JL Sargent Posted October 30, 2014 Author Share Posted October 30, 2014 Carl, that sounds great. I do appreciate it. Looking forward to our visit next month. Quote Link to comment Share on other sites More sharing options...
mark1101 Posted October 31, 2014 Share Posted October 31, 2014 (edited) I have a pair of those round Jabo horns with JBL 2441 2" drivers that I'm using in a two way active setup in my basement. This horn/driver combination is so revealing that I want to try a quieter amp (been using various tube amps mostly) with these horns. Maybe a digital offering like a T amp or that Emotiva mini, etc. Wattage doesn't have to be a whole lot either. I suspect 20w per channel a plenty. The main concern is keeping the noise as low as possible. For example: 10% THD at rated output not ok. Any thoughts appreciated. Active.....hmm........and you have noise. Can I ask if the amps you are using have gain controls? If you have an active system and can't reduce the gain on your amps, and are using your processor to do this, you are going to get noise. Changing amps won't fix it. Edit.........to qualify that.........changing amps won't fix it unless you don't have gain controls and you change the amps to amps with gain controls. Then you should be able to dial out the noise if the amps are half way decent. Edited October 31, 2014 by mark1101 1 Quote Link to comment Share on other sites More sharing options...
JL Sargent Posted October 31, 2014 Author Share Posted October 31, 2014 Hey Mark, I have mostly used old tube amps with no gain control with 3 different active crossovers, Rane 22, Beringer processor that Dave modified to have a tube stage. Some other one I can't name. On the amps I recently tried a cheap little digital 5w per job with a gain control and realized a better performer in this direction might make me happy. That's how we got here. I think you are right on about the gain control. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted October 31, 2014 Share Posted October 31, 2014 My Indeed has a gain control. I'll be curious as to how it works for you. 1 Quote Link to comment Share on other sites More sharing options...
mark1101 Posted October 31, 2014 Share Posted October 31, 2014 Basically, you want the processor to be a "gain pass through"..........you do not want to add or subtract gain in the processor ideally. Of course there are controls that let you do this and temp users to use it as a "volume" control for amps with no gain controls. This is where you can go wrong and create a noise issue. Amps without gain controls should never be used in an active crossover system. It's as simple as that. The most important point about digital processors is that you hit them with the correct signal level. Too low a signal level into the digital processor is the kiss of death. Then..........open the gains on your amps only as much as needed to play as loud as you would ever normally listen. In my case I make sure That I am REALLY USING my preamp to its max and only using the amps to the min. That's the trick to avoid noise. With no gain controls you are forced to use the processor to lower the output which reduces the signal level into the amp and the S/N ratio...........and the amps are wide open hissing away in the first place. It's just makes matters worse. Try this.........Put on some tunes........Set the gains in the processor to 0. Turn your amp gains completely off. Turn the preamp to about 75% of its range.......almost pegged. Now raise the gains of your amp till its as loud as you would ever listen. Hopefully, it's not distorting. If it is, lower the preamp just a hair until it is not distorting. Then, repeat raisin the amp gains till its as loud as you would normally listen. I bet you don't even go to 30-40% of the range of the knobs. You can then tweek as needed to understand exactly how much preamp you can use before it distorts. Use the max you can.........and the least amount of amp you can. That should give you the lowest noise. Another issue is that some processors (in fact most I've used) are not really preamp volume control friendly. In other words they oeprate best at one input level..........lower the volume significantly on the preamp and the S/N drops. You can usually hear the system dynamics drop slightly. Basically, I listen in a pretty narrow range of preamp volume settings on my system. It's just a sweet spot my processor prefers that produces the best sound. 1 Quote Link to comment Share on other sites More sharing options...
JL Sargent Posted October 31, 2014 Author Share Posted October 31, 2014 That's good stuff right there. I will try that! Certainly makes sense too. Mrtie said he would get the Emotiva amp out to me today. I will report back my results after I get it. Quote Link to comment Share on other sites More sharing options...
Coytee Posted October 31, 2014 Share Posted October 31, 2014 I agree with everything Mark has said. I had lots of hiss issues in the beginning. I was using a McIntosh MC-2102 with a dbx BX1. The dbx had an input sensitivity (if I recall) of 1V and I think the Mac was 2.25'ish? I matched them in the active. I could never get away from the hiss unless I drowned it out. Today, with the Crown's, it's virtually dead silent. I started with everything off. Went to the Crown's and turned them on at full gain. Reduced the gain until I couldn't hear any hiss (around 50% mark). Turned on the next item and went through the process. Now I know that for normal listening, I can have the crowns around 25% of their gain and this allows my preamp to go to "full" volume if I want it a bit loud (not deafening loud I might add) and the active is reacting nicely. If Mark comes over and I want to drown him out, then I just bump the gains on the Crown's until he cries uncle. 2 Quote Link to comment Share on other sites More sharing options...
JL Sargent Posted October 31, 2014 Author Share Posted October 31, 2014 Certainly this pre/amp handshake is more critical than I realized. It might be that Marks suggestion will yield as much noise reduction as the quieter amp! I have really enjoyed the musical nature of these horns but the noise between tracks has been too much for me. I'm excited about improving on this. Quote Link to comment Share on other sites More sharing options...
mark1101 Posted October 31, 2014 Share Posted October 31, 2014 (edited) I'm not aware that Emotiva even makes a unit with gain controls. In fact, I have heard a lot of people complain about hiss on Klipsch speakers with Emotiva.....due to their high gain design philosophy. I would avoid Emotiva......seriously. Edit: To be clear in my above post.......when I said to set the processor to 0.......I meant no gain/no attenuation......right in the middle where it does nothing. Edited October 31, 2014 by mark1101 Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted October 31, 2014 Share Posted October 31, 2014 I'm not aware that Emotiva even makes a unit with gain controls. YEP Quote Link to comment Share on other sites More sharing options...
JL Sargent Posted October 31, 2014 Author Share Posted October 31, 2014 I'll have some first hand experience before too long. Quote Link to comment Share on other sites More sharing options...
russ69 Posted November 1, 2014 Share Posted November 1, 2014 (edited) I've had some luck using a pad (attenuator) between the pre-amp and amp. You only need about 3 or 6 db in most cases with normal efficiency loudspeakers. They are a lot cheaper than buying a new amp. Edited November 1, 2014 by russ69 Quote Link to comment Share on other sites More sharing options...
JL Sargent Posted November 1, 2014 Author Share Posted November 1, 2014 Thanks Russ, but the recommendations have been to use MAX preamp with MIN amp. Your suggestion is just the opposite of that adding additional attenuation between those two. I suspect the problem is mostly about noisy amps anyway. Quote Link to comment Share on other sites More sharing options...
russ69 Posted November 1, 2014 Share Posted November 1, 2014 Thanks Russ, but the recommendations have been to use MAX preamp with MIN amp. Your suggestion is just the opposite of that adding additional attenuation between those two. I suspect the problem is mostly about noisy amps anyway. I think it's the same thing? I have had very good success with this on various systems and all 5 of my systems are dead quiet. Here's a linky: http://www.upscaleaudio.com/a-discussion-about-idle-hiss/ Quote Link to comment Share on other sites More sharing options...
Marvel Posted November 1, 2014 Share Posted November 1, 2014 Thanks Russ, but the recommendations have been to use MAX preamp with MIN amp. Your suggestion is just the opposite of that adding additional attenuation between those two. I suspect the problem is mostly about noisy amps anyway. I think it's the same thing? I have had very good success with this on various systems and all 5 of my systems are dead quiet. Here's a linky: http://www.upscaleaudio.com/a-discussion-about-idle-hiss/ That's what I was thinking, too. Most amps have their gain settings on the very front end, which would be the same. Bruce Quote Link to comment Share on other sites More sharing options...
JL Sargent Posted November 2, 2014 Author Share Posted November 2, 2014 That article is good read. Thanks. Quote Link to comment Share on other sites More sharing options...
NBPK402 Posted November 2, 2014 Share Posted November 2, 2014 I got the Topping T chip amps up and running in my Bi-amp setup with the Yamaha P2500s amps and the MiniDSP 2x4s... They are doing a great job! Quote Link to comment Share on other sites More sharing options...
JL Sargent Posted November 2, 2014 Author Share Posted November 2, 2014 I got the Topping T chip amps up and running in my Bi-amp setup with the Yamaha P2500s amps and the MiniDSP 2x4s... They are doing a great job! That's good to hear. It's kind of amazing that a amp so small can sound good. Where did you buy those? 1 Quote Link to comment Share on other sites More sharing options...
NBPK402 Posted November 2, 2014 Share Posted November 2, 2014 I got the Topping T chip amps up and running in my Bi-amp setup with the Yamaha P2500s amps and the MiniDSP 2x4s... They are doing a great job! That's good to hear. It's kind of amazing that a amp so small can sound good. Where did you buy those? I bought mine from Amazon.com. Quote Link to comment Share on other sites More sharing options...
JL Sargent Posted November 4, 2014 Author Share Posted November 4, 2014 I installed the Emotiva mini in my system driving the two Jabo horns and it has made a remarkable improvement. There is no audible noise at my normal listening level. I also set it all up per Marks recommendations and I have a very quiet system now. Thanks for all the great tips/suggestions. I have some Jack Johnson playing right now and for the first time it is quiet between tracks! Quote Link to comment Share on other sites More sharing options...
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