derrenleepoole Posted August 12, 2010 Share Posted August 12, 2010 [quote name='Beedster' post='922350' date='Aug 12 2010, 09:26 AM']LOL, and you're the one talking of inaccurate conjecture? I'm with Bassbod on this, Class D have a hiss whilst older classes had other, and louder, noises to which we'd become accustomed. There is sufficient variability in component tolerances, even within models, for the hiss to be more pronounced on some individual amps than others. Furthermore, some people are more bothered by the hiss than others. When these people meet these amps, they post here.... Simples C[/quote] I think you missed my point there! That's NOT my point of view, but a view expressed by many others who assumed that because the amp is made by Ibanez, it's some how not high end. I'm with most people on this, and know from experience that amps hiss and the degree to which they hiss varies considerably. I personally don't hear a hiss on mine. I had an older SWR Workingman 10 combo and that practically screamed white noise out, so much so that I had to turn the tweeter off which still didn't help! Quote Link to comment Share on other sites More sharing options...
gafbass02 Posted August 12, 2010 Author Share Posted August 12, 2010 Ive managed to get a little more time with it and although its still bad enough that im still gonna try another ive worked out a few other issues that were contributing, a series of factors that have only caused this issue with this amp, but its still very noisy BUT i feel i should also say it sounds awesome, way better than the markbass imho. Very cool bit of kit indeed, despite a bit of hiss (on this one) Quote Link to comment Share on other sites More sharing options...
Faithless Posted August 12, 2010 Share Posted August 12, 2010 Can't tell about the hiss, but, ff anyone's after letting that Ibby PS combo go, I'd be tempted to buy it.. really struggling to find a used one.. easy Faith Quote Link to comment Share on other sites More sharing options...
synaesthesia Posted August 12, 2010 Share Posted August 12, 2010 All amplifiers have two stages of amplification, the preamp stage and the power amp stage. Both have signal to noise ratios. Typically for hi-fidelity audio you'd be looking at -85dB noise floor. Compound the two stages and the noise floor rises. Typically, the noise floor of MI (musical instrument) specific power amps are high. The class D modules tend not to be of the typical MI spec though the applications are MI. e.g. the B & O module is quite common amongst the tiny class D amps and are also used in higher than MI fidelity. The culprit is probably in the preamp, and if defective probably due to a hi filter section being faulty. The graphic EQ is a section that notoriusly contributes a higher noise level to the overall compound signal. If your unit has an efx loop, plug your instrument into the return and if the noise level is the same, then it is the power amp. If the noise level is lower, than it is the preamp section. Quote Link to comment Share on other sites More sharing options...
gafbass02 Posted August 12, 2010 Author Share Posted August 12, 2010 (edited) It definitely sounds like a preamp section/gain issue. Theres no fx loop on the amp tho, shame. Cheers though bud Against my better judgment ill be (CAREFULLY) using the amp and my LM2 BFB compact at cafe rene in gloucester tomorrow night (FRI 13th AUG) if anyone is curious. Edited August 12, 2010 by gafbass02 Quote Link to comment Share on other sites More sharing options...
deksawyer Posted August 12, 2010 Share Posted August 12, 2010 [quote name='Beedster' post='922147' date='Aug 11 2010, 11:17 PM']Hey mate, it's a Class-D amp, they hiss, full stop. It annoys some people whilst other seemingly don't notice it. Either way, I've returned two Class-Ds on that basis and won't own another until the technology has matured a little. C[/quote] Not quit true. My TecAmp Puma 500 has a Class D power section and it doesn't hiss, certainly no more so than any other amp I've owned. D. Quote Link to comment Share on other sites More sharing options...
escholl Posted August 13, 2010 Share Posted August 13, 2010 This is absurd, the hissing has nothing to do with amplifier class. That particular hissing is white noise, and if the level of hiss is dependent upon the preamp volume as was mentioned, then the hiss is very likely from the thermal noise generated by high value resistors early on in the signal path. Amplifiers do no hiss like that because they are a certain class, they hiss because they have gain and deal with real-world physics and components. Some amps are quieter than others simply because they may be better designed or use a higher grade of components. Quote Link to comment Share on other sites More sharing options...
gafbass02 Posted August 14, 2010 Author Share Posted August 14, 2010 Gigged it tonight, backline only in stereo with my LM2 and compact. ... ..... Christ!!! LOUD !! Pleased Gaf Quote Link to comment Share on other sites More sharing options...
wateroftyne Posted August 14, 2010 Share Posted August 14, 2010 Yay! Quote Link to comment Share on other sites More sharing options...
gafbass02 Posted August 14, 2010 Author Share Posted August 14, 2010 Didn't notice the hiss either. Quote Link to comment Share on other sites More sharing options...
EBS_freak Posted August 17, 2010 Share Posted August 17, 2010 [quote name='gafbass02' post='925279' date='Aug 15 2010, 12:33 AM']Didn't notice the hiss either.[/quote] Perhaps the snake was sleeping. Quote Link to comment Share on other sites More sharing options...
Toasted Posted August 17, 2010 Share Posted August 17, 2010 [quote name='Beedster' post='922147' date='Aug 11 2010, 11:17 PM']Hey mate, it's a Class-D amp, they hiss, full stop. It annoys some people whilst other seemingly don't notice it. Either way, I've returned two Class-Ds on that basis and won't own another until the technology has matured a little. C[/quote] Chris, My Markbass F500 doesn't hiss. Joe. Quote Link to comment Share on other sites More sharing options...
EBS_freak Posted August 17, 2010 Share Posted August 17, 2010 What happens if you take a DI? A lot of hiss can be due to noisy tweeters but when DIed or lined out, there is very little noise. I'm not familiar with the connectivity on Promethans though... Quote Link to comment Share on other sites More sharing options...
Toasted Posted August 17, 2010 Share Posted August 17, 2010 Te DI on my F500 is totall silent. I just plugged it in and listened through headphoes. Quote Link to comment Share on other sites More sharing options...
EBS_freak Posted August 17, 2010 Share Posted August 17, 2010 (edited) [quote name='Toasted' post='927206' date='Aug 17 2010, 09:09 AM']Te DI on my F500 is totall silent. I just plugged it in and listened through headphoes.[/quote] Enough said. Each amp has to be taken in turn. The success of the amps is all down to the design. The problem is that alot of class D amps are running off the shelf power stages which aren't that good for bass amp application. Even SWR spent a long time getting into the game and came out with an average at best solution. I'm not sold on class D yet but its all down to what you are trying to do with it. I'm not convinced that class D has the thump and low end response of more traditional amps but that's just me and what I can hear/feel. If you don't miss that, then class D is great. (and I know that there will be people who come back to this saying that class D absolutely wallops it out etc... but thats the point, it's opinion and hard to quantify. You can chuck all the science you want at me but those gigs I have played with class D, well, they just don't do it for me) I've heard great sounding class D and poor class D. Work out what works for you. Not all hiss, some do. Go figure. Edited August 17, 2010 by EBS_freak Quote Link to comment Share on other sites More sharing options...
Toasted Posted August 17, 2010 Share Posted August 17, 2010 It seems that proper coupling of the power section to the electrical input makes a lot of difference in these amps. It might even be the physical layout, I guess. Quote Link to comment Share on other sites More sharing options...
wateroftyne Posted August 17, 2010 Share Posted August 17, 2010 Hi folks Quick update from me - I used my combo on Saturday night with an acoustic band who are very dynamic (LOUD loud bits, lots of very quiet bits and lots of gaps of silence). The venue was a reasonable-sized room, and as it was a ticket do there was a 'listening' crowd, i.e. pin-drop silence in the quiet bits. No-one noticed any hiss from either the combo (which was being driven fairly hard) or the FOH via the DI. It did a great job. EBS - I know what you mean about the whole Class D thing. I sort-of feel the same way. The Acoustic Image head I owned sounded great, but there was no body or heft to the notes. The TC has changed my opinion, though - no-more diet bass for me. Quote Link to comment Share on other sites More sharing options...
derrenleepoole Posted August 17, 2010 Share Posted August 17, 2010 I'm gigging mine again on Sunday at a jazz/blues festival in Darwen, small to medium sized room I think. I'll try to take note of the sound properly and write up my experiences. I usually use mine with a Trace Elliot BLX 10" extension speaker too, just to give a bit more umph and headroom and don't DI We don't play loud anyway, but it's nice to have that extra speaker for a fuller tone. Quote Link to comment Share on other sites More sharing options...
Grand Wazoo Posted August 17, 2010 Share Posted August 17, 2010 I am loving my promethean, I find it a quality bit of kit actually. Quote Link to comment Share on other sites More sharing options...
Musicman20 Posted August 17, 2010 Share Posted August 17, 2010 [quote name='Grand Wazoo' post='928044' date='Aug 17 2010, 09:28 PM']I am loving my promethean, I find it a quality bit of kit actually.[/quote] How does it compare to the MB combo? Quote Link to comment Share on other sites More sharing options...
synaesthesia Posted August 17, 2010 Share Posted August 17, 2010 [quote name='EBS_freak' post='927202' date='Aug 17 2010, 09:03 AM']A lot of hiss can be due to noisy tweeters ....[/quote] False. tweeters add no noise, they reproduce a signal sent to it. Quote Link to comment Share on other sites More sharing options...
gafbass02 Posted August 17, 2010 Author Share Posted August 17, 2010 Hopefully I'll get my new one turned around soon. Typically today I got my OBBM cable for it, and the cab should arrive anyday and my combo won't be here :-/ cruel world!! Quote Link to comment Share on other sites More sharing options...
Grand Wazoo Posted August 18, 2010 Share Posted August 18, 2010 [quote name='Musicman20' post='928224' date='Aug 18 2010, 12:00 AM']How does it compare to the MB combo?[/quote] Well it's interesting you asked, because I plugged the prom head into the MB speakers and it sounded awesome, the MB head and the Prom one have slightly different sounds, but but once connected to larger speakers you can tell just how powerful and hi-fi this amp can be, I mean it is awesome as it is in it's small 1x10 combo but it does compromise a lot on the low side of things whereas when you let it breath through a bigger set of cones it does perform a lot better. All in all I am more than pleased, and thank you for suggesting it to me, originally I thought it was a bit dear, but then I went to try one and I had to get it. Quote Link to comment Share on other sites More sharing options...
Faithless Posted August 18, 2010 Share Posted August 18, 2010 I'll be definetly taking one of those PS5110's combos, when I get the money together.. Quote Link to comment Share on other sites More sharing options...
EBS_freak Posted August 18, 2010 Share Posted August 18, 2010 [quote name='synaesthesia' post='928233' date='Aug 18 2010, 12:11 AM']False. tweeters add no noise, they reproduce a signal sent to it.[/quote] ...and how the tweeters handle that signal can lead to hiss. Quote Link to comment Share on other sites More sharing options...
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