymmetrically which not only sounds indiscernible from tube distortion, but obviously better when you hear the right circuits. This is where I can just keep rambling on since this recent task has been ongoing for about 20 years starting when I was an ignorant amateur modding and building gear 20 years ago, and finally enrolled in college for the science of electrical and electronics engineering 13 years ago. I'm unsure if I can truly bring my creations and inventions to the commercial market through my own manufacturing scheme or licensing if not selling designs, but I know I can produce something superior to everything up to this point that should be a huge leap in analog and outperforms both vacuum-state and solid-state. Overdriven transistors produce a fuzz style distortion that sounds interchangeable to overdriven valves, and there's a ridiculously simple solution to resolving the excessive upper range bandwidth magnitude of even order harmonics that makes *s!!t* raspy, crusty, swooshy, sloshy and also adds that white noise hiss everyone has grown to loathe about solid-state, and for good reason.

That's another series of ranting paragraphs in itself about my belief as to why major mfr. have done very little about it until recent years, it's only just been in digital semiconductor designs, and they still haven't completely resolved it. The short story there is I think it's a mixture of ignorance due to the nature of engineers that have advanced educations and are thinking in terms of numerical value vs actual organic performance that satisfies human hearing, and some that know maintaining a bit of these short comings ensures their tube lines keep luring in massive pools of customers and in the grand scheme of commercial manufacturing, they're making the most dependable and consistent profits off valves. Majority of players will eventually turn to valves and primarily depend on them over semiconductor technology.

Anyway, with my current goal, it seems the most realistic product I can design and potentially get onto the commercial market is a signal conditioner that wipes out high order harmonics even and odd and wipes out 60-cycle hum and other RF noise whether it's getting into your single coils, your pedals, your wires or even into your humbuckers. One of the the specific things I achieved as a blindly experimenting amateur was my overdrive I designed from the ground up to replace my dissatisfactory tube screamer wiped out all the ground buzz but didn't significantly compromise the upper bandwidth range we still desire to hear, especially regarding even order harmonics. With these goals, I'm primarily focused on a full fledged preamp that will eventually get a power stage, and a signal conditioner to go on the effects loop to wipe out noise without signal compromise, and also get rid of the hiss, slosh, rasp and static-like sound of semiconductors so ever present in majority of digital and solid-state gear.

#3
Quote from: RookieRecurve on March 31, 2024, 08:39:55 AMI see these pop up often around me, but not for that price!  There's one I saw for $100 with only one of the two channels working.  I thought about buying it to try and fix it, then flip it.  It would be too loud for me, but they are pretty amazing amps.  The ease of access to incredible schematics makes these a great buy.

I saw a guy on youtube that flips gear for a living and he nabbed one for $40! He said it was his very first amp so he made a video with it then sent it on it's way to someone who had bought it.

I am a shred and sweep player so it's a little harsh in the bass due to the very high, even order harmonics added by semiconductors, but in combining the dirty channel with my modeler and an overdrive pedal I actually designed around this amplifier's dirty channel used to overdrive the modeler, I get perfectly useable lead tones. I also have a Zoom G5 on the way to replace the one I have that some crazy b*t** smashed, and those with the 12AX7 in them turn damn near any amp into a thoroughbred.
That coupled with this and I have a brutal metal amp but really, an every genre amp. It's so friggin loud I could never actually use this much volume and in a live setting, I would definitely be using earplugs.

It's all about gain stage cascades and teaming the right devices. Solid-States have some universal problems shared by 99% of them, but Crate is highly underrated and players with really high standards would rather spend 3 grand on known gear combinations than experiment and get something built for $500 that is every bit as good as the 3 G's arrangement. The Zoom G5 is an example within itself because when you run the processor without the tube engaged, it's very digital and quite truly sounds cheap, but when you switch the tube in and crank it's gain, it makes every single patch you design for modeling whatever amp, pedal and speaker combination sound amazing. The harshness, "swooshing" etc. to your bass is completely filtered out of the signal by the tube's limited bandwidth. The 12AX7 is said to have a maximum of 20Khz for audio, but typical is actually 10 Khz. The semiconductors will add ridiculous harmonic bandwidth like 40 Khz to a 100 Hz bass note!
This trait is why solid-states continue to be the whipping boy of the industry and because digital circuits are still using solid-state semiconductors, 90% of those units aren't designed to compensate so the war wages on! I shutter at the sight of digital modelers and FX I see selling for $1500 and I can hear all those extremely high, even order harmonics still coming out of them and trashing the signal, but not every player is sweeping and shredding for it to matter.
The technology guarantees people will always spend big money on tube amps, and even I'm still guilty of that.
#4
I have a decent sized collection of heat sinks, but what I pulled out of my Beowolf projector that some criminal destroyed was a rather startling piece of salvage. It has a "heat pipe" too big to even adapt over to a CPU!
This for people that don't know, is a water cooled heat sink that's passive. The internal chambers and ducting use infinite distillation so the coolant rises to the outermost pipes from the core point where it's encountering the source of heat and was vaporized, is cooled quickly through the thermal process moving air, recondenses and runs back down to the core of the system again and whatever the device is that's generating all the heat.

The one out of that projector is absolutely massive so when I get a project that calls for it, I'm going to be all excited I discovered and saved it lol.
#5
Amplifier Discussion / Re: Watts vs Volume (db)
March 26, 2024, 04:22:59 PM
Quote from: saturated on March 26, 2024, 02:34:14 PM
Quote from: g1 on April 05, 2014, 01:37:52 PMIn car audio competitions you measure SPL.  Does a given system with a 200W amp sound twice as loud as the same system with a 100W amp?


I got tickled when I read this  :) as much as I groan when I hear them thumpers driving by I am intrigued by the idea of a contest which I presume the goal is to be the loudest?

If so I think I will keep an eye out for any local event like that it would be fun to watch
 8)

That question is why you really want to understand what VAR is, how to calculate the capacitor for your selected speaker, and then run tests using a sine wave @100 Hz to see how many VAR/Watts it actually sees from that amplifier, probably 10 Khz or at least around 6 to 7 too.

The kid that set the original world record that's since been broken used a specific series of pioneer subwoofer and that series of subwoofer amplifier. Pioneer spared no expense and recruited a degree bearing engineer and techs to design the entire line. They designed the amps so what they produced @1 Khz was also the same as they produced @100 Hz as well as all the way down to 25 Hz, this is why VAR is actually a critical detail when it comes to how much volume you can expect from the lows, mids and highs of a particular woofer and amplifier set, and what is the quality also going to be like.

A speaker whose resonance Q ranges down to 100Hz and still sees 75% of the VAR/watts it will see at 1 Khz will be an absolute monster, even if it's only rated for 90dB rather than 100. The dB sensitivity is still generated by 1-watt @1 meter, so it's not the critically defining feature to how much volume it's ultimately going to produce. It's just a test produce for reference when you're speaker shopping. If it's 110dB vs 95dB, but the 95dB speaker handles 5x the wattage, it's generally going to be louder than the one rated at 110dB when you max their wattage, but it won't be obscene when you compare them, and it's also likely to be better quality in sound fidelity.

I don't have extremely deep interest in car audio, but I do like having a competition class subwoofer in the trunk of my vehicle. My focus for audio engineering will always be focused on music equipment, but also when it comes to signal processing technology, that's going to include car too. I have some rather clever ideas for subwoofer crossovers that will give you brutal volume and thump out of a cheap ass subwoofer and amplifier that I've used in the past. When I finally moved to a competition subwoofer and much stronger power amplifier, it was significantly louder, but only about 20% with a significant amount of rumble. The cheapo was still only about $80 total investment excluding the enclosure I built, and the competition one setup was about $350! It was definitely worth it, but it also wasn't an obscenely dominating increase in performance. I've also been through 3 competitions subwoofers since that one after accidently frying it and having to buy 2 more is what was obscene.
#6
Preamps and Effects / Re: what exactly is a preamp
March 26, 2024, 01:53:15 PM
The best way to regard a preamp is as a SSA; Small Signal Amplifier which is the technical term. It gives a small amount of amplification to the device used to directly produce sound, and has some amount of control over altering the signal, even if it's just a single knob.

In reality, every pedal on a pedal board is a preamp and then your guitar amplifier itself will have a preamp with a power amplifier in it. They pre-amplify the signal before being sent to a power amplifier. They are also conditioning your signal in such a way that it will potentially be in much better condition for the power amp to have stability and evenness in it's performance of power amplification.
It may even only provide unity gain, which means a factor of 1x, and balance impedance for the sound source it is specifically designed for.
A preamp is also regarded as an "addition/subtraction" stage of signal amplification; features of the signal directly created by the sound source are both added and taken away.
#7
The Dr Boogey is probably exactly what you're after. It's someone's solid state pedal version of a Mesa Boogie which are generally wicked metal amps, and you can choose from a variety of general stomp boxes to stick in front of it and "sludge" it up.
https://www.taydaelectronics.com/pcb/diy-guitar-effects/mesa-boogie-distortion-diy-pcb-guitar-effect.html

My bet is the Big Muff Pi or even a tube screamer coupled with the flexibility of the Dr. Boogey will do just about any sound you're after. If not one of those pedals in front, something sludgy and truly "awful" but notoriously popular would be a fuzz face, but fuzz faces are low impedance input and biased completely wrong, so they're a crude form of a Class A-B circuit stealing input bias voltage from your guitars signal, and don't always do so well stacked with other boxes. Now with all that said, they do however give you a very rich, high gain and sludgy fuzz style distortion and can be modded easily enough to be more flexible.

#8
Amplifier Discussion / Re: Watts vs Volume (db)
March 25, 2024, 04:22:02 PM
Quote from: g1 on March 20, 2024, 08:39:30 PM
Quote from: JonnyDeth on March 20, 2024, 02:56:58 PMWell, looks like I wasted all that time going to college for electrical engineering, thanks for the clarification  ::)
If you can't apply it, I guess you did.
Amplifiers are rated into resistive loads to take reactive power out of the equation. 
Note that I specified amplifiers in my earlier comment to exclude what you said about speakers.

When one walks into a new room, it's best not to have the flamethrower on and start out with the idea that everyone else has it wrong.

Get a grip, you're the one being rude. The thread is about wattage, dB and output of a combined devices and how they relate to one another.
What I said is absolutely critical, and I was simply offering some factual information that is helpful based on the entire purpose of the thread from the OP. I wasn't rude, and I wasn't condescending, I just made a point, and you had an immature reaction twice over now. You literally tried to crybully me and I'm not interested. I'm under the impression I already need to be prepared to block you after that immature harassment.

VAR is what truly matters unless you're operating at a single frequency. Not all companies test their amplifiers the same way, but those that do it correctly will test it into an RLC tank circuit, or at least, an LC circuit. If they have built something truly special, they will test it with an LC circuit for 100 Hz, 1000 Hz and 10,000 Hz and they will also test it with sweep going from 100 Hz to 10,000 Hz.

So, any given amplifiers selected at random won't necessarily perform as well at 100 Hz as they do at 1 Khz.

Typically, the further you stray from a 1000 Hz sine wave in frequency, the worse the amplifier will perform in it's production of VAR, and for general purposes, we can use the 3 fixed frequency points defined by factors/divisors of 10 in the >< connotation of 1000 Hz, and regard VAR as watts.
An amp screaming loud with 100 watts @1 Khz may only push 20 watts at 100 Hz, and thus the owner is grossly dissatisfied with it's performance. Now a lot of amp manufacturers will produce a design that is so effective, but there are some out there that will produce nearly the same wattage at 100 Hz as they do at 1 Khz and 10 Khz. These are often used in the subwoofer competition industry and when a brand really wants to make an impact, they will produce test data for those 3 frequency points, design a speaker specifically for a selected frequency point, and that amp and speaker in combination will be at resonance producing the spec'd wattage because the manufacturer took a lot of pride in it's design.

You can always do the math using your desired speaker and run the tests yourself after calculating the necessary capacitor value to see what you get at 100, 1000 and 10,000 Hz.
#9
Amplifier Discussion / Re: Watts vs Volume (db)
March 20, 2024, 02:56:58 PM
Well, looks like I wasted all that time going to college for electrical engineering, thanks for the clarification  ::)
Speakers aren't resistive loads, and there are many types of amplifiers. In regard to audio frequency amplifiers, VAR is absolutely critical.
#10
They're not for everyone, but the classic overdrive channel will give you AC/DC and that sort of stuff, the modern overdrive takes you more to Megadeth, Cannibal Corpse etc. so, thrash and 90's death metal. On the bright side, they're one of the few vintage SS that handled pedals and they do well with just about any modeler.

In shredding on it this morning though I must admit, even with a really good sound and response, there is a strange "sterility" or "dead" emotion to their tones at times. I remember 20 years ago someone regarding them as the "hi-fi" home stereo equivalent of guitar amps lol. I think it's primarily when you really crank their volume, they have a dead as stone texture to them, hence 90's death metal.
#11
Amplifier Discussion / Re: Watts vs Volume (db)
March 20, 2024, 08:56:50 AM
The problem with this perspective is ultimately useable volume and wattage when you do a more thorough test of 100 Hz, 1 Khz, and 10 Khz with a sine wave. 1-watt @1 meter is using a 1 Khz sine wave, so it's dB rating isn't always the most reliable in terms of overall performance and projection.

Relative to this is the hardware distorting within a certain pitch range, as well as the speaker. You have to be prepared for potential crossover distortion, and many amps greatly lose efficiency in the lower frequencies at any volume. I agree that the speaker is one of the most important components regarding performance all across the board, and changing speakers may give you better performance and with a few more dB of useable volume, and that's a lot.

You must also take into realization that RMS/Peak wattage isn't telling you a whole lot in again, relationship to 100 Hz, 1 Khz and 10 Khz. Once you incorporate a speaker as the load on the circuit, you aren't dealing with watts, but the VAR of a resonant circuit. This is the precise point at which current and voltage meet in phase, and you get the most power transfer.
I've seen the most efficient systems built by using 100 Hz instead of 1 Khz exclusively to rate a speaker as well as the amp, and the VAR in equivalent effective wattage might be 10 watts compared to a 1 Khz sine wave resonating at 100 VAR(watts), or it might still be 100 VAR(watts) when using a 100 Hz sine wave, and that's phenomenal.

This is the final attribute where you also start to realize efficiency is overrated. I would rather have 100 effective watts of Class-A @ 100 Hz than Class-A/B or worse yet, Class-D. A really well-designed Class-A amp focused on VAR for 100 Hz resonance just as much as 1 Khz will be an animal not much can compete with. It's why some of these really old tube amps that weigh 150lbs will be just 30 or 40 watts, but they can compete with a modern Class-A/B or D that's full blast and rated 200.
#12
Amplifier Discussion / Score! Crate GX-212 for $70
March 20, 2024, 08:35:18 AM
100% American made, 30 years old and with the Crate speakers that replaced the flimsy Celestion Rockets they previously used(I have some of those too). I hit the cabinet with a degreaser, and it's electrically still a beast. They even had the casters for it, but no foot switch which I can easily build if I truly desire one; I don't.

This is probably the most "sterile" of their SS series, but still ear bleeding loud and the wattage is 100% useable when maxed out. I designed my very first distortion pedal directly around this preamp's lead channel, and have used it ever since on every piece of gear including 2024 digital modelers for 15 years now.
I can crank gain through the roof for sweeping and shredding, and don't even have ground buzz and without a noise gate using the overdrive I designed. It gives me something to use in my gym or roll outside onto the deck or into the front yard and rain hell down on my neighbors  ;D