[sofakng]

I purchased Beyer Dynamics DT770/Pro-80's about six months ago and I'm now getting into electronics so I'm thinking about building a small amplifier (CMoy?) but I'm wondering what exactly it's going to do for me.

The headphones are always used with my computer (for gaming and music) through a Creative Labs X-Fi XtremeMusic sound card.

Does anybody have any suggestions for me? I'm not looking to spend a lot of money on this but instead view it as an beginner electronics project with some sort of benefit at the end.

Thanks for any advice!

 

[FallenAngel]

It makes a difference, build one.

 

[GreatDane]

if you build it, they will come

A more powerful amp should improve the sound especially LF.

 

[Namrac]

I was very happy with the change amping my 80's made, the bass in particular. It cleans itself up quite a bit, and goes a bit deeper when it's got some power.

 

[sofakng]

Thanks for the information!

Do you guys have any suggestions on which opamp chip that I should buy?

 

[jcx]

pros are low sensitivity and 80 Ohms is on the low impedance end of the spectrum

few CMOY op amp choices will be really capable of driving them well, those that have enough current output:

LM6172 - "twitchy" 70 MHz GBW, maybe still a little light on current drive

RC/JRC/NJM4556 or 4580 - not well respected among op amp rolling crowd but the 4556 is used in Gado's RA-1

the other single op amp options with high enough output current are surface mount and/or current feedback instead of the easier for beginners unity gain stable Voltage feedback type


other diy options would be any of the buffer-in-the-loop projects or discrete amps with >100mA, +/-10V output range

 

[sofakng]

Quote:

Originally Posted by jcx /img/forum/go_quote.gif pros are low sensitivity and 80 Ohms is on the low impedance end of the spectrum few CMOY op amp choices will be really capable of driving them well, those that have enough current output: LM6172 - "twitchy" 70 MHz GBW, maybe still a little light on current drive RC/JRC/NJM4556 or 4580 - not well respected among op amp rolling crowd but the 4556 is used in Gado's RA-1 the other single op amp options with high enough output current are surface mount and/or current feedback instead of the easier for beginners unity gain stable Voltage feedback type other diy options would be any of the buffer-in-the-loop projects or discrete amps with >100mA, +/-10V output range

Thanks for the information! What do you mean by single op-amp choices? Is it better to use two op-amps together for better sound?

Also, what would be your first choice? It sounds like the LM6172 is what you're recommending...

 

[jcx]

"CMOY" is a beginner project using one op amp/channel - sometimes with dual op amp chips so only one chip is used - simple build gets many people started but their are few choices in DIP packages that can handle the current needed, also to get real headroom extension you need at least 2x9V battery supply or a power supply of some sort, for your cans I'd want +/-12 V supply or higher with most op amps

the 4556 has the highest current rating and fair specs but doesn't get recommended here often


multiple op amps, paralleled or buffered/multilooped circuits are the next stage in op amp headphone amps but may require more care in circuit design and op amp part choice

there are some schemes for paralleling op amps but the most popular "A47" project circuit makes unusual demands on the op amps and can't be reccomended without reservations

I've both paralleled LM6172 and used buffer in loop multiloop circuits

check out HeadWize - Project: Designing an Opamp Headphone Amplifier (A HeadWize Design Series Paper)

and other articles/projects on Headwize

and Audiologica

 

[eddieyee]

Hi,

If you are intending on building an amp, I would highly recommend the mini3 due to it's amazing sound and power output. I also have the pa2v2, but the mini3 is significantly different in the sound-- it is driving my HD650's. Keep in mind, i have not built an amp before, so I don't know the difficulty in a CMOY or the mini3, or any other amp for that matter. I bought the mini3 off rockhopper, and the p2av2 from electric avenues. Both are excellent people to deal with.

good luck in your build.

 

[Kabeer]

Quote:

Originally Posted by jcx /img/forum/go_quote.gif also to get real headroom extension you need at least 2x9V battery supply or a power supply of some sort, for your cans I'd want +/-12 V supply or higher with most op amps

Would this really make that much of a difference? I have a mini3 and a PPAS running on a single 9v battery, but the PPAS is supposed to have a large current output.

 

[FallenAngel]

Quote:

Originally Posted by Kabeer /img/forum/go_quote.gif Would this really make that much of a difference? I have a mini3 and a PPAS running on a single 9v battery, but the PPAS is supposed to have a large current output.

The PSU voltage and the voltage swing capabilities of the opamp will set the voltage swing of the amp. Generally, the more the better.

 

[Kabeer]

I see, I think I will have to try a home amp and see how much of a difference it would make...problem is I dont wanna spend bucks.
Maybe the Millett Starving student....

 

[intoart]

When I bought my integrated amp (Cambridge Audio 340A), I was not even thinking about headphones. I guess I just got lucky, because its HP output sounds absolutely fantastic with my 770 Pro/80s! I am not convinced that a separate HP amp could provide any additional benefit, though I am willing to try it. What home amp uner $300 has exceptionally good synergy with those particular 'phones?