Thus, building the first one and listening for a few months. Now I want one with bigger OPTs to compare.
Best three sound improvements I ever made (all almost free):
1) Keep hair cut away from ears so we are not wearing natural ear muffs.
2) Clean ears frequently. Stuff sitting on your eardrums and a narrowed ear canal = bad sound.
3) Remove eyeglasses when listening since we were not meant to have hard reflective surfaces covering part of our faces.
And these are almost free "system upgrades." Remember that we are part of the system since we receive the sound!
My hearing is still fine. I used to be able to hear above 20 kHz, which is the most annoying thing you can imagine if you have ever heard that. I can still hear an 18 kHz test tone, and it also is extremely annoying.
In an ideal world I'd find a proven design, fabricate, and build a pair of EL84 monoblocks. This isn't an ideal world. I can only do a kit right now, and I don't have a whole lot of room either. By the time I did it I might change my mind anyway and go off into the land of single-ended or something like that.
The man who helped me tune my current speakers over the years had a variety of speakers including the ElectroVoice Patrician 800 corner horns with 30" bass drivers and a giant pair of Bozak speakers with four 12" drivers, four midrange drivers, and 4-tweeter arrays per speaker. He had a bunch of McIntosh tube stuff but finally sold it all to go solid state. Things were different back then.
Patrician 800
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Good single ended output transformers take up more space, and are heavier, versus push pull transformers
Those old 19kHz doppler burglar detectors used to bug me, as did the 15,734Hz TV flyback transformers.
Can hear loud 13kHz in my one and only ear.
I heard the 5 driver model of the 30 inch EV Patrician. 30, 12, 8, Mid horn, T350.
Most likely, there was very low intermodulation distortion (5 frequency bands)
Just the crossover parts by themselves could give you a trip to the Hernia Surgeon.
Those old 19kHz doppler burglar detectors used to bug me, as did the 15,734Hz TV flyback transformers.
Can hear loud 13kHz in my one and only ear.
I heard the 5 driver model of the 30 inch EV Patrician. 30, 12, 8, Mid horn, T350.
Most likely, there was very low intermodulation distortion (5 frequency bands)
Just the crossover parts by themselves could give you a trip to the Hernia Surgeon.
Well, Christmas came early this year!
I should be able to measure for and order OPTs on Monday when the new power transformer arrives.
It was supposed to be in Hong Kong as of this morning. Apparently US Customs opened my package, which doesn't usually happen.
And this is why I like kits. No shopping and no fabrication, just paint work because I hate silver. I don't have to replace anything if I don't want to. I'm sure the WIMA coupling and bypass caps are not genuine. I'll get genuine this time. I don't trust the power supply caps so I'll order some good ones this time. The carbon volume pot is being replaced with a $15 SMD stepped attenuator that people like. No great expense there. Cathode bypass caps will be Nichicon Muse I guess. Any suggestions for PCB-mount tube sockets? The Micalex ones (or whatever they are) in the ST-35 kit are awful. Their death grip on the tubes is going to break the PCBs one day. It's ridiculous. PCBs shouldn't go through that kind of stress. Cheap porcelain ones come in the kit and one is starting to loosen a bit in the other amp.
I even got a free Chinese newspaper. I'll run OCR and translation on it and get up to date on current events.
I should be able to measure for and order OPTs on Monday when the new power transformer arrives.
It was supposed to be in Hong Kong as of this morning. Apparently US Customs opened my package, which doesn't usually happen.
And this is why I like kits. No shopping and no fabrication, just paint work because I hate silver. I don't have to replace anything if I don't want to. I'm sure the WIMA coupling and bypass caps are not genuine. I'll get genuine this time. I don't trust the power supply caps so I'll order some good ones this time. The carbon volume pot is being replaced with a $15 SMD stepped attenuator that people like. No great expense there. Cathode bypass caps will be Nichicon Muse I guess. Any suggestions for PCB-mount tube sockets? The Micalex ones (or whatever they are) in the ST-35 kit are awful. Their death grip on the tubes is going to break the PCBs one day. It's ridiculous. PCBs shouldn't go through that kind of stress. Cheap porcelain ones come in the kit and one is starting to loosen a bit in the other amp.
I even got a free Chinese newspaper. I'll run OCR and translation on it and get up to date on current events.
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During the long development of NGO’s amplifier, I vaguely recall some discussion of the Mullard Long Tailed phase splitter. Here is an item I don’t recall ever getting properly analyzed.
For good balance of the output signals to the following stage, it is required that the circuit satisfy the relation (mu + 1)*Rk >> rp + Rl. Taking Mu to be 83 as a worst case, the LHS of the relation calcs out to 6888. The RHS is 242. And the simulation tells us tells us the signals differ by 1.45 %. That would be sufficient for most applications.
But that difference can be reduced quite a bit by installing a longer tail. For those who don’t want a SS device in the audio path, a simple resistance to -150V is an alternative. And the difference reduces to 0.28 %. 150V sets a safe limit to avoid H-K insulation damage.
The negative voltage can be easily derived from the same HV winding on the PT as the B+. And can be used to provide biasing for a fixed bias stage as well. An 0D3 or 0A2 will set the -150V. Or Zeners if desired. Some people like to see the gas tubes glow. I’ve found they are more stable than Zeners. Zeners are very much affected by temperature.
I’ve done this on some builds. Both positive & negative voltages are rectified from the same HV CT winding of the PT. No odd taps are required. And the rectified result is full wave for both polarities. The rectifier modules are constructed on simple terminal strips. All screwed to a supporting scrap of wood during assembly & soldering. When finished the entire module is installed in the chassis as a single unit with connecting wires already in place.
There is more to this equation, maybe later. 😀
For good balance of the output signals to the following stage, it is required that the circuit satisfy the relation (mu + 1)*Rk >> rp + Rl. Taking Mu to be 83 as a worst case, the LHS of the relation calcs out to 6888. The RHS is 242. And the simulation tells us tells us the signals differ by 1.45 %. That would be sufficient for most applications.
But that difference can be reduced quite a bit by installing a longer tail. For those who don’t want a SS device in the audio path, a simple resistance to -150V is an alternative. And the difference reduces to 0.28 %. 150V sets a safe limit to avoid H-K insulation damage.
The negative voltage can be easily derived from the same HV winding on the PT as the B+. And can be used to provide biasing for a fixed bias stage as well. An 0D3 or 0A2 will set the -150V. Or Zeners if desired. Some people like to see the gas tubes glow. I’ve found they are more stable than Zeners. Zeners are very much affected by temperature.
I’ve done this on some builds. Both positive & negative voltages are rectified from the same HV CT winding of the PT. No odd taps are required. And the rectified result is full wave for both polarities. The rectifier modules are constructed on simple terminal strips. All screwed to a supporting scrap of wood during assembly & soldering. When finished the entire module is installed in the chassis as a single unit with connecting wires already in place.
There is more to this equation, maybe later. 😀
Attachments
Whoooooooooaaaaa! That is way over my head. It will take a long time to try to digest that. But thank you. I may be able to digest it over time.
Driver tubes are 6N1P-EV if anyone needs that.
At the risk of aggravating some others here, maybe it's time for me to start a thread for the amplifier instead of the OPTs. If we put all this stuff in this now very long thread, then people looking for EL84 OPT info will get lost, and people looking for this kit will get lost. I encounter that so much when I look for info. If another thread annoys people here, so be it.
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No problem, we don't need to be an Isaac Newton or Werner von Braun to sort these things out.
I'll post something on OPT loadlines later as the snow continues to fall. What power toobz did you finally choose
I'm losing track.
There are many of the curious & lurkers who follow these threads looking for Jewels of Knowledge.
That makes it worthwhile to do these reports. 👍
I’d recommend Heyboer Transformers. Their products are superior to Edcor and Hammknd. I had them make me several 8712 ohm (33 to 1 at 8 ohms) opts rated at 20 watts 20-20kHz. These units have 2-1/4” stack on 1” lam (1/4” more stack than Hammond 1645 5000 ohm 30 watt opts) and provide superb performance with EL84M tubes at 420 plate and 330 screen volts. They would be custom wound but their prices are very reasonable.
www.heyboertransformers.com.
Tim Smith
www.heyboertransformers.com.
Tim Smith
It is very important for everyone to recognize both English/Chinese and Russian (Cyrillic) alphabet lettering for tubes as they are very easily confused online. People mix Russian and English together, and since N and P and V and R mean different things in the two languages, it is impossible to know what you are referring to without specific reference to English or Russian lettering conventions. China follows English lettering for the most part.
Russian naming:
------------------------
First figure is heater voltage, 6 volts
Second figure is configuration:
С (latin S) = single triode
Н (latin N) = dual triode
Э (latin E or EE) = beam tetrode
П (latin P) = power pentode
Ф (latin F) = triode-pentode
Third position is a type marker (to separate like tubes from each other)
Fourth position indicates tube housing
С (latin S) = big glass tube with octal or other special socket
П (latin P) = small glass tube with 7- or 9-pin socket (Noval)
Л (latin L) = Loctal socket
Fifth and sixth position (after dash) are quality markers
K (latin K) = vibration resistant
Е (latin E) = increased mechanical quality
В (latin V) = prolonged lifetime 5,000 hr
P (latin R) = prolonged lifetime 10,000 hr
Driver tubes are English 6N1P-EV (Russian 6Н1П-ЕВ)
This table is a public service, LOL. 🙂 Save it as there is a bewildering amount of confusion out there and it took me many hours to figure it out.
- The power tubes from China are 6P14 (there is no Russian 6P14 tube). They actually don't sound bad but have a terrible reputation for inconsistency. Ones from Beijing and not Shuguang or some other factory are said to be the best in Chinese discussion forums.
- The Russian version is 6P14P (Russian 6П14П). I have those, and they work just fine, with a 3,000 hour rated life. Spec sheet posted earlier.
- The 6P14P-EV (Russian 6П14П-EB) is an improved reliablity 6P14P (Russian 6П14П) with a 5,000 hour rated life and the same specs otherwise.
- The "ultimate" tube said to at least equal the performance of old EL84 tubes is 6P14P-ER (Russian 6П14П-EP) with a 10,000 hour rated life and the same specs otherwise except a slightly higher heater current. They are said to have used some gold in the grid to get the life. I use these.
Russian naming:
------------------------
First figure is heater voltage, 6 volts
Second figure is configuration:
С (latin S) = single triode
Н (latin N) = dual triode
Э (latin E or EE) = beam tetrode
П (latin P) = power pentode
Ф (latin F) = triode-pentode
Third position is a type marker (to separate like tubes from each other)
Fourth position indicates tube housing
С (latin S) = big glass tube with octal or other special socket
П (latin P) = small glass tube with 7- or 9-pin socket (Noval)
Л (latin L) = Loctal socket
Fifth and sixth position (after dash) are quality markers
K (latin K) = vibration resistant
Е (latin E) = increased mechanical quality
В (latin V) = prolonged lifetime 5,000 hr
P (latin R) = prolonged lifetime 10,000 hr
Driver tubes are English 6N1P-EV (Russian 6Н1П-ЕВ)
This table is a public service, LOL. 🙂 Save it as there is a bewildering amount of confusion out there and it took me many hours to figure it out.
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Thanks. I haven't contacted them (yet). Thermionic offered two options, but I know little about them other than they are very nice people and Stephe had a good result with one product. Primary Windings has a 25 watt off-the-shelf option but I know nothing about them. The company from Poland does not sell their own transformers with end bells. Then there is Edcor and Hammond. Also another custom winder was mentioned above who I have not contacted. There also is Hashimoto. So we have at least 5 maybe 6 or 7 options, which is good to know.
I'm leaning toward the off-the shelf product from Primary Windings, but I wish someone here had some verified experience with them. They are not expensive in my book, and they are the biggest ones that will fit physically with a 25 watt rating and supposedly a 20-30kHz (-1dB) response, which I am supposing is at 1 watt since that seems to be the norm. Ultra-linear from those would go unused.
https://primarywindings.com/product/25w-8000-ohms-ultra-linear-push-pull-output-transformer/
I will verify Monday if they will physically fit. I think they will.
Great info, thanks. Their website implies they only do guitar replacement OPTs.
There is a (very) long thread about a Tubelab SPP build. The OP used Primary Windings, was happy with the result.
https://www.diyaudio.com/community/threads/tubelab-spp-first-timer-build.388172/page-19#post-7223301
I really wish that I hadn't said that. I put ideas into my own head. An extremely compact pair of PP monoblocks would be nice. I just don't have the time right now. I wonder just how small I could make them ... oh I need to just forget about this ...
Unfortunately, he didn't really write anything about sound quality. I'll send him a message, but he hasn't been online here for the past few months.
I found this link. https://jandkaudiodesign.blogspot.com/
jandkaudiodesign AT gmail.com
Is it just him? Where is he located?
They need to redo their website, which makes it seem like they only do guitar transformers.
420V with 330 screen? This amp runs at about 340V with 300V regulated screen, and that's considered "tube abuse" by some. 😲
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Yes, that’s Ken Loo. I thought I mention he is located in Penang. Apologies for my lack of clarity.
@jhstewart
Please repost this valuable analysis in the new build thread: https://www.diyaudio.com/community/threads/huaji-audio-6p14p-el84-6n1p-pp-amp-kit-build-2.406195/
Done.
Looking through the J&K Audio blog, they seem very passionate about transformers. That is a good sign. They also answer their email, unlike some others I have tried to contact.
J&K Audio - very nice folks. Very helpful. A little over budget.
Heyboer did not reply.
Thermionic Labs - very nice folks. Very helpful. One option within budget, but I'm going to try Primary Windings.
I spoke with John at Primary Windings. If anyone needs to reach him, the best bet is by phone. He was very nice and pointed me to some information about testing transformers and what I should be looking for. He explained a few things about magnetics and why to measure transformers at relatively low power and then what happens at high power. Very informative. He then sent me the exact dimensions of his 25 watt 8k PP transformers, and they will fit. Barely, but they will fit. He said he could custom make a pair of slighlty smaller 15-20 watters, but since the 25 watters are already designed, and they seem to fit, why not just use those. Unfortunately, he is swamped with work and the holidays are here, so it has to wait until after the first of the new year. So in January it looks like I have a solution.
John also sent this link and suggested I read what it says about transformers: https://primarywindings.com/wp-content/uploads/2017/04/Williamson-Amplifier.pdf
Heyboer did not reply.
Thermionic Labs - very nice folks. Very helpful. One option within budget, but I'm going to try Primary Windings.
I spoke with John at Primary Windings. If anyone needs to reach him, the best bet is by phone. He was very nice and pointed me to some information about testing transformers and what I should be looking for. He explained a few things about magnetics and why to measure transformers at relatively low power and then what happens at high power. Very informative. He then sent me the exact dimensions of his 25 watt 8k PP transformers, and they will fit. Barely, but they will fit. He said he could custom make a pair of slighlty smaller 15-20 watters, but since the 25 watters are already designed, and they seem to fit, why not just use those. Unfortunately, he is swamped with work and the holidays are here, so it has to wait until after the first of the new year. So in January it looks like I have a solution.
John also sent this link and suggested I read what it says about transformers: https://primarywindings.com/wp-content/uploads/2017/04/Williamson-Amplifier.pdf
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How about Audionote TX-OP-200 from HiFi Collective
https://www.hificollective.co.uk/catalog/TX-OP-200-1-IE-PP-F.html
TX-OP-200-1-IE-PP-F: Audio Note 15W, 8K / 4, 8 ohm PP IE Core Output Transformer
TX-OP-200-1-IE-PP-F
Audio Note push-pull output transformer (as featured in the Old Audio Note Oto amplifier)
Suggested valves - EL84/ECL86/6V6
Max Cl. A Power: 15 w
Primary / Secondary Impedances: 8K / 4 and 8 Ohms
Primary / Secondary wire: copper / copper
Core material - IE
Mounting - Frames
OLD CODE - TRANS-200
https://www.hificollective.co.uk/catalog/TX-OP-200-1-IE-PP-F.html
TX-OP-200-1-IE-PP-F: Audio Note 15W, 8K / 4, 8 ohm PP IE Core Output Transformer
TX-OP-200-1-IE-PP-F
Audio Note push-pull output transformer (as featured in the Old Audio Note Oto amplifier)
Suggested valves - EL84/ECL86/6V6
Max Cl. A Power: 15 w
Primary / Secondary Impedances: 8K / 4 and 8 Ohms
Primary / Secondary wire: copper / copper
Core material - IE
Mounting - Frames
OLD CODE - TRANS-200
I don't know anything about them. They would need end bells, and I can't determine from their website if it's an option.
Edcor USA has a 25% screen tap 15W PP transformer with 8000 Ohm P-P impedance, 8R output only.
EM 0776 PP
They also have a design for 40% screen tap 15W PP transformer with 8000 Ohm P-P impedance, 8R output only.
EM 0775 PP
These are not listed on their web site, but my understanding is that anyone can order them since the development was paid for already.
EM 0776 PP
They also have a design for 40% screen tap 15W PP transformer with 8000 Ohm P-P impedance, 8R output only.
EM 0775 PP
These are not listed on their web site, but my understanding is that anyone can order them since the development was paid for already.
I built a push pull 7591 amplifier, with an Edcor 10k 10W push pull.
I used the 7591s in triode wired mode; no global negative feedback.
The only negative feedback was the connection of the screen to 100 Ohms, the other end of 100 Ohms to the plate.
Triode Wiring:
Less Power
Less Distortion
No Negative Feedback (many don't call triode wiring negative feedback; I am one of the few that does call it that; so I defer to the other's definition.
More Simple
Finesse
Sounded very good, and tested well on the test bench.
I used the 7591s in triode wired mode; no global negative feedback.
The only negative feedback was the connection of the screen to 100 Ohms, the other end of 100 Ohms to the plate.
Triode Wiring:
Less Power
Less Distortion
No Negative Feedback (many don't call triode wiring negative feedback; I am one of the few that does call it that; so I defer to the other's definition.
More Simple
Finesse
Sounded very good, and tested well on the test bench.