This is very interesting, and useful information.
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On an amp that asks me to raise the input gain until the red light blinks, and then back off a tad, I'd like to know what level that leaves my signal at, and if that's the level the amp puts out at the effects "send" jack.
There are a lot of pedals that are sort of borderline capable of being run in an effects loop, so this information would help, especially if you're considering a pedal you haven't bought yet.
There are a lot of pedals that are sort of borderline capable of being run in an effects loop, so this information would help, especially if you're considering a pedal you haven't bought yet.
Freq response curves for controls all at midpoint, plus curves to show the action of eq controls at max and min.
Power output: Full power at varying loads (max), plus duty cycle and/or percentage of full power that the amp can do continuously without thermal or other shutdown.
Power output: Full power at varying loads (max), plus duty cycle and/or percentage of full power that the amp can do continuously without thermal or other shutdown.
A multimedia based "spec sheet" for lack of a better term, would be useful to me.
Creating youtube videos demonstrating your amps Q ranges with a visual aid to is more helpful to me than text alone.
I've spent a fair amount of time reading specs that I only partially understand hoping I can find a video that demonstrates exactly what it means to my ears.
Creating youtube videos demonstrating your amps Q ranges with a visual aid to is more helpful to me than text alone.
I've spent a fair amount of time reading specs that I only partially understand hoping I can find a video that demonstrates exactly what it means to my ears.
For me:
Watts RMS at useable loads
Frequency response graph with EQ flat at a few different power levels
HPF specs if it has one
Details on any built in compression or limiting
Weight
Dimensions
Features
Beyond that I have to hear or play a bass amp in a live setting to decide if I like it.
Watts RMS at useable loads
Frequency response graph with EQ flat at a few different power levels
HPF specs if it has one
Details on any built in compression or limiting
Weight
Dimensions
Features
Beyond that I have to hear or play a bass amp in a live setting to decide if I like it.
Bass tone isn't actually that complicated. I liked the old mesa "pitch, punch, and power" description. That lets me know what you are trying for. There are lots of other good words you can use. In order of frequency:
Rumble
Deep
Fat
Thick
Punch
Complete
Nasal
Filtery grind
Chimey grind
Attack
Shimmer
Air
Just tell me what you designed it to sound like. Most people seem focused on things that effectively amount to loudness, but that's kind of an outdated approach in the world of so many super powerful amps. The shape of the effective HPF and LPF, and the shape of the mids, are really all that matter.
The D800 seems focussed on deep with chimey grind, with the plus you can morph the deep into fat. Ignore EQ options I'm just talking about the basic sound.
The TH500 is all fat, thick, and punch.
Etc ...
Rumble
Deep
Fat
Thick
Punch
Complete
Nasal
Filtery grind
Chimey grind
Attack
Shimmer
Air
Just tell me what you designed it to sound like. Most people seem focused on things that effectively amount to loudness, but that's kind of an outdated approach in the world of so many super powerful amps. The shape of the effective HPF and LPF, and the shape of the mids, are really all that matter.
The D800 seems focussed on deep with chimey grind, with the plus you can morph the deep into fat. Ignore EQ options I'm just talking about the basic sound.
The TH500 is all fat, thick, and punch.
Etc ...
Hmm, I seem to get chimey grind, attack, shimmer, and air from mine, along with all the other descriptors you mention, from mine.
I know I'm going to be in the minority here, but in addition to a comprehensive set specs, I'd like to be able to see or at least have easy access to the exact testing methodology used to arrive at those specs. Especially since there doesn't appear to be a standard in the industry and many specs are subjective marketing materials at best. As far a simple spec that I look for when all else fails; I look for wattage, driven 20 to 20K (not 1K) at a given impedance, quickly compared with input voltage and max amperage draw.
Another vote for some information on pot linearity. Graphs help too. I think of my D800+ as a precision instrument with a lot of design and science behind it - strut that stuff!
I also want to vote for some kind of language to describe character, but there are definitely some inherent challenges due to subjectivity. Perhaps relation within product lines or comparison to lineage or similar.
I also want to vote for some kind of language to describe character, but there are definitely some inherent challenges due to subjectivity. Perhaps relation within product lines or comparison to lineage or similar.
Agedhorse:
Kudos to you for creating this thread! Many TB'ers have already listed some good spec parameters, so I won't repeat those.
If the amp in question has one or more preamp tubes in the gain stage, I am always interested in the voltage that those preamp tubes are receiving. I say that because in my experience, preamp tubes that receive a healthy voltage of around 300v provide much better tone (IMO) than starved plate designs.
And if the amp in question has power tubes, I would like to know the B+ plate voltage being fed to those bottles as well.
Thanks!
Kudos to you for creating this thread! Many TB'ers have already listed some good spec parameters, so I won't repeat those.
If the amp in question has one or more preamp tubes in the gain stage, I am always interested in the voltage that those preamp tubes are receiving. I say that because in my experience, preamp tubes that receive a healthy voltage of around 300v provide much better tone (IMO) than starved plate designs.
And if the amp in question has power tubes, I would like to know the B+ plate voltage being fed to those bottles as well.
Thanks!
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Al Kraft
Supporting Member
- May 2, 2016
- 10,775
- 40,454
- Disclosures
- Mesa Boogie beta product tester and player support
For me, no matter how many specs, frequency sweep vs XYZ plots, etc. you're willing to provide, I'd still need to play and hear the amp before making my decision to buy. I think having some background on the design approach itself and the specific goals would actually be more useful to me than more specs. The specs we got for the Subway series were quite comprehensive and reflective of real world capability - I'm not sure what else I'd need to see to get me to make a decision to go try out the amp. My ears believed the specs, but more importantly liked the sound and feel of the amp.
I find discussions on design approach and design trades to be very useful - and it was what got me interested in the D-800. Those insights help me to decide if the amp's design performance and feature set are well aligned with how I typically operate my amp. IME specs alone rarely tell the whole story, albeit if they're honest specs they do provide important parts of the story. So I vote for more design insight and discussion rather than more technical data, charts and graphs (beyond what we got for the Subway heads).
As a data point I'll just say that every product I was ever involved in designing could be accurately described by its specs, but the testers and operators frequently had comments that related more closely to the consequences/results of design trades than were actually reflected in the final hard specifications themselves. Feel free to characterize my response as a non-answer, but I tried!
I find discussions on design approach and design trades to be very useful - and it was what got me interested in the D-800. Those insights help me to decide if the amp's design performance and feature set are well aligned with how I typically operate my amp. IME specs alone rarely tell the whole story, albeit if they're honest specs they do provide important parts of the story. So I vote for more design insight and discussion rather than more technical data, charts and graphs (beyond what we got for the Subway heads).
As a data point I'll just say that every product I was ever involved in designing could be accurately described by its specs, but the testers and operators frequently had comments that related more closely to the consequences/results of design trades than were actually reflected in the final hard specifications themselves. Feel free to characterize my response as a non-answer, but I tried!
an honest but still fairly basic power section RMS wattage spec of course, maybe rated at varying degrees of distortion and a simple note that such-and-such percentage of distortion is acceptable and sometimes even preferred by players.
any HPF/LPF action, and the slopes involved. if those filters change with levels or distortion settings or whatever then say so, that can be something to boast about without getting overly detailed.
if there's an onboard compressor then some explanation of what it does in terms of ratios and attack times and what it means when the "busy" light turns on.
any HPF/LPF action, and the slopes involved. if those filters change with levels or distortion settings or whatever then say so, that can be something to boast about without getting overly detailed.
if there's an onboard compressor then some explanation of what it does in terms of ratios and attack times and what it means when the "busy" light turns on.
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Not an easy question to answer. I'll start by stating the obvious. What you present should be more than technical information, it has to encompass a philosophy of everything that should be presented.
The specification sheet helps peak potential customer interest by laying out what the product can do, in technical terms. Hopefully this gets them in the door to try the product. The specifications should be a part of a comprehensive package that presents the information in different ways and at different levels.
Detailed technical specs are appreciated by only a very narrow group. They don't really mean a lot to most players. Of course, specs need to be provided. When you go too much in depth, most people's eyes gloss over. Finding the right balance is the difficult part, which prompted your question.
The answer is to provide a comprehensive package that provides information that appeals to wide audience. This should take the form of a web page that presents the information at many levels. This goes beyong a specification sheet. It should include an overview, features, image gallery (I personally love gut shots, they will show up on the internet anyway), videos, even reviews, and at the end, the technical specification.
Images and videos are so important, many people are visual in nature. There can be an introductory video, another can be technical in nature. The technical video can present the specs in a way that the players can relate to.
Specifications should feature what you want to highlight, otherwise they should be simple and not too detailed.
-A dBV noise spec and basic measurement conditions over a specified bandwidth should be at the top
-Operational input and output specs
-Bandwidth
-Tone stage - sell the features
-Maximum input level, dBu
-Maximum output level, dBu
-THD+noise at different input levels for useful frequencies for combined second and third harmonics, dBu
-Power requirements
-Weight
-Dimensions.
Something that a spec sheet can't provide is a visual presentation of the specifications, for example, the tone stage. How nice would it be if there were an interactive tool that allows one to turn the tone knobs and visually see the changing plot of the EQ over the bandwidth. This is complicated where the volume setting dictates how the tone stage performs. DAW EQ plugins can serve as examples as to how this can be presented. An alternative is to present the tone stage in a video or sets of static images for various tone settings.
Easier said than done. Be careful what you ask for.
The specification sheet helps peak potential customer interest by laying out what the product can do, in technical terms. Hopefully this gets them in the door to try the product. The specifications should be a part of a comprehensive package that presents the information in different ways and at different levels.
Detailed technical specs are appreciated by only a very narrow group. They don't really mean a lot to most players. Of course, specs need to be provided. When you go too much in depth, most people's eyes gloss over. Finding the right balance is the difficult part, which prompted your question.
The answer is to provide a comprehensive package that provides information that appeals to wide audience. This should take the form of a web page that presents the information at many levels. This goes beyong a specification sheet. It should include an overview, features, image gallery (I personally love gut shots, they will show up on the internet anyway), videos, even reviews, and at the end, the technical specification.
Images and videos are so important, many people are visual in nature. There can be an introductory video, another can be technical in nature. The technical video can present the specs in a way that the players can relate to.
Specifications should feature what you want to highlight, otherwise they should be simple and not too detailed.
-A dBV noise spec and basic measurement conditions over a specified bandwidth should be at the top
-Operational input and output specs
-Bandwidth
-Tone stage - sell the features
-Maximum input level, dBu
-Maximum output level, dBu
-THD+noise at different input levels for useful frequencies for combined second and third harmonics, dBu
-Power requirements
-Weight
-Dimensions.
Something that a spec sheet can't provide is a visual presentation of the specifications, for example, the tone stage. How nice would it be if there were an interactive tool that allows one to turn the tone knobs and visually see the changing plot of the EQ over the bandwidth. This is complicated where the volume setting dictates how the tone stage performs. DAW EQ plugins can serve as examples as to how this can be presented. An alternative is to present the tone stage in a video or sets of static images for various tone settings.
Easier said than done. Be careful what you ask for.
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Oh, dear friend agedhorse, your quest evokes two maxims from my years at university, not quite back in the horseless carriage days:
"A camel is a horse designed by a committee." By the time you publish all the info that people want it'll be a camel, indecipherable to all but ... well, it'll defy scrutiny. But they're sure they want it, aren't they?
"Oh little girl, with your nose pressed against the windowpane of life, there is no jelly donut." This came from an economics professor and it's a really interesting [to me] way to say that you can't always get what you want, even when you know what it is.
I suspect that most people will expect and demand that you provide them with information that will support their prejudices. One quote I encountered recently is germane: "More words explain more, less words confuse less." Author forgotten.
Good luck, Don Quixote.
"A camel is a horse designed by a committee." By the time you publish all the info that people want it'll be a camel, indecipherable to all but ... well, it'll defy scrutiny. But they're sure they want it, aren't they?
"Oh little girl, with your nose pressed against the windowpane of life, there is no jelly donut." This came from an economics professor and it's a really interesting [to me] way to say that you can't always get what you want, even when you know what it is.
I suspect that most people will expect and demand that you provide them with information that will support their prejudices. One quote I encountered recently is germane: "More words explain more, less words confuse less." Author forgotten.
Good luck, Don Quixote.
That's what the romance about tubes (pre or power stage) is all about, in'nit? That tubes distort the signal in pleasing ways.
- Feb 12, 2006
- 61,042
- 5
- 220,986
- Disclosures
- Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
Interesting... why would a 20kHz power spec, or even a 20Hz power spec be appropriate for a bass amp?
Just so you know why I ask, there isn't a bass cabinet on earth that could take rated power at 20Hz... which is why there is a high pass filter included in most of the newer, higher level products. Maybe 30Hz (not that it makes any practical difference, but at least 30Hz is getting closer to reasonable).
As to the 20kHz spec... many of the newer amp designs, especially the higher powered models, include something called Zobel network protection. In order for a Zobel network to survive 20kHz full power testing, it would have to be huge (at least 10x the size typically seen) and it would NEVER even be approached in the real world because the power spectrum has the real world 20kHz power being probably 30-40dB below the 100Hz spectrum (which is how HF components inside most amps are sized). Some of the newer amps even have protection networks that automatically reduce power by a factor of 10-20 (or shut off the amp) in the event that a high level high frequency signal is present (to protect both the amp and any high frequency driver attached to the amp).
Normally for bass amps, I use 30Hz - 5kHz for rated power testing (your tweeters would last maybe a few mSec at 5kHz) but there would be no difference at 20Hz. I don't do rated power tests (other than duty cycle controlled) above 5kHz due to Zobel network protection.
This is how providing too much info can be misleading, since pretty much no big modern amp can meet rated power at 20kHz for more than MAYBE a second without risking damage. Sure I could install a larger Zobel network for testing (I do for design phase work), but that would not be representative of how the amp is shipped.
OK well then 400 watts RMS with <2% distortion from 30 hz to 5khz continuous +- 3db, something like that is what I look for in modern amps and never see it, I haven't checked Mesa amps though. Maybe the damping spec might be nice too.
As I've mentioned before, if you want to provide your customers accurate information about what they're buying (or have already bought), you need to include a power vs distortion curve.
As far as your explanation of saying that THD varies with frequency to emulate an overdriven amp, I'm not buying it. I'm sure there are players that want overdrive but I bet that there lots more that want it clean and solid. Are these magic distortions created in the preamp or amp stages?
As far as your explanation of saying that THD varies with frequency to emulate an overdriven amp, I'm not buying it. I'm sure there are players that want overdrive but I bet that there lots more that want it clean and solid. Are these magic distortions created in the preamp or amp stages?
