Eti 480 trouble

Hayden · 11th August 2004, 06:43 AM

I’ve built an Eti 480 amp (not the best amp I know) the problem is that the output volume is low, when I turn up the input signal the amp gets to about 30% of its potential then its distorts. I have checked all the components if their in working order and if their in the right spots. I keep setting vr1 to get the right voltage but it keeps changing.
Can any one help? Are there any well known problems with this amp?

Thanks

Netlist · 11th August 2004, 03:14 PM

Hayden
Do you have a link to a schematic?

/Hugo

Netlist · 11th August 2004, 03:28 PM

Found it...
What happens to the rail voltages? Are they stable?

/Hugo

mikee12345 · 12th August 2004, 01:43 AM

The general consensus ive seen is -it was stable with Transistors available at its time of design but now,not so!

http://www.alphalink.com.au/~cambie/ETI480/ETI480.zip

http://www.alphalink.com.au/~cambie/

Hayden · 12th August 2004, 03:44 AM

rails are OK
drops about 5v when inputs are high

Centauri · 12th August 2004, 04:52 AM

Check voltage across zener ZD1 (should be about 5.6V) and voltages across resistors R5 and R10 (should be about 5V each).

Also, with input shorted, is there any measurable DC or AC voltage on the output?

Cheers

Hayden · 12th August 2004, 10:33 AM

OK just blown the 2 protection resistors
Where can I get the schematic that shows the voltages of each component etc?

Centauri · 12th August 2004, 01:57 PM

Protection resistors?? this amp has no protection. Which resistors do you mean?

BTW which version did you build - the 50W (2 transistors) or 100W (4 transistors) ?

Cheers

Greg Erskine · 12th August 2004, 09:42 PM

hi Hayden,

Did you look at the Cambie site as mentioned by mikee12345?

http://www.alphalink.com.au/~cambie/

This site has more info on the ETI480 than you probably want to know.

Hayden · 13th August 2004, 12:17 AM

100w it is
100 ohms across the fuse went up in smoke.
don't know why I haven't changed anything since I last powered it up.

11th August 2004, 06:43 AM	#1
Hayden diyAudio Member Join Date: Aug 2004 Location: Mackay Australia	Eti 480 trouble I’ve built an Eti 480 amp (not the best amp I know) the problem is that the output volume is low, when I turn up the input signal the amp gets to about 30% of its potential then its distorts. I have checked all the components if their in working order and if their in the right spots. I keep setting vr1 to get the right voltage but it keeps changing. Can any one help? Are there any well known problems with this amp? Thanks

12th August 2004, 09:42 PM	#9
Greg Erskine diyAudio Member Join Date: Jan 2002 Location: Sydney/Australia	hi Hayden, Did you look at the Cambie site as mentioned by mikee12345? http://www.alphalink.com.au/~cambie/ This site has more info on the ETI480 than you probably want to know. __________________ Greg Erskine

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
Trouble in a new DIY amp.	andRookie	Tubes / Valves	33	7th May 2007 09:04 AM
DH 220 trouble	jmgreenlee	Solid State	11	8th April 2007 07:25 PM
trouble	Sherkhan	Chip Amps	1	12th July 2004 02:41 PM

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 August 2004, 03:14 PM	#2
Netlist diyAudio Moderator Emeritus Join Date: Jan 2003	Hayden Do you have a link to a schematic? /Hugo

11th August 2004, 03:28 PM	#3
Netlist diyAudio Moderator Emeritus Join Date: Jan 2003	Found it... What happens to the rail voltages? Are they stable? /Hugo

12th August 2004, 01:43 AM	#4
mikee12345 diyAudio Member Join Date: Nov 2002 Location: NZ	The general consensus ive seen is -it was stable with Transistors available at its time of design but now,not so! http://www.alphalink.com.au/~cambie/ETI480/ETI480.zip http://www.alphalink.com.au/~cambie/

12th August 2004, 03:44 AM	#5
Hayden diyAudio Member Join Date: Aug 2004 Location: Mackay Australia	rails are OK drops about 5v when inputs are high

12th August 2004, 04:52 AM	#6
Centauri diyAudio Member Join Date: Jul 2003 Location: Newcastle, Australia	Check voltage across zener ZD1 (should be about 5.6V) and voltages across resistors R5 and R10 (should be about 5V each). Also, with input shorted, is there any measurable DC or AC voltage on the output? Cheers

12th August 2004, 10:33 AM	#7
Hayden diyAudio Member Join Date: Aug 2004 Location: Mackay Australia	OK just blown the 2 protection resistors Where can I get the schematic that shows the voltages of each component etc?

12th August 2004, 01:57 PM	#8
Centauri diyAudio Member Join Date: Jul 2003 Location: Newcastle, Australia	Protection resistors?? this amp has no protection. Which resistors do you mean? BTW which version did you build - the 50W (2 transistors) or 100W (4 transistors) ? Cheers

13th August 2004, 12:17 AM	#10
Hayden diyAudio Member Join Date: Aug 2004 Location: Mackay Australia	100w it is 100 ohms across the fuse went up in smoke. don't know why I haven't changed anything since I last powered it up.