[gaz2613]

Hi guys this will be my second DIY project and I am really looking forward to building it.

Just a quick question please, does anyone know the best way to implement a power on led as I would like a visual indicator on the front for aesthetics.

What voltage would it need to be and would I need to tap into the power supply and add an extra regulator circuit to drop the voltage to around 3 volts for the led?

 

[JamieMcC]

Hi congratulations on going with Whammy it's a neat amp pretty straight forward to build and sounds superb.

Hiflying9 the thread creator here posted some details on the diyaudio thread about setting up a led indicator light

His schematic can be found here

https://www.diyaudio.com/forums/pass-labs/317803-whammy-pass-diy-headphone-amp-guide-10.html

 

[gaz2613]

Hi congratulations on going with Whammy it's a neat amp pretty straight forward to build and sounds superb.

Hiflying9 the thread creator here posted some details on the diyaudio thread about setting up a led indicator light

His schematic can be found here

https://www.diyaudio.com/forums/pass-labs/317803-whammy-pass-diy-headphone-amp-guide-10.html

Thanks for this I did come across this before but the voltage of the LED is not specified. I've asked on that forum to see if I can find out.

 

[jimmers]

Thanks for this I did come across this before but the voltage of the LED is not specified. I've asked on that forum to see if I can find out.

You choose the voltage of the LED.
Depending on LED type (colour etc.), specified at 20mA, LEDs range from less than 2V to over 3V forward voltage drop, whichever type you use that circuit will supply the LED with around 10mA which is fine.

 

[Allanmarcus]

Hi guys this will be my second DIY project and I am really looking forward to building it.

Just a quick question please, does anyone know the best way to implement a power on led as I would like a visual indicator on the front for aesthetics.

What voltage would it need to be and would I need to tap into the power supply and add an extra regulator circuit to drop the voltage to around 3 volts for the led?

I used this which doubles as a power switch
https://www.aliexpress.com/item/32802930968.html
I got the blue, 110v version and it works great

 

[gaz2613]

She lives! Running in now with some Spotify music... I tried Burson op-amps but they aren't compatible. Will start looking into other op-amps that work.

Hi your build looks very nice indeed. I am still waiting for my board to arrive. I couldn't help but notice you said the Burson op amps are not compatible. I am sure I have seen other people using them but theres a resistor you have to change to 10k to make the amp unity gain stable if I recall.

 

[JamieMcC]

fyi I've had no problems using the Burson V6 Vivid or V6 Classic also the Chinese Marantz discrete hdam module clone. They were all plug and play with very low dc offsets.

 

[gaz2613]

Okay guys I have spent quite a bit of time and money on obtaining OP Amps for testing and here are by findings:

Tested using HiFiMan HE400i headphones and a Topping D50 DAC. I used FLAC audio 96Khz 24 bit. Evanescence Synthesis album.

Dual Op Amps (8P-DIP):

AD823ANZ:
Operating Voltage: 36v MAX
Slew Rate: 22v/µs
DC Offset: L 0.5mV / R -0.2mV
FET: Yes
Notes: Vocals very good but some mids and treble sounds a little raspy.

LM833-N:
Operating Voltage: 36v MAX
Slew Rate: 7v/µs
DC Offset: L -0.1mV / R 3.4mV
FET: No
Notes: Very good all round OP Amp with clear vocals, good soundstage and natural bass.

LM833P:
Operating Voltage: 36v MAX
Slew Rate: 7v/µs
DC Offset: L 22.9mV / R 26.2mV
FET: No
Notes: Very good OP Amp with clear vocals and good soundstage. Improved version of the LM833-N although DC offset is considerably higher.

RC4580 (Texas Instruments):
Operating Voltage: 18v MAX
Slew Rate: 5v/µs
DC Offset: L 14.2mV / R 14.1mV
FET: No
Notes: Good general OP Amp with tiny noticable distortion amounts with certain types of music, sounds best with dance music.

OPA2134PA SoundPlus:
Operating Voltage: 18v MAX
Slew Rate: 20v/µs
DC Offset: L 0.6mV / R 0.4mV
FET: Yes
Notes: Very clear with good soundstage and vocals very pronounced. Very nice OP Amp.

OPA2228PA
Operating Voltage: 18v MAX
Slew Rate: 2.3v/µs
DC Offset: L -0.2mV / R -0.1mV
FET: No
Notes: Very good, clear up front vocals, very good mid and treble, wide soundstage, overall I like this OP Amp.

OPA2107AP
Operating Voltage: 18v MAX
Slew Rate: 18v/µs
DC Offset: L -0.2mV / R -0.3mV
FET: Yes
Notes: Very clear and concise right through all the ranges. Vocals very prominent and wide soundstage. I really like this one.

LME49720NA
Operating Voltage: 17v MAX
Slew Rate: 20v/µs
DC Offset: L 0.8mV R 1.6mV
FET: No
Notes: Nice all round OP Amp with good soundstage. Very clear but mellow sounding.

AD746JNZ
Operating Voltage: 18v MAX
Slew Rate: 75v/µs
DC Offset: L -0.3mV / R -0.2mV
FET: Yes
Notes: Very nice sounding with wide soundstage, clear mids and treble with punchy bass. I really like this one.

LM4562NA:
Operating Voltage: 17v MAX
Slew Rate: 20mv/µs
DC Offset: L -0.4mV / R -1.1mV
FET: No
Notes: Very good all round OP Amp with clear vocals and good soundstage.

NJM4556AD:
Operating Voltage: 18v MAX
Slew Rate: 3v/µs
DC Offset: L 5.8mV / R 5.4mV
FET: No
Notes: Nice OP Amp with clear vocals, wide soundstage and balanced bass. Mids and trebles seem a little softer compared with other OP Amps.

Burson V6 Vivid Dual:
Operating Voltage: 33v MAX
Slew Rate: 45v/µs
DC Offset: L -2.0mV / R -1.5mV
FET: Yes (Fully Discrete)
Notes: Premium OP Amp obviously by far the best I've tried so far. Deep and wide reaching soundstage and up front clear vocals. My number one choice.

Next time I will be testing the following SOIC OP Amps on 8P-DIP adapters:

OPA1622, OPA1662, OPA2210, OPA2189 and OPA1692

Hope some of you find this helpful.

 

[JamieMcC]

Good info thanks It would be extra helpful if you would add what phones and dac you are using to your post above for further context along with maybe price of op amp.

Congrats on the whammy build as well.

 

[gaz2613]

Good info thanks It would be extra helpful if you would add what phones and dac you are using to your post above for further context along with maybe price of op amp.

Congrats on the whammy build as well.

Edited OP. apologies. I didn't add prices because my currency is pound sterling and most here use the American dollar.

 

[gaz2613]

Okay guys, as promised here is a review of the rest of the OP Amps I bought to test in the whammy. These ones are all on 8P-DIP adapters:

Again I used my HiFiMan HE400i headphones and Topping D50 DAC. I used FLAC audio 96Khz 24 bit. Evanescence Synthesis album.

8P-DIP Adapter based OP Amps:

OPA1622 SoundPlus:
Operating Voltage: 18v MAX
Slew Rate: 10v/µs
DC Offset: L -152.6mV / R -154.2mV
FET: No
Package: VSON-8
Notes: This is an excellent OP Amp, High clarity, wide sound stage, no noticable distortion, this one is truly stunning from the mids and trebles right through to the vocals. DC offset is extremely high in this one. Maybe due to the extra onboard components of the DIP adapter. There are some resistors and capacitors.

OPA1662 SoundPlus:
Operating Voltage: 36v MAX
Slew Rate: 17v/µs
DC Offset: L 76.2mV / R 74.8mV
FET: No
Package: SOIC-8
Notes: Very wide sound stage, clear with good mids and trebles, vocals prominent and up front. Overall nice sounding OP Amp. DC offset is also quite high.

OPA2189:
Operating Voltage: 36v MAX
Slew Rate: 20v/µs
DC Offset: L -0.1mV / R -0.2mV
FET: No
Package: VSSOP-8
Notes: This is quite a nice OP Amp with clear vocals, wide soundstage and balanced mids and trebles. Very low DC offset.

OPA1692 SoundPlus:
Operating Voltage: 36v MAX
Slew Rate: 23v/µs
DC Offset: L -34.8mV / R -34.9mV
FET: No
Package: SOIC-8
Notes: Crystal clear, good sound stage and up front vocals. Sounds really nice this one.

OPA2210:
Operating Voltage: 18v MAX
Slew Rate: 6.4v/µs
DC Offset: L -0.1mV / R -0.2mV
FET: No
Package: SOIC-8
Notes: This OP Amp sounds incredible. Very wide soundstage, clear mids and treble with vocals just at the right distance. This one really brings out the finer details. Very low DC offset. Really like this one.

 

[Allanmarcus]

OPA2210:
Operating Voltage: 18v MAX
Slew Rate: 6.4v/µs
DC Offset: L -0.1mV / R -0.2mV
FET: No
Package: SOIC-8
Notes: This OP Amp sounds incredible. Very wide soundstage, clear mids and treble with vocals just at the right distance. This one really brings out the finer details. Very low DC offset. Really like this one.

Thanks for all the reviews. Can you go into a little detail what is needed to use this opamp and what changes are needed to the board to use it?
Thanks.

 

[gaz2613]

Thanks for all the reviews. Can you go into a little detail what is needed to use this opamp and what changes are needed to the board to use it?
Thanks.

Hi thanks for your interest. The chip is simply a smaller package chip soldered onto an adapter board to plug directly into the op amp socket so no modifications are required.

 

[Jimmy24]

So I built this amp a few weeks ago and I just wanted to say this amp is amazing. I'm a bit surprised there isn't much talk about it. It sounds more impressive than the amp kits I've built in the past, even ones that are much much more expensive. I can say without a doubt this is the best amp kit I've built. The amp is paired with my Modi Multibit and HD 650's. Deep soundstage, accuracy, clarity, and lifelike realism I've ever heard. Price wise, I doubt it can be beat! Thank you to Wayne and 6L6 for making such an incredible amp. Truly phenomenal!

Op-amp impressions:
I highly recommend the LM833N which is cheap and compliments the Mimby and HD 650's very well. It has a warmth to it that really gives it a lifelike and engaging feel to the music.

The Burson V6 Vivid has a very accurate and neutral sound. Clarity here is unmatched. Soundstage is a bit deeper than the LM833N but you don't get the warmth of the LM833N.

Burson V6 Classic is similar to the Vivid's but its a little more laid back and less in your face. Probably better for classical and jazz music. Sound is still very detailed. It may have slightly more soundstage than the Vivids.

I have the OPA2210 and OPA2107AP coming in so I will give my impressions on those once it comes in.

Cheers!

 

[Jimmy24]

The OPA2107's are out of this world. Biggest soundstage I've heard so far without compromising detail, clarity, and most of all punch. There seems to be an improvement in bass as well. Wow, truly truly stunning! Like the LM833N it has warmth and is very immersive. Favorite so far!