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Any of the channels with no out put will not be happy for long. All channels have their own switching amplifier and all channels need a load, unless bridged where 1&2 become 1 channel. The load helps the amp from building to much voltage and creating the magic white smoke.
Where are you getting this from? Solid-state amps are fine running with no load. If we were talking tube amps you would be correct.
Specifically, the 4180 would be perfectly happy running with 2 channels with zero load forever but it cannot be bridged. The SD 250.2 is only 85W per channel at 4 ohms (125W at 2 ohms) while the 4180 is 180W at 4 ohm (it's also stable at 2 ohms). I'd say the 4180 would be a better fit and give him more power and volume on those 6x9s. Certainly worth the try with nothing to lose.
Where are you getting this from? Solid-state amps are fine running with no load. If we were talking tube amps you would be correct.
Specifically, the 4180 would be perfectly happy running with 2 channels with zero load forever but it cannot be bridged. The SD 250.2 is only 85W per channel at 4 ohms (125W at 2 ohms) while the 4180 is 180W at 4 ohm (it's also stable at 2 ohms). I'd say the 4180 would be a better fit and give him more power and volume on those 6x9s. Certainly worth the try with nothing to lose.
ok. So question...would i be better off using the BT4180 for the spl 6.5s & horns up front off channels 1&2 and detachable tour pak 6.5s off 3&4? Then ditch the SD 250.2 and just bridge my SD 800.4 to the spl 6x9s in the lids? Would this be the correct wiring?
Where are you getting this from? Solid-state amps are fine running with no load. If we were talking tube amps you would be correct.
Specifically, the 4180 would be perfectly happy running with 2 channels with zero load forever but it cannot be bridged. The SD 250.2 is only 85W per channel at 4 ohms (125W at 2 ohms) while the 4180 is 180W at 4 ohm (it's also stable at 2 ohms). I'd say the 4180 would be a better fit and give him more power and volume on those 6x9s. Certainly worth the try with nothing to lose.
My 2 year degree in electronics along with a quick google search " Class D amplifiers should not run without load because the load is used to damp the LC output filter and prevent the filter-chokes from generating excessive voltages. Some class D amplifiers may survive running without a load, in particular if they are protected with catch-diodes. If a class D Amp has a input signal and amplifies it it has to have a load. No input load no harm no foul. Now where did you get your information?
First of all Jack I wasn't trying to get into a pissing contest with you but was trying to stop, or slow down, the spread of misinformation on this forum. Maybe you said what you said because you actually believe it to be true. Although I knew what you were saying was wrong (or at least very outdated) I did want to know where you were getting the info from.
Secondly, the google search you did was quick indeed. Everything you said in between talking about your 2 year degree and asking where I get my information came up on the first hit on my search...verbatim (see below). Read through the rest of that thread and do some more researching. You'll find what I'm saying to be true. A "switching amplifier" (aka a class D amp) is NOT going to go up in "magic white smoke" without speakers attached.
Third, let's remember the OP was asking about his particular amp in a particular application. A BT4180 will work just fine with 2 channels used and 2 channels unloaded (no speakers attached) and he'll get more power to those 6x9s by using it instead of the SD 250.2.
You don't actually believe that you can't have a 4 channel amp with only 2 channels used do you?
Class D Amp Google Search
My quick google search (properly credited):
Paul is founder of PS Audio. The TLDR part is 1:44-3:27:
ok. So question...would i be better off using the BT4180 for the spl 6.5s & horns up front off channels 1&2 and detachable tour pak 6.5s off 3&4? Then ditch the SD 250.2 and just bridge my SD 800.4 to the spl 6x9s in the lids? Would this be the correct wiring?
Currently, you have these horns and SPLs in parallel on ch 1&2 on the 800.4. What are you using for x-overs? Are you happy with the sound? Out of curiosity what model 800.4 do you have?
You won't need to split the front outputs to both amps as the 800.4 is only powering the 6x9 rears. The 6x9s are on the bridge connections for ch1/2 and ch3/4 (but I'm sure you know that). Otherwise, the wiring looks ok.
Currently, you have these horns and SPLs in parallel on ch 1&2 on the 800.4. What are you using for x-overs? Are you happy with the sound? Out of curiosity what model 800.4 do you have?
You won't need to split the front outputs to both amps as the 800.4 is only powering the 6x9 rears. The 6x9s are on the bridge connections for ch1/2 and ch3/4 (but I'm sure you know that). Otherwise, the wiring looks ok.
I'm using the diamond audio crossovers that came with the horns.
So just split the front rcas across the front and rear amp inputs on the BT4180 only? And the rear rcas only feed the rear rca inputs on the Soundigital 800.4. Correct? I have seen on YouTube where guys are bridging this sd800.4 with these hertz 690s. I'm assuming the gain has to be almost off for that not to blow them.
FYI, I ran a sound stream 4 channel amp for a year with only 2 channels. Many ppl here run 4 channel amps with only a pair of speakers and never upgrade to utilize the other 2 channels.
I'm using the diamond audio crossovers that came with the horns.
So just split the front rcas across the front and rear amp inputs on the BT4180 only? And the rear rcas only feed the rear rca inputs on the Soundigital 800.4. Correct? I have seen on YouTube where guys are bridging this sd800.4 with these hertz 690s. I'm assuming the gain has to be almost off for that not to blow them.
Well that's not what I was describing exactly but that would also work. The bottom line is you have a set of front channels and rear channels. If you want the SPL6.5/Horns and the 6.5s in the TP playing the front channels and only the 6x9s playing the rears then yes, what you describe is how you'd wire it. I thought you'd want the fronts only to be the SPL6.5/Horns and the rears to be both TP 6.5 and SPL 6x9s. That way when the TP was removed you'd still have the rear channels in the lids. Honestly, though there isn't a right way or wrong way to do this (rears get somewhat lost at speed anyway) but at least if you have both front and rears in play with or without the TP you can compensate somewhat using the fader when the TP is removed.
You will want to reset gains on both amps as the application will now be different. I would also recommend upping the x-over on the 6x9s as they will be getting significantly more power. It's big power at low freqs that cook speakers.
FYI, I ran a sound stream 4 channel amp for a year with only 2 channels. Many ppl here run 4 channel amps with only a pair of speakers and never upgrade to utilize the other 2 channels.
In fairness to Fireball I think he was thinking of when the amp would have active inputs and no speaker load ("No input load no harm no foul"). This would be the case with the TP removed. Even if you do have an active input when you have no speakers connected to that amp there will still be no current flow as there would be an open across the outputs.
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