[HeadphoneAddict]

So far my ranking #1-4 for opamp combos that are all better than stock:

1. LTC6241HV/LMH6655 - Sounds similar to Predator but slightly smoother and less aggressive , good with everything
2. LMH6622/THS4032 - not quite as warm or forward as #3 but good with everything (I am told similar to iQube)
3. LM6172/THS4032 - warm with more forward mids, good with full size cans, especially Grados - sound is kinda between Predator and 2MOVE
4. THS4032/LMH6172 - less forward and better with many IEM or non-grado full size, more similar to Pico

Stock is not bad, it is just a little more recessed than I like in the mids which puts it just below the Pico or HR Micro Amp.

 

[lucifix]

Hi guys,

I have been searching extensively on the internet for how to DIY these opamps and need some help on getting the surface mounted soic8 opamps to dip8 adapters.

Two links are here:
SO8 to 8-pin DIP Adapter (p/n 970601)
Single-to-dual Op-Amp Adapter (p/n 020302)

Which one do I get for the viper?
I read that "There are single and dual 8 pin op-amps. Check the datasheet to be sure, but normally dual op-amps are used in the above-mentioned examples."
So i'm not too sure which to get because isn't one opamp, not two, mounted onto one adapter?

Thanks!!

 

[Goddess.]

Quote:

Originally Posted by HeadphoneAddict /img/forum/go_quote.gif So far my ranking #1-4 for opamp combos that are all better than stock: 1. LTC6241HV/LMH6655 - Sounds similar to Predator but slightly smoother and less aggressive , good with everything 2. LMH6622/THS4032 - not quite as warm or forward as #3 but good with everything (I am told similar to iQube) 3. LM6172/THS4032 - warm with more forward mids, good with full size cans, especially Grados - sound is kinda between Predator and 2MOVE 4. THS4032/LMH6172 - less forward and better with many IEM or non-grado full size, more similar to Pico Stock is not bad, it is just a little more recessed than I like in the mids which puts it just below the Pico or HR Micro Amp.

THS4032 is an awful sounding opamp. The entire line LT1355/1358/1361/1364 is vastly better for audio. LM6172 is a class-B biased opamp that sounds like class-B.


LTC6241HV is very nice, but it's no way better than the LT13xx series. No wonder, it's CMOS. Try the LT6234, that's better.


One not meaningless thing is that the THS4032 and even worse the LMH6622 CAN'T be used in the Viper due to absurdly high Input Bias Currents, respectively 3uA and 4.7uA, which means absurdly high DC voltage offsets on the outputs, that could hurt the coils of your phones (especially if IEMs). The circuit is trimmed for the 600nA of the LT1364; here we're talking 5 to 8 times the DC voltage on the output; so if, say, the offset was 5 mV before, now it will be 25 to 40 mV. Not bad.

 

[Goddess.]

The "problem" with these 4-channel designs is that the ground opamp can make the main opamp misbehave (messed up feedback loops). So, maybe by mixing two awful sounding opamps, you may get a good sounding amp, LOL.

One other thing is that the low available supply voltage limits the performance of any opamp not designed for low supply voltages (the LMH6622 doesn't stand more than 13V, the LTC6241HV no more than 11V). The LT13xx series, for instance, performs best with +/-15V supplies = 30V.

On the other hand, the THS4032 sounds awful with any supply voltage, and notably enough, it easily clips when powered with 9V total. This is no audio opamp, nor low voltage opamp.

 

[lucifix]

Very insightful info there..
Do you know anything about the adapters I asked earlier on?

 

[evilmerlin]

At least those LT13XX ones come in DIP8, making it easier to try them. Do you use them as the Main or the Ground? If its the main, what do you use as the ground?

 

[Goddess.]

Quote:

Originally Posted by evilmerlin /img/forum/go_quote.gif At least those LT13XX ones come in DIP8, making it easier to try them. Do you use them as the Main or the Ground? If its the main, what do you use as the ground?

I do not have the Viper. With the LT1361 or LT1364 in the main (try the LT1358 as well, a bit more mellow and more full than the 1364), I'd use another fast slewing opamp in the ground, possibly also high current (tends to yield more fullness). Perhaps the LT1355 or LT1358, or also the LM6172.


edit- my absolute favorite LT13xx is the LT1360 (single) or LT1361 (dual). Bit more full with vocals than the 1364, yet no midbass excess.

 

[Goddess.]

Quote:

Originally Posted by lucifix /img/forum/go_quote.gif Hi guys, I have been searching extensively on the internet for how to DIY these opamps and need some help on getting the surface mounted soic8 opamps to dip8 adapters. Two links are here: SO8 to 8-pin DIP Adapter (p/n 970601) Single-to-dual Op-Amp Adapter (p/n 020302) Which one do I get for the viper? I read that "There are single and dual 8 pin op-amps. Check the datasheet to be sure, but normally dual op-amps are used in the above-mentioned examples." So i'm not too sure which to get because isn't one opamp, not two, mounted onto one adapter? Thanks!!

For the dual SMD opamps, you need the Browndog 970601; for the single SMD opamps, you need to mount two of them on a Browndog 20302.

Be warned that it's not that easy.

 

[evilmerlin]

Quote:

Originally Posted by Goddess. /img/forum/go_quote.gif I do not have the Viper. With the LT1361 or LT1364 in the main (try the LT1358 as well, a bit more mellow and more full than the 1364), I'd use another fast slewing opamp in the ground, possibly also high current (tends to yield more fullness). Perhaps the LT1355 or LT1358, or also the LM6172. edit- my absolute favorite LT13xx is the LT1360 (single) or LT1361 (dual). Bit more full with vocals than the 1364, yet no midbass excess.

Just curious here, if you do not have the Viper, then how do you know how those opamps will sound like in it. Won't the capcitors and circuitry affect the final output?

 

[lucifix]

Hmm I know roughly how to look at a spec sheet but how to I tell which is a dual and which is a single smd opamp?

And to the rather technical parts, would 'tinning' be the best way to go about soldering the soic8 s to the browndogs?

The components are pretty damn tiny but its worth a shot at it especially for a novice, there's this certain thrill to this

Worse come to worst I may have them sent to a shop to get soldered.

 

[Goddess.]

Quote:

Originally Posted by evilmerlin /img/forum/go_quote.gif Just curious here, if you do not have the Viper, then how do you know how those opamps will sound like in it. Won't the capcitors and circuitry affect the final output?

I'm just talking about the sound of the opamps themselves. I heard them in the most "neutral" condition possible, the analog stage of a DAC.


The technical matters instead are... just that.

 

[Goddess.]

Quote:

Originally Posted by lucifix /img/forum/go_quote.gif Hmm I know roughly how to look at a spec sheet but how to I tell which is a dual and which is a single smd opamp? And to the rather technical parts, would 'tinning' be the best way to go about soldering the soic8 s to the browndogs? The components are pretty damn tiny but its worth a shot at it especially for a novice, there's this certain thrill to this Worse come to worst I may have them sent to a shop to get soldered.

Sorry, I don't speak inglish

Would you explain what you mean by tinning?


Look at the drawing of the pin connections of the opamp in the datasheet - those with the + power supply on pin 8 are duals, while those with the + power supply on pin 7 are singles.

 

[Goddess.]

Oh, tinning = soldering? Yes, that's the way.

 

[lucifix]

Quote:

Originally Posted by Goddess. /img/forum/go_quote.gif Sorry, I don't speak inglish Would you explain what you mean by tinning? Look at the drawing of the pin connections of the opamp in the datasheet - those with the + power supply on pin 8 are duals, while those with the + power supply on pin 7 are singles.

Surface mounting components onto a circuit board

"To solder something onto the surface of a circuit requires a process called tinning. Tinning is when you apply a small amount of solder onto the materials you are joining before you connect them. In this case, it involves putting some solder on a contact on the surface of the circuit board then attaching the component to the solder pool"

I am completely new to this so please correct me if I used the term wrongly.

 

[lucifix]

This makes the LMH6655 a dual smd opamp, as referenced with this spec sheet

heh im starting to get good at this