Advice Modifying Behringer HP Amp

Arturo · 25th April 2008, 04:53 PM

I'm an introductory level electronics "diy"er and had a bad experience tracking with a Behringer HA4600 Headphone Amplifier this week. I was playing drums on a session and this particular hp amp along with akg k240 headphones just didn't have the full range sound needed to properly monitor the dynamic sound of a drumkit. The hp amp seemed particularly lacking on its input side. It just couldn't take very much low frequency audio without clipping. I've got my hp amp opened up here on my bench and am wondering if there are any upgrades I can perform to perhaps the power transistors or perhaps an opamp on the input side that I can replace to at least slightly increase the performance of such a device. Thank you.

Jim Williams · 26th April 2008, 04:15 PM

There is a nice headphone DIY project posted over at the National. com web site using the LME49710 opamp and their new 250 ma 2k v slew rate buffer. BB also makes a similar part, the buf 634. Placed into the feedback loop of a great opamp, it's tough to beat. I use the buf 634 for my headphone amps with DC servos, it's loud enough and super clean. It hurts drummers. And it's cheap and easy to build. National also make an eval pcb with the buffer and an opamp, ready to go, just add a power supply.

Jim Williams
Audio Upgrades

Arturo · 26th April 2008, 09:28 PM

Thank Jim. I was going to try to build my own headphone amp if I couldn't modify the ha4600 so this is very useful information. I'm going to try to get the schematic and/or line diagram from behringer so I can compare the circuits. I'm a little obsessed with diy audio gear and mods right now so if you all have any more advice on this hp amp topic please post. Thanks.

CoteRotie · 26th April 2008, 10:32 PM

It's easy to mod Behringer equipment for much better performance. Follow the steps below exactly:

1. Locate a schematic for the unit in question.
2. Remove the power cord from the unit and set aside.
3. Open the unit carefully and get your soldering iron hot.
4. Locate all the capacitors on the schematic and remove them. Discard.
5. Remove everything else on the schematic and discard.
6. Throw away the cheap chassis & anything else that remains.
7. Save the power cord as a spare.
8. Buy something that works better.

Good Luck,

John

Arturo · 27th April 2008, 01:59 AM

John, I agree however this is the only piece of behringer gear I have ever owned because it did what I needed it to at a price that I couldn't beat. I would rather build my own headphone amplifiers. Jim would you give me some clues as to how I would go about building a 4 channel headphone amp out of the parts you've previously suggested?

adamcal · 27th April 2008, 02:35 PM

a couple of years ago I bought a 4700 (the upgraded/louder version) as a stop gap while I was going to upgrade my whole headphone setup, but its still there, still working and to date has been loud enough for everything ive done (I record about 3 bands a week)

I also bought a 2nd (if I need more than 4 sends) and a 3rd as a spare (expecting them to fail, and they are cheap enough to buy a spare) I haven't opened the spare yet.

most behringer is total crap, but the HA4700 has been fine.

Arturo · 27th April 2008, 05:09 PM

Thanks Adam. I need to be more honest about the purpose for my initial post. The reason I asked about this Behringer unit was because I used it, experienced its short-comings and then decided to find out if it could be improved. What I really hoped to achieve was to learn a little about a small amplifier circuit and what goes on in the best ones. I would really love to hear about a really great hp amp circuit that someone has designed and uses, like the one Jim mentioned. I would like to know what goes into a great hp amp and how I can build one myself. Thanks everyone.

CoteRotie · 27th April 2008, 11:42 PM

Quote:

Originally Posted by Arturo

John, I agree however this is the only piece of behringer gear I have ever owned because it did what I needed it to at a price that I couldn't beat. I would rather build my own headphone amplifiers. Jim would you give me some clues as to how I would go about building a 4 channel headphone amp out of the parts you've previously suggested?

Just taking the opportunity to poke a little fun at Behringer. It's great that you want to build your own headphone amp. Let us know if you have any questions once you decide on a circuit topology and I'm sure we can help.

Regards,

John

Arturo · 15th May 2008, 06:47 PM

Just a bump. I think to utilize those opamps and buffers on my current behringer circuit board the circuit would need a complete overhaul...or would it? Just curious. I'm sorry for not posting the docs yet. Let me call behringer and try to get a hold of them then I will post. Thanks.

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25th April 2008, 04:53 PM	#1
Arturo Gear interested Join Date: Mar 2008 Posts: 7	Advice Modifying Behringer HP Amp I'm an introductory level electronics "diy"er and had a bad experience tracking with a Behringer HA4600 Headphone Amplifier this week. I was playing drums on a session and this particular hp amp along with akg k240 headphones just didn't have the full range sound needed to properly monitor the dynamic sound of a drumkit. The hp amp seemed particularly lacking on its input side. It just couldn't take very much low frequency audio without clipping. I've got my hp amp opened up here on my bench and am wondering if there are any upgrades I can perform to perhaps the power transistors or perhaps an opamp on the input side that I can replace to at least slightly increase the performance of such a device. Thank you.

27th April 2008, 02:35 PM	#6
adamcal Lives for gear Join Date: Dec 2002 Location: Melbourne, Australia Posts: 1,099	a couple of years ago I bought a 4700 (the upgraded/louder version) as a stop gap while I was going to upgrade my whole headphone setup, but its still there, still working and to date has been loud enough for everything ive done (I record about 3 bands a week) I also bought a 2nd (if I need more than 4 sends) and a 3rd as a spare (expecting them to fail, and they are cheap enough to buy a spare) I haven't opened the spare yet. most behringer is total crap, but the HA4700 has been fine. __________________ Adam Calaitzis www.toyland.com.au

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26th April 2008, 04:15 PM	#2
Jim Williams Lives for gear Join Date: Feb 2004 Location: beautiful Carlsbad, CA Posts: 3,886	There is a nice headphone DIY project posted over at the National. com web site using the LME49710 opamp and their new 250 ma 2k v slew rate buffer. BB also makes a similar part, the buf 634. Placed into the feedback loop of a great opamp, it's tough to beat. I use the buf 634 for my headphone amps with DC servos, it's loud enough and super clean. It hurts drummers. And it's cheap and easy to build. National also make an eval pcb with the buffer and an opamp, ready to go, just add a power supply. Jim Williams Audio Upgrades

26th April 2008, 09:28 PM	#3
Arturo Gear interested Join Date: Mar 2008 Posts: 7	Thank Jim. I was going to try to build my own headphone amp if I couldn't modify the ha4600 so this is very useful information. I'm going to try to get the schematic and/or line diagram from behringer so I can compare the circuits. I'm a little obsessed with diy audio gear and mods right now so if you all have any more advice on this hp amp topic please post. Thanks.

26th April 2008, 10:32 PM	#4
CoteRotie Gear addict Join Date: Sep 2006 Location: SF Bay Area Posts: 323	It's easy to mod Behringer equipment for much better performance. Follow the steps below exactly: 1. Locate a schematic for the unit in question. 2. Remove the power cord from the unit and set aside. 3. Open the unit carefully and get your soldering iron hot. 4. Locate all the capacitors on the schematic and remove them. Discard. 5. Remove everything else on the schematic and discard. 6. Throw away the cheap chassis & anything else that remains. 7. Save the power cord as a spare. 8. Buy something that works better. Good Luck, John

27th April 2008, 01:59 AM	#5
Arturo Gear interested Join Date: Mar 2008 Posts: 7	John, I agree however this is the only piece of behringer gear I have ever owned because it did what I needed it to at a price that I couldn't beat. I would rather build my own headphone amplifiers. Jim would you give me some clues as to how I would go about building a 4 channel headphone amp out of the parts you've previously suggested?

27th April 2008, 05:09 PM	#7
Arturo Gear interested Join Date: Mar 2008 Posts: 7	Thanks Adam. I need to be more honest about the purpose for my initial post. The reason I asked about this Behringer unit was because I used it, experienced its short-comings and then decided to find out if it could be improved. What I really hoped to achieve was to learn a little about a small amplifier circuit and what goes on in the best ones. I would really love to hear about a really great hp amp circuit that someone has designed and uses, like the one Jim mentioned. I would like to know what goes into a great hp amp and how I can build one myself. Thanks everyone.

15th May 2008, 06:47 PM	#9
Arturo Gear interested Join Date: Mar 2008 Posts: 7	Just a bump. I think to utilize those opamps and buffers on my current behringer circuit board the circuit would need a complete overhaul...or would it? Just curious. I'm sorry for not posting the docs yet. Let me call behringer and try to get a hold of them then I will post. Thanks.