I'm truly curious, this day and age we can't test a lot of gear. I wanted to DM Mr. Pass, for his opinion and keep it to myself but I'm not seeing how to message privately on the board, so public it is. Please no inflammatory opinions, I'm not trying to start some Audiogon ******* contest.
I just spent 2 years building new cabinets and Pass crossovers for my JBL 4333a and looking to find a good match for them. I'm a rock and blues guy, not a lot of jazz, but I love most music.
I've tried a class D amp that was not cheap and it sounded harsh, too much gain, hissed, not a good match. I'm currently running my refurbished M-504. Almost purchased a Pass XA25 from Reno but hesitated and it sold. It's hard these days to spend thousands on an amp you have never heard. I am truly open to anything and my budget is decent. I am also open to building my own, vintage, or used.
So please, you guys are a very knowledgeable and friendly group, help me make a short list.
Thanks
I just spent 2 years building new cabinets and Pass crossovers for my JBL 4333a and looking to find a good match for them. I'm a rock and blues guy, not a lot of jazz, but I love most music.
I've tried a class D amp that was not cheap and it sounded harsh, too much gain, hissed, not a good match. I'm currently running my refurbished M-504. Almost purchased a Pass XA25 from Reno but hesitated and it sold. It's hard these days to spend thousands on an amp you have never heard. I am truly open to anything and my budget is decent. I am also open to building my own, vintage, or used.
So please, you guys are a very knowledgeable and friendly group, help me make a short list.
Thanks
Using Azurahorns on the 2420. The drivers are in custom cabinets. Not original cabs from JBL.
I have not tried tubes. I have a tube DAC, nothing else. I thought about Atmas-sphere M60s but hate to purchase blind.
Just about anything would do as an experiment. Even an old console 5-15wpch. amp would make those speakers play loud. You may end up liking it a lot. Some of those old 6BQ5/EL84/7189 amps are really superb. I have an old pair of Electrohome 7189 mono organ amps that are very good, and cheap.
I've used UcDs driven directly into multiple CDs and never had a hiss issue, so you have something else wrong somewhere. The UcDs aren't as quiet as NCores.
Not seeing the point of a tube amp that's noisier than the NCore when there's a noise issue.
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Hello Mcdaniels, same here, loves almost all kind of music, but I do not understand it, nor how they are able to make it , choose instruments or writing notes. But I have worked with electronics and audio for 25 years, so my understanding of how to reproduce recorded music is way better. Hence this message or advise if you like.
Seen from a purely scientific or analog design perspective you are, most likely, barking up the wrong tree. Take a look at the pieces of equipment that is very often in use to play back music: a music source which provide the music signal, an amplifier to increase the amplitude of the low signal by x10 or even 100 times (big amp), then the signal ends up in your crossover for dividing the frequencies + adjust levels due to different drivers sensitivity, and finally ends up at the driver chosen to reproduce that frequency range. The speaker then transform the analog electrical signal into air pressure waves, or sound and send those out in the room. In my experience, and its easy to measure, it is the room who alters/changes the sound reproduction the most, second your speakers/crossovers. Those two are able to mess up your frequency vs amplitude with +/- 20 db (room) and often +/-8 db nonlinearity in the speaker. Your music source and any decent amplifier, any normal brand, have linearity of +/- 0.5 dB (CD) and maybe +/-1 dB for the amp. Same with distortion, your speaker puts easily 2-3% distortion to your sound, a subwoofer maybe 8%, and again, the source adds 0.05% and maybe 0.5% for the amp. Maybe not the "audiophile" reply you where hoping for, but still true.
Here is how to fix it: You say that some parts of the frequencies sound harsh or hissed, this tells me that some higher midrange have ugly peaks in response (level). Buy or borrow something to converts your signal from time domain to a representation in the frequency domain, (FFT) so you can measure the room response and your speakers. Just search on this forum, a umic and a laptop with REW is a very good solution, but a excel sheet and a radio shack Db level meter, pluss tone generator will work (for amplitude problems, not phaze).
Buy some spare resistors and condensators, measure and test with different resistors and x-over frequency, polarity and speaker placement. Get rid of, or smoothen the peaks between 100 and 2000 Hz, leave the dips for now. Now it will sound much better already. (lazy version: if the crossover freq looks good and you only have small peaks you can fix it with a good parametric equalizer🙂 try to only decrease level on the eq, not boost) If you have a dedicated listening spot, experiment with some sound absorbers covering 1.st refeflections (first wall the sound hits before your ears).
So the answer to which amp you should buy is really simple, buy a amp that can deliver rated power into the lowest impedance your speakers has between 30-15000Hz, second is just how loud you want to play. With those speakers (i love them by the way, had to google them, this was back when Klipch and JBL and other US brands research made hifi into what it is today) I would go for a powerfull amp, say average output +/-50 volt sinus, unclipped in a 8 ohm load, but thats taste, I play loud. Good luck🙂 best regards Simon.
Seen from a purely scientific or analog design perspective you are, most likely, barking up the wrong tree. Take a look at the pieces of equipment that is very often in use to play back music: a music source which provide the music signal, an amplifier to increase the amplitude of the low signal by x10 or even 100 times (big amp), then the signal ends up in your crossover for dividing the frequencies + adjust levels due to different drivers sensitivity, and finally ends up at the driver chosen to reproduce that frequency range. The speaker then transform the analog electrical signal into air pressure waves, or sound and send those out in the room. In my experience, and its easy to measure, it is the room who alters/changes the sound reproduction the most, second your speakers/crossovers. Those two are able to mess up your frequency vs amplitude with +/- 20 db (room) and often +/-8 db nonlinearity in the speaker. Your music source and any decent amplifier, any normal brand, have linearity of +/- 0.5 dB (CD) and maybe +/-1 dB for the amp. Same with distortion, your speaker puts easily 2-3% distortion to your sound, a subwoofer maybe 8%, and again, the source adds 0.05% and maybe 0.5% for the amp. Maybe not the "audiophile" reply you where hoping for, but still true.
Here is how to fix it: You say that some parts of the frequencies sound harsh or hissed, this tells me that some higher midrange have ugly peaks in response (level). Buy or borrow something to converts your signal from time domain to a representation in the frequency domain, (FFT) so you can measure the room response and your speakers. Just search on this forum, a umic and a laptop with REW is a very good solution, but a excel sheet and a radio shack Db level meter, pluss tone generator will work (for amplitude problems, not phaze).
Buy some spare resistors and condensators, measure and test with different resistors and x-over frequency, polarity and speaker placement. Get rid of, or smoothen the peaks between 100 and 2000 Hz, leave the dips for now. Now it will sound much better already. (lazy version: if the crossover freq looks good and you only have small peaks you can fix it with a good parametric equalizer🙂 try to only decrease level on the eq, not boost) If you have a dedicated listening spot, experiment with some sound absorbers covering 1.st refeflections (first wall the sound hits before your ears).
So the answer to which amp you should buy is really simple, buy a amp that can deliver rated power into the lowest impedance your speakers has between 30-15000Hz, second is just how loud you want to play. With those speakers (i love them by the way, had to google them, this was back when Klipch and JBL and other US brands research made hifi into what it is today) I would go for a powerfull amp, say average output +/-50 volt sinus, unclipped in a 8 ohm load, but thats taste, I play loud. Good luck🙂 best regards Simon.
My home made 4333a with Nelsons crossover love my passlabs 150.5.
I've tried smaller first watt 25w class a amps, and it is really good.
You don't need or want more power unless your deaf.
But the bigger amp has extended response in both directions and an extra level of control over the bass driver.
I've tried smaller first watt 25w class a amps, and it is really good.
You don't need or want more power unless your deaf.
But the bigger amp has extended response in both directions and an extra level of control over the bass driver.
I'm not knocking the Ncore, just not my style, I debated even typing the brand. It's the only amp that hissed, my other amp is dead silent. I believe there is an issue with that amp so I returned it to the manufacturer.
I can get some measurements next time I have a quiet house. My room could not be worse. 24 foot ceilings, 20ft wide, 35 ft long into the kitchen, entire right wall is glass that slides open. The horns throw that sound perfect to the kitchen, you know, where everyone actually hangs out.
The 2405 and 2420 have attenuators, set to Harmon house curve.
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Sounds like it's an issue with that particular module as NCores are exceptionally quiet, drive low Z fine and low distortion as verified at ASR.
Thank you.
Ever tried a Krell, Conrad Johnson, Levinson, Threshold, Mac? I'm eyeballing a lot of the super nice 90's SS amps. The problem is the shipping/weight.
sorry no i havent.
im super happy with what i have so spending more money to chase a possibly illusive 5% improvement doesnt work for me.
im super happy with what i have so spending more money to chase a possibly illusive 5% improvement doesnt work for me.
I know a guy who runs an old Marantz 1060 amp with those in a relavite big space. That is a vintage 30w class AB transistor amp with a linear psu. A modern equivalent could be the relative cheap Marantz PM5005 or similar amplifiers from Yamaha, Denon and the likes.
Those speakers are 92dB sensitive i read in the specs, so i guess any +16w amp should be enough and the specs say max 75W (And JBL specs are accurate). Tube amps should work also, class D is hard to say as they were made with class AB in mind i think (back in the days (mid 1970's) when class D was still bad) and those speakes are often requiring higher Rout than class D can give which can lower the bass response with modern class D amps.
So i think a well build class AB with linear PSU will be your best guess.
Edit: a simple testing method to test if that is the issue, is adding a 5Ohm high wattage resistor (at least 20w, preferable more) in series with the + of the speaker and see if the sound is better. It will lower the volume and is not safe on long term, but it can show you if the low Rout of your amp is the issue. If the sound is better use an AB or even better a class A or tube amp without the resistor and it will sound better.
Those speakers are 92dB sensitive i read in the specs, so i guess any +16w amp should be enough and the specs say max 75W (And JBL specs are accurate). Tube amps should work also, class D is hard to say as they were made with class AB in mind i think (back in the days (mid 1970's) when class D was still bad) and those speakes are often requiring higher Rout than class D can give which can lower the bass response with modern class D amps.
So i think a well build class AB with linear PSU will be your best guess.
Edit: a simple testing method to test if that is the issue, is adding a 5Ohm high wattage resistor (at least 20w, preferable more) in series with the + of the speaker and see if the sound is better. It will lower the volume and is not safe on long term, but it can show you if the low Rout of your amp is the issue. If the sound is better use an AB or even better a class A or tube amp without the resistor and it will sound better.
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Thank you waxx! I'm trying to further understand your comment. I have read it slowly 5 times now and googled a bit. After a couple drinks last night I determined it was best to revisit in the morning....
The Marantz is a good looking and very affordable piece. This is my main system and I'm being a bit more showy with it. I've always wanted separates, could never afford them. I love tinkering and playing with different gear. I also love comments like this that drop little knowledge bombs in them you have to figure out.
I'm trying to understand "those speakers are often requiring higher Rout than class D can give". Do you simply mean a high-current versus low-current amplifier? Circlotron and tubes are high current versus class D low-current? How does one determine this when speaker/amp matching? Speaker impedance graph?
https://www.easytechjunkie.com/what-is-a-high-current-amplifier.htm
"A high-current amplifier's value only becomes clear with a basic understanding of what makes up power. The signal that an amplifier delivers, usually expressed in watts, is made up of a combination of voltage and amperage. Voltage measures how much "pressure" the power flow has while amperage measures how many electrons are actually flowing down the wire in a given period of time. Calculating wattage is done by multiplying the voltage by the amperage. For example, while a low-current amplifier may generate 100 watts by sending 4 amps of current down the wire at 25 volts, a high-current amplifier would send 16 amps of current at 6.25 volts.
Impedance is the key variable in determining whether or not a high-current amplifier will work best in a given situation. Typically measured in ohms, impedance measures how much a speaker resists a signal that is sent to it. Speakers with lower impedance require a higher current power supply, while speakers with higher impedance demand relatively less current and relatively more voltage. A sound system with low impedance speakers will typically benefit from a high-current amplifier.
Low impedances typically occur in two situations. The first is with high-end speakers, many of which, such as large electrostatic "ribbon" speakers, are designed specifically with low impedance. It also occurs when many speakers get connected to one amplifier channel. Two speakers with 8-ohm impedances, which is the norm for consumer-grade home electronics, connected in series will present a 4-ohm impedance to the amplifier. Connection of multiple speakers to a single amplifier channel is also a frequent occurrence in public address (PA) systems."
Rin and Rout of an inverting amplifier:
http://www.ittc.ku.edu/~jstiles/412...and Ro of the Inverting Amplifier lecture.pdf
Thanks
it's indeed a high current amp, as high current amps mostly have a higher output impendance before the conversion to speaker impendance. Class D is a pure voltage amplifier, while with transistors and tubes it's more a mixed current/voltage amplificiation i though.
And a linear psu is mainly because most smp's in commercial amps can't deliver the current (for "cutting costs reasons" mostly, not technical). If you have an overbuild SMPS that won't matter, but in most amps the SMPS is the limiting factor.
And a linear psu is mainly because most smp's in commercial amps can't deliver the current (for "cutting costs reasons" mostly, not technical). If you have an overbuild SMPS that won't matter, but in most amps the SMPS is the limiting factor.
Adcom GFA-555 II ...Classic design, overbuilt, quiet...clean, I think it a good choice for your rebuilt classic monitor.
-------------------------------------------------------------------------------------------------------------------------------------------Rick...
-------------------------------------------------------------------------------------------------------------------------------------------Rick...