no spike protection allowed

tryonziess · 11th May 2007, 04:58 PM

is there a good quality high powered chip amp without internal spike protection which i could use in a 250 watt output project.

drummer_Dave · 11th May 2007, 05:29 PM

I'm not trying to be rude or anything, but what is your reasoning for not wanting spike protection? you could use several lm3886 or lm4780 in bridge and or series configurations to get up to your power requirements, but they still have spike protection. I am very interested to find out what you are planning here.

here's a link to a very nice project

BPA300 Eagle File .BRD - No Catches

good luck

jackinnj · 11th May 2007, 06:47 PM

OPA549 from Texas Instruments -- bridge two of these -- note that most chipamps have some kind of current protection -- amplifier chips want good heatsinking.

you could also use an LM4702 and parallel some HexFETs -- but you need to get the bias up to a couple of volts (or use Lateral MOSFETs) -- somewhere I posted a schematic from an article that Borbely wrote up for audio amateur.

BWRX · 11th May 2007, 07:07 PM

Quote:

Originally posted by drummer_Dave
here's a link to a very nice project

BPA300 Eagle File .BRD - No Catches

It has potential to be a nice project. There were a lot of problems with the first design posted by DJexprice.

tryonziess · 12th May 2007, 09:24 PM

i have noticed fluctuations on the scope when certain low frequency music is playing are similar to the fluctuations when the 3886 is clipping. i just wanted to rule out the possibility that spike might be coming on when it is not needed to protect the chip. i do not know enough about this subject to explain this phenomenon other than trial and error. substituting and observing are my best methods at this time

jackinnj · 13th May 2007, 01:33 PM

Quote:

Originally posted by tryonziess
i have noticed fluctuations on the scope when certain low frequency music is playing are similar to the fluctuations when the 3886 is clipping. i just wanted to rule out the possibility that spike might be coming on when it is not needed to protect the chip. i do not know enough about this subject to explain this phenomenon other than trial and error. substituting and observing are my best methods at this time

What was the thermal impedance of the heat sink you were using? (or can you give us an idea of its approximate surface area).

tryonziess · 13th May 2007, 05:52 PM

the area of copper was 5x12 inches 1/2 inch thick with 11 5x1 fins. the sink temperature never reached 100 f. the only fluctuations occured at roughly 80hz and below into a 12 inch woofer. actual volume was quite "loud". no more specifics since i would not no what to look for. i am only following a hunch that spike might be a little hasty in its activation. it could be something else, but i have good clean response until these parameters come together. this is a new endeavor and i am learning as i go.

11th May 2007, 04:58 PM	#1
tryonziess diyAudio Member Join Date: Apr 2007	no spike protection allowed is there a good quality high powered chip amp without internal spike protection which i could use in a 250 watt output project.

12th May 2007, 09:24 PM	#5
tryonziess diyAudio Member Join Date: Apr 2007	why no spike i have noticed fluctuations on the scope when certain low frequency music is playing are similar to the fluctuations when the 3886 is clipping. i just wanted to rule out the possibility that spike might be coming on when it is not needed to protect the chip. i do not know enough about this subject to explain this phenomenon other than trial and error. substituting and observing are my best methods at this time

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
OPT Voltage spike protection with zeners	bigwill	Tubes / Valves	8	17th July 2009 04:24 AM
How much ripple on B+ is allowed?	Rundmaus	Tubes / Valves	11	16th October 2005 02:19 AM
Anyone use these Spike Feet?	m1abrams	Multi-Way	2	22nd July 2004 06:54 PM
Blackgate Super-E configuration! Polarized cap allowed?	w00t	Chip Amps	1	20th June 2004 07:40 AM
How much DC offset allowed in headphone amp?	jwb	Headphone Systems	2	5th August 2003 11:15 AM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

11th May 2007, 05:29 PM	#2
drummer_Dave diyAudio Member Join Date: Oct 2006	I'm not trying to be rude or anything, but what is your reasoning for not wanting spike protection? you could use several lm3886 or lm4780 in bridge and or series configurations to get up to your power requirements, but they still have spike protection. I am very interested to find out what you are planning here. here's a link to a very nice project BPA300 Eagle File .BRD - No Catches good luck

11th May 2007, 06:47 PM	#3
jackinnj diyAudio Member Join Date: Apr 2002 Location: Llanddewi Brefi, NJ	OPA549 from Texas Instruments -- bridge two of these -- note that most chipamps have some kind of current protection -- amplifier chips want good heatsinking. you could also use an LM4702 and parallel some HexFETs -- but you need to get the bias up to a couple of volts (or use Lateral MOSFETs) -- somewhere I posted a schematic from an article that Borbely wrote up for audio amateur.

13th May 2007, 05:52 PM	#7
tryonziess diyAudio Member Join Date: Apr 2007	the area of copper was 5x12 inches 1/2 inch thick with 11 5x1 fins. the sink temperature never reached 100 f. the only fluctuations occured at roughly 80hz and below into a 12 inch woofer. actual volume was quite "loud". no more specifics since i would not no what to look for. i am only following a hunch that spike might be a little hasty in its activation. it could be something else, but i have good clean response until these parameters come together. this is a new endeavor and i am learning as i go.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)