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...
View ArticleCX-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...
View ArticleFlexible 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...
View Article01a 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...
View Article01a 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...
View Article4P1L 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...
View Article3B7 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...
View Article4P1L: 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...
View Article46 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...
View ArticleDHT 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...
View Article4P1L 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!
View Article01a 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...
View Article01a 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...
View ArticleGyrator 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...
View Article4P1L 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...
View ArticleGyrator 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...
View ArticleC-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...
View ArticlePentode 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...
View Article“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...
View ArticleVT-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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