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The power of music.
The best part of Friday night. Put a record on – Evan Parker’s “the topography of the lungs” and opened a bottle of Brixton’s Atlantic Pale Ale. Curry delivery is on its way. What else can you ask to...
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CX-301a DHT Pre-amp Build from Malaysia
A fantastic build of the 01a preamp using the gyrator PCB from Cheah: I have just completed my 01a preamp with STP3NK60ZFP output follower. The preamp sounded great !! A great looking preamp using Rod...
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Flexible HT Power Supply (Part V)
I’m now back in business. Building a new 4P1L PSE output stage so will reuse the 300B/4P1L Flexible PSU. I never managed to post an update on the troubleshooting I had to do to get this HT PSU to its...
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01a Preamp (Gen2) Universal HT Supply
Introduction I received many requests throughout this year of folks building the 01a preamp (Gen2) asking for advice on the HT supply design. Well, I have my own incarnation which serves multiple...
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01a Gen2 Preamp Build from Barry French
Barry French has recently build his version of the 01a Preamp Gen2. Here are a couple of pictures: And Barry’s impressions: “The 01a Amplifier is a stunner, personally I feel it leaves the 26 out in...
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4P1L PSE project started
A new amplifier build has begun. The 4P1L PSE is coming to life. First top plate developed and arrived this morning. A succesful layout for being the first one. Need to submit for machining the other...
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3B7 DHT Preamplifier
An enthusiast blog reader (Paul Prinz) implemented a nice version of the DHT preamplifier using the gyrator PCB but for the 3B7 triode. The 3B7 triode has a pair of DHT triodes on the same bottle. It...
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4P1L: pump up the current!
Background I’m a firm believer than sharing knowledge and experience is the best way forward to continue learning yourself. It always pay pack at some point. This time Paul Prinz, a fellow implementer...
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46 driving 45 – SE Amp
My favourite valves together Recently I revisited a beloved amp, the SE 45. This time I will share a more orthodox design without sand in play. Surprised? Well, I love lots of iron as well and here is...
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DHT preamp “The Mule”
The birth of the Mule The name I guess says it all. This is yet another DHT preamp with the gyrator PCB. So what’s different? Simply, a breadboard DHT preamp module ready to be abused. I’m planning to...
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4P1L PSE Amp: assembling top plates
The additional machined top plates arrived yesterday. I assembled them this morning. Just need to assemble the chassis now before soldering!
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01a Preamp Gen2: New Build
Yet, another 01a preamp. This time with a beautiful machined top plate and wooden frame: Will try the Russian filament resistor which we tested at Andy Evans’ and sounded amazing. Just need to build a...
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01a Preamp Gen2: Build Complete
Yesterday I started with the build of a new 01a preamp Gen2. I made some component changes during the build process thanks to Andy Evans who reminded me of the Russian FT-2 teflon capacitors. I had a...
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Gyrator PCB board updated (Rev06)
After some further testing and prototyping, I’ve updated the gyrator board PCB to provide additional protection to the lower FET device with: Protection Zener (D3) between drain and source...
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4P1L PSE Amp Finished!
I’ve been travelling a lot lately so haven’t had the chance to update on this project. A couple of weeks ago I finished the 4P1L PSE Amp: 4P1L PSE Amp The amp is outstanding, just like previous...
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Gyrator FET options (More!)
Someone had to invest and sacrifice some gyrator boards to test various lower FETs (either depletion or enhancement devices as well as TO-92 or SMD options). That was me. Why? Because I want to push...
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C-299/CX-299 DHT Preamplifier
The start of a different DHT experience with the Mule I built the “Mule” to provide enough flexibility to test other DHTs as pre-amplifier / line stage. Using the gyrator board, the flexibility is...
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Pentode driver with gyrator load
If you need gain and good drive, our friend the pentode is there. However, with the high anode resistance, it’s hard to implement as a driver. With a resistor load you get good results, but not...
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“Schade” SE Amp Example
Introduction On my last post I covered how the gyrator PCB can be used in a pentode driver. The pentode driver is the best candidate in a “plate to plate” / shunt feedback or “Schade” feedback...
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VT-25 DHT Preamplifer
VT-25 in action Now I’m back from our long trip, I found some time to play with the “Mule“. I wanted to revisit my old VT-25 preamplifier. Many years ago I had my first VT-25/10 preamplifier which...
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