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A slightly different kind of voltage amplifier
(which is a current feedback amplifier) Lately I have been looking again for a discrete transistor voltage gain amplifier for line level duty that isn't just another op amp. I keep coming back to...
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CFA audio gainblock - a second take
This is either an ingenious interfacing of the output buffer and current feedback amplifier by adding second arm to the central current mirrors ... or it's another really bad idea(tm). It simulates...
View ArticleRJM Audio in 2017 [modular simplicity]
The time of year where I like to draw up some plans for the next 12 months. This years output looked something as follows, Lowering the noise floor by shielding the power transformers of my Sapphire3...
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The (Zener) Z-Reg Voltage Regulator
Companion regulator to the S-Reg. Same board dimensions and connection layout. For line level audio. Same idea as before rectified 2x12 VAC input, +/- 12 V output. 50 mA max output current unless the...
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The (Shunt-Source) S-Reg Voltage Regulator
S-reg voltage shunt-source regulator for line-level audio circuits. This is designed to accept rectified 12x2 VAC input, producing +/-12 V output split rails. Features soft-start and over-current...
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The (Xross-type) X-Reg Voltage Regulator (Stabilizer)
I've come this far so I might as well complete the trifecta. This is the X-Reg circuit, with a new layout and component numbering to match the new S-Reg and Z-Reg boards. Each is a drop in replacement...
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Introducing Project Unity
Following on from this post and this post, we arrive in time for the holidays with Project Unity. Merry Christmas everyone. Four circuits: Unity, Unity H, Unity B, Unity BH. line preamp, Headphone amp,...
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Project Unity Board Layout
Two boards, each board configurable for line and headphone variants. Powered by nominal +12 V -12 V split regulated supply, though 9-15 V rails can be used without modification. Attached Thumbnails...
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Dual Bridge Rectifier PCB
I'm sure there are dozens of people on diyaudio who could do up this layout, but hey, it was a super-quick modification of the cartridge loading board I was doing anyway ... so to continue the series...
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Phono Stage Cartridge Loading Auxiliary PCB
By request. Simple 4 option loading for MC or MM cartridges. Stereo board, 80x50 mm. Part of the "useful elements" series. Inputs are bidirectional (pass through), the signal only has to be connected...
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A power amplifier.
Another request. The Sapphire4 and Unity (H) boards were based on the 47 Labs Treasure 0347 amplifier circuit, and the original was not so far away that I couldn't "de-modify" the Unity (H) board back...
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Very Simple Phono Stage VSPS200 20th anniversary mono edition
The classic VSPS slightly updated and fitted with a very simple Zener voltage regulator. Relaxed, spacious, easy to work on 80x100 double sided mono circuit boards. The eagle .sch and .brd files,...
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CrystalFET 2 MM passive phono preamplifier with JFET amplification
In hindsight the original CrystalFET suffered from overreach. To obtain the 55 dB midband gain required for an MC phono stage lots of other things I might have wanted to build into the design like...
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Sapphire 4 headphone amplifier [Rev. 4.1m]
[in progress] Development thread starts here. While I consider this my best work to date, the documentation trail has become hopeless scattered and I don't have a write up of the project on my web page...
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Phonoclone 4.4s (and 4.5b)
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....
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