- 6,960 Posts. Joined 9/2007
- Select All Posts By This User
Recent Images In This Thread
- brandDIYtagged by joe, 2/11/15
Related Forum Threads
- The Soekris R-2R DAC: Technical Details Last post on 9/8/16 at 10:31pm in Dedicated Source Components
- "Double Barrel" Fully machined aluminum closed back headphones Last post on 2/23/15 at 9:47am in DIY (Do-It-Yourself) Discussions
- CUSTOM DIY NOISE CANCELING HEADPHONES BETTER THAN BOSE QC15. For 30 Bucks! Last post on 8/13/12 at 11:32am in Portable Headphones, Earphones and In-Ear Monitors
- FS: Millett Hybrid MiniMax Last post on 10/29/11 at 3:04pm in Amplification For Sale / Trade
- I think I blew out my Left channel on my GILMORE LITE Last post on 11/30/10 at 4:13am in Headphone Amps (full-size)
DIY Cable Info and Resources
Last edited: 3/18/16
- Diy Beginners GuideLast edited: 7/22/13
- List Of Diy Headphone AmpsLast edited: 11/22/12
I was honoured to be approached by iBasso with their first venture into IEM territory and they asked me to provide a review of their recently released earphone. iBasso are well know for their...
Jomo Audio is a Singapore local company that crafts in ear earphones that sound and look wonderful. They are well known and highly respected in Singapore but have little exposure in Europe. So...
Elephone Whisper Noise Cancelling Earphone Quick Review by mark2410 Thanks to GearBest for the sample. Full review...
Disclaimer: These headphones were sent to me thanks to the Oppo loaner program. They have since been returned and sent to the next reviewer. Want a headphone that sounds excellent, is easy...
Introduction: Unfamiliar Territory A couple of years ago, I was telling my father-in-law about my audio and music hobby. He asked me if the equipment I had was made by "Pioneer, Sony" or...
my DAC design - pup1 DAC - Page 3post #31 of 6742/25/11 at 5:18amJust wondering if this can be configured to feed the Carrie like the Grub?
Head-Fi's Best Sellerspost #32 of 6742/25/11 at 5:28amThread Starter
If you look at the picture of the board, point 1A is the 5V USB taken after the ferrite and right next to it is a ground.
So I suspect that yes it can. I haven't read all the latest on the Carrie, but I know that there was some start-up issues that were happening if you didn't take the power off the bottom of one of the caps on the grubDAC, so I can't say 100% that it would work.
And also the pup1 is the full length of the 1455C801 case. You'd have to look at something like the 1455C1201post #33 of 6742/25/11 at 4:21pmpost #34 of 6742/25/11 at 11:05pm
Does the IV opamp put out enough power to drive headphones directly do you think? Is the power supply robust enough to handle such a load? This would make a really cool single board solution for portable listening.post #35 of 6742/26/11 at 11:11pmQuote:
You'll have to wait for cobaltmute to answer that one.
Meanwhile, for those of you who commit to building one of these, I can perhaps supply some of the TI chips. Since it's for prototyping, the TI sample program should apply. Just be aware that if I supply you with the chips, you can't eventually sell the device except for a price that will only recoup your miscellaneous parts investment (not the chips). Those are Head-Fi rules, anyway.
I'll coordinate with cobaltmute on those of you who have requested a PCB and send you what I can. I'm pretty sure I can supply the DAC chip and perhaps some of the TPS's. I'll take stock tomorrow and we'll see.
post #36 of 6742/27/11 at 12:17ampost #37 of 6742/27/11 at 5:46amThread Starter
As I've said, I'd deal with the PMs on Monday, but everyone that has PM'ed me will get a board.
So that you can have this before you commit, this is an up to date Digikey BOM:
I only have a BOM for Digikey for this project. It is complete, short the Hammond 1455C801 case.post #38 of 6742/27/11 at 10:55ampost #39 of 6742/27/11 at 11:47ampost #40 of 6742/27/11 at 12:24pmQuote:
Hmm ... looks like they'll have the 10K resistor on 3/23. In the meantime, this one should work: P10.0KCACT-ND
As for the PCM2707, I think DigiKey has stopped stocking them altogether. Let's just assume that I will provide you with those, along with the DAC chip. I don't have the opamps, but may be able to supply a lot of the TPS chips, too. Once cobaltmute gets me a count of the PCB's he's going to distribute, I'll get a better idea what I can supply and announce it here.
post #41 of 6742/27/11 at 6:01pmThread Starter
If your tastes involve listening at quiet to moderate levels, you could likely get away with it. Higher impedance cans would also be a better choice.
The charge pump for the negative output rail only outputs 60mA and this is used for both channels. Low impedance cans will likely draw more than this design can output.
That being said, I'm listening to "Buena Vista Social Club" at -20dB in foobar with my HD650 and it sounds great.post #42 of 6742/28/11 at 6:48pmThread Starterpost #43 of 6742/28/11 at 8:13pmpost #44 of 6743/3/11 at 7:43pmThread Starter
As an update for the prototype team, tomb is going to send me the PCM chips to me to include with the boards when I mail them out. I will ask for the money for shipping and the addresses of those that are getting protos when I am ready to ship.
I've been asked about op-amp rolling, and here are my thoughts on that.
So far, I've attempted to use three DACs on the board
- THS4222 - extremely high speed, but was not stable at all
- LMH6643 - this is the current choice for me. Personally, I think the board sounds so good with this, I haven't seen the need to try others
- LME49721 - this is a "slow" opamp and seems to be stable when the other start to be unstable and show offset issue.
There is two choices for the rails and this can affect your choice of op-amp
- Regulated - using the BOM parts, you get +-2.5V on the rails.
- Unregulated - don't install the regulators, and jumper 1A to 1B and 2A to 2B. You have to understand what you're dealing with though. USB input power can be 4.75 - 5.25V. The charge pump will invert that to equivalent negative voltage. The issue comes that the charge pump droops as it gets more loaded. The rail will droop up to 0.5V, so the negative rail could end up at about -4.25V. When considering op-amps, for safety, I would consider +-4V as working, but they need to be able to handle +-5.25V.
If you are looking at the regulated option, consider rail-to-rail output amps to ensure that you don't have issues.
As I mentioned in the initial post for prototypers, the layout of the board, may be prone to offset issues. My board is stable with the LMH6643, but I have built one (where I put the output resistors on the bottom side) and it had offset issues on one channel (150mV IIRC). You will need to check your build for offset, and if it is excessive, the easy fix is to replace the LMH6643 with a LME49721.
Minor offset, depending on your setup, you can live with. If there is any stage that is AC coupled, you are good, If you have a DC servo in your signal chain, you are also likely good depending upon its range. If you are full DC coupled with no servo, you'll have to look at the offset and your gain and decide upon your risk tolerance.post #45 of 6743/4/11 at 5:17am
Mine is only 20mV from USB ground to the Left channel output, and 29mV on the right. Measuring from Left and Right output to the output Ground was only 3mV and 5mV, respectively - not an issue at all, IMHO.
- my DAC design - pup1 DAC
Head-Fi's Best Sellers
- Diy Beginners Guide
- › Campfire Audio Vega (and Dorado and Lyra II) - Head-Fi TV 2 seconds ago
- › Need Help From AudioPhiles 13 seconds ago
- › dropping $ on a e10k - anything better around this price range? 1 minute ago
- › MrSpeakers ETHER Flow and ETHER C Flow -- Inspired by Electrostatic... 3 minutes ago
- › Dapper for Mac updates: App to sync iTunes with your DAP 4 minutes ago
- › NEW Aurender A10 Music Server, Player & DAC 5 minutes ago
- › NEW Fostex TR-70, TR-80 & TR-90 6 minutes ago
- › FiiO X1 II (2nd Gen) w/ Bluetooth! 6 minutes ago
- › Earbuds Round-Up 6 minutes ago
- › VE - A New and Impressive Earbuds Brand 6 minutes ago
- › iBasso IT03 by sonickarma
- › Jomo Audio Samba Pro CIEM by sonickarma
- › Elephone Whisper by mark2410
- › OPPO PM-1 by maxh22
- › iBasso Audio DX80 High Resolution Audio Player by rebbi
- › 1MORE Capsule Dual Driver In-Ear Headphones with In-line Microphone... by B9Scrambler
- › RHA MA750i by High-End-Addict
- › Hidizs AP60 HiFi Mini Bluetooth Lossless MP3 Portable Music Player... by HiFiChris
- › 64 Audio U10 by Brooko
- › FiiO X1-II High Resolution Lossless Music Player (2nd Generation)... by noobandroid
- › Flawless Album Suggestions
- › The Audiophile Scene in a Third World Country...
- › Mad Lust Envy's Headphone Gaming Guide,...
- › Mad Lust Envy's Headphone Gaming Guide,...
- › Mad Lust Envy's Headphone Gaming Guide:...
- › Chord Mojo FAQ
- › Head-Fi Logo Gear
- › All about iPod Touch 6G as digital transport
- › List of major HiFiMan HE1000 reviews,...
- › Can I change my user name? Can I delete my...