I took a 30 year break from hardware. Had stuff to do. Now I'm thinking back to my learning days in electronics with a Swan 350 and trying to recall tube theory. Channels like yours help a lot.
Thanks for sharing this. I'm halfway through a 300B build and I'm going to use a 5VAC center tapped transformer for each 300B. Not only does this eliminate the need for rectifying, it also eliminates the need for a hum-balancing pot. I'll let you know how it turns out.
Hello, first of all, thank you for this work. I was dealing with these systems in the 1980s. Later, when transistor and integrated systems came out, I put these systems on the shelf. But even today, I still hear the sound of the systems of that time and I miss them. When I decided to return to these systems, I came across your channel. Everything is very good, thank you again. I watched all your episodes, but I couldn't find or overlooked how the 100 Ohm 2W potentiometer is adjusted. About this topic and what we need to read from the mA meter Please share information about what the value should be. I wish you continued publications and all the best. Hakan GÖKSEL from Turkey
Glad to see an update on this amp! I built one as per your schematic last month, but with all-hammond iron and the 374BX power transformer, plus separate PSU too. Used a 6v toroidal transformer for the 300B filaments and the whole setup is whisper quiet. Super impressed with the results! I'm wondering do you have any thoughts on the Rod Coleman regulators? I'm thinking about trying them out and seeing if there's actually a difference. Thanks for all the time you've put into sharing this project! I've really enjoyed putting mine together
@SkunkieDesignsElectronics hi! little update: I did eventually get a pair, and the difference was pleasantly surprising. The DC supply needs to have quite a bit of capacitance and some extra filtering pre-regulator too to appreciate it the most, thus drawing more current as well. That said, for the price of the kits I'm very satisfied with them even if it does mean the filament transformers need to be beefier. At the moment I'm also looking into swapping out the 6SN7 cascode driver for a single stage C3o (6.3v version of the C3m) pentode which will hopefully bring some more differences to appreciate too. I'm not sure how it measures up performance-wise but these kinds of pentodes seem to get a good rep as drivers for the 300B. At the very least I'd say the filament regulators are a must-try. Might make for a good video!
That Solen cap, with the bubbly sticker, don't know why but really would bug me.😂 I know it doesn't affect anything, but my OCD would have that haunt me.😂 Any idea why it's like that? I've worked with a fair few Solens, never seen that before.
@@SkunkieDesignsElectronics I see, yeah that makes sense. Even reasonable price caps soon add up money wise, I should probably use some I don't use in other projects.
@Skunkie Designs Electronics Mouser (part no. 833-1N5341B-TP) has 6.2V 5W Zener diodes for $0.41 for 1 and $3.29 for 10. So, if you are worried about too much voltage to the heaters, why not just put two or three Zener diodes in parallel? (Other V_Zener values around 6.3V for astronomically priced at Mouser, and I did not check Digikey.)
@@SkunkieDesignsElectronics Looking at the schematic again: I see said the blind man to his deaf dog 🙃 I must have gotten confused with heating with DC vs. AC from the previous video (the Monday Monologue). Yes, 0.2V would not be of concern based on your "within 10%" tolerance statement regarding the heaters, unless I am confused again 😉 Thanks 👍
I still don't like heaters over 6.5 or under 6.2, and might add a resistor just to keep these fairly rare CV181-Z tubes happy :) Thanks for the comments!
As a New Mexican, I'm very sad to see that Edcor transformer kick the bucket as it did. Aside from Green Chiles, there are few other exports from our state worth talking about.
Hey, I have a couple of questions: -at some point you went with DC heating on your 300B and I could not find the video in which you discussed your choice. Can you point to that? -if this is a 'budget' 300B amp what would be an all out build? Other than the spending more on better iron & components? Is this your favorite design?
@@interesting7906 H-30-5S or H-30-3.5S at $1100. Another high end option would be Electra-print. Their high end solid silver 300B OT are around $2000. I know people spec 300B OT at 3.5K but I think that is for lower plate voltages? I'm happy to give up a watt or two of power for the lower distortion a 5K unit will have.
@@SkunkieDesignsElectronics I was curious about that 5K or 3K primary. What's the deal there? Do you have a vid that discusses the best OT primary inductance/resistance to use? What about 300B tubes? I heard EmissionLabs are the best for the money then there are the high end options Elrog or WE.
Basically lower Z will help the power at the expense of some distortion. Pretty sure if you are buying the high end OT you can likely run 3.5K, using cheaper ones, it's better to go to 5K. I've been happy with the 300B-Z tubes.
I took a 30 year break from hardware. Had stuff to do. Now I'm thinking back to my learning days in electronics with a Swan 350 and trying to recall tube theory. Channels like yours help a lot.
Thanks for sharing this. I'm halfway through a 300B build and I'm going to use a 5VAC center tapped transformer for each 300B. Not only does this eliminate the need for rectifying, it also eliminates the need for a hum-balancing pot. I'll let you know how it turns out.
Thanks, bought a Hammond 374 myself recently
You have a vast knowledge Stephe
Great video Skunkie. I think you showed some different options. Always great to see your videos I'm always learning something from you.
Hello, first of all, thank you for this work. I was dealing with these systems in the 1980s. Later, when transistor and integrated systems came out, I put these systems on the shelf. But even today, I still hear the sound of the systems of that time and I miss them. When I decided to return to these systems, I came across your channel. Everything is very good, thank you again.
I watched all your episodes, but I couldn't find or overlooked how the 100 Ohm 2W potentiometer is adjusted. About this topic and what we need to read from the mA meter
Please share information about what the value should be. I wish you continued publications and all the best.
Hakan GÖKSEL from Turkey
Start with it in the center, if you ever hear any hum/noise adjust slightly to eliminate it.
thank you
Doraville Ga???
Yup
Glad to see an update on this amp! I built one as per your schematic last month, but with all-hammond iron and the 374BX power transformer, plus separate PSU too. Used a 6v toroidal transformer for the 300B filaments and the whole setup is whisper quiet. Super impressed with the results! I'm wondering do you have any thoughts on the Rod Coleman regulators? I'm thinking about trying them out and seeing if there's actually a difference.
Thanks for all the time you've put into sharing this project! I've really enjoyed putting mine together
I haven't tried them, and would love to hear your thoughts on them vs these basic 5V regulators.
@SkunkieDesignsElectronics hi! little update: I did eventually get a pair, and the difference was pleasantly surprising. The DC supply needs to have quite a bit of capacitance and some extra filtering pre-regulator too to appreciate it the most, thus drawing more current as well. That said, for the price of the kits I'm very satisfied with them even if it does mean the filament transformers need to be beefier. At the moment I'm also looking into swapping out the 6SN7 cascode driver for a single stage C3o (6.3v version of the C3m) pentode which will hopefully bring some more differences to appreciate too. I'm not sure how it measures up performance-wise but these kinds of pentodes seem to get a good rep as drivers for the 300B. At the very least I'd say the filament regulators are a must-try. Might make for a good video!
That Solen cap, with the bubbly sticker, don't know why but really would bug me.😂
I know it doesn't affect anything, but my OCD would have that haunt me.😂 Any idea why it's like that? I've worked with a fair few Solens, never seen that before.
I think it was reused from another build with a lot of hours on it.
@@SkunkieDesignsElectronics I see, yeah that makes sense. Even reasonable price caps soon add up money wise, I should probably use some I don't use in other projects.
@Skunkie Designs Electronics Mouser (part no. 833-1N5341B-TP) has 6.2V 5W Zener diodes for $0.41 for 1 and $3.29 for 10. So, if you are worried about too much voltage to the heaters, why not just put two or three Zener diodes in parallel? (Other V_Zener values around 6.3V for astronomically priced at Mouser, and I did not check Digikey.)
This is AC not DC. The usual "fix" is use a small value resistor, a 0.1 ohm 1W would work here, to drop .2V, but .2 volts doesn't concern me.
@@SkunkieDesignsElectronics Looking at the schematic again: I see said the blind man to his deaf dog 🙃 I must have gotten confused with heating with DC vs. AC from the previous video (the Monday Monologue). Yes, 0.2V would not be of concern based on your "within 10%" tolerance statement regarding the heaters, unless I am confused again 😉 Thanks 👍
I still don't like heaters over 6.5 or under 6.2, and might add a resistor just to keep these fairly rare CV181-Z tubes happy :) Thanks for the comments!
Hi good video ........what is the best valve for you to drive a 300b without a coupling transformer
cascoded 6SN7 really sounds nice.
@@SkunkieDesignsElectronics Hi.....what is your favorite brand of anode filter capacitors
The "normal" audio note ones are nice and not crazy $$$
@@SkunkieDesignsElectronics Ok tank you very much
Thanks 😁
Did Edcor ever give you a response? I'm actually about to start on this build and was wondering if you might have a better suggestion?
I would 100% use Hammond power transformers and no, Edcor ignored my email about this.
Noted, thanks for the suggestions, will go with Hammond for this build.
As a New Mexican, I'm very sad to see that Edcor transformer kick the bucket as it did. Aside from Green Chiles, there are few other exports from our state worth talking about.
Yes, disappointing. I contacted them about this and will report their response.
Hey, I have a couple of questions:
-at some point you went with DC heating on your 300B and I could not find the video in which you discussed your choice. Can you point to that?
-if this is a 'budget' 300B amp what would be an all out build? Other than the spending more on better iron & components? Is this your favorite design?
Iron. When I started on this everyone was saying you need to use $1000 silver wire OT etc.
@@SkunkieDesignsElectronics What kind of Iron Tamura? Lundhal? I refuse to use 1000 wire. 😂
@@interesting7906 H-30-5S or H-30-3.5S at $1100. Another high end option would be Electra-print. Their high end solid silver 300B OT are around $2000. I know people spec 300B OT at 3.5K but I think that is for lower plate voltages? I'm happy to give up a watt or two of power for the lower distortion a 5K unit will have.
@@SkunkieDesignsElectronics I was curious about that 5K or 3K primary. What's the deal there? Do you have a vid that discusses the best OT primary inductance/resistance to use? What about 300B tubes? I heard EmissionLabs are the best for the money then there are the high end options Elrog or WE.
Basically lower Z will help the power at the expense of some distortion. Pretty sure if you are buying the high end OT you can likely run 3.5K, using cheaper ones, it's better to go to 5K. I've been happy with the 300B-Z tubes.