amp problem peavey 2600

[gharbud]

hi all, i am using a peavey 2600 amp to power 2x jbl twin speakers which are rated at 400w rms, when using this amp i get the signal lights come on when im at half volume on the mixer and then when i get to just over 0db on mixer the ddt lights on amp will start to flicker??? but when i use my kam kxr1500 amp i never get any signal lights or peak lights to come on atall even at nearly full volume, just seems a bit strange as both these amps are only 2months old and the peavey was nearly triple the price of the kam one, i dont know wether i am damaging anything or not when using the peavey amp

thanks graham

[mattydinx]

the DDT lights indicate the limiter is kicking in, this may simply be due to the fact you're sending a signal over 0dB from the mixer, and the amp (some are sensitive like that)

Have you tried running the amp with the gain on full, and set the volume level with the master fader on your mixer? - Do the DDT lights light up before the mixer reaches 0dB in this scenario?

The limiter is in place to protect your speakers, as long as it's loud enough for purpose I wouldn't worry too much.

[Booche]

I'm taking it that you have the volume on full on the amp and then just adjusting it on the mixer ?

If so have you got a gain control on your mixer ? again if so check that that isn't set to high as for some reason mines the same (PV1500) if the gain on my mixer (Citronic 10:4 mk 4) is quite high up the clip lights seem to flash :eek:

The only reason i noticed it was the gain was my son managed to turn it up (4yr old Dj in training :P)

Other then that im out so maybe someone else could help

[Creature]

the peavey amp is also 200 watt a channel more than the kam one - not sure if this would show up more.

The peavey clip lights are a lot more sensitive than teh kam ones but then thats a good thing.

as above set amp volume/gain to full

if your mixer has a gain try at around 10 oclock and should be ok as well as loud enough.

if im doing general music my gain on mixer is at 12 oclock but if i am playing rock music the gain is reduced to 10 ok.

as Booche asks what mixer are you using

[Andy Goodtimes]

It is important to get the gain structure right and the Peavey is a bit over sensative anyway, my mixer in particular has a very high output sensativity and I have to lower the little pot on the rear of the mixer in order to get output and input sensativity something like matching.

[TONYTIGER]

It is important to get the gain structure right and the Peavey is a bit over sensative anyway, my mixer in particular has a very high output sensativity and I have to lower the little pot on the rear of the mixer in order to get output and input sensativity something like matching.

I may be wrong but a lot of gear from USA has 2.5mv compared to 0.75mv input sensativity as in the UK.

[gharbud]

thanks for the replys guys, on my mixer i dont have a gain control wel i dont think i do, im using the behringer 1622fx only the mic input channels have a gain control, i use the four stereo ones and this doesnt have it, if anybody else uses this mixer help would be appreicated thanks

[Excalibur]

thanks for the replys guys, on my mixer i dont have a gain control wel i dont think i do, im using the behringer 1622fx only the mic input channels have a gain control, i use the four stereo ones and this doesnt have it, if anybody else uses this mixer help would be appreicated thanks

Errrr, I'd think from memory ( cos the piccies on the manual are hard to read ) the Berry is overrun with gain controls. I've got an older powered model, but pretty similar.

[csg]

I may be wrong but a lot of gear from USA has 2.5mv compared to 0.75mv input sensativity as in the UK.

0.75mV? err, no, thats less than many phono cartridges

-10dBU, considered to be domestic equipment line level signal is approx. 775mV

most pro gear operates at +4dBU, equating to roughly 2.5V, that is where our confusion might be coming from.

Anyhow, to get back onto subject, it is simply a question of gain structure, and the differences in the limiting and clip sensing circuits between the two amplifiers.

With out doubt, the peavey will have superior limiting and clip sensing circuits, and DDT is known to be one of the best clip limiting circuits found in amps at any price level. The fact that you have the DDT leds flickering simply shows that you have run out of headroom and are reaching the limits of what the amp can deliver.

If, at this operating level, your speakers remain distortion free, and you have enough volume, then you have no issues. The DDT circuit will continue to do its job, protecting both your amp and your speakers.

If you find yourself running out of level and having to push things to the point where the DDT lights are on a lot of the time, then at this point your sound quality will start suffering as the compression from the DDT circuit reduces your dynamic range. At this time, it will be time to look at larger amplifiers and / or a louder speaker system ( which has little to do with "how many watts it is....)

The reasons as to why the Kam amp peak indicator lights are not indicating at similar levels could be several:

1) the Kam has more available headroom, and is able to actually deliver more real world power into the load ( speaker impedance) that you are operating at

2) the Kam has a lower input sensitivity, requiring more voltage drive from your mixer to reach the clip point of the amplifier

3) The Kam has peak limiters that respond to clipping in a different way to the Peavey - i.e. they may be referenced to respond to 1% distortion rather than ay 0.1%

Anyway you look at it, the subject of gain structure is a big subject that audio engineers ( of which i am one of 18 years standing) take a long time to perfect.

Put simply

1) adjust your input gain controls on your mixer that, with the PFL for that channel enabled, the music source drives the input stage to around) dB on your VU meters

2) Adjust your master section so that your mixers output VU's read around 0dB

3) Bring your amp attenuators up to the point were you have sufficient volume for what ever job you are doing ( sufficient meaning enough for the loudest part of the evening)

4) back your master off on the mixer to give you a suitable volume for starting the night.

hope that helps, any questions, throw them my way!

[TONYTIGER]

0.75mV? err, no, thats less than many phono cartridges

-10dBU, considered to be domestic equipment line level signal is approx. 775mV

most pro gear operates at +4dBU, equating to roughly 2.5V, that is where our confusion might be coming from.

Anyhow, to get back onto subject, it is simply a question of gain structure, and the differences in the limiting and clip sensing circuits between the two amplifiers.

With out doubt, the peavey will have superior limiting and clip sensing circuits, and DDT is known to be one of the best clip limiting circuits found in amps at any price level. The fact that you have the DDT leds flickering simply shows that you have run out of headroom and are reaching the limits of what the amp can deliver.

If, at this operating level, your speakers remain distortion free, and you have enough volume, then you have no issues. The DDT circuit will continue to do its job, protecting both your amp and your speakers.

If you find yourself running out of level and having to push things to the point where the DDT lights are on a lot of the time, then at this point your sound quality will start suffering as the compression from the DDT circuit reduces your dynamic range. At this time, it will be time to look at larger amplifiers and / or a louder speaker system ( which has little to do with "how many watts it is....)

The reasons as to why the Kam amp peak indicator lights are not indicating at similar levels could be several:

1) the Kam has more available headroom, and is able to actually deliver more real world power into the load ( speaker impedance) that you are operating at

2) the Kam has a lower input sensitivity, requiring more voltage drive from your mixer to reach the clip point of the amplifier

3) The Kam has peak limiters that respond to clipping in a different way to the Peavey - i.e. they may be referenced to respond to 1% distortion rather than ay 0.1%

Anyway you look at it, the subject of gain structure is a big subject that audio engineers ( of which i am one of 18 years standing) take a long time to perfect.

Put simply

1) adjust your input gain controls on your mixer that, with the PFL for that channel enabled, the music source drives the input stage to around) dB on your VU meters

2) Adjust your master section so that your mixers output VU's read around 0dB

3) Bring your amp attenuators up to the point were you have sufficient volume for what ever job you are doing ( sufficient meaning enough for the loudest part of the evening)

4) back your master off on the mixer to give you a suitable volume for starting the night.

hope that helps, any questions, throw them my way!

Sorry missed the 7 out easy done but what i said now checked with some one who knows better than me and i was correct.

[csg]

absolutely, easily done, just 1000 times the difference!

cheers
chris