Do It Yourself

This has been needed for a while. For those with problematic DAC's that put out a bit of DC, and balanced headphone amplifiers happy to amplify said DC and produce differential DC on the output... http://gilmore.chem.northwestern.edu/protector.jpg This is the one case where ti kan's protection board does not work, unless you want to use 2 of them.

I was going to build a balanced isolation transformer. But I had difficult to choose form either EI or toroid. Regardless of price and size, which theoretically will be better (in performance)? I was planning to build around 2KVA. Does anyone have experience?

finally. higher signal to noise ratio, more than 110db. takes signals up to 20 volts peak to peak unbalanced, 40v peak to peak balanced. no input attenuator that adds noise for those stupidly high voltage dacs. ( requires 30v power supplies) (volume control in the middle) thd about .005% no feedback. work in progress 4 layer board. preamp2025f.PDF

Is there a balanced to unbalanced (single ended) board that is recommended? Twisted Pear has two options but they use op amps, and then there's the Broskie Cathode Follower, and Unbalancer Two. Those two use tubes. What else is out there?

I have all my parts and finally have some free time to balance the HD650 stock cable with 2 female XLR connectors. I have done some searching and these two threads in particular were the most helpful: http://www.head-fi.org/forums/showthread.php?t=205655 http://www.head-fi.org/forums/showthread.php?t=89411 My knowledge of balanced configurations is limited so I'll try and compile all the information I've gathered tonight:

I am probably starting to much thread here but anyway, here is another one. I heard about the Bamaslama amp, and now I want to build one. schematic: PSU amp Is the relay needed because of the power supply design ? Does it make a "plop" when you power the amp ? Can I use cheap dual op-amp or something special is needed there ? Then what kind of relay do I need ? Are all resistors 1/4W ? Do i need matched pair for the second stage tube ? What will be the DC offset like ? What is the filament wiring like ? What will be the approximate price to build it ? I will use cheap coupling caps in the first time. Lots of question as always,

http://www.diyaudio.com/forums/showthread.php?s=&threadid=82520 $249 plus shipping. You can run it at full power if you have 240 volts available for primary, or at 70% power if you run it as 120 in 120 out. Shipping for 100 lbs...

Is it too ambitious of a beginner project to try and do like, a BantamDAC and Mini^3 or Pimeta in a single enclosure? Note that my experience with casework and surface mount soldering is zero, not even having made either standalone. I think the casework is going to be the hardest part of this, based on what I've read from past DIY stuff, and I guess the question boils down to "is the casework for two-in-one a bad idea to do before doing a single?" if I'm not mistaken.

Anyone know anything about these? How would these compare to Amb's regs, or even the micro GRLV? Someone asked me about them. I'm normally very leery of the shit that Partsconnexion sells (Bybee? Burson? etc.). https://www.partsconnexion.com/BELLSPX17-85570.html https://www.partsconnexion.com/BELLSPX79-85599.html

Just grabbed a pair of 207, almost new, cost $400... Gonna wanna diy an amp for it, better under $3,000... is kgss seriously overkill? Just wanna have a taste at the famous stax, no interested in the superior models, yet.

I got my Buffalo DAC yesterday. I'm having a few problems with the IVY stage, but when I've had it working correctly it sounds flippin' sweet. I do wonder, though, if I can do better for an output stage. Of course, there's the zapfilter, but I imagine using some nice transformers for the I/V conversion or maybe some autoformers would be pretty tops. Anyone have any experience on best sounding method for I/V conversion? Tubes? Opamps? Transformers? Simple resistor (and differences between resistor brands)?

I need to pick up three sets of tube sockets for my Dared 845 amp and I assume I need 2 pcb mount 12ax7, 2 6sn7 pcb mount (do they make a 7n7 pcb mount?) and a pair of 845 bayonet type sockets. I really prefer high quality over saving a few bucks. Any ideas on where to buy also ceramic and teflon is one better than the other? The reason I ask is I found a local tech here in the East Bay (SF area) that will do the work if I source the sockets. Great older guy who grew up in the radio and recording industry. Thanks in advance for any help that you can provide.

folks, if i wanna build a single ended amp (amp for headphones, but not electrostatic amp), which model(s) is the best choice?

So I am planning on ordering a bunch of the BC546 and BC556 for the Unbalanced\Balanced board and I'll need to measure, sort, label and store them. 1. can I store them in a regular plastic parts bin with dividers? 2. can I stick labels on the pins and fold the labels closed?

I'm in the process of putting together an Elenco XP-720K bench power supply kit. The kit has 3 ICs and 1 transistor in T0-220 package format. The instructions have the builder bending the legs 90 degrees and then mounting the devices on the heat sink. This seems normal enough. However, to hook wires up to the devices, the instructions instruct the builder to tin the wire and solder it to the correct leg. The instructions are here: Elenco XP-720K manual To me, this approach seems likely to result in a fragile device. Is this a normal thing to do? I assume that there are connectors I could use. Would it be better to use connectors. Or can you suggest yet anot…

So, I'm working on a pair of monoblocks. swt61 has seen these monster heat sinks. 12.2" wide x 12" tall with 2.925" fins and 0.326" base, weight is 13 pounds... and I got four. I've done some thermal plots of 6 devices per heatsink on a small PCB. Each device is dissipating 14.8W x 6 devices x 4 channels ~ 350W. I'm wondering how much further I can push the devices. The sim data is very close to actual temperatures and since I don't want to drill holes under the devices for thermal probes, the simulator will be gospel. I don't really want to move the devices apart anymore, as I have a PCB in mind I'd like to accommodate, plus a design of my own. Datasheets for devices:…

So I have a Bijou built by dBel84 (Don) and am curious about the negative feedback. With the pot turned all the way down (7 oclock) it seems to have no negative feedback and is perfect for my AKG 340's . As you turn the pot clockwise you get less and less sound. Am I supposed to turn the negative feedback up when using Grado's and Ultrasones ( I know everybody at head-case loves Ultrasones) If I turn it up too much it seems to loose a lot of the lushness of the amp. I am still trying to figure out the best spot for my low impendence phones. Anybody got any advice? Chris

Wondering what type of plastic Stax uses for the (black) jacks on their amps. Or if anyone knows of a black plastic or material that is machinable and plays nice with high voltage. I don't know what Stax uses, thought it might be bakelite as it is hard and brittle but it fails the "409" test for bakelite and a sliver that I cut from one floats as well (bakelite is heavier than water). You can sometimes identify plastics by the way they burn. Couldn't ignite the (tiny) slivers that I had. Possibly a phenolic smell after heating, might be a lower density resin related to bakelite. DIY jacks are usually made from white teflon (or delrin). Black coloured materials t…

I was looking around for something to bling my tubes around the base on the casework and found a nice and cheap way to do it for those little amps like the Starving student and CTH, EHHA and others with wee tubes. Looking around in Lowes hardware stores I found these solid brass Brainerd door viewers: If you unscrew the ends you end up with a pair of brass surrounds. One end fits the CTH and Ehha size tubes and the other fits the Starving student tubes so you'll need to buy two viewers to get a matching pair @ $7 or so each. When added to the case, you get this nice bling surround. They are pretty deep as you can see so you may need to trim them down depe…

Here are my BOM for a pair of BH. https://www.mouser.tw/ProjectManager/ProjectDetail.aspx?AccessID=b44788bc7f for GRLV and GRHV. copied from Carbon build thread. http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=b6d687c7f7 http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=54687aa8fa Parts I already have or going to buy from local dealer are NOT included like LEDs, insulators, IC sockets. Someone need to check if all resistor value are correct. I hope I could finish it at the end of April

Hi all, Im planning to build a blue hawaiii using the version 6s bipolar amp boards (kgbhver6sbipolar.zip) and the kgsshv dual 2 new power supply, (kgsshvpssicfetdual2new.zip) Gerber files are in https://drive.google.com/drive/folders/0B_iJFfZStuVhSE5nOHBVdTByR1k Has anyone tried this combination? will the psu provide sufficent current (the voltages are fine +-400V -+15V and 580V) Does anyone know what ratings I need for the transformer Im guessing for the secondaries 2x 6.3 5A (el34s draw about 1.5A each plus I want plenty of headroom) 2x 360V 230mA 18-0-18V 200mA Does the kgsshvpssicfetdual2new offer delayed start for…

Posted this on the other forum, but I get the feeling the audience here will probably enjoy this as well. If I'm breaking any rules by posting this here too please let me know....or just delete it. Cheers. I've started building a pair of Zaph's Bargain Mini's (ZBM) along with Zaph's SR-71. I'll be documenting my build progress in this thread with pictures and comments. Making this thread somewhat for your entertainment and for me to use it somewhat as a log of progress (or lack thereof) as these will basically be my second and third woodworking projects to date. Hope you enjoy this thread as much as I (hopefully) will enjoy the build! I'm planning on building the bo…

so, I've been playing around with some diodes on a power supply and found some I like, but I think I'm cutting it too close with the current rating. The transformer is 82VCT 50VA R-core and I have a 300mA fuse on each rail after the main supply capacitance, which is around 3000uF per rail. I wouldn't expect any more than 300mA per rail, hence the fuse choice. That being said, there is in-rush and the like to consider, and blowing a bridge isn't too exciting in my book. So, without admitting how stupid I was, and how low I went... in your opinion, what's a good rule of thumb?

I want to tackle and finally finish this PINT amp I recently acquired. It's old school and I scored the board for next to nothing, so what the heck. I know the project ended up ceasing because of the crankiness of the 8397. There’s got to be a way to tame this thing. At this point, I’m not sure if I’ve fried the opamps, but I can say that the 8397 gets very very hot. I’m using the LM6172 as my GND channel opamp and this is getting quite warm as well. This is when I power the amp with at least 18v or 24v. I'm getting an unusual amount of DC Offset -- basically the rail supply for each reading that I've done. At first the amp seemed to work but music sounded hollow and not …

So who is going to be building one of THESE new Buffalo DACS using the ESS ES9018 Sabre32 DAC Chip? This may just be the DAC I have been looking for as it can take PCM up to 32bits and 192kHz as well as DSD. This may just get me back into some DIY.