Generated by All in One SEO v4.9.10, this is an llms.txt file, used by LLMs to index the site. # VT52.com Blast from the Past ## Sitemaps - [XML Sitemap](https://vt52.com/sitemap.xml): Contains all public & indexable URLs for this website. ## Posts - [Blog](https://vt52.com/blog/) - [Last round of PCBs](https://vt52.com/2025/05/13/last-round-of-pcbs/) - One more round of PCBs. Should have everything in the pipeline now for the 4P1L headphone amp, plus some test options for the driver tube, maybe do a shootout between all the little russian tubes.I've designed the PCBs so they are modular and can be used stand-alone on a test board, or become part of - [Groundbreaking](https://vt52.com/2025/05/05/groundbreaking/) - Having more fun making PCBs. This time a ground loop breaker, or also just a star-point for earth and ground. - [Novalty](https://vt52.com/2025/05/06/novalty/) - More PCB fun :)Little board to hold all the small tidbits for the 6E6P. These little high-gm shits are prone to all sorts of oscillation nasty-ness. So, instead of burning my fingers trying to solder those tiny MKP caps and ferrite beads onto the noval sockets, I am just making PCBs for the tubes I - [Loctal 4P1L pcb](https://vt52.com/2025/05/08/loctal-4p1l-pcb/) - Four days off of work, so time to finalize the PCB designs and send out the order.Here's one for the 4P1L, along with a schematic of what is on the board.The teflon Loctal sockets have 1.25mm pins which will allow me to put ferrite beads directly over them, removing the need to add wire-through versions - [PCB Salvo 1](https://vt52.com/2025/05/09/pcb-salvo-1/) - Got some days off, so started finishing the PCB designs and just ordered the first batch.Noval socket + circuit - 5842- 6S45P- 6S4P- 6JxxP (6J9P, 6J11P, 6J49P, D3a) (triode)- 6E6P (triode)Loctal socket + circuit- 4P1L (triode)- 2P29L (triode)Div- Ground-loop Breaker / star-grounding- Lundahl LL2763 winding hookup- Lundahl LL2765 winding hookup - [PCBs ordered](https://vt52.com/2025/04/28/pcbs-ordered/) - Started making layouts for PCBs and sent the first two for the Lundahl transformers. Cheap as snot at $12 for 20, including shipping at JLCPCB. - [Quality of Life PCBs](https://vt52.com/2025/04/28/quality-of-life-pcbs/) - Designing some small PCBs to hold the tube socket and any local circuitry. Quality of Life stuff.noval socket pcb for 6E6Ploctal socket pcb for 4P1Land a small pcb to feed in the mains supply from a 230V~ euro plug, fuse and filter it, plus a circuit to attach ground to earth. - [Lundahl layouts](https://vt52.com/2025/04/27/lundahl-layouts/) - Working out how the Lundahl transformers are connecter so I can make some PCBs for easier connecting. - [Wayback Machine](https://vt52.com/2025/04/14/wayback-machine/) - Made a backup from a Wayback Machine copy of my site from 2022. This is just pre-botch and after some tinkering I have a workable source for all the old text/pictures. So, good news on that front. Now I have to find the time and energy to revive all those pages on the new site. ## Pages - [Home](https://vt52.com/) - stuffz Read blog Read more - [Links](https://vt52.com/links/) - Bartola [click] : Ale "Gyrator" Moglia's awesome DIY site with tons of projects, information and cool cartoonsMV Audio Labs [click] : THD measurements, insights, knowledgediyAudio [click] : Forum with every kind of audio related topic - [Home](https://vt52.com/home/) - So life happens and you forget to check in on your old site... turns out the whole thing was corrupted at some point and two million russian hackers spammed the living crud out of your site using the contact form. GG.Trying to set up a new version now, but it is going to take a - [PCB - Solid-State B+](https://vt52.com/projects/projects-pcbs/pcb-solid-state-b/) - Goals- passive supply- full-wave SiC or tube option- two LC/RC networksParts- SiC diodes + heatsinks- 700V MKP caps- holes for power resistors (RC)- screw terminals for chokes (LC)- holes for e-Choke MEC50/MEC100 (LC) 20/04/2025Schematic for the B+ pretty much done. A connector for D1/CT/D2 will allow the use of a tube rectifier instead should I - [Amps](https://vt52.com/projects/amps/) - Headphone amp [4P1L] click here - [Headphone Amp 4p1l/6e6p](https://vt52.com/projects/amps/new-plans/) - Goals- K.I.S.S. for first new project (c'mon Jim, you can do it!)- drive headphones at 22-35R- volume control- line-level input from DAC- re-use components from old projects- prepare for external PSU in future07/04/2025So I'm not reinventing the wheel on this one. My free time is limited so I want to just enjoy the music and - [Russian naming](https://vt52.com/tube-data/russian-naming/) - Ever wondered what the cycillic letters were in our alphabet? Below is a list of the russian letters, their translation and the meaning. These definitions are mainly for receiver tubes. position 1: Denotes the whole number of the heater/filament voltage, i.e. 6 for 6.3V position 2: A A Pentagrid converterB Б - [PCB - Indirect Filaments](https://vt52.com/projects/projects-pcbs/pcb-indirect-filaments/) - Goals- seperate pcbs to allow using supply/signal chassis- pcb for transformer, rectifier and first filter caps- pcb with regulator– soft-startParts- TO220 diodes for SiC, UF recovery or low Vf diodes- MIC29302WT regulator for low loss: 3A, 1.5-25V, 0.38V drop-out - [Setup](https://vt52.com/projects/stuff/) - CURRENT SETUPsource: PC / JRiverdac/amp: Marantz HD-DAC1 (usb, 24/192, dsd)headphones: Hifiman HE1000se + Focal ElegiaNEXT STEPSamp: 4P1L s.e. triode amp - [Projects](https://vt52.com/projects/) - PCBs (4)amplifiers (1)current setup - [Plans for 2025](https://vt52.com/projects/plans/) - GENERAL- get this site figured out (logo, theme, get old data back online)- upgrade headphone systemPROJECTS- pcb for solid-state B+ supply click here- pcb passive filament supplies (IHT and DHT) click here- pcb regulator/soft-start for indirectly heated filaments click here- headphone amp 4P1L click here - [About](https://vt52.com/about/) - time - [Projects - PCBs](https://vt52.com/projects/projects-pcbs/) - solid-state B+ click hereindirect filament supply click heresolid-state rectifier click herecontrol logic click here - [PCB - Logic](https://vt52.com/projects/projects-pcbs/pcb-logic/) - Goals- collect PSU status- delayed power-up- individual enable for each PSU channel- detect cable disconnectsPCB for power-up logic– audio-signal filaments first– rectifier tube filament or solid-state B+ after delay– detect cable disconnect and shut down affected supplies - [PCB - Solid-State Rectifier](https://vt52.com/projects/projects-pcbs/pcb-solid-state-rectifier/) - Goals- for external B+ or filament supply chassis- bridge or full-wave option- single CLC/CRC sectionParts- 1200V/11A SiC diodes + heatsinks- holes for 700V MKP or high-µF electrolytic- bleed resistor to discharge/load supplyExternal signaling/control- input: enable supply- input: cable disconnected (shut down supply)- output: powered up - [Speakers](https://vt52.com/projects/built/) - [Tube Data](https://vt52.com/tube-data/) ## Categories - [Uncategorized](https://vt52.com/category/uncategorized/) ## Tags - [6e6p](https://vt52.com/tag/6e6p/) - [ground](https://vt52.com/tag/ground/) - [4p1l](https://vt52.com/tag/4p1l/) - [headphone](https://vt52.com/tag/headphone/) - [pcb](https://vt52.com/tag/pcb/) - [lundahl](https://vt52.com/tag/lundahl/) - [2763](https://vt52.com/tag/2763/) - [2765](https://vt52.com/tag/2765/) - [transformer](https://vt52.com/tag/transformer/) - [6s4p](https://vt52.com/tag/6s4p/) - [noval](https://vt52.com/tag/noval/) - [loctal](https://vt52.com/tag/loctal/) - [6s45p](https://vt52.com/tag/6s45p/) - [5842](https://vt52.com/tag/5842/) - [2p29l](https://vt52.com/tag/2p29l/) - [6j49p](https://vt52.com/tag/6j49p/) - [d3a](https://vt52.com/tag/d3a/) - [6j11p](https://vt52.com/tag/6j11p/) - [filament](https://vt52.com/tag/filament/) - [iht](https://vt52.com/tag/iht/) - [raw](https://vt52.com/tag/raw/) - [earth](https://vt52.com/tag/earth/)