What Amplifier Specifications Do You Feel Is Beneficial?

[Bubble]

I doubt if tonal personality is a trade secret. It's too easy to measure the frequencies to expect it to be secret. "There's a app for that!"

I'm thinking from 20 years and back when I heard that, probably at a dealer. A Fender sounds like a Fender, Marshall sounds like a Marshall etc. And don't throw those hokey sounding stomp boxes away, you can make some great songs with them.

 

[eigentone]

Agreed.

Take a look at the Subway D-800+ manual, see if those descriptions make more sense to you?

Yes, the explanations in the Subway manual make sense. However, I was requesting a description along the lines of "The DEEP switch engages a Low Shelf Filter with a cutoff frequency of 85 Hz, gain of 6 dB, and a slope of 6 dB/octave. The DEEP switch also engages a 6 db/octave Low Pass Filter at 1.5 kHz". Or if it were in the specs, it could be communicated in fewer words.

Specifically, the description in the Subway manual stopped short of providing the filter/EQ's cutoff frequency, gain, Q, slope. That information is much more meaningful to me than something like "…cleans sounds fly out of the speakers with immediacy and authority". It's also more succinct.

 

[Old Garage-Bander]

Some sort of meaningful spec for the average joe to understand what is going on with the Master control, as you turn it more to the right. For example, with the Subway 800, if I turn the Master all the way to the right, am I getting the full 800 watts at 4 ohms, or did that already happen before I got that far ? I'm probably not asking this in the right terms, but perhaps just a chart showing what type of volume taper is in the amp. Am I getting everything at straight up 12 o'clock, or do I need to go further, etc. ?

Calibrated Master and Gain pots and a chart. 3 on gain with 4 on master equals 12.3 % of full power output, with an input level of X.
Is that what you're thinking?

 

[jnewmark]

Calibrated Master and Gain pots and a chart. 3 on gain with 4 on master equals 12.3 % of full power output, with an input level of X.
Is that what you're thinking?

In a word, yup.

 

[Ross W. Lovell]

The output limit LED will give you a pretty good indication of when you have crossed the threshold into the output tube emulation limiting, and from this threshold you have ~6dB of available compliance between the threshold and and actual clipping. 6dB is in reality quite a bit as that represents a quadrupling of power in terms of dynamic range. I haven't seen this on a guitar amp though... butthen again it's "always too loud"



So I asked in the original post for this to remain respectful. I don't care if you don't like my story, or Paul's story. Please do not participate anymore, you are the only one who has crossed this line and continue to do so.



Tube compliment is pretty standard, though we (or at least I) don't get too deep into the subjective nature of tubes in general because there's too much emotion which in many cases are driven by those selling tubes. This road is paved with many "emperor has no clothes" challenges.

We don't get too heavy into disclosing which speakers we use or what the differences, or derivations might be. I've been down this road before and it's just not very productive. The performance and data provided speaks for itself, though I will think about this some more.

The manufacturers of custom parts are proprietary information. You would like to know, so would competitors, and especially the guys running the "copy-shops".

The LabSeries is a solid state amp. This was was sold and marketed as a guitar amp. I just liked the way it sounded.

 

[agedhorse]

Calibrated Master and Gain pots and a chart. 3 on gain with 4 on master equals 12.3 % of full power output, with an input level of X.
Is that what you're thinking?

This presumes that the player knows what the output level of his bass is under those playing conditions... which is affected by strings, set-up, and how hard he digs in. I just don't seeing this as being practical, and in fact might end up being more confusing to those who think they know.

 

[Old Garage-Bander]

If only every bass manufacturer listed the output impedance of the instrument with its stock pickups, all knobs up full, or some such way that we could start to grapple with impedance matching our basses to our rigs.

I guess if the input impedance is really high it will work with hi as well as low Z output impedance basses?

Except for tube amp output to speakers. Matching impedance has gone out if vogue. Make outputs low enough compared to inputs or inputs high enough compared to outputs, without going to extremes and 99.9% of everything will work with 99.9% of everything. Tweakable impedance controls are the stuff of pedals, or should be if that's what you want. Don't make everyone else pay for exotic features we'll never use.

 

[Al Kraft]

Agreed.

Take a look at the Subway D-800+ manual, see if those descriptions make more sense to you?

I think many of us would agree that the Subway manuals are a pretty good benchmark in terms of specs and actually some design feature insight. I like the balance between useful directions in English and some technical tidbits for the "engineering spirits" among us. Telling us how to get the most out of the design features and special circuits (e.g. voicing control) is where I think the extra attention really pays off for new owners, maybe more so than showing us circuit specifications or schematics.

As a data point on a head that I own and really like a lot, I suspect the TH500 manual is partially responsible for some people actually being disappointed with amp. I think the Aguilar guys and their products are great, but their manuals make even understanding which way to push the button (in or out) to get pre or post EQ DI out a challenge and aren't really clear as to why the clip light can be ignored.

To me that head has some real magic in it, but unless someone helps you break the code on "The Drive circuitry surrounds the midrange controls, enabling you to get a huge variety of tonal characteristics by simply adjusting the GAIN, MID LEVEL and MID FREQ controls", there's nothing in the manual to help you "get the most out of the product" (and it has a lot to give IMO).

While the manual provides some clear, useful descriptions and specs (honest ones based on my experience) it doesn't give me a lot of real insight into using the special characteristics they've put in their circuitry. More specs, charts and graphs could help some, but some additional descriptions in simple English (as if you were addressing a small child or golden retriever) could be very helpful. And let me finish by saying again that I really like my TH500 and have great respect for Aguilar engineering, manufacturing and customer support.

 

[Old Garage-Bander]

I have in fact already included some of the details in how the spec's were derived (certainly a lot more than most provide).

When we compare amps, we generally don't worry about specs., we listen and listen and listen to how the features work, how it feels, how player friendly it is, and how it measures up to out collective tastes.

We include a mic/line level switch which covers all bases without the typical problems associated with another level control (including breakage)

Well darn, you got me covered. I'm not much help then sorry.
Oh hey! Wait! You know what I'd like to see? (Coming from the guy who just pissed all over specs in general).
Amp output power at 16 Ohms. (I suppose you guys do that already too?)

Anyway, thanks for starting this thread. It has been really interesting.
Hope it gives you some of what you're looking for.

 

[HolmeBass]

Except for tube amp output to speakers. Matching impedance has gone out if vogue. Make outputs low enough compared to inputs or inputs high enough compared to outputs, without going to extremes and 99.9% of everything will work with 99.9% of everything. Tweakable impedance controls are the stuff of pedals, or should be if that's what you want. Don't make everyone else pay for exotic features we'll never use.

Yeah I wasn't asking for tweakable, just a listing of input impedance in the spec sheet and/or manual.

But I realized it may not be that important as we rarely know the output impedance of our basses, and as long as input impedance is nice and high it doesn't matter much if at all.

 

[Old Garage-Bander]

What angry diatribe? Andy stated his experience in the HiFi/audiophile business. It echoes my own in the service department of a high end stereo store. Talk about bloated specifications and expectations!!

Exactly...
Anyone who was involved in stereo equipment in the seventies, or even just shopped for stereo gear back then knows the irreparable damage the industry, as a whole, did to itself. Back then a stereo salesman was perceived as being only second in line to a used car salesman on the sleaze-meter.

 

[Old Garage-Bander]

All we can provide is the performance metrics, ie. the tube passed our screening and aging tests and meet the target that the designer has set for the tube. Rejects may not be bad tubes, but not meet our criteria (which may be very different than other manufacturer's needs). Using our tubes guarantees that a particular level of performance (electrical and mechanical) has been met and we are confident in what we are supplying (along with a longer than standard warranty).

Hope this helps.

Might this be also that you may source tubes from different manufacturers. As long as they meet your specs/needs/quality standards does it matter who "sucked out the air"?

 

[spankdaplank]

How about a sentence or two after each spec explaining (as simply as possible) the meaning of the spec in layman's terms in an effort to be digestible to a larger audience.

 

[Old Garage-Bander]

Yes, the explanations in the Subway manual make sense. However, I was requesting a description along the lines of "The DEEP switch engages a Low Shelf Filter with a cutoff frequency of 85 Hz, gain of 6 dB, and a slope of 6 dB/octave. The DEEP switch also engages a 6 db/octave Low Pass Filter at 1.5 kHz". Or if it were in the specs, it could be communicated in fewer words.

Specifically, the description in the Subway manual stopped short of providing the filter/EQ's cutoff frequency, gain, Q, slope. That information is much more meaningful to me than something like "…cleans sounds fly out of the speakers with immediacy and authority". It's also more succinct.

You've just uncovered the difference between engineering and marketing.
And guess who gets to design the brochure?

 

[Old Garage-Bander]

How about a sentence or two after each spec explaining (as simply as possible) the meaning of the spec in layman's terms in an effort to be digestible to a larger audience.

Easier said than done, unfortunately. Kudos to those who try. One person's easy is another's impossibly complicated.
Finding that sweet spot between the guy who wants to know every minute detail about his amp but want's it in monosylable words but without insulting the reader by sounding like a Dick and Jane reader, is the holy grail.
You are indeed the rare person who is interested in wanting to know more.

 

[walterw]

Some sort of meaningful spec for the average joe to understand what is going on with the Master control, as you turn it more to the right. For example, with the Subway 800, if I turn the Master all the way to the right, am I getting the full 800 watts at 4 ohms, or did that already happen before I got that far ?

power amps don't really work that way.

it kinda doesn't matter where the volume knob is; if the input signal is quiet enough then it won't produce much power, while if that signal is loud enough it'll produce all its power. there's no "6 on the knob = 475 watts" or anything.

i suppose if you had a big multi-segment dB meter on there like you see on a home stereo then said meter could be marked with output watts at each step; i think it would have to be watts at a given ohms for it to be any kind of accurate though. (looking over at my '80s sansui home stereo box it has a big LED meter display, marked "w/8Ω". in practice the LEDs jump around so much with use that i could never get a clear idea of "how many watts" just by looking at it.)

 

[D.M.N.]

While this seems good on the surface, it would be so incredibly time consuming and costly that it's not likely to happen except as somebody's labor of love.

Okay, well at the very least where the output rating came from, what parameters were used to reach the stated power, and how much THD there is at that rating. I suggested those as they were what Dynaco used for their Hifi systems I believe, but really just knowing what you used to get the rating would also be satisfactory.

 

[agedhorse]

I would want the frequency of the control nobs, plus value at full off and full on.....

In my D-800 manual, it stats the "flat setting" is at noon and freq. But only states <80 hz. Well 40-80 is a large range.


View attachment 2475418

indeed it is large... exactly one octave large! Shelving filters are typically described differently because the -3dB point shifts with boost/cut. I typically specify the boost/cut one octave away from the knee) which minimizes the influence of slope. If you were thinking that the bass eq control was a peak-dip style filter than this could explain the confusion.

I'll just mention the things that I don't usually see but I wish I did:

The other thing that is almost NEVER on bass amps, but is important to me, is power draw. How many (electrical) amps are being pulled out of the wall at 1/8 power, etc. As the sound guy for my band, I need to know how many circuits I need and which equipment needs to go on what circuit. The bass amp, if it's powerful enough and depending on the class of amp, sometimes is a factor in that decision.

Tom

Let me address this, because it's actually a great question. In general, the safety testing agencies require that the product be marked with the power or current draw at the greater of 1/8-rated audio power (or higher duty cycle IF the amp is marketed and intended to be used this way) into the lowest rated load. I use power draw because all the products I develop are international in nature and the power will remain constant, but the current will vary with the AC line (mains) voltage. The reason amps are marked and tested this way is to accurately reflect the average power consumed when driven to the point of clipping. Since most of the amps I design are intended to be overdriven quite hard (and do so without any troubles), you will see that I use a more conservative value which is usually greater that 1/4-power (or >25% duty cycle). I know that some amps on the market are labeled differently, and some of these amps do not do well when driven hard into overdrive/clipping. Since the amps I design amps have inrush current limiting (maybe another spec to add???), using the number on the back of these amps is a good estimation of the load on the circuit, and with dynamic loads it would be prudent to load the circuit to no more than 80% of rated ampacity. YOu would just need to divide the rated power draw by the line voltage to get the line current. (or use 1800 watts for a 15 amp circuit and 2400 watts for a 20 amp circuit, then derate by 20%)

A pre-amp and a power amp, commonly together called "an amplifier".

I think this is just terminology, I use head, amp, amplifier all interchangeably.

I thought from the original post, this was in reference to any amps spec sheets in general, not necessarily just yours. And my point was what "i " look for in the specs. I guess I didn't understand your directions.

In some ways it is about spec sheets in general, and I am trying to address those comments in a more general way.

Well darn, you got me covered. I'm not much help then sorry.
Oh hey! Wait! You know what I'd like to see? (Coming from the guy who just pissed all over specs in general).
Amp output power at 16 Ohms. (I suppose you guys do that already too?)

This is certainly an easy thing to do, and it wouldn't surprise me to see some 16 ohm cabinets as amps continue to grow. There's only so much power a 110 or 112 can handle, so when faced with say a 1200 watts into 4 ohm and 600+ watts into 8 ohm amp, 16 ohm cabinets may end up being a survival strategy if nothing else

Might this be also that you may source tubes from different manufacturers. As long as they meet your specs/needs/quality standards does it matter who "sucked out the air"?

There are times when we have to source from alternate sources, but fortunately not very often. It takes a lot of work to properly qualify a new part but if we are seeing an increased defect fallout rate during our in-house QC, we are faced with unavailability, or a change in the manufacturer's processes, we may have to use an alternate supplier or different date code, or a variant from the same supplier/manufacturer. This is why we have focused on which parameters are most important for each amp, and in some cases we might have 2 different 12AX7's with different part numbers for different applications (like one may be low microphonics for V1, while another might be smoother response in V2 etc. but has too high microphonics for the V1 position.

One of the toughest challenges is qualifying alternate parts. The guys are really focused on this because it's so darn important (to us as well as the customers)

 

[pickles]

The point of specs is to help a customer understand what the amp will DO when they use it. I think a lot of players have convinced themselves they know what some spec means, but many/most of those ideas are wrong. So they flip gear in spite of having lots of specs.

For example people talk about damping factor making notes more seperate, and being able to hear the nuance of fingers on strings. I don't know if thats true, or what DOES control that. I just know I don't want my bass to sound blurry.

But when you get subjective in descriptions there is too much temptation to say "this amp is perfect for every bass, style, cab, and venue, that'll be 900 bucks please". And if you list the specs that are verifiable, customers draw nearly random conclusions about the amp based on thier limited understanding and/or deeply felt misconceptions.

So basically I don't envy your predicament.

 

[_Some Dude]

The point of specs is to help a customer understand what the amp will DO when they use it. I think a lot of players have convinced themselves they know what some spec means, but many/most of those ideas are wrong. So they flip gear in spite of having lots of specs.

For example people talk about damping factor making notes more seperate, and being able to hear the nuance of fingers on strings. I don't know if thats true, or what DOES control that. I just know I don't want my bass to sound blurry.

But when you get subjective in descriptions there is too much temptation to say "this amp is perfect for every bass, style, cab, and venue, that'll be 900 bucks please". And if you list the specs that are verifiable, customers draw nearly random conclusions about the amp based on thier limited understanding and/or deeply felt misconceptions.

So basically I don't envy your predicament.

Add in people who try to apply HiFi theory to musical instrument application....