New Amplifier - ULD Extreme

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#261
Hi all, I have decided to use 5 amps per speaker to keep the amps running into 4 Ohms. The input will be line level outs from my Rotel RSX-1058.

I need a x-over at 500Hz with a slope of 6dB. Can I use the input section of the amps to achieve this? I assume I will need a buffer of some type to enable one line level to run 5 amps. Any suggestions would be welcome.

Thanks

Terry
 
#263
pheonix358 said:
Hi all, I have decided to use 5 amps per speaker to keep the amps running into 4 Ohms. The input will be line level outs from my Rotel RSX-1058.

I need a x-over at 500Hz with a slope of 6dB. Can I use the input section of the amps to achieve this? I assume I will need a buffer of some type to enable one line level to run 5 amps. Any suggestions would be welcome.

Thanks

Terry
Click to expand...


Terry
Line out of the Rotel to one of these http://www.altronics.com.au/index.asp?area=item&id=K5570 then into the amps.
jaycar should have them too.


Using 2 or 3 way speakers?
Remember It takes more power to drive woofers than it does tweeters.
eg 100watt for woofers, then approx 15watt for tweeters.
This depends on the efficiency of the drivers ie 88db woofers, 92db tweeters

allan
ps these numbers were just quest-a-met's, example.
 
#264
awpagan said:



Terry
Line out of the Rotel to one of these http://www.altronics.com.au/index.asp?area=item&id=K5570 then into the amps.
jaycar should have them too.


Using 2 or 3 way speakers?
Remember It takes more power to drive woofers than it does tweeters.
eg 100watt for woofers, then approx 15watt for tweeters.
This depends on the efficiency of the drivers ie 88db woofers, 92db tweeters

allan
ps these numbers were just quest-a-met's, example.
Click to expand...


Thanks Allan, these and most other similar kits have woefull specs. Using these amps and feeding them from a lower speced active is wasting the effort.

SC this month has one that is better, and I may use it for the buffer section but I only need the active at 6dB slopes and for the design of the loudspeakers this will be much better than say 12 or 24dB.

Seems a pity to throw in multiple op amps in front of the ultra amp in this thread.

Any comments appreciated.

Terry
 
#265
awpagan said:



Terry
Line out of the Rotel to one of these http://www.altronics.com.au/index.asp?area=item&id=K5570 then into the amps.
jaycar should have them too.


Using 2 or 3 way speakers?
Remember It takes more power to drive woofers than it does tweeters.
eg 100watt for woofers, then approx 15watt for tweeters.
This depends on the efficiency of the drivers ie 88db woofers, 92db tweeters

allan
ps these numbers were just quest-a-met's, example.
Click to expand...


More info, the speakers are three way, the x-over mids to tweeters is at 5k and only uses one cap so it can stay as a passive. The x-over at 500Hz is the one I want to get rid of. Four amps will run the eight MW267 woofers and the last amp will run the Mids (MW144) and tweeter (MDT337) All drivers are Morel.
 
#267
awpagan said:
Terry
this maybe helpful
http://sound.westhost.com/bi-amp2.htm



As per crossover at 500Hz hmmm

I prefer not to crossover between 300Hz and 3kHz
Personal preference thing, to me it just seems the most audible zone.

allan
ps I'm not using active crossovers at present.
Click to expand...


Hi Allan, many people do not like crossing at these ranges, that is why I want 6dB slopes, the transfer from bass to mid becomes barely noticable due to both drivers operating and combining over a very large range.

Many of my designs crossed at these sought of points and all were successful in the market place. Since I am losing my vision these are likely to be my last set. They will be the best I can do.

Thanks for the link, I agree with most points raised but with the drivers I am using it is actually better to cross with shallow slopes at 500 Hz.

Terry
 
#268
awpagan said:

eg 100watt for woofers, then approx 15watt for tweeters.
This depends on the efficiency of the drivers ie 88db woofers, 92db tweeters
Click to expand...
Hi,
100W to 15W is a ratio of >8dB
The speaker drivers would need to be ~8dB different in sensitivity if of the same impedance. i.e. 88dB/W 8ohm bass to 96dB/W 8ohm tweeter.
or 88dB/2.8V 4ohm bass to 93dB/W 8ohm tweeter.
 
#269
AndrewT said:

Hi,
100W to 15W is a ratio of >8dB
The speaker drivers would need to be ~8dB different in sensitivity if of the same impedance. i.e. 88dB/W 8ohm bass to 96dB/W 8ohm tweeter.
or 88dB/2.8V 4ohm bass to 93dB/W 8ohm tweeter.
Click to expand...


The tweeter I am using is 94dB. The woofers when combined will give 96dB and the 4 mids will provide 93dB. The mids are 15 Ohm each for a total of 3.5 Ohm and in this system will need to be dropped back, probably with a single 0.5 ohm resister, that will bring them up to 4 Ohm. The mids fill in the middle really well. This is why I need 6dB slopes, it all integrates very well.

I have used these drivers together in a simpler system and it is great. Only uses 4 parts in the x-over.

In this new system the power available with 4 bass amps to 1 mid/tweeter amp will mean the bass amps have a very easy life with lots of head room.

Terry
 
#271
AndrewT said:
the treble benefits from lots of headroom as well.
Click to expand...


It most certainly does! Since the HF amp only handles 500Hz and above it should have oodles of headroom.

Can anyone help with 6dB filters for this amp. I would have thought it would be posssible using the input section of the amp. Am I wrong? I went through Wiki and didn't find anything on first order active.

Terry
 
#273
Back to the main thread (ULD Extreme)

SoundsGreat said:
Hi,



Am sorry if I said something wrong ! Yes what you say is to an extent true ! these sites can be bit painful at times !

Hope someone will offer you that much need space !

As for me,Am off to the PCB guy on monday to give the orders for the board 😀 ! cannot wait to finish it and hear :hphones: !!

Regards.
Click to expand...

This thread appears to be getting off track...
SoundsGreat, How is the progress of building the amp? all has been quiet for a while. I have been watching this thread with great anticipation...
 
#274
Hi,

SoundsGreat, How is the progress of building the amp? all has been quiet for a while. I have been watching this thread with great anticipation...
Click to expand...

Well what to tell ? I've hit a major road block :xeye: !! I wanted to check and buy off the components before ordering the PCB and was very sad to know that the main output devices are not at all available !! not only in my city but in the entire of India :bigeyes: !!

Damn :dead: !!! The FARNEL India site is saying coming soon from the god knows when,but still not sign of it :smash: !!

So from my end untill either I get that or some other alternative is recommended to me Am putting this on back burner, Very sad but cannot help it 🙁 !!

Was really looking forward to building this one but Alas !!!!!!!!!

Regards.
 
#276
Ok, As long as there is still enough interest I will cough up some cash for the first cut. Assuming some tweaking will be required for at least another cut.
Although I have some experience with the original amp & mods I am more of a speaker guy than an amp guy so I may need a little help in testing it thoroughly; I am in Alphington Vic which is just around the corner from AKSA, Hugh would you be able to offer some help in this department if I brought around a fully built prototype?
If anyone else is interested in some boards let me know and I will give you the cost details; Carl if you would like some boards let me know, my shout.
 
#277
Hi,

Tad thanks a tonne for the offer :djinn: !!!

Will surely let you know bout the same,my only worry is bout the shipping and customs (here we have terrible customs folks).So will see how much duty it attracts and such will get back to you.

Am very glad that you are ready to help 😀 !!

Regards.
 
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