agedhorse

If this was a language translation issue, that's fine but I was addressing exactly what you wrote even if  that's not what you thought you wrote.

When this kind of thing comes up, and you are using a translation app, recognize that it's possible that your translation is not accurate and when questioned about what you have posted, consider that you could have made the mistake and be respectful in your follow-up responses.

I deal with the international community every day, I am very careful how I write responses and how it's possible that they might be mis-interpreted and rarely encounter disrespectful responses unless there is more to the story that I am unaware of.

Have a good day.

6 minutes ago, Beedster said:

I suggest you work out the answer for yourself while you fix your own amp

Yes, that's always his option as well. 

34 minutes ago, nuno1959 said:

Well my dear sir, before going on & on about it, you could always read what i answered before which addressed all of your concerns about sharing schematics  as in this small bit of crucial info you seemed to have missed entirely such as :

 

1 - You ask "...Even if the information is not yours to share?..."

Obviously you seem to have missed completely when i wrote - "...2nd I would OBVIOUSLY ask them 1st if that's ok with them BEFORE doing it..."  

 

Was there a word i misspelled there to the point you didn't get it ? Sorry, life IS too short to waste yet... here you are.

AGAIN. So.... excuse me if i sound dismissive but really !?

Where i come from respect is NOT owed, it's earned & wasting somebody else's time by asking what was already answered.... well, let's say it's not the best way to do it ?

As far as i'm concerned,  i won't be coming back to answer you over this ridiculous "worry" of yours

Have a great life

I was just responding to YOUR post where you SAID  you would share them... did I misunderstand what you wrote?

8 hours ago, nuno1959 said:

Right.........

 

You are always welcome to disagree with me, but you can probably do so a little more respectfully IMO.

6 hours ago, nuno1959 said:

Thanks for the input even though it brings little to the original purpose of this thread and don't be so shocked :

1st IF Epifani will give me the schematic, it's obviously because they are open for members of their client base to have it, i have been, for some 20 odd years & 3 rigs

2nd I would OBVIOUSLY ask them 1st if that's ok with them BEFORE doing it

Around my circle of friends and family that's how people function, the rest of the world.... 

3rd I doubt they would be so upset about it anyway because as i'm sure you now, a good electrotech can reverse engineer any circuit and make a similar one buying the right components + i'm sure all Epifani's proprietary tech will be patented, etc.... so how hurt will they be if a handful of nerds make their own "Epifani amp"...

4th - And just out of curiosity, have you asked that to Bheringer for example ? Because they are notorious for doing that only in a LARGE INDUSTRIAL SCALE..

So chill a little my man, i'm sure we'll all survive 😉

 

 

You might have a different perspective on this if you have had your designs appropriated from confidential documentation that was passed on to a competitor against your will. I have, it took money out of my pocket and the companies that produced those products.  This may explain our different perspectives.
 

Most modern designs are pretty difficult to reverse engineer without spending considerable effort and cost of doing so. Documentation reduces this cost to do so. Many companies do not release documentation for this reason alone. 

5 hours ago, nuno1959 said:

Will do and if i do get the schematics i'll be more than happy to share them here

 

Even if the information is not yours to share?

3 hours ago, Downunderwonder said:

Isn't that what I said??

 

Sine peak volts X to -X

Square X/X

 

Power twice as much for the square.

 

Sometimes I feel I am losing my mind.

Not quite, unless I read it wrong...

17 hours ago, Downunderwonder said:

If you search for a picture of RMS of a sine wave it will show the RMS point at .707 of the clean peak.

 

The RMS of a pure square wave is the full peak value.

 

Power is Current x Voltage.

Current is Voltage ÷ Resistance.

 

Substituting for Current we see Power is Voltage squared ÷ Resistance.

 

Noting that 0.707 is 1÷ square root of 2,

The power of the square wave is double the RMS power of the clean sine.

 

Trace rating an amp as 250W/500W Peak, maybe a little off the wall as nobody would pay to listen to one putting out the full 500W for more than a few microseconds, could handle mighty transient peaks.

Almost. The power of a square wave is equal to the RMS power of a sine wave and 1/2 the power (.707 x the voltage) of the peak power of a sine wave.  

Peak power is defined for a sine wave at 2x the RMS power, and when Trace advertised 500 watts peak power, that's exactly the same as 250 watts RMS. It has nothing to do with burst power (which has an entirely different definition and applied primarily to broad band signals).

Power RMS is equivalent to the area under the voltage curve x the current curve, and when integrated over time becomes energy. 

On 15/06/2025 at 21:06, Count Bassie said:

The guy who's been repairing my amps the last 6 or so years there me that measuring at 1KHz takes less power than lower frequencies, so the rated power brings a higher number. This is incorrect? 

 

Yes, for the most part that is incorrect. There may be a trivial difference at very low frequencies due to filter cap time recharge constants, but it will be less than 1/2dB at 30Hz on a properly designed amp and often much better.

Note that meters can be inaccurate at very low frequencies, which why special meters are used for broad band audio measurements.

2 hours ago, Count Bassie said:

Power is measured differently than it used to be. The numbers get blown up and it seems like power just ain't what it used to be. It is, it's just sold "differently"... Advertising...

Not necessarily. I'm still measuring the same way today as I did in the 1970's and every product I have designed uses power based on RMS metrics and states THD. For MI applications, especially where the distortion harmonics components may be integrated into the signal in both the preamp and power amp, I have standardized on 10% because after a lot of test player contributed their perceptions, 10% was pretty much the sweet spot where most players liked both the tone and texture. The most common numbers I see for bass amps range from about 5% to 20%, depending on the application. For guitar amps intended to be overdriven as part of their native tone, 10% to 30% is more common. Of course, the amps must be tested and safety certified under these conditions if being honest.

For pro audio, the numbers are different of course, and as powers increase the duty cycle factors into the equation. This is most common at very high powered pro audio amps, where after a second or two, the limiting algorithms fold the power back to about 1/2 the rated power and in big powered speakers, the HPF may shift upwards and the crossover points may also shift along with the limiting thresholds. This was all started with Meyer, Renkus Heinz, Apogee and later with JBL, etc. This has allowed maximum performance with minimum damage and warranty claims.

6 hours ago, BassmanPaul said:

What's the old saying? Nothing ventured, nothing gained!  

or lost...

1 hour ago, Beedster said:

That’s what I meant, we knew we had to be careful. I think lightweight lures us into thinking it’s not so easily damaged 👍

Agreed, a false sense of security

Actually, the damage to the older gear tended to be more catastrophic if it falls the same way. Broken parts, bent sheet metal and such is not uncommon when an amp takes a fall, usually the lighter weight gear is easier to repair in that regard. It used to be common for a fall to break the transformer mounting screw(s), causing the transformer to cause collateral damage to whatever initially survived.

Why not a simple splitter Y cable?

Steve1250 - If you are still having issues with your D-800, message me and I will help you get it sorted out. 
 

Be sure to let me know where you are located so I get you accurate info. 

4 hours ago, Sean said:

How close are we to helping the OP in making a decision on what to buy?

 

😉

Or how many (because one is never enough) 😄

Why can a 50W guitar amp sound as loud as a 500 watt bass amp (into appropriate speakers)?

1. Hearing is much more sensitive at guitar frequencies than bass frequencies

2. Guitar speakers are generally significantly more sensitive at guitar frequencies, than bass speakers are at bass frequencies, often by a factor of 10dB

3. Guitar amps are often driven into distortion, which increases the effective compression and average power density.

4. Guitar speakers tend to beam more because of the frequencies (including harmonics) that they are reproducing, this increases the on-axis volume.

35 minutes ago, joel406 said:

If you're using watts, you're doing it wrong.

Not by industry convention you aren’t.

9 hours ago, Dan Dare said:

 

As a designer, agedhorse will be interested in reading data sheets, etc, but the great majority of amp buyers won't be. They just want something that will do the job for them. Most class D heads, save for those made by those who like to gild the lily a little (Behringer, TC, we're looking at you) do have similar claimed power outputs, which is unsurprising, given that they are using similar power modules. Tonal differences are largely due to preamp designers' preferences, who they are aiming their product at (Is it good for metal?), etc.

 

 

Understood, though the assumption that Behringer and TC are using similar power modules (actually, the power amp and power supply are an integral part of the main board) isn't accurate. The power supplies/power amps are very different, though they both share a similar ambiguity (creativity) with regards to the way they rate their output power.

I was referring specifically to those who quote power off of a power module data sheet, without understanding the depths of what they are looking at. There is a ton of critical data between the lines of the data sheet, in fact that's what my US patent is based on with regards to some specific technology applications with a couple of lines of older ICEPower parts. We received this patent while working with directly the ICEPower engineering team on some of these off-sheet attributes, and these basic concepts got incorporated into the newer series power modules. This is what allowed us (Genz Benz) to do what everybody said could not be done, and we did it with higher reliability than those who used the modules within the limitations of the data sheets too. All Shuttle, ShuttleMax and Streamliner amps use various portions of that patented technology, them the patent was acquired by Fender and was theirs to use as well.

8 hours ago, Dan Dare said:

 

Not sure I understand what you've written. It seems there may be some missing words. If you compare the spec's of many of the class D amp heads from the usual suspects, they do produce approximately the outputs I mention. There may be small variations, but for real-world, practical applications, the generalisation will suffice. Not all of us wish or need to delve that deeply into specifications, etc. We just want to know what will work for us.

Your understandings and conclusions based on how you are reading the specs from the data sheets is flawed. 

Don’t go poking around creating new problems.

Surrey Amps is fully qualified to service your amp correctly, I can work with them directly to solve the problem. If you create new problems, the cost is sure to go up, 

3 hours ago, Stub Mandrel said:

I have found that some LED lighting can introduce various unexpected hum behaviours.

2 hours ago, Steve1250 said:

My D800 was having a similar issue some time ago, I found a screw missing from the bottom of the casing, replacing that cured the problem, might be worth a quick look 

Both of these are possibilities, not terribly common but possible.

9 hours ago, FugaziBomb said:

But measured at 1% (I think?) THD.  The reason tube amps sound louder is because they are delivering more watts than their rating as the are routinely pushed passed that percentage of THD.  If you do that with a solid state amp, it hard clips and sounds nasty, but tube amps sound nice when they start to clip.

Solid state amps don’t have to sound nasty beyond 1% THD, those that do haven’t designed around this parameter. Some tube amps clip very similarly to some solid state amps. Some us different than all. 

Is the amp quiet without the pedalboard, bass straight into the amp?

Where are you located? What is your power source?

there is also a possibility that there is a ground loop between the amp and pedalboard, or even a single pedal on the board. 

6 hours ago, Dan Dare said:

 

This. Most class D amp heads use power modules from Hypex, IcePower, Pascal and similar. The modules are readily available, proven, reliable designs and it simply isn't worth amp makers designing their own/reinventing the wheel.

 

Most modules are at or around two power ratings - either 300w into 8 ohms/500w into 4 ohms or 500w into 8 ohms/700w into 4 ohms. Some amp brands inflate their power claims. I have a Carvin that claims 1000w, but it's no louder than my 700w Aguilar if you turn both up to the point that the clip light flashes. I wouldn't be surprised in the Peavey mentioned is the same.

 

Watts are cheap nowadays. All amps have a volume control, so unless funds are really tight, buy the more powerful version, be sensible with the volume control and don't over-drive your speakers (you'll know when you do because they will make horrible noises). Your sound will benefit from the additional headroom and when/if the time comes to up the size of your rig, the amp will still be up to the job, saving you from having to sell and upgrade it (which always costs).

You just might be misunderstanding how power amps are rated and specified however, therefore your generalization inaccuracy.