Vacuum Tube Headphone Amplifier Using Vintage WWII 1626 Triode - Part 3
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- Опубликовано: 27 авг 2024
- The final product to be delivered for Christmas. My measurements became voltage instead of power as the 70 ohm headphones required only 1 volt RMS for a SPL of 120 dB
Your work is superb.
I love the clear bottom! Great job and beautiful amp.
Great work! I love your approach. Easily my favorite tube audio related channel.
What a great and thoughtful gift. I hope your grandson can appreciate the value in this piece of gear, most young-uns are so used to the “small is better” items. He’ll have the biggest and best amp among his friends, probably be the only kid in school with an amp, let alone a professionally built vintage style amp. Thanks so much for your videos and the ideas you share. I hope y’all had a great Christmas and God Bless. Looking forward to the next vid. How bout an amp using some more 6BG6’s with a few or more 6S?7 pre’s, preferably 6SN7’s?
Beautiful amp. Love the clear bottom!
Well done David 👍 Well I wouldn't worry to much about that small oscillation here, as I guess it's happening at FULL volume (?), and he'll NEVER need a 120 db in his ears anyway!!! 😁
Very cool! An inspiration to me,thanks for sharing .
Great project ! very instructive and inspiring .. thanks ! Best wishes !
that amp is really neat for sure i use a little bear p8 tube headohone amp great video thanks for sharing
very nice,great job.
came out nice!
I there, apologies if you've answered this already but I was hoping you could tell me how you're measuring the frequency response? Which software and your input particularly!
Thanks in advance!
I use a HP 8903 instrument with a software program from Pete Millett's website that interfaces a PC (my laptop) to the HP 8903. The HP 8903 is usually available on Ebay and Pete's website has the software for free. To interface the 8903 with a PC it is also necessary to have a HPIB adapter - usually sold separately from the 8903. Here is a link to Pete's site and the 8903 with a lot of information.
www.pmillett.com/hp_8903_software.htm
In addition, I have made a number of videos on installing and configuring the software as it can be a bit confusing.
Hope this helps and best of luck..
Thank you!!!
I'm a radio operator and I have tube guitar amps but I didnt understand what it did. You say it sounds great ?
Amazing . What does it do ?
Looks great.. Are those cathode bypass caps for the output tubes final? I ask ‘cause one is axial while the other is a radial type of different manufacture..
Yes, that is true. They are different types but are of the same values. I am usually pretty picky about those types of things but I was pushed for time to get it done by Christmas so I used two different types of capacitors. You are very observant. Thanks for your comment
Great wealth of videos! I am utilizing the knowledge here to help upgrade my lab and skills. My question do you have a simple list of your videos? I tried your website but is was down. Thank you.
Hi Bill,
I am pleased to hear you enjoy my videos. I do not have a list but have almost 300 videos posted so I think if you just search for ElPaso TubeAmps within RUclips, you will get a complete list going back almost 10 years.
ElPaso TubeAmps
, I am about to restore some Macintosh tube equipment and feel prepared to check performance parameters thanks to your videos. Thanks
I am a real fan of McIntosh. 50+ year old equipment still works great. May need some new electrolytic power supply capacitors and certainly replace any selenium bias rectifiers and it will probably be good to go. Some people seem to thing that all the coupling capacitors need replacement but I don't see it that way. If they are bad, then they need to be replaced, otherwise, I leave them along. Best of luck with your project.
ElPaso TubeAmps Thanks for advice, I am a McIntosh fan as well, I purchased my equipment in the 80’s and still use it and works fine just some minor repairs. I have my dads C20 preamp, that I am restoring and wanted to baseline its performance before I started looking into restoring. I have restored old test equipment and radios, and have more time to look into it now and am building up my lab. It is very modest at this point , some HP equipment and Tektronix, I am building it up which is why I was looking for videos what others have done. Your videos have helped me tremendously. Thank You
Hi Bill,
I am glad my videos help.
I use a C20 every day in my home theater. It is likely to run for hours each day. I got it at an estate sale for $20 - yes, $20. It had a bad PS capacitor which I figured out quickly as it was blowing fuses then the capacitors and rectifier for the DC filament supply went bad so that was replaced. No other problems. It had its original Telefunken tubes in it - and still does. Great piece of equipment. I am sure you will get your shop up and running and enjoy it.
Are you aware of the "Aikido" topology? This was developed by John Broskie. The Aikido is a single ended, zero feedback, OTL - though it certainly could be transformer coupled. The Line Driver would be a great pre-amp for your Grandson's Headphone Amplifier. Check it out: glass-ware.stores.yahoo.net/index.html Broskie writes a blog that is very informative, "Tube Cad Journal" - there's a link on his Glassware site. What was your final schematic?
Thank you for the information. I have been considering an OTL amp for some time, using a cathode-follower circuit for some low power. Probably would have been a great idea for the headphone amp. I didn't show the final schematic from LTSpice but I can send it to you if you want. You have to write me direct at theaudioshop@sbcglobal.net as I can't attach it in RUclips. I am working with a gentlemen to upload these LTSpice models and provide a link for download but it isn't working yet. You will, of course, need LTSpice installed and the Koren_Tubes file to run it.
Thanks, I'll do that. I'm really glad you did a few videos on LTSpice. I need to get into it!
Hi Bro can share for me this schematic. Thanks alot.
I have the schematic as a LTSpice model so if you download LTSpice you will be able to open it but I can't attach a file in RUclips. You can email me directly and I will send you my file.
ltspice-iv.en.lo4d.com/windows
would have been nice to use a 2x KORG NU-TUBES 6P1's one for each channel and 4x ECC88's two for each channel all running of 50V 6A with the heater for the input 6P1's of 1.5-3.0V.
I just looked up the KORG NU-Tube 6P1. I have to admit, I was not aware of it. I see they are kind of pricey. As for the 6DJ8, I believe that is a Hi-Mu triode so I would have a lot of gain. I do have a bunch of really nice 6DJ8's that I need to make something with. I will have to think about it. Thanks for your comments.
I've built the hybrid headphone 6P1 amp from a board by Pete Millet. It is a very nice single triode tube sound but prone to microphonic if there is vibration to the chassis. It was a difficult build due to the crowded layout of the board. I prefer the sound quality of the 6p1 tube to the 6DJ8 tube. 6P1 is not a super linear tube but it has the triode magic qualities that we like about tubes. I also built a 1626 amp Single ended amp with 12SL7 as a driver tube. It has a lovely balance sound for 3/4 watt amp. High frequency is not velvety as a 2A3 but the low frequency is significantly better than 2A3. I will swap the 12SL7 for something better, like a 12SJ7. For small signal, it's hard to beat an EF86 pentode in the preamp section. I like the 1626 without the NFB, and I like it even better without the capacitor on the cathode. 6DJ8 is as bland as 12ax7, high mu with high distortions. Sell your 6DJ8 to finance your next build, a 12SJ7 1626 amp. El Paso TubeAmps, I love your videos on audio. I am glad you are going away from high power push pull amps. Keep posting because that's how I know you're doing well. Take care.
I do have a calling to the high power amps, AF and RF, but I think I have accomplished pretty much all I need to with them. I do have to do one more moderate level triode amp with the Svetlana 572-10 triodes just because I have all the parts.It is interesting what you say about the 6DJ8. While I have lots of them, I never use them and I have no equipment that uses them. I shy away from all high-mu triodes and have found in the Williamson designs the 6SL7 first stage makes the amplifier too easy to drive - something like 100 mV for full output. I prefer a drive level more like 1.5 to 2.5 volts for a power amplifier and use what I consider the improved Williamson design that HeathKit put out decades ago with two 6SN7's.I have some 2A3's but never got too much into them because of their filament voltage and if I understand it right, the vintage 6B4G is a 2A3 with an octal base and a 6 volt filament. As I have mentioned in some of my videos, I like the sound of the 6B4G amp on my shelf even though it is only about 10 watts and less than perfect.As for the 1626 - that is an interesting one as it is rated as a class-C RF amplifier and is used in the WWII air craft radios. I love the way it looks. I think that is what my real attraction to it is.I haven't tried the Russian tubes like the 6P1 but maybe someday I can pick some up and build with them.I have to admit, there is something really appealing about the openness of an amplifier with no NFB. As long as we can settle for just a few watts they can sound amazing. I wonder what it is about that sound that we like as we know its distortion products are probably pretty high...Many thanks for your comments and encouragement.
KORG NU-TUBES 6P1 is a newly designed triode tube for low signal, not to be confused with the Russian 6P1. It lights up like the magic eye tubes. I'd like to build a 6B4 if I can source the tubes. The low dissipation requirement of 1626 would work great with LED bias in place of the cathode resistor and bypass capacitor. My 1626 amp sounds a bit roll off at above 10Khz, and I don't have any analytic tools to sort it out. Like you I have a small stash of 1626 to experiment. Btw, I love the chassis work you did for the 1626 headphone amp.
Dave,
Good job. FWIW, I'd like to see what distortion is like using a 12BH7 for the small signal work.
Happy holidays!
You've added another chapter to the "Darling" saga. Bob Danielak has been "messing" with the 1626 for years.
Eli D.
The 1626 is a pretty little tube and hard to resist. Something about the triode, maybe it's simplicity, makes it appealing. I listen to a 10 watt pair of vintage 6B4G triodes in a "Williamson" style amplifier in my shop sometimes hours per day and I think they sound great. I never tire of the sound although I tire of the program material... In reality, the 1626 is not very powerful, even in PP, as I have built an amplifier using a pair and could get about 3 or 4 watts max if I remember correctly. As mentioned in the video, since this is a power amplifier and will most likely be driven from a smart phone or any other "Aux" level device, I made it deliver its best power with a volt or so input for a volt output. A gain of unity, so why bother as the headphones can be driven to the same volume level right out of the phone... but we know vacuum tubes make everything sound better - right? :-)
It will be a while before I have it back in the shop as it is with my grandson and I think he will enjoy it for a while. In time I may get it back for some more tests. Thanks for your thoughts and comments.