Should I be careful w synth bass into bass amp?

[bluzeyone]

Well, that was interesting.

Right?

I know! It was cuz Casios are plasic!

[ITGITC]

garnermike,

 

Honestly, I'm not trying to offend you. I'm just trying to help you find the answer.

 

Here's what you said:

 

I have listed the the half-dozen or so amps that do not function/sound like they should and once did.

 

I also have 4 bass EQ pedals in my attic that likewise do not work anymore, again via playing the Casios through them.

 

OK, maybe it's not the preamp being the affected part, but I made the assumption...

 

After some number of gigs where it sounds terrific (big fat low thump),

 

suddenly the attack/responsiveness of playing the individual notes lessens (bit of a delay happens),

 

a sorta echo/reverb effect sets in, and some notes are squarely there, full-force, while others are distant sounding and delayed in firing/sounding.

 

...buy/use a different/new bass amp head and/or EQ pedal (into the same or different bass cab) and all reverts back to normal---

 

until that head's sound undergoes the same corruption over time.

 

So using only a Casio CTK-5000 or a Casio CTK-6000 - no Roland E-09 or any other keyboard - you have broken six or more amplifiers and four EQ pedals.

 

You are not certain that the problem is the preamp. That's an assumption.

 

The sound is fine at first for some number of gigs. (Is that two gigs, three gigs, fifty gigs?)

 

This problem comes on suddenly. There is no warning at all that it's about to happen?

 

The tone changes. You described this as:

 

* a slower attack

* an increased latency and responsiveness from when you hit the key to the time you hear the sound

* Echo and reverb effects are added to the sound

* Some notes play correctly, while others don't

* If you replace the amplifier or the EQ pedal that you have broken with a new one, this fixes the problem... until, over time, it happens again.

* Your experience has shown that it will certainly happen again.

 

Is this correct?

 

Again, I'm only trying to get to the bottom of this because frankly, I'm pretty tired of it being dragged out.

 

You have gotten quite a few responses from members of the forum, including me, who say that this has never happened to them - that they've never experienced problems in the preamplifier section of a musical instrument amp by playing a Casio or any other instrument through it. One member who replied is an Electrical Engineer. Others are professional musicians, and have been all their life. They all say that they have never experienced this.

 

You even have I-missRichardTee asking the forum this:

 

... these guys can be rather dense at time. Does any intelligent minded member know why Casio keyboard would be doing what garnermike reports?

 

Yet your response to all of us who have tried to help you is this?

 

Look, guys,...don't tell me that I can't somehow adversely affect bass amp pre-amps playing the Casios through them. Unless you have had the experience like mine with Casios, please don't make blanket statements that I can't damage a solid or a tube bass amp pre-amp --- I indeed have with the Casios. I am simply reporting my experiences. OK, maybe it's not the preamp being the affected part, but I made the assumption...

 

 

So garnermike, I'm going to ask you the question that everybody who has taken their time to thoughtfully offer you their advice wants to know:

 

Did you take any of this equipment, a Casio CTK-5000 or a Casio CTK-6000 keyboard, six (6) or more amplifiers plus four (4) bass EQ pedals, to a technician and ask him to check them out?

 

The representative for Casio is a member here. I feel certain that he would like to know if the problem is with Casio equipment because you are squarely putting the blame on this particular brand.

 

I don't know what the solution is, garnermike. However, if after breaking over six amplifiers and four EQ pedals you don't feel the need, or the intellectual curiosity, to take any of this equipment to a tech, and you refuse to consider the advice that all of us have offered you...

 

Perhaps you should drop it and move on.

 

Good luck.

 

Tom

 

[Dave Bryce]

That's ok garnermike, these guys can be rather dense at time. Does any intelligent minded member know why Casio keyboard would be doing what garnermike reports?

Wow.

 

Calling people who are trying to answer your questions and help you out dense...that should work in your favor remarkably well going forward.

 

I have run bass synths for years through my pro-grade bass amps with absolutely no issues whatsoever.

Me, too.

 

Hell, I've beaten the daylights out of Sunn, Ampeg, SWR, Markbass, GK, and Peavey amps with all sorts of bass (and non bass) synth sounds. No problems at all.

 

Moreover, I've been in the musical instrument and pro audio communites for about 30 years - both in sales and manufacturing, working for both keyboard and boutique pro audio companies. In that time, this is honestly the first report/mention I've heard of bass synths doing any damage to any type of pre-amps.

 

I suppose it's possible that something like this has eluded everyone I know...but it is hard to imagine. At least two of the guys in this thread have shown themselves over the years to be quite well versed in EE, so my inclination is - like most of my dense friends here - to be skeptical.

 

Also, as far as I know, many (if not most) preamps in professional amplifiers are designed to be overdriven without being damaged. I would imagine that the ones in bass amps are certainly designed that way....but I suppose anything's possible.

 

However...I, too, find it peculiar that only an inexpensive model of a specific manufacturer's keyboard would do this. Frankly, if this specific keyboard did this to every amp I plugged it into, I'd get the keyboard in question checked out.

 

In the meantime, I work with Alex Aguilar, who designed the Aguilar Amplification bass amps. I'll ask him for what I certainly would call an expert opinion and report back shortly with his response.

 

dB

 

[Dave Bryce]

I work with Alex Aguilar, who designed the Aguilar Amplification bass amps. I'll ask him for what I certainly would call an expert opinion and report back shortly with his response.

Alex says no way.

 

He says any professional bass amp/preamp is going to be designed with some kind of protection to keep it from getting damaged. He says the worst thing that can happen is (surprise) they distort (which some players actually desire, of course), but there's no way to damage them with audio signal from a keyboard without really going over the edge - feeding them waaaaay too much signal for a sustained period of time...and even then, he says it's unlikely. He says tube pres are especially safe - they can handle just about anything.

 

Mike - I don't know what your Casios are doing....but whatever it is, it does not sound like the audio signal is the cause of the problem.

 

dB

 

 

[I-missRichardTee]

It did not sound like the questions the user of the Casio, brought up were being taken seriously. Obviously we differ, and that's ok ( Stu Smalley )

[Steve Force]

What do you mean he isn't being taken seriously? He keeps insisting, against all more learned, expert opinions, that somehow his situation defies all known physics. Me, I'll take Dan's EE knowledge and experience, Alex Aguilar knowledge and experience, and my own heavy abuse of bass amps as thoughtful response.

 

Or is that also evading the point?

[I-missRichardTee]

Steve no reason for us to argue .. all I am saying is, in my opinion, the responses the user of the Casio was receiving, at the time I intervened, did not seem to be taking his words seriously.. as if to say his experiences were somehow invalid due to science. So I took up his cause, I "had his back" , why? Because I have been in the same position and know what it feels like.

I have no issues with you, or anyone here, personally! Just trying to be supportive. edit.. I am not knocking science itself, in any way. Thank you

[J. Dan]

What IQ would qualify a response? I think most of the guys responding are pretty intelligent. Not only do I have an engineering degree, but I specifically took classes focused on analog circuits, and have designed/built my own circuits as a hobby over the last 20 years or so. There is nothing in an analog preamp circuit that would introduce delay/echo, period. That, in the analog world, would require something like a bucket brigade device (BBD) with enough stages to introduce audible delay. That type of circuit doesn't magically manifest itself from being fed by a Casio.

 

Now if you mean the sound cuts out and there is a delay before it comes back in, then that comes from discharging the power supply capacitor and the time it takes to build back enough charge. That would be caused by WAY over driving the power amp section. However, you would most likely hear distortion before getting to that point. If you're doing that, get a bigger amp. But there's nothing magic about Casio.

[JeffLearman]

As a kid, I remember plugging the speaker output from a 100-watt solid state guitar amp into the input of an inexpensive solid-state stereo. Sounded funny, but didn't break anything. I admit that at the time I knew I was breaking the rules. I got years more use out of that stereo, until it was finally stolen.

 

More recently I asked a friend EE who does audio stuff to do the math. He said that, based on the most common components and designs, overdriving a solid-state input would sink current through a particular resistor, and the most likely failure mode would be burning out that resistor from too much heat.

 

He did the math and said it would probably take hours of continuous 100-Watt signal.

 

Hi-Z inputs are pretty robust. I just can't imagine what any piece of audio equipment (other than a 110 V AC cord) could do to damage a hi-Z input. Furthermore, if they could be damaged to add reverb and echo or change dynamic response, I'm sure we'd have damaged them on purpose decades ago, just to get those nifty effects!

 

So, color me perplexed. I'm confident that there has to be some other explanation for Garnermike's experiences. I'd love to get my hands on a damaged item to see how it sounds, and compare it to a fresh one.

[bluzeyone]

Honestly have to start asking questions like "Where is the board/gear stored?" "Is it damp, climate controlled?" "Exposed to storm conditions?" That could be a factor. The issue he's having is real. Its just not possible with properly working gear. I can't think of any other reasons.

[I-missRichardTee]

That's ok garnermike, these guys can be rather dense at time. Does any intelligent minded member know why Casio keyboard would be doing what garnermike reports?

Wow.

 

Calling people who are trying to answer your questions and help you out dense...that should work in your favor remarkably well going forward.

 

I have run bass synths for years through my pro-grade bass amps with absolutely no issues whatsoever.

Me, too.

 

Hell, I've beaten the daylights out of Sunn, Ampeg, SWR, Markbass, GK, and Peavey amps with all sorts of bass (and non bass) synth sounds. No problems at all.

 

Moreover, I've been in the musical instrument and pro audio communites for about 30 years - both in sales and manufacturing, working for both keyboard and boutique pro audio companies. In that time, this is honestly the first report/mention I've heard of bass synths doing any damage to any type of pre-amps.

 

I suppose it's possible that something like this has eluded everyone I know...but it is hard to imagine. At least two of the guys in this thread have shown themselves over the years to be quite well versed in EE, so my inclination is - like most of my dense friends here - to be skeptical.

 

Also, as far as I know, many (if not most) preamps in professional amplifiers are designed to be overdriven without being damaged. I would imagine that the ones in bass amps are certainly designed that way....but I suppose anything's possible.

 

However...I, too, find it peculiar that only an inexpensive model of a specific manufacturer's keyboard would do this. Frankly, if this specific keyboard did this to every amp I plugged it into, I'd get the keyboard in question checked out.

 

In the meantime, I work with Alex Aguilar, who designed the Aguilar Amplification bass amps. I'll ask him for what I certainly would call an expert opinion and report back shortly with his response.

 

dB

 

DB... You are correct. But I heard intelligent people basically saying, mgarner's experience was not happening, or could not be happening, because it is scientifically impossible.

I was lending support to a long time player.

Rabid mentioned something about a "burn in period"... as if a brand new amp, like a set of tires, has a breaking in period. IS THIS TRUE?

I said intelligent minded and rather dense, because one must simultaneously speak for the general science of amplifiers, side, and also the highly unusual 'data"that apparently contradicts it! Both sides ought to be given credit. When a highly atypical situation comes up that seems to contradict commonsense.. that is this situation. And mgarner has not responded to the tech looking at his gear suggestion.

But I must say, when I have brought issues with gear into to a tech, the tech does not necessarily have an answer to all my peculiar observations about the piece of gear.

Here is an odd one, that reminds me of this situation. the top guy at Manny's music, who played synths and sold them on mass. He once told me he hears differences between individual models of the same synth!!! Could a tech explain this?

If that very savvy guy came on this board to report this "fact", I wonder how his observation would be received?

Scientists, must have an "open mind".. to a particular situation, which seems to go counter to the general theories of electronics. We ought not in anyway discount a particular ( presumed sincere ) case of observed facts, just because they go against general theory.

 

Re my " can be rather dense " remark.. I am sorry. I have applauded the mind/experience, in particular of JustDan many times, and continue to admire his brain power, as well as many here.

 

[I-missRichardTee]

As a kid, I remember plugging the speaker output from a 100-watt solid state guitar amp into the input of an inexpensive solid-state stereo. Sounded funny, but didn't break anything. I admit that at the time I knew I was breaking the rules. I got years more use out of that stereo, until it was finally stolen.

 

More recently I asked a friend EE who does audio stuff to do the math. He said that, based on the most common components and designs, overdriving a solid-state input would sink current through a particular resistor, and the most likely failure mode would be burning out that resistor from too much heat.

 

He did the math and said it would probably take hours of continuous 100-Watt signal.

 

Hi-Z inputs are pretty robust. I just can't imagine what any piece of audio equipment (other than a 110 V AC cord) could do to damage a hi-Z input. Furthermore, if they could be damaged to add reverb and echo or change dynamic response, I'm sure we'd have damaged them on purpose decades ago, just to get those nifty effects!

 

So, color me perplexed. I'm confident that there has to be some other explanation for Garnermike's experiences. I'd love to get my hands on a damaged item to see how it sounds, and compare it to a fresh one.

As usual, you give another thought provoking aspect to questions that come up.

You mentioned a friend EE ..... " sink current through a particular resistor, and the most likely failure mode would be burning out that resistor from too much heat." I note ( electronics are not my field of knowledge, even minimally ) you used the word "FAILURE". I am hypothesizing here but... Failure is not what mgarner is speaking about.

Reminds of metal fatigue... there is a wide continuum of the metal, from when new to when it fails. Could not electronics mirror this fact from the world of chemistry? I do not know, merely asking. But this is not a failure of the amp.

[I-missRichardTee]

What IQ would qualify a response? I think most of the guys responding are pretty intelligent. Not only do I have an engineering degree, but I specifically took classes focused on analog circuits, and have designed/built my own circuits as a hobby over the last 20 years or so. There is nothing in an analog preamp circuit that would introduce delay/echo, period. That, in the analog world, would require something like a bucket brigade device (BBD) with enough stages to introduce audible delay. That type of circuit doesn't magically manifest itself from being fed by a Casio.

 

Now if you mean the sound cuts out and there is a delay before it comes back in, then that comes from discharging the power supply capacitor and the time it takes to build back enough charge. That would be caused by WAY over driving the power amp section. However, you would most likely hear distortion before getting to that point. If you're doing that, get a bigger amp. But there's nothing magic about Casio.

I am sorry JustDan... you ought to be aware of my admiration for your knowledge.

[I-missRichardTee]

Honestly have to start asking questions like "Where is the board/gear stored?" "Is it damp, climate controlled?" "Exposed to storm conditions?" That could be a factor. The issue he's having is real. Its just not possible with properly working gear. I can't think of any other reasons.

Questions like this have never entered my mind.. but I am interested in knowing if electronics can be affected by weather, and corrosion that ensues.

 

Again, is there a break in period for a synth?

Can a tech explain the notion that every synth of the same model, sounds ever so slightly different, if, yes, why?

Then we have CEB's thoughtful observation ..."It isn't necessarily a volume thing. It is a not giving the speaker a moment to breathe thing."

 

[MoodyBluesKeys]

I'm not an EE (although I did take the first 2 years of EE in college), but I've worked on electronics for 59 years now, in broadcasting, 2-way radio, musical electronics, and computers.

 

None of the synths I'm familiar with have a break in period; although the first few hours of operation of any electronic device have a somewhat higher failure rate than later.

 

Electronic devices of the same model - Electronic components have tolerances (example - a 100 ohm marked resistor that is rated at 5% may in fact be anywhere from 95 to 105 ohms). Tolerance is the amount of variation that is considered acceptable for the original sale of any specific manufactured product (even non-electronics - there is a tolerance for the actual size of a 2x4 board). Some components are available in different tolerances (i.e. resistors can be purchased with 0.5% tolerance, 2%, 5%, 10%, even 20%)

 

The number of actual components can be far more than the visible number. Example - a typical Intel computer processor contains several million transistors).

 

Therefore, two synths of the same model may have a considerable possible variation in what the components actually measure. This is also modified by the fact that some of the components will be less than nominal and others more than nominal.

 

When the Hammond tonewheel organs were originally built, a part of the manufacturing process was to have a skilled factory worker change certain components in the generator circuitry and in the preamplifier circuitry, in order to have the instruments be closer to the same. The original schematics are even marked with "factory selected" in a number of places.

 

Many components also vary based on their operating temperature (this is one major cause of drift in the old synths for the first hour or so that they are powered).

 

Beyond this, as components age, they tend to drift in value from what they measured when first built. An example - Hammond B3 the first couple of preamp tube circuits used some fairly high value resistors in the plate circuit - around 50,000 ohms. It was not unusual in servicing one of them that was 40 or 50 years old to find that the resistor now measured several million ohms.

 

In the early days of integrated circuit components, when some of the most famous synths were being made (such as the Prophet 5), the circuits also were noisy and had non-linearity (still happens, but less) - some of the favorite things about such instruments actually come from these flaws (just as the key click of a Hammond was a flaw, but has been accepted as a vital part of the classic sound).

 

IN all fairness, modern component tolerances are generally tighter than they were back in the 1940's. But, they still exist, and components still shift in value with age.

 

[I-missRichardTee]

I'm not an EE (although I did take the first 2 years of EE in college), but I've worked on electronics for 59 years now, in broadcasting, 2-way radio, musical electronics, and computers.

 

None of the synths I'm familiar with have a break in period; although the first few hours of operation of any electronic device have a somewhat higher failure rate than later.

 

Electronic devices of the same model - Electronic components have tolerances (example - a 100 ohm marked resistor that is rated at 5% may in fact be anywhere from 95 to 105 ohms). Tolerance is the amount of variation that is considered acceptable for the original sale of any specific manufactured product (even non-electronics - there is a tolerance for the actual size of a 2x4 board). Some components are available in different tolerances (i.e. resistors can be purchased with 0.5% tolerance, 2%, 5%, 10%, even 20%)

 

The number of actual components can be far more than the visible number. Example - a typical Intel computer processor contains several million transistors).

 

Therefore, two synths of the same model may have a considerable possible variation in what the components actually measure. This is also modified by the fact that some of the components will be less than nominal and others more than nominal.

 

When the Hammond tonewheel organs were originally built, a part of the manufacturing process was to have a skilled factory worker change certain components in the generator circuitry and in the preamplifier circuitry, in order to have the instruments be closer to the same. The original schematics are even marked with "factory selected" in a number of places.

 

Many components also vary based on their operating temperature (this is one major cause of drift in the old synths for the first hour or so that they are powered).

 

Beyond this, as components age, they tend to drift in value from what they measured when first built. An example - Hammond B3 the first couple of preamp tube circuits used some fairly high value resistors in the plate circuit - around 50,000 ohms. It was not unusual in servicing one of them that was 40 or 50 years old to find that the resistor now measured several million ohms.

 

In the early days of integrated circuit components, when some of the most famous synths were being made (such as the Prophet 5), the circuits also were noisy and had non-linearity (still happens, but less) - some of the favorite things about such instruments actually come from these flaws (just as the key click of a Hammond was a flaw, but has been accepted as a vital part of the classic sound).

 

IN all fairness, modern component tolerances are generally tighter than they were back in the 1940's. But, they still exist, and components still shift in value with age.

A Big THANK YOU!

[garnermike]

First, wasn't me who called anybody "dense."

 

The answer is "yes" to all your questions.

 

Sent 2 Carvin BX500 heads back to Carvin to check out their "blown" state. Received both back, saying they found no issues, but they replaced the preamps anyway (?). Once received back, the amps, played with my Casios, sounded the same "blown" way...awful. Sold both to bass guitar players locally I know who love them, and have had no issues with them. I was fully upfront with them about my experience before selling them.

 

BTW, the Carvin techie, a keyboard player and left hand bass player, in a long phone call, said that his own experience has been that keyboards will fry bass amp keyboards preamp over time. His suggested solution, one that he uses, involves using several additional pieces of gear, centered on a compressor and a limiter. I tried that approach, to no avail.

 

The two Ampegs were returned for refunds. Total blown, non-functioning, according to the retailer's report.

 

I still use the Fender Rumble 350 head on occasion as backup, but only through the backside "return" effects loop and first thru a bass EQ pedal. Using it thru its normal frontside preamp jack just gives me the adverse sound I've describe earlier.

 

Have I returned the Casio keybords to Casio for examination? No. But I have 3 of them, sitting in my attic, unused, as the Roland is performing flawlessly for some 40 gigs now, so I haven't done anything more with those CTKs yet. If there is a Casio rep reading this, send me a UPS shipping label, and I'll ship them all back to you and you can have at them. And I have nothing against Casio--my goodness, since 2002, I've purchased 5 of their boards, and love that one bass patch I have used---it's the best I've found.

 

The first CTK lasted about 100 gigs before my bass sound went south. The latest other two lasted much fewer gigs (<40) before souring.

 

I have had this poor result thru several different bass heads. I have several bass cab options I can used, and I've used them all. No difference in the adverse sound I've described.

 

I am not ungrateful for any advice I get on this forum. I did not start this thread, but appreciate that it was started. I have "refused" no advice; I have read every post, and have thought about what's been offered up. But when one of the posted replies essentially said "it's impossible; can't happen," that got to me a bit---I think it would get to anybody who's gone thru what I have, and who has spent the time and money I have trying to resolve it. Again, I know what my experience has been.

 

I will gladly move on, as a you suggest. Like I've always said, I was just reporting on my experience.

 

[MoodyBluesKeys]

I don't have any Casio boards. I was playing an electric bass before I switched to keyboards (because of cramps in my fretting hand). I had two big Trace-Elliot amps, with separate speaker cabs. Each of the amps had two inputs into a single control, one marked for passive, the other for active basses. My Gibson RD Artist was active, my Epiphone Les Paul is passive.

 

I first started using a Kurzweil K2000VP for bass (with the excellent added patches from the Bass Gallery CD) - worked great into the active jack, the volume controls set about the same as when playing the Gibson, so the levels were presumably about the same. Now, I use a PC361 and PC2 - I still have one of the Trace amps, but don't carry it around unless I'm doing nothing but bass at the particular gig (my K10 or EV SXA100+ are better for general all around use).

 

If it is a level problem, a simple attenuator between keyboard and bass amplifier should remedy the problem - IF the problem is being caused by over-driving the bass amp in the normal frequency range. Admittedly, SOME synth patches with a lot of very low frequency components may well be over-driving even at a moderate listening level (because the speakers are not reproducing the very low frequencies). In all fairness, these very low frequencies would also equally damage a keys amp.

 

Each of my Trace amps had a 7 band equalizer designed for bass guitar frequencies. I did find better results in reducing the lowest frequency gain - it pushed more of the sound into the area where it is heard better and gave better overall definition.

 

It would be interesting to put an audio spectrum analyzer on the Casio with the particular patch, and see visually just what frequencies are coming out.

[J. Dan]

To me everything is pointing to an issue with the casios, not the amp. Amps came back with no problem found but still sounded bad with the casio, yet sounded fine with a bass, and with a roland keyboard. Only the casios sound bad. That tells me there's a problem with the casio. Couple that with the fact that the poor sound was an "echo" type sound. As I stated, nothing in a preamp circuit would do that. A digital keyboard on the other hand, who knows?

[Brettymike]

What IQ would qualify a response? I think most of the guys responding are pretty intelligent. Not only do I have an engineering degree, but I specifically took classes focused on analog circuits, and have designed/built my own circuits as a hobby over the last 20 years or so. There is nothing in an analog preamp circuit that would introduce delay/echo, period. That, in the analog world, would require something like a bucket brigade device (BBD) with enough stages to introduce audible delay. That type of circuit doesn't magically manifest itself from being fed by a Casio.

 

Now if you mean the sound cuts out and there is a delay before it comes back in, then that comes from discharging the power supply capacitor and the time it takes to build back enough charge. That would be caused by WAY over driving the power amp section. However, you would most likely hear distortion before getting to that point. If you're doing that, get a bigger amp. But there's nothing magic about Casio.

 

Great call Dan , I would put money on this that you are totally correct , with the capacitors being sucked dry.

 

Nothing wrong with the Casio , just a seriously LOW bottom end (less than 20hz?) being over driven to death through an amp copping it. You know , those huge power drawing signals which you can only FEEL , not HEAR.

 

Brett

[garnermike]

Thank you MBK, J. Dan, and Brettymike. We have a good organ/digital keyboard repair shop in Raleigh. When I can find the time (have some health issues going on right now), I may just take the boards and a transcript of this thread to them, and ask them to test/measure in an effort to de-code the issue.

 

And J. Dan, you asked if "sound cuts out and there is a delay before it comes back in". Answer is no. Nothing approaching a "cut-out" of sound. Just a slower attack, echo effect, and a distant-sounding tonality.

[Brettymike]

They would have to do "A/B/C" comparisons of the various keyboard brand bass outputs on an Oscilloscope or something .

 

Brett

[garnermike]

Just a short follow-up. Since last describing/reporting on my problems playing Casio CTK boards through bass amps (see above on this thread), I am now up to 68 gigs using the Roland E-09 through my bass amp with no amp issues.