Do It Yourself

Recently a distant friend grabbed a few of this pot, called bi p260p, made by plastic，sounds like some common Brit stuff. seems nothing special at all. But lol, I gotta lol first, P&G is OEM by this company... Actually, P&G is the cherry-picked version of this pot, the tolerance of this pot is 10% (means channel unbalance), we could just pick 10 of these, and select them by ourselves. No need to pay the price of P&G. btw, made by plastic is actually the element is plastic. link http://www.bitechnologies.com/products/panel_pots_sg.htm http://www.bitechnologies.com/ProAudio/ProAudio/index.htm

I know some of the newer and cheaper Chinese digital scopes are all the rage (Keysight, etc.) I am toying with buying a refurbed Tek 2465A, completely working, for a decent price. I know these have a proprietary IC in them, that if it fails, turns these into a doorstop (though I seem to recall this IC being available now...). Good idea or bad? For some reason, I've always wanted one of these... Flail away.

I think there are enough woodworkers on HC to warrant a thread now. Between Myself, Milo (AKA Al, AKA DOTU), Naaman, Doug, Jeff, Marc and I know there are others. I thought it might be nice to have a thread to keep up to date on various projects, new tools, new accessories and new enovations. For example: A new enovation I find very interesting, is a new blade stop safety system from The Felder Group. Like the system from SawStop, it's immediate, and it drops the blade out of the way before any damage to digits can be done. Unlike the SawStop system, it doesn't use a sacrificial cartridge to stop the blade. Don't get me wrong, the SawStop system was nothing short of …

BASS CAPACITOR Ok, someone explain what a digital capacitor is? Thanks.

I just got a PCB that has a void in the solder mask on top of the board. It is not a scratch, the mask is kinda piled up around the void. It looks like a contaminant may have kept the mask off that area. There are some epoxies online to fix this. I was wondering if you guys know of something locally obtainable to fix this?

So it looks like the old B&W speakers are ok, which leaves pretty much only the amp as the culprit. Specifically, it seems like one channel is problematic. The sound it puts out sounds very very muffled, distorted, and scratchy. I opened up the amp and didn't see anything that to my untrained eye appears to be obviously kablooey. However, I did note that one of the fuses on the board looks different than the others. It's not blown but could that be it? Anyone see anything else?

Well as a natural progression in this hobby, I find myself with more gear than power cords. In the past I have built power cords with 12 GA wire from Ram Electronics and VH Audio but the ones I have built are too damn stiff. All of my gear sits fairly close to the wall so I need a flexible medium weight cable for my power cord builds. I looked at the bulk cable offered at Take Five and Sonic Craft but they are a little on the expensive side and too heavy to stay properly seated in the IEC. Any recommendations for bulk cable would be appreciated.

Schematics and photos attached! I got my belated Christmas present from Justin the other day, a lovely KGSS amp. Finally I got to hear my new Stax 007 Mk2 (Omega 2) in all their glory. Knowing that I was going to install my own Goldpoint 1 dB/step attenuators, and a Left to mono switch (to check headphone balance), I asked Justin to agree to construct a KGSS without wiring the input connections to the back panel or installing a volume control (yes, he did test and burn in the board). Leaving me with some fun to do on my own! The first thing I discovered is that the KGSS is extremely sensitive. I judged it has at least 15 dB too much extra gain, even with consumer (nomi…

Kevin says Collins radio potentiometer is pretty dawn good, could anyone provide a little more details about Collins radio？ http://www.head-fi.org/t/677809/the-stax-thread-iii/2895#post_10778293

I am starting this thread for all that are or will be building JoaMat's mini T2 to share information, ideas, thoughts and experiences. The attached schematic is an updated one .The resistors in the BOM are thick film ones and can be replaced with thin film ones for likely better outcome. The power supply requirements for this amp are +400VDC, -460VDC (EL34 output stage), +220VDC (6922/6DJ8 front end), +15VDC, -15VDC (servo, cathode current source) and 6.3V filament supplies for the 6922/6DJ8 and EL34 tubes that can either be AC or DC. I also plan to use the +15VDC for the CPC1117N high tension delay. EDIT (Feb. 2020): updated schematic and BOM (Thanks Joa…

I've just stumbled across this http://www.st-andrews.ac.uk/~www_pa/Scots_Guide/audio/Analog.html are there other sites of a similar intent that you can recommend. (This is to save me trawling through threads at HF. )

Does anyone know a supplier that sells the square wood tube amp cases with the metal top for mounting the tube & transformers?

My apologies if this is in the wrong forum. Years ago I came under the possession of a beat up pair of Realistic Nova Pro headphones at a garage sale for two dollars. Not in the best condition, but serviceable enough for use. For a while now in the absence of speakers and disposable funding, they've served not only as my main choice for computer audio but also the headphones I carry with me to provide personal audio on the go. In the past two months alone, I have opened them up multiple times to replace oxidized connections, resoldering almost every connection in the left can alone, to maintain their functionality. Yeah, even though they're collector's items of sort…

planning to build an electrostataic amp for my SRM L700. I have built several amps for my Moving coil earphones (HD650, K601, K702...), but never built an electrostataic one, I read some topics about it, also some diagrams of amps , there are still some questions need your help. 1. Never saw the full differential structure (for example, opa1632, lme49724) used in the electrostataic amp, why? 2. The electrostataic earspeakers have much larger impedance than moving coil ones, the only capacitive impedance is isolated by the output resistor (usually 5.1k), so...the electrostataic amp works like without loads? 3. Why the output resistor is usually 5.1k ? …

How crazy lazy would it be for me to buy 3 of these and slap them into an enclosure, with a single big ass toroid transformer? It would be an 6 channel amp, I'd probably not use the 6th channel, as my speaker set up is 5.1 right now. Any recommendations for a Toroid feeding 3 of these? AMP5 kit - Tripath TA2022 41Hz Audio:AMP5 kit Although, I might just get one for starters and build a small desktop amp for 2 channel speaker set up for my computer workstation. -Ed

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.

so due to a comment i made over there, someone wanted to know if i had the eddie current dht filament schematic. here it is. eddiecurrentfilament.PDF

33 Step 100K Stereo Volume Control tube Preamplifier - eBay (item 150423738955 end time Apr-13-10 19:23:07 PDT) No personal investment, but Craig wanted to know so I thought I'd ask

just curious, has anyone tried using other tubes in the Blue Hawaii than the 6CA7/EL34? I ended up with a set of boards, and was looking at some datasheets over the weekend. I started looking at the 6BG6GE, 3D21A/WB/7403, 12E1, EL360, 6146, etc.... I started looking more at the 3D21A, but noted that the one major concern is that the transconductance is about half that of the EL34 which means that the gain will probably be about 6dB lower than the EL34, and depending on headroom in the cathode drive circuit this could result in significantly higher distortion. (Also, I might not get enough voltage swing without making other changes that would raise the source impedance …

Hey guys, I need to put together a wallwart for a project I'm working on. Is there any place that sells empty wallwarts you can put your own traffo in? I'm looking to get a 24-36vac center-tapped output. Any suggestions on a plug with three contacts to use for it, also? -edit- found an empty shell and a suitable traffo at jameco. Any ideas on a plug?

If you see an LOD plug that looks like this one, you might consider running in the opposite direction. Being the fair-minded guy that I am, I will say that this connector has certain things going for it and if those things are really important to you, you might not brand it a sadistic work of the devil. It's the most compact plug I've seen. The locking barbs work great. And the case itself is relatively easy to assemble. On the other hand... the contacts are staked in place. You can't pull out the ones that you don't want that are in the way. You have have to bend the pins that are adjacent to the ones you want out of the way to make any room to work at all…

I just happened upon this site, their cases are awesome, and they have a cool power distributor case thing too. http://www.hexateq-av.com/products.html

I have a pair of 2n5457/5458 JFETs on a small board as part of a bias scheme for a 12AX7. The circuit also has a 9v battery. I cannot get the voltage dialed down, so I checked the JFETs. The resistance from gate to source (and gate to drain) read the same in both directions: roughly 1k ohm. These are dead, aren't they?

I'm trying to fix my grandma's Westinghouse electric griddle from the 50s. The resistor (at least I think that's what it is) has failed. Unfortunately, whatever insulating material was used to encase it has melted, so there is no way to make out any part value labeling. Is there some general "close enough" value part I can replace it with or is an exact replacement the only way? I know this isn't audio related, but I thought I would try asking here before seeking out a vintage appliance repair forum (which I'm sure exists somewhere).

EDIT 8/4: attach updated GB details and remov outdated chart EDIT 7/31: attach updated GB details and remov outdated chart EDIT 7/27: attach GB details and remov outdated chart EDIT 7/23: attach PCB cost quotes and limit first time poster to 4 set of amp boards max. EDIT 7/19: proposing use of HV Carbon V5 board to replace both V2 and V3 boards. See posting # 190. EDIT 7/13: attach snapshot of final order entries and board count. EDIT 7/12: This GB is officially closed as of 7/12/2015. Due to the changes Kevin made to the PS boards, it'll take a few more days for these boards to be checked before I officially request quotes from the …