Thanks Tom. I will look at it.
I posted, what I thought was, a comical look at speakers cables. BUT THE COCONUT AUDIO STUFF IS FANTASTIC. It's like a combination of great comedians and Sc-Fi writers. Woody Allen, "Professor" Erwin Corey, Rod Serling, Groucho Marx....the list could get really long..did I forget Ernie Kovaks. I love it. WHUPS, I'm aging myself, lets add Richard Lewis, Robin Williams and George Carlin. How could I forget Gracie Allen.
I think its apparent...I'm impressed.
I posted, what I thought was, a comical look at speakers cables. BUT THE COCONUT AUDIO STUFF IS FANTASTIC. It's like a combination of great comedians and Sc-Fi writers. Woody Allen, "Professor" Erwin Corey, Rod Serling, Groucho Marx....the list could get really long..did I forget Ernie Kovaks. I love it. WHUPS, I'm aging myself, lets add Richard Lewis, Robin Williams and George Carlin. How could I forget Gracie Allen.
I think its apparent...I'm impressed.
Last edited:
Ya know, not every post need deliver advertising copy and a product plug. Particularly to those of us who recommended the 1200 as a frontend during the initial Modulus design pass.
To indulge in a bit of history the original suggestion of the 1200 was, partially, based on analysis of discrete CMRR considerations---such as the measurements you've linked---whilst pursuing the research mentioned here. The circuits of figures 13 and 14 in the 1200 datasheet are graceful in getting round some of these limitations and copying them in the Mod was/is also good practice. A few other tasty solution flavours do exist but, for the most part, they're not meaningfully better or worse. Just somewhat different in the tradeoffs.
Ya know, not every post need deliver advertising copy and a product plug. Particularly to those of us who recommended the 1200 as a frontend during the initial Modulus design pass.
And I thank you for the recommendation. I do not operate in a vacuum. That is one of the things I really enjoy about this forum. I've received many bits of information including website feedback, requests for future products, input on where my products line up in the greater scheme of things, feedback on my documentation, help dealing with the obsolescence of parts, business advice, accounting advice, and even a bit of intellectual property law advice from members of this forum and regular readers of this thread. You know who you are and I thank you.
That said, it takes more than a circuit topology and a couple of ICs to make a great product and even more to make a business. Most importantly it takes a monetary investment, willingness to take a risk, and solid execution. That's where I come in. I could have bought a pretty nice Audi A4 with the money I have invested in Neurochrome. There's certainly been times where I've had a couple of sleepless nights after making a large investment. The time when I bought my APx525 springs to mind. I have never regretted making those investments, though. I'm tickled pink, and eternally thankful to my customers, that I am now starting to see a return on those investments. This would not have happened without my execution, investment, risk tolerance, and loyal following of customers, many of whom I would consider friends.
I'm proud of my accomplishments and of my products. I apologize if that shines through a bit strong at times.
Anyway. I should take my own advice and stop procrastinating. It's time for the next scheduled event on my calendar: Lunchtime Hockey. I don't exercise. I just play.
Sorry for the OT.
Tom
Last edited:
passthru implementation
hi all,
I have bought a Modulus+Power-86 kit, however not started yet. I am planning to replace my 2-ch power amp with Modulus-86. I also use a subwoofer; that is my system is a 2.1 configuration.
line level signal first enters into the main amp. it then moves to subw amp with a passthru connection provided within the main amp.
how can i implement this passthru connection? is it OK if I just add an RCA out (L/R is not important) connector in contact with one of the main input terminals? do i mess up the input impedance by doing so?
hi all,
I have bought a Modulus+Power-86 kit, however not started yet. I am planning to replace my 2-ch power amp with Modulus-86. I also use a subwoofer; that is my system is a 2.1 configuration.
line level signal first enters into the main amp. it then moves to subw amp with a passthru connection provided within the main amp.
how can i implement this passthru connection? is it OK if I just add an RCA out (L/R is not important) connector in contact with one of the main input terminals? do i mess up the input impedance by doing so?
It is clear that your approach is proper in terms of handling the 2-ch signal before the subw amplification.
Do you think that sound engineers may be putting different levels of low freqs into L and R channels? In short, does it really worth a summing amp + inverting buffer, or just a simple tap from the signal input terminal of Modulus-86 to subw amp?
(I am a little bit confused)
Do you think that sound engineers may be putting different levels of low freqs into L and R channels? In short, does it really worth a summing amp + inverting buffer, or just a simple tap from the signal input terminal of Modulus-86 to subw amp?
(I am a little bit confused
)
If the recording engineers are mixing the tracks in stereo then the left and right channel signals will be different. It doesn't make sense to mix everything above some frequency in stereo and below in mono.
Yes. I think it's worth the two opamps needed to build a summing amp and an inverting buffer.
Tom
Yes. I think it's worth the two opamps needed to build a summing amp and an inverting buffer.
Tom
Taking the thought a bit farther. Lets assume one is watching a movie and one scene is a view, filmed from the perspective of a stationary actor, watching a loud, low pitched locomotive slowly coming in from the distant right, then passing in front of the actor and continuing into the distance to the left. If the low frequencies are below the capabilities of your front speakers, wouldn’t a right and left channel subwoofer be needed to convey the sound moving with the image? Some say the movement of sound is handled above 80Hz. That may be true in moves soundtracks..I don't know. Some also say subs are omnidirectional so they can be put in a corner. I do know there are a few jazz recordings with two upright bass players on opposite sides of the stage and on a well mic'd recording and with capable speakers you can tell right from left down to about 41Hz, which is the lowest note on a 4 string bass.
In summary, my question is, if one's front speakers only go down to 60hz, wouldn't two subs be neeeded. If thats not true why bother paying $$$ for big speakers with low range capability. Just by two small speakers that go down to, lets say 60hz and buy one subwoofer. I don't believe that for a second
In summary, my question is, if one's front speakers only go down to 60hz, wouldn't two subs be neeeded. If thats not true why bother paying $$$ for big speakers with low range capability. Just by two small speakers that go down to, lets say 60hz and buy one subwoofer. I don't believe that for a second
Depends. A college buddy of mine referred to subs as "mumble boxes" for a reason.
Supposedly the ear/brain combo has trouble perceiving direction once the frequency is low enough. That's why you can get away with one sub in some systems, but that is a compromise.
There is no doubt that you'll have a measurable directivity wobble around the XO between the main speakers and the lone sub. This gets worse if you plant the sub in the corner.
A better solution would be to use two subs - one per speaker in the stereo pair. The WAF may be a bit lower with this solution as the subs tend to take up some room and need to be away from the wall.
Tom
Supposedly the ear/brain combo has trouble perceiving direction once the frequency is low enough. That's why you can get away with one sub in some systems, but that is a compromise.
There is no doubt that you'll have a measurable directivity wobble around the XO between the main speakers and the lone sub. This gets worse if you plant the sub in the corner.
A better solution would be to use two subs - one per speaker in the stereo pair. The WAF may be a bit lower with this solution as the subs tend to take up some room and need to be away from the wall.
Tom
In practice, at least with rock/pop stuff from the last 40 years or so, the bass does tend to be effectively mono. Plenty of counter examples of course, but seems to be true in general.
A couple years ago, I attempted to write a program that used FFTs to programmatically analyze digital music files and determine if the bass was mono or panned mostly to one channel. I had a number of "control" tracks that I tried to use to test the software. I don't recall all the details, but I there were a number of parameters to be defined, and I lost interest before I determined a robust set of parameters that yielded consistently predictable results.
My goal, though never realized, was to be able to analyze my music collection and with some fairly high confidence say x% has mono bass.
If anyone is interested, I could probably resurrect the project (e.g. throw it on GitHub).
Sorry for the off topic!
That is right on!
You know, there may be a few that could need to know how an adder helps?
Right on! I do like more effective.
Also, I don't mind the labor for buffers when needed--my friend Kean makes the effective buffers. I did check that excessively. Please don't expect more than the best buffer with excellent power supply styles immunity. On a list of what it does better than all else, that would be just buffer. So, if you need one, then you probably do need that one. However, if you needed something else, then fast-forward to a different post.
It would be alright with me if the fellow who made the best chip amp has a conversation with the fellow who made the best buffer.
That's because we're probably in need of both.
A request I'd like to make of both those guys is a bit of gain please.
Thanks for the info. I spent time reading the wiki solder info in the link you provided. I'm a little confused. Most all solders were listed as not good for gold. My confusion stems from the fact that most RCAs and good quality XLRs have gold plated solder cups and probably have been soldered with 63/37 for ages and later switched, to lead free, for RoHS compilance.
The wiki doc mentions potential problems with gold connections and dissolution of the gold. It also mentions that 63/37 is not good for gold. You mention that both triple eutectics are not recommended for gold. What solder would be best for soldering stranded copper wire to gold plated connectors? Are any of the halogen and lead free solders designed for, or work well with, gold?
Thanks
I've used 60/40 Sn/Pb solder on gold plated connectors for decades without issues.
If you read the Wikipedia article you linked to above, you'll find that the amount of gold needed to cause embrittlement of the joint is 4 %. The amount of gold in the joint when you solder to a gold plated connector is much, much, much, MUCH, **MUCH** (did I say much?) smaller than that.
Gold plating is commonly used on PCBs. They don't use any special solder when they assemble those.
I think you may be trying to create a problem where there is none.
Tom
If you read the Wikipedia article you linked to above, you'll find that the amount of gold needed to cause embrittlement of the joint is 4 %. The amount of gold in the joint when you solder to a gold plated connector is much, much, much, MUCH, **MUCH** (did I say much?) smaller than that.
Gold plating is commonly used on PCBs. They don't use any special solder when they assemble those.
I think you may be trying to create a problem where there is none.
Tom
Thanks Tom. I'm reading so much trying to learn it and that make me question things. When a doc says something is not recommended for gold, and since I have so little knowledge, It drives me to ask questions.
In the overall scheme of things solder is cheap. My thought was, if I'm going to buy a spool of something, why not get something recommended for gold and silver. A 1 pound spool of .031 Dia. solder will outlive me.
In the overall scheme of things solder is cheap. My thought was, if I'm going to buy a spool of something, why not get something recommended for gold and silver. A 1 pound spool of .031 Dia. solder will outlive me.