Years ago I moved from the country back into the city. This was a move that required me to clean out heaps of stuff that I really didn't want to clear out. In our old place we had two houses on the block, one of which had been converted into an enormous studio room with NO walls, and a 14 by 14 metre shed. To say that I amassed a collection of speakers and stuff would be an understatement.
One of the things I got rid of were a pair of Richard Allan CG-10 drivers that I never got around to sticking in a box. Indeed, I never even got around to measuring their parameters.
Recently on EBAY I came across a pair of these...
I was surprised at the condition of these - the cones look new. Needless to say they are not, the date code is 1973.
I have measured and used the CG-12, HD-15 and a bunch of other Richard Allan drivers in the past and found them...
in my electronics workshop I have always had a stereo. Eight years ago I looked on the shelf and decided there was all the makings of an integrated preamp - DSP - Crossover and four power amplifiers.
That is the price of always making an extra board or two when I build a "thing" - you end up with a massive collection of bits.
I duly shoe-horned this lot into a case that is about 3" high. Tuned it up and didn't think a lot more.
Fast forward 8 years to two weeks ago, and there I was listening to the radio while wondering what to build next, and I thought the left tweeter sounded a bit low.
I swapped input to the amp L-R, and yep, it was. Odd - as the DSP treats L and R exactly the same, there is no balance control in there. So I swapped the speakers. Hmm, it wasn't the tweeter. It was inside the "box".
Posted 7th March 2017 at 03:00 PM byalexcp (My DIY projects)
Updated 13th March 2017 at 09:20 PM byalexcp
I purchased an Aikido Cathode Follower 2 (ACF-2) All-in-One 9-Pin PCB from Glass-Ware.com. The PCB is designed by John Broskie, the editor of Tube Cad Journal (tubecad.com), and the flexibility that he designed in is quite remarkable. The PCB allows to test various configurations, which is often not a feature of a design committed to a PCB. The quality of the PCB is outstanding; it withstands multiple soldering and desoldering without complaint. It is an outstanding product IMHO.
The schematic seems to be simple, with a cathode follower loaded by a triode current source. JJ E88CC with 221ohm cathode resistors shows 0.003% THD with pure 2nd harmonic, and select 6N1P-VI achieve 0.005%. (My 6N1Ps are hit or miss; some of them have much higher 2nd harmonic, and some of them have a mix of 2nd and 3rd at Ia=6ma and Ua=140V).
As I tested my ACF, I noticed excessive hum at its outputs - audible buzz in the speakers and 0.15% THD+N, well above the THD.
Posted 18th February 2017 at 03:53 AM byrjm (RJM Audio Blog)
Updated 21st March 2017 at 11:31 PM byrjm(update to 300m production release)
The classic VSPS slightly updated and fitted with a simple filtered Zener voltage regulator (Z-Reg).
Relaxed, spacious, easy to work on 80x100 double sided mono circuit boards.
The eagle .sch and .brd files, LTSpice .asc file, and Gerber zip package are all provided below.
Works fine with the NE5534A, or use whatever op amp you choose.
revision and edit history:
200a initial release
200b changed to 70x90 hole spacing
200c C3 package changed to PCM37.5, updated C3 part listing in BOM to Kemet
200d changed regulator back to the Z-reg add R9,10 to BOM
200e move C1 and C2 capacitors 90 degrees
200f further layout tweaks
200g even more layout tweaks
200h are we done with this yet?
200i - skipped -
200j - skipped -
200k removed brestrict layer and re-did the power planes using only rect/split
200l - skipped -...
Posted 15th February 2017 at 11:11 PM byrjm (RJM Audio Blog)
Updated 25th March 2017 at 11:36 PM byrjm(BOM 40b8 and photo uploaded)
The RJM Audio Phonoclone phono stage circuit has not changed since the first board was produced. The previous iterations just refined the layout and applied various approaches to the voltage regulation.
Most of you are probably only aware of the X-Reg sporting Phonoclone 3, but there were actually quite a few earlier versions with LM317 and LM7812 regulators.
The Phonoclone 4 applies a major revision to the board layout, making it more logical with grouped, standardized I/O connections. The X-Reg has been replaced with the S-Reg shunt regulator circuit. Overall the BOM has been considerably simplified and the parts cost reduced.
For the moment, the boards are back-compatible with earlier Phonoclone revisions, with the anachronistic 2.5"x3.5" mounting holes. Future versions will move to the 70x90mm mounting holes to be compatible with the Sapphire and CrystalFET boards.
A small number of evaluation boards (double sided,...
Posted 8th February 2017 at 12:30 PM byabraxalito Updated 13th February 2017 at 03:48 AM byabraxalito
I've been looking for something like this on Taobao for a few years now. A cheap player which includes a digital output so I can pair it up with one of my DACs. There have been cheap players, and there have been FLAC players but never cheap FLAC players - the cheapest prior to this one being a media player around 500rmb. This one goes into the pocket change category as its just 88rmb. What's more it includes Bluetooth. Order placed - will update after I've played with it.
Just received this - the heart of the beast is the Actions Semi ATS2825, some information about its features is available here : http://www.actions-semi.com/en/productview.aspx?id=195.
Whereas a connector for headphones (top right) is shown on the photo, this doesn't support any analog out (my board has no connector fitted there). Its purely digital output - a header for I2S and...
Just yesterday evening, I received my iNuke NU3000DSP.
I've been playing around with it for a while and I absolutely love playing with the settings. I've tried out almost everything and even as a main driver it'd sound better than my current amp.
i've made speakon connectors already, but the xlr plugs aren't working. Can someone help me set up how to connect an unbalanced source like seperate RCA's to two XLR's? Like one XLR plug with the White RCA and anothe one with the Right. The pinout is confusing as some don't state Viewed from the from or Viewed from the back.
Cheers, though. I love this amp for subwoofer duty.
Posted 7th February 2017 at 01:47 PM byGrasso789 Updated 25th March 2017 at 03:11 AM byGrasso789
Recently it has been archieved to capture, store, propagate and play back audio with the full human hearing frequency range (16 to 16000 Hz) and contrast (7 Bel). Still, if a big sound source or several sound sources at once are the matter of content, such playback sounds artificial, because all is emitted from one small single acoustic source. In order to hear, what is going on, we use both ears simultaniously, turn our head in different directions and will detect the electro-acoustic device.
While an indetectable electro-acoustic reproduction incorporated six microphones, storage and transmission channels and a house-sized sphere covered by loudspeakers on the inside and containing the listener, we can help imagination at least a little bit by introducing sonic differences between left and rite. We also want this stereo, after Greek stereos shape, to integrate thoroly and easily with already existing mono electro-acoustics. We may double transmission and storage channels,...