TEA2025B can I use it as phone amp?

Hosam · 22nd February 2011, 03:53 AM

I have this chip from my old radio in good shape so I wonder how to build a headphone amp from it after I read the data sheet related from ST I just don't know how to start with it any ideas?

pacificblue · 22nd February 2011, 07:15 PM

Yes, you can use it. Depending on the impedance your headphones have, you should consider a resistor in series to the phones as protection.

The TEA2025 is rather noisy and in a headphone that will be more obvious than in a radio.

Hosam · 23rd February 2011, 10:16 AM

Quote:

Originally Posted by pacificblue

Yes, you can use it. Depending on the impedance your headphones have, you should consider a resistor in series to the phones as protection.

The TEA2025 is rather noisy and in a headphone that will be more obvious than in a radio.

does 10k resistor enough?
for the noisy issue what do you think I should use to filter output

if you think this fair enough I'll try to build it then share the results here

Mooly · 23rd February 2011, 11:28 AM

Quote:

Originally Posted by Hosam

does 10k resistor enough?
for the noisy issue what do you think I should use to filter output

if you think this fair enough I'll try to build it then share the results here

I imagine pacificblue was thinking more in terms of around 47 to 100 ohms.

The IC will work OK, just be sure to follow the recommended minimum gain in the data sheet... in fact just follow the circuit in the ST data sheet but include the output resistors. Make sure you decouple the IC across the supply pins.

Hosam · 23rd February 2011, 12:03 PM

at the data sheet they mention the IC has protection for the output with 800ohm resistor then do I need to add more that that for protection?

Mooly · 23rd February 2011, 12:09 PM

The 800 ohm is built into the IC to improve performance. You need to add your resistor in series with the headphones (which means adding it in series with the 470uF caps in the diagram). Also it would be wise to add a resistor (say 2K2) from across each output to ground (to ensure the 470uF caps charge before plugging phones in)

Hosam · 23rd February 2011, 12:16 PM

sound good tip so I'll apply them then test the result thank you for your help

pacificblue · 23rd February 2011, 06:44 PM

Quote:

Originally Posted by Hosam

for the noisy issue what do you think I should use to filter output

You cannot filter that noise out by any reasonable means. All you can do is try the amp and decide, if you can live with what you hear.

Hosam · 25th February 2011, 08:40 AM

as you said I just try then listen maybe after all its ok and doesn't count as big problem.

22nd February 2011, 03:53 AM	#1
Hosam diyAudio Member Join Date: Jan 2011 Location: Syria - Canada	TEA2025B can I use it as phone amp? I have this chip from my old radio in good shape so I wonder how to build a headphone amp from it after I read the data sheet related from ST I just don't know how to start with it any ideas?

22nd February 2011, 07:15 PM	#2
pacificblue diyAudio Member Join Date: May 2008	Yes, you can use it. Depending on the impedance your headphones have, you should consider a resistor in series to the phones as protection. The TEA2025 is rather noisy and in a headphone that will be more obvious than in a radio. __________________ If you've always done it like that, then it's probably wrong. (Henry Ford)

23rd February 2011, 12:09 PM	#6
Mooly diyAudio Member Join Date: Sep 2007	The 800 ohm is built into the IC to improve performance. You need to add your resistor in series with the headphones (which means adding it in series with the 470uF caps in the diagram). Also it would be wise to add a resistor (say 2K2) from across each output to ground (to ensure the 470uF caps charge before plugging phones in) __________________ ------------------------------------------------------- *A simulation free zone.* *Design it, build it, test it.*

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
I want your head phone amp Ideas	pk386	Solid State	9	8th May 2007 05:59 PM
27 head phone amp or.??	JandG	Tubes / Valves	0	27th January 2007 05:42 PM
Head Phone AMp / Mic	jleaman	Everything Else	3	14th April 2006 04:48 PM
Ultimate Tube head phone amp.	tube-lover	Tubes / Valves	14	13th July 2005 04:25 PM


	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

23rd February 2011, 12:03 PM	#5
Hosam diyAudio Member Join Date: Jan 2011 Location: Syria - Canada	at the data sheet they mention the IC has protection for the output with 800ohm resistor then do I need to add more that that for protection?

23rd February 2011, 12:16 PM	#7
Hosam diyAudio Member Join Date: Jan 2011 Location: Syria - Canada	sound good tip so I'll apply them then test the result thank you for your help

25th February 2011, 08:40 AM	#9
Hosam diyAudio Member Join Date: Jan 2011 Location: Syria - Canada	as you said I just try then listen maybe after all its ok and doesn't count as big problem.

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

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