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OpAmps for the Viper-D2? - Page 3

post #31 of 126
You guys ever try any Linear Technologies stuff? I've heard LT1115 and LT1128 are supposed to be pretty good, but their both singles... anyone every try these, or do you know of any duals? I'm looking to order a few parts to try out...
post #32 of 126
Ask Ron (HiFlight) he knows everything about these. He be the expert.
post #33 of 126
My main pair of cans are K240's (600 ohms) which are pretty tough to drive. I've got an AD8397 on the way, and I'll post my thoughts on it when it gets here.

I'm also going to pick up an LT1364 next time I'm placing an order...
post #34 of 126

conversion of "high gain" D2 Viper

If anyone is interested, I'm also going to try to convert this "high gain" pcb that I have here to match the standard one.

Changes planned are:

- swap the 50k pot for an Alps RK0971221Z05 10k pot
- change R100, R91, R93, R102 to 1.5k (bottom side) to match the std board

The high gain PCB also has zero ohm jumpers in the "L1" and "L2" position (topside near the USB connector), while the standard board looks to have 4.7 ohm resistors in these positions. I don't have access to resistors that low at the moment, and they are a bit tricky to access, so I'm going to leave them for now and hope they work ok as-is.

That's all the differences I spot between the two boards.

I'm also going to pick up a Hammond 1455C1201BK box to put it in. My first time trying to house something like this, so I hope it's not too tricky... Any advice or suggestions appreciated.

- Dave
post #35 of 126

Is there anybody... OUT THERE? <<>>

Not really getting any traffic on this thread... Anybody still rolling on the D2?

I'd also like to hear of any other mods people may have an interest in trying (e.g. cap upgrades - never heard any follow up from MONVMENTVM). I might try some things if anyone wants to suggest something...

I'm still burning in my regular board, and I hope to have the "high gain undo" mods done tonight on the other board...

I'm also really curious to hear what opamps are in the Boa so I can try them out...

Anybody else?
post #36 of 126
Originally Posted by HeadphoneAddict View Post
After I pointed out the 6172 in LR and 4032 in the second socket, HiFlight tried it and loved it. But, neither of us had tried the 55002 in place of the 4032, so he tried it and liked it.

I didn't like the 55002+4032 as much, nor the 6172+6172, but wonder about flipping mine the other way around with the 4032 in main with 6172 in the second one.

Then there is the 4032 in main with 55002 in the ground channel. I don't know if either of us has tried that one.
I finally got around to swapping the LM6172 in the main socket and THS4032 in the ground channel.

The original combo was best with things like my Grado RS-1, but too forward in the mids and rolled off in the treble for my Freq Show IEM or a-JAYS. With the opamps swapped it is perfect for the Freq Shows, q-JAYS, Denon D2000, HD600, but too shrill or treble boosted for the RS-1 (APS V3 cabled).

Swapping the THS4032 for the AD8397 was similar, as was the ISL55002, but the LT134 is still a little rolled off, while the AD8397 is maybe slightly brighter but a little edgier.
post #37 of 126
Had a PM asking me how to roll opamps in the D2 Viper.

This is just such a hard thing to do adequately via typing with no photos available. I've give you this bit of information, but I can't do better than this. I am not sure I can answer more questions, because everything is in here.

If you have the opamps soldered onto a DIP8 adpater or those that come ready to plug into the sockets, open your D2 viper. If you don't have them ready to install, you've got the wrong guy.

To start, turn off the amp and unplug it from everything before you start. I don't know what size tool it takes - I got a cheap one at home depot with a bunch of unlabeled tips, and tried them all till I found one that fits. With the amp laying flat, remove only the two top screws on the front panel and the rear panel, and the top half of the amp case can be lifted off.

With the front of the open amplifier facing you, you will see one LT1364 opamp plugged into a socket that lies between the volume knob and battery. Of the 8 pins securing the opamp to the socket on the circuit board, the pin on the left front corner is pin #1. You might want to take a photo of it, so if you have to put it back in you know which way it is facing. After you pry the glue off the edges of the opamp adapter (that is holding it in place), you can pop it out. Use your best judgement to get this opamp loose. Break the amp and it isn't my fault.

The new opamp when viewed from the top will clearly have two rows of 4 pins. If you have one that was soldered onto an adapter, ignore the pins that come right off the chip and only pay attention to the ones near the edges of the adapter. On the adapter, one of the 8 pins will have a square of solder toping it, instead of a circle like the other 7 pins. The one with the Square is pin #1.

If your opamp is not a smaller SOIC opamp soldered onto a bigger DIP adapter, but is actually a DIP8 opamp (like some LM6172), orient the chip so the notch on the top of the chip is on your left. Pin #1 will be the one closest to you on the left.

So, line it up with the empty socket and insert it with pin #1 on the front row, with pin #1 on the left. When you press to seat the opamp into the socket, press on the edges of the adapter not the center where the chip sits, or you may break the solder connections between the opamp and the adapter.

To do the opamp for the ground channel, you will find it to the left side of the battery closer to the rear of the amp (with the front of the amp still facing you). This opamp socket is rotated 90 degrees counter-clockwise. So, instead of the rows of pins running left/right, they run front/back - so pin #1 is now on the front right (with the volume knob of the amp facing you). This means pin #1 will be closest to the battery. Remove and replace as before.

You might need to put a small piece of foam or something soft like styrofoam (but not flammable) on top of the opamp to keep it from unseating when the amp is bumped around or dropped. Or a small amount of blue-tack against the edge of the opamp where it meets the socket could hold it down.

Turn on the amp, plug in headphones and a source (ipod or USB cable), and test it. If it works you can re-install the lid. The amp can pick up RF interference with the lid removed, so if you hear noise like it's picking up the hard drive moving, try putting the lid on first. If that doesn't fix the noise, you may have a bad opamp or one with the wrong specs for the amp design. If it's making painfully loud squealing, or totally silent with music playing, then you did something wrong or you killed the opamp, or it isn't seated tightly, or is in backwards, or it isn't compatable with the amp.


post #38 of 126
PS: Two other good opamp combos

1) LMH6622 main/THS4032 ground channel - this is in between the opamps I talked about in my 7/1/08 post. So, the sound falls between LM6172 main/THS4032 ground (for full size phones) and the THS4032 main/LM6172 ground (for IEM). This is good with both full size phones and yet not too forward with IEM. I left mine with these in it for a while, until #2 below came up.

2) LTC6241HV main/LMH6655 - this is the "Predator clone" combo discovered by HiFlight. I am finding it good with IEM and full size headphones, and really like it a lot. Here are my notes on this, and it is what I currently have in the D2 right now - http://www.head-fi.org/forums/f105/m...ml#post4661267
post #39 of 126
This is an amazing resource for opamp rolling in the D2! Thank you so much Draco63 for compiling them and to Larry and Hiflight for the testing!

I'm in the process of getting a D2 and a set of opamps from Hiflight and this thread is going to help immensely!
post #40 of 126
Yep. It's a terrific compiled source for the few D2 Viper owners there are of us out there. I bookmarked this thread a long time ago.
post #41 of 126
iBasso need to re-release the D2 Viper. No doubt about it.
post #42 of 126
The IC2(Left) is the main right?
While the IC7(Right) is the ground?

post #43 of 126
Originally Posted by 123cans View Post
Yes. BTW; I believe you can hardly do better than the stock configuration (at least with balanced full-spectrum phones), especially as the LT1364 is excellent, but hear for yourself.
Thanks for the quick reply!

I changed the opamp to LMH6622/THS4032 last week.
Previously I placed it the other way round that why I felt that it sound very thin. (Mix up the ground and the main)

You should really try this setup recommended by HeadphoneAddict.
I felt that it improved the D2 by a mile over the stock D2.
post #44 of 126
Yep - I wont recommend anything that sounds worse than stock
post #45 of 126
Hope the picture can be seen. credit goes to powertoold

[QUOTE/]Originally Posted by powertoold View Post

Hey Headphone,

I didn't think the ISL55002 was that great either. The sound didn't feel natural. I didn't read your whole thing on the 6172, but maybe your BrownDog had a loose leg. The left channel thing happened to me too once; I'm not sure what I did.

Mrarroyo, almost all DIP opamps have a notch on one side (horizontally) that looks like a half-circle. On the circuit board, there is also a half-circle diagram. If you match up the two half-circles when you install the opamp, it should be fine. If you don't see the half-circle on your opamp, then line up the opamp to the socket in such a way that you can read the opamp normally (ie. left to right) when the half-circle on the circuit board is on your left.

Here is a picture (the BrownDog is also self-explanatory):[/QUOTE]
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