Hi all
I'm about to undertake my first DIY tube amp project (power or integrated) and need some recommendations of schematics and designs that would be a good place to start.
I've looked at kits and whilst that is convenient it does seem a lot like lego (and I have a Elekit preamp to cover that). Ideally I'm looking for something that has a fairly well regarded schematic, parts list and if possible an explanation of why certain parts are placed where they are and what function they have. The guitar amp guys seems to have access to lots of these but I can't find much from the audio world.
Obviously I love the Kondo and Luxman stuff but every time I find a schematic I see comments posted that lead me to believe the layouts are incorrect or have errors. I'm just a beginner and yes I'm aware my DIY will sound nothing like a well established company that uses the finest parts, but that's ultimately not the point of this project. The goal is to build something and to learn whilst doing it.
Best
I'm about to undertake my first DIY tube amp project (power or integrated) and need some recommendations of schematics and designs that would be a good place to start.
I've looked at kits and whilst that is convenient it does seem a lot like lego (and I have a Elekit preamp to cover that). Ideally I'm looking for something that has a fairly well regarded schematic, parts list and if possible an explanation of why certain parts are placed where they are and what function they have. The guitar amp guys seems to have access to lots of these but I can't find much from the audio world.
Obviously I love the Kondo and Luxman stuff but every time I find a schematic I see comments posted that lead me to believe the layouts are incorrect or have errors. I'm just a beginner and yes I'm aware my DIY will sound nothing like a well established company that uses the finest parts, but that's ultimately not the point of this project. The goal is to build something and to learn whilst doing it.
Best
A simple EL84 Push pull seems like a good first project. Now this may not suit your needs exactly, but its essentially the ECC82 phase splitter from the Philips datasheet and the EL84 outputs on a single 100x100mm board.
I have a board design for that for free, if point to point seems daunting at first.
See attached the board files, if you are any good with eagle, send me a PM and i will email you the boardfiles to adapt to your own needs.
I have a board design for that for free, if point to point seems daunting at first.
See attached the board files, if you are any good with eagle, send me a PM and i will email you the boardfiles to adapt to your own needs.
Attachments
I have a couple questions on it. What values for R1 and C1? B+? Output transformer impedance?
Anyone built this?
Anyone built this?
Do you want a kit complete with parts, chassis, transformers, etc, like an Elekit?
Do you want a PCB to stuff, choose your own transformers, make your own PSU, drill and punch holes in your own chassis, etc?
Or do you want to do a from-scratch build, point-to-point wiring and all?
Do you want a PCB to stuff, choose your own transformers, make your own PSU, drill and punch holes in your own chassis, etc?
Or do you want to do a from-scratch build, point-to-point wiring and all?
R1 is the cathode resistor for the EL84, this depends slightly on B+ but at a conservative setting of 250V in class A or class AB 150R 3W should suffice.
C1 is the bypass capacitor in axial 15mm pitch 47-100uF 25Vdc will suffice.
output transformer 7K anode-anode for most configurations, but i deliberately left out those blanks so people would study the excelent Philips EL84 datasheet, with reccomended operating points. for triode or UL operation.
As far as i know, about half a dozen amplifiers have been build with this board. So i know it works, but its free so YMMV. I have a dedicated thread to free PCB designs, but i want to take a hands-off approach.
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Is 15 wpc enough?
Can recommend the Tubelab (forum on this site) SPP (simple push pull). Board available if you want to go that route or build it point to point with turret boards. It uses EL84, GZ34 and ECC81 tubes.
Complete build series here:
DIY EL84 Amp Project: Part 2, Circuit Board and Chassis Preparation | Wall of Sound | Audio and Music Reviews
The most expensive parts are the transformers. Overseas shipping is the killer but see link below for British made "iron". I've not used these but I believe others have with decent results.
25W 7600 Ohms Ultra Linear Push Pull Output transformer – Primary Windings
Mains transformer Mullard 5-10 Stereo – 600V @200mA CT, 6.3V @4A and 6.3V/5V @ 2A – Primary Windings
Can recommend the Tubelab (forum on this site) SPP (simple push pull). Board available if you want to go that route or build it point to point with turret boards. It uses EL84, GZ34 and ECC81 tubes.
Complete build series here:
DIY EL84 Amp Project: Part 2, Circuit Board and Chassis Preparation | Wall of Sound | Audio and Music Reviews
The most expensive parts are the transformers. Overseas shipping is the killer but see link below for British made "iron". I've not used these but I believe others have with decent results.
25W 7600 Ohms Ultra Linear Push Pull Output transformer – Primary Windings
Mains transformer Mullard 5-10 Stereo – 600V @200mA CT, 6.3V @4A and 6.3V/5V @ 2A – Primary Windings
Thanks for the responses all. Very helpful and lots for me to read and digest. I’d like to have a go at p2p wiring, probably with turrets, that will help my brain understand translating a schematic into a layout more than a pcb (might just be me). I’ll do some digging around transformers here in Singapore, although postage from the UK is normally ok, especially when they remove the VAT.
toydestroyer,
In Singapore you can get tubes and transformers at Martin Electronics and Well Audio Labs, located on the ground floor of Burlington Square.
In Singapore you can get tubes and transformers at Martin Electronics and Well Audio Labs, located on the ground floor of Burlington Square.
Thanks. I’ve looked through their windows many times. Being a bit of a newbie at this those shops are a little intimidating 🤣. I see Mouser does free shipping to Singapore too, so the Tubelab parts shouldn’t be too difficult to source.
Have a look at this 300b thread for a relatively easy build. A 300b SE amp can be very sweet sounding. Shuguang 300b-98 or PSVane 300b HiFi pairs from AliExpress at good prices. Not point to point. For that have a look at this DIY 300b thread
Budget 300B Build Video Series
Ebay 300B PC board kit
Budget 300B Build Video Series
Ebay 300B PC board kit
I've done a couple of video series on from scratch amp builds. One was a small footprint, sweet sounding 6BM8 build. If it is your first amp, it might be easier using a slightly larger chassis than I did, it's a tight fit!
6BM8 "tiny tube amp" build + Video Series
6BM8 DIY Stereo Tube Amplifier Series - YouTube
The other is a 300B build that someone else already linked to using the JC Morrison design. I've got it running and it sounds nice, but I believe there is more there with some minor tweaks.
This next schematic is something in between, that I haven't done a video on yet, that is in the middle of these others two and is my daily use amp. It's very reasonably priced and sounds amazing.
6BM8 "tiny tube amp" build + Video Series
6BM8 DIY Stereo Tube Amplifier Series - YouTube
The other is a 300B build that someone else already linked to using the JC Morrison design. I've got it running and it sounds nice, but I believe there is more there with some minor tweaks.
This next schematic is something in between, that I haven't done a video on yet, that is in the middle of these others two and is my daily use amp. It's very reasonably priced and sounds amazing.
Attachments
Looking forward to the EL34 amp videos. I do like the sound of EL34s and an amp made for them is interesting.
I see the slightly smaller edcor transformers on it and am also curious about them, I hear good things about them. I see some online say to use the largest outputs you can for better low end and others say that oversizing is bad and to use ones that are just right.
Your amps have already developed a quality look and are becoming easily identifiable as yours.
I see the slightly smaller edcor transformers on it and am also curious about them, I hear good things about them. I see some online say to use the largest outputs you can for better low end and others say that oversizing is bad and to use ones that are just right.
Your amps have already developed a quality look and are becoming easily identifiable as yours.