[A2029]

Thanks Mischa. For the dummy load resistors - would 5W resistors be enough? I know @L0rdGwyn used much more substantial resistors, but then again he plugs it to the speaker taps. Not headphone out...

For headphone amp measurements, even 2-3W metal film should be plenty. Stay away from inductive wirewounds if possible.

 

[Jaeger18]

Beautiful amp!
I am jealous - none of my amps (and I have quite a few) have VU meter...

It really changes the listening experience, so instead of ONLY using your ear, now there is a reason to use your eye.

I found those meters We had a bit of "trial and error" getting them to work properly, but I'm glad Mischa did as they do look nice. You are teasing us tho..... by only showing one...

Only if you call me "daddy" lol, jk... Tbh the reason why i got attracted to 1101 AUDIO in the first place is because of you. You were the one who gave Mischa showcase his work. So i thank you for luring me to Mischa... Nw, more pictures coming, but i think you will be disapointed since out of the 50 pictures that i took i think this is the best one lol...

Looks awesome! Which VU meters are those?

If money wasnt the issue i wouldve gone with ( https://www.don-audio.com/Vintage-Meters-VM-B10R-LED-1mA-Retro-VU-Meter-LED-Illuminated ) but after lots of consideration i took Mischa advice and use S45 500UA VU Meter ( http://www.jjyaudio.com/productview.asp?sid=1491 ) instead. It is much cheaper but still retains the vintage aesthetic.

Sweet! Totally gorgeous. But the VU meter indicates you need to turn the volume up. Lots.

i cannot go past 11 o clock, 9 oclock is the ideal volume to me... One more thing to mention, i think VU meter's needle fluctuates depending more on the volume of the DAC rather than the volume of the AMP. so in my case, eventhough the volume of the AMP is 0, the needle still goes up and down whenever i maxed out my DAC.

 

[L0rdGwyn]

Thanks Mischa. For the dummy load resistors - would 5W resistors be enough? I know @L0rdGwyn used much more substantial resistors, but then again he plugs it to the speaker taps. Not headphone out...

I think I used 25W non-inductive wirewounds, which is way overkill for headphones lol. I put BNC connectors on the output, works great for connecting the Autoranger or a scope. Having a switchable dummy load is convenient for quickly seeing how load affects distortion, frequency response, or making quick output impedance measurements. I have been meaning to build one for speakers as well. Would use 4, 6, 8, 16ohm dummies with speaker binding post inputs and BNC outputs, just haven't gotten around to it yet, maybe I will make a shopping list today.

 

[Zachik]

I think I used 25W non-inductive wirewounds, which is way overkill for headphones lol. I put BNC connectors on the output, works great for connecting the Autoranger or a scope. Having a switchable dummy load is convenient for quickly seeing how load affects distortion, frequency response, or making quick output impedance measurements. I have been meaning to build one for speakers as well. Would use 4, 6, 8, 16ohm dummies with speaker binding post inputs and BNC outputs, just haven't gotten around to it yet, maybe I will make a shopping list today.

I think I will avoid going overboard, and use 3W resistors...
Probably 300, 150 or 120, 64 and 32 ohms?
Still thinking of a way to avoid the expensive 3P switch from Goldpoint - maybe use 3 or 4 plugs for 1/4" out for the discrete loads? but how do I make it such that only plug with plugged-in cable loads the amp? maybe switching 1/4" jack?
(sorry for my rumblings...)
Also need a project box / case. (or do I want to throw more money Dave's way for a nice case??)
BNC is a nice idea for scope connection, but I think I would more likely use it straight to the Motu M4. If I end up using 1 OUT jack - maybe I will just put both!
@L0rdGwyn - if I throw in a BNC connector, do I need to do anything special when wiring it? A resistor or anything? or is it just going to be in parallel wired to the 1/4" jack?

At least that gives me something to think about and eventually to keep me doing some DIY stuff (when I get to the execution phase)

 

[L0rdGwyn]

I think I will avoid going overboard, and use 3W resistors...
Probably 300, 150 or 120, 64 and 32 ohms?
Still thinking of a way to avoid the expensive 3P switch from Goldpoint - maybe use 3 or 4 plugs for 1/4" out for the discrete loads? but how do I make it such that only plug with plugged-in cable loads the amp? maybe switching 1/4" jack?
(sorry for my rumblings...)
Also need a project box / case. (or do I want to throw more money Dave's way for a nice case??)
BNC is a nice idea for scope connection, but I think I would more likely use it straight to the Motu M4. If I end up using 1 OUT jack - maybe I will just put both!
@L0rdGwyn - if I throw in a BNC connector, do I need to do anything special when wiring it? A resistor or anything? or is it just going to be in parallel wired to the 1/4" jack?

At least that gives me something to think about and eventually to keep me doing some DIY stuff (when I get to the execution phase)

I just used a Hammond case, don't think it is worth the cost of a custom case, for me it is a tool, so it doesn't need to look nice.

Just like an RCA, BNC is hot and ground, nothing special needed. I use BNC to RCA adapters if I want to run the output directly into the ADC. Keep in mind with a DAC/ADC measurements setup, you will not be able to do square wave analysis. Due to bandwidth limitations of the DAC, it cannot create an accurate square wave, you need a dedicated signal generator for that and the output needs to be read on an oscilloscope. So, I prefer BNC for flexibility.

 

[Xcalibur255]

Sooo....... I feel like I'm the only person here who mainly listens with his eyes closed?

 

[Galapac]

Sooo....... I feel like I'm the only person here who mainly listens with his eyes closed?

That is the only way I can truly enjoy the music and "feel" the landscape of the music around me.
Otherwise my other senses get in the way and it becomes background noise, sometimes like this thread.

 

[bcowen]

Sooo....... I feel like I'm the only person here who mainly listens with his eyes closed?

LOL! You're not. I'm just hoping @L0rdGwyn doesn't do his test measurements with his eyes closed.

 

[Zachik]

I just used a Hammond case, don't think it is worth the cost of a custom case, for me it is a tool, so it doesn't need to look nice.

Agreed! Will probably do the same.

Just like an RCA, BNC is hot and ground, nothing special needed. I use BNC to RCA adapters if I want to run the output directly into the ADC.

I am thinking maybe have both (RCA or 1/4" and BNC) for convenience. Did you use a Goldpoint 3P selector for the various loads? Those are pretty pricey, especially since it is for a novelty tool and all...

Keep in mind with a DAC/ADC measurements setup, you will not be able to do square wave analysis. Due to bandwidth limitations of the DAC, it cannot create an accurate square wave, you need a dedicated signal generator for that and the output needs to be read on an oscilloscope. So, I prefer BNC for flexibility.

I actually have a dedicated signal generator
To measure FR of an amp - don't you need a sine wave? and do a frequency sweep from 20Hz to 20KHz? feed the amp with said sweep, and measure the output from headphone jack (through the load box and the M4)?

 

[L0rdGwyn]

Agreed! Will probably do the same.


I am thinking maybe have both (RCA or 1/4" and BNC) for convenience. Did you use a Goldpoint 3P selector for the various loads? Those are pretty pricey, especially since it is for a novelty tool and all...


I actually have a dedicated signal generator
To measure FR of an amp - don't you need a sine wave? and do a frequency sweep from 20Hz to 20KHz? feed the amp with said sweep, and measure the output from headphone jack (through the load box and the M4)?

I think I did use a Goldpoint, I was on a kick, but I'm sure you can come up with something cheaper.

If you use a program like Arta or REW, you can do it multiple ways. Arta uses pink noise, you can do sweeps in REW.

 

[Xcalibur255]

That is the only way I can truly enjoy the music and "feel" the landscape of the music around me.
Otherwise my other senses get in the way and it becomes background noise, sometimes like this thread.

I was going to click the like button on your post but it appears the like buttons have vanished!

 

[cdanguyen08]

I was going to click the like button on your post but it appears the like buttons have vanished!

Just liked your post to see if they really vanished!

 

[Xcalibur255]

Just liked your post to see if they really vanished!

I figured it out. Just within the last hour the uBlockOrigin Firefox extension started blocking and hiding the like buttons on the site. Weird.

 

[A2029]

Agreed! Will probably do the same.

I am thinking maybe have both (RCA or 1/4" and BNC) for convenience. Did you use a Goldpoint 3P selector for the various loads? Those are pretty pricey, especially since it is for a novelty tool and all...

I actually have a dedicated signal generator
To measure FR of an amp - don't you need a sine wave? and do a frequency sweep from 20Hz to 20KHz? feed the amp with said sweep, and measure the output from headphone jack (through the load box and the M4)?

You can get away with using a super cheap 2 pole rotary switch. Number of positions will be your number of desired resistances to test. I.e. If you wanted a switch for 300, 150 or 120, 64 and 32 ohms, you would get a 2 pole, 5+ position switch.

 

[LoryWiv]

Sooo....... I feel like I'm the only person here who mainly listens with his eyes closed?

Yes, this is the best way to really appreciate music! Not always practical, but definitely best!