[leftside]

I find this post inspirational. The motivation and enthusiasm you display here is, to be honest, quite rare IMO even for serious hobbyists. People like yourselves are the ones that keep all this alive too and carry it forward another generation. I wish you both joy and success in your amp building endeavors.

Mischa over on the 1101 Audio thread is also a young guy with great passion. The heavy Mac amps I have are a dying breed, but headfi gear (including with tubes) is getting more and more popular.

 

[whirlwind]

I find this post inspirational. The motivation and enthusiasm you display here is, to be honest, quite rare IMO even for serious hobbyists. People like yourselves are the ones that keep all this alive too and carry it forward another generation. I wish you both joy and success in your amp building endeavors.

Well said, I agree.

Custom tube amps are just too freakin cool IMO.

 

[L0rdGwyn]

I've spoken with Glenn, turns out I am going to build my MH4 amp. I've already sourced many of the parts and the chassis is being built, looks like I will be doing this sooner than I expected!

I was sort of getting all of this stuff ready to go for whenever Glenn was available to build it, guess I was leading myself down this path and didn't know it. I've started drafting the schematic, with Glenn as my consultant.

Here are the Yamamoto sockets I will be using, these things are so expensive, but once you have them in hand you know why. That middle rectifier socket can take 5V UX4 rectifiers (e.g., 5Z3, 80) or 4V European recifiers (e.g., 45-IU, U18/20, RGN2504). A pair of series resistors will drop the voltage for the 4V rectifiers.



Here is the diagram from Landfall for the chassis. It will be anodized in gold, should have it before Christmas. I diagrammed it myself and sent it to them. Sockets will be bottom mounted. I moved the rectifier socket up 3/4 of an inch from the back row. I will eventually get a globe RGN2504 or RN4004, thought it would be more aesthetic to have the globe more centered.

 

[maxpudding]

Haha I would say so! Lots of learning to be done. I am comfortable with the building aspect, testing and troubleshooting is where I need to focus my time. I'll also be investing in some much-needed safety equipment (isolation transformer, dim bulb tester). I'll certainly update here as I go along!



Thank you for your kind words. Hopefully some success will come of it, there certainly will be growing pains, but the most satisfying experiences are not without their challenges. Looking forward to having some fun with this

LGOTL? Best of luck and congratulations on your achievement.

 

[mordy]

I've spoken with Glenn, turns out I am going to build my MH4 amp. I've already sourced many of the parts and the chassis is being built, looks like I will be doing this sooner than I expected!

I was sort of getting all of this stuff ready to go for whenever Glenn was available to build it, guess I was leading myself down this path and didn't know it. I've started drafting the schematic, with Glenn as my consultant.

Here are the Yamamoto sockets I will be using, these things are so expensive, but once you have them in hand you know why. That middle rectifier socket can take 5V UX4 rectifiers (e.g., 5Z3, 80) or 4V European recifiers (e.g., 45-IU, U18/20, RGN2504). A pair of series resistors will drop the voltage for the 4V rectifiers.



Here is the diagram from Landfall for the chassis. It will be anodized in gold, should have it before Christmas. I diagrammed it myself and sent it to them. Sockets will be bottom mounted. I moved the rectifier socket up 3/4 of an inch from the back row. I will eventually get a globe RGN2504 or RN4004, thought it would be more aesthetic to have the globe more centered.

Hi LG,
Amazing! Good luck on building the LGOTL!

 

[Monsterzero]

I've spoken with Glenn, turns out I am going to build my MH4 amp. I've already sourced many of the parts and the chassis is being built, looks like I will be doing this sooner than I expected!

I was sort of getting all of this stuff ready to go for whenever Glenn was available to build it, guess I was leading myself down this path and didn't know it. I've started drafting the schematic, with Glenn as my consultant.

Here are the Yamamoto sockets I will be using, these things are so expensive, but once you have them in hand you know why. That middle rectifier socket can take 5V UX4 rectifiers (e.g., 5Z3, 80) or 4V European recifiers (e.g., 45-IU, U18/20, RGN2504). A pair of series resistors will drop the voltage for the 4V rectifiers.



Here is the diagram from Landfall for the chassis. It will be anodized in gold, should have it before Christmas. I diagrammed it myself and sent it to them. Sockets will be bottom mounted. I moved the rectifier socket up 3/4 of an inch from the back row. I will eventually get a globe RGN2504 or RN4004, thought it would be more aesthetic to have the globe more centered.

Ha! I will have you know that today I made coffee. Jealous?
Seriously,im quite impressed. Curious to see if you start getting requests to build amps for others. Good luck with the build.

 

[L0rdGwyn]

Thanks all

It will actually be a single-ended triode design, so maybe I will call it the LGSET? LSET? Haven't given it much thought lol. The amp will definitely have Glenn's fingerprints on it since much of the design will come from his amps, not to mention he is helping me with the schematic. Hopefully people don't mind if I post here as sort of a build log, still relevant to the thread I think! Many of the components for the amplifier circuit have already been chosen, so that part is relatively straightforward and the schematic is probably mostly done already. What I need to work on is the power supply, will have some variation of a tube-rectified CLC design. I have to decide what I am going to do with the driver tube filaments, whether it is filtered DC or lifting them off ground, etc.

Going to cost me a pretty penny to get started, here is my shopping list so far not including circuit components:

Drill press - been working with a hand drill so far, but that won't cut it for this build (no pun intended)
Dim bulb tester - I could build this myself, but I'll probably just buy one
Isolation transformer - have been considering one of these to isolate my system from the wall outlet, so I'll be killing two birds with one stone!
Digital oscilloscope - for measuring frequency response, power output, FFT function for eyeballing distortion profile
Signal generator - sine wave and square wave analysis

Optional:
Keithley 2015 DMM and distortion analyzer - I definitely don't need this, especially since Glenn has already done some distortion analysis with the E424 tubes in his preamp. BUT man, I really do want one. With a low distortion input signal, it can measure THD down to 0.001%, which is plenty low for a tube amp. This way, I could see how changing components affects THD and optimize the tube bias. Could also measure how different tube loadouts affect the distortion. They are expensive though, around $600 on the used market. I think long-term it would be a very useful tool to have. Don't have to decide right now, we will see...

I already have a variac, tube tester, and other building materials. Also making my way through two books by Morgan Jones, Valve Amplifiers (circuit design focused) and Building Valve Amplifiers (practical building and testing focused).

 

[whirlwind]

I've spoken with Glenn, turns out I am going to build my MH4 amp. I've already sourced many of the parts and the chassis is being built, looks like I will be doing this sooner than I expected!

I was sort of getting all of this stuff ready to go for whenever Glenn was available to build it, guess I was leading myself down this path and didn't know it. I've started drafting the schematic, with Glenn as my consultant.

Here are the Yamamoto sockets I will be using, these things are so expensive, but once you have them in hand you know why. That middle rectifier socket can take 5V UX4 rectifiers (e.g., 5Z3, 80) or 4V European recifiers (e.g., 45-IU, U18/20, RGN2504). A pair of series resistors will drop the voltage for the 4V rectifiers.



Here is the diagram from Landfall for the chassis. It will be anodized in gold, should have it before Christmas. I diagrammed it myself and sent it to them. Sockets will be bottom mounted. I moved the rectifier socket up 3/4 of an inch from the back row. I will eventually get a globe RGN2504 or RN4004, thought it would be more aesthetic to have the globe more centered.

Very cool, I will look forward to your build log...if you start a new thread give me a heads-up.

I think I am going to need six of those Yamamoto sockets for my amp, they are expensive , but undeniable great quality.

The EL3N Yamamoto sockets are so much better than those Chinese sockets that it really is not even a fair comparison.

 

[2359glenn]

Thanks all

It will actually be a single-ended triode design, so maybe I will call it the LGSET? LSET? Haven't given it much thought lol. The amp will definitely have Glenn's fingerprints on it since much of the design will come from his amps, not to mention he is helping me with the schematic. Hopefully people don't mind if I post here as sort of a build log, still relevant to the thread I think! Many of the components for the amplifier circuit have already been chosen, so that part is relatively straightforward and the schematic is probably mostly done already. What I need to work on is the power supply, will have some variation of a tube-rectified CLC design. I have to decide what I am going to do with the driver tube filaments, whether it is filtered DC or lifting them off ground, etc.

Going to cost me a pretty penny to get started, here is my shopping list so far not including circuit components:

Drill press - been working with a hand drill so far, but that won't cut it for this build (no pun intended)
Dim bulb tester - I could build this myself, but I'll probably just buy one
Isolation transformer - have been considering one of these to isolate my system from the wall outlet, so I'll be killing two birds with one stone!
Digital oscilloscope - for measuring frequency response, power output, FFT function for eyeballing distortion profile
Signal generator - sine wave and square wave analysis

Optional:
Keithley 2015 DMM and distortion analyzer - I definitely don't need this, especially since Glenn has already done some distortion analysis with the E424 tubes in his preamp. BUT man, I really do want one. With a low distortion input signal, it can measure THD down to 0.001%, which is plenty low for a tube amp. This way, I could see how changing components affects THD and optimize the tube bias. Could also measure how different tube loadouts affect the distortion. They are expensive though, around $600 on the used market. I think long-term it would be a very useful tool to have. Don't have to decide right now, we will see...

I already have a variac, tube tester, and other building materials. Also making my way through two books by Morgan Jones, Valve Amplifiers (circuit design focused) and Building Valve Amplifiers (practical building and testing focused).

Have you figured out the grid circuit resistance yet?

 

[L0rdGwyn]

Have you figured out the grid circuit resistance yet?

Just getting to this section in my books, so please correct me. What I am reading is to use the maximum permissible value. According to Philips datasheet for EL34 in triode mode, max value is 700K but doesn't state fixed or cathode bias. But the 6L6G, KT66, and KT77 have a max of 500K for cathode bias, so better to go with the lower value.

How about 470K grid to ground on the power tubes too?

 

[L0rdGwyn]

Very cool, I will look forward to your build log...if you start a new thread give me a heads-up.

I think I am going to need six of those Yamamoto sockets for my amp, they are expensive , but undeniable great quality.

The EL3N Yamamoto sockets are so much better than those Chinese sockets that it really is not even a fair comparison.

Will do! Maybe it is worth starting a new thread when I get to the thick of it...

No doubt Yamamotos are great, have a nice heft to them and the pin tension feels just right.

 

[L0rdGwyn]

You know what @2359glenn , I am sitting here looking at this very nice Goldpoint selector switch I purchased, and I am beginning to realize all of these power tubes basically use the same cathode bias resistor...

Don't have a triode-connected class A datasheet for EL34, but calculated it manually for a 5K load and got around 500ohm, then found a triode class A schematic with with 470ohm. Datasheets for the other three tubes have them at 470ohm, 490ohm, and 500ohm.

Starting to think this switch isn't necessary, at least with these tubes.

Edit: tracing the load lines for a -13V bias point with 250V B+, cathode resistor values have changed but the pattern is the same, same value for 6L6G, KT66, and EL34 at 590ohm. KT77 needs a higher resistor it looks like. I might just drop the switch altogether.

 

[mordy]

Looks like a good day to enjoy some warm tube glow:

 

[L0rdGwyn]

Hey guys - I made a new thread for my amp build on the DIY section, here's a link, I'll update there from now on.

https://www.head-fi.org/threads/l0rdgwyns-single-ended-triode-diy-amp.921105/

 

[Xcalibur255]

Our snow is melting today too. Thankfully there's more coming. For a moment I was afraid I was going to have to see the ground.