Vacuum Tube Push-Pull Amplifier Kit - Part 1

[@ianmedium]

Love the packaging, it reminds me of kits I would buy as a child, the days before everything became so slick, slick costs money and does nothing practically so give me news paper wrapping and recycled boxes any day as it saves money!

[@garyhoo1863]

Glad to find these videos. I just finished this amp kit and relied on these videos to build it due to not being able to get information from of China because of their New Year and then the epidemic. The kit I got did not have a loudness circuit, so I did not do that modification. It also included a 100K volume pot so I left that as is. I did not rearrange the transformers since their windings are perpendicular to each other. The results was complete silence at full volume. I did include the LEDs in the tube sockets, figuring if it looked too chintzy I could cover them with a piece of black electrical tape. To answer the question below, yes, ground the 0V terminal, also ground the black binding posts, the power supply board, the power transformer shell, and the grounding tab on the power source socket. One thing I noticed in the video, it did not appear that the two power transformer 115V windings were wired in parallel, as they should be for a 115VAC input. Very happy with the outcome and was impressed with the quality of the components. One thing to note, if you connect the volume pot circuit board upside down, your volume control will work backwards (don't ask how I know.)

[@almonzowilder4091]

Wow. My transformers installed parallel the way the holes were drilled.

[@martinda7446]

😁

[@doughale1555]

When in high school I helped my electronics teacher build a tube PA amplifier for the schools sports stadium. It was quite high powered with a 750 volt B+. It’s output transformer was to drive a 70 volt line. After I got it working for the first time, I turned it off leaving it on the bench while I was cleaning up. After a while my teacher picked it up to put away and threw it across the bench. He very calmly said, “Doug, I see that I need to teach you about bleeder resistors.” It took another few days to repair the damage - and install a hefty size bleeder across the 750 volt B+! But it sounded real good driving a dozen stadium loudspeakers.

[@MarkTillotson]

The flat on an LED is the cathode marker, lead length is not - its purely to allow rapid assembly and varies from manufacturer to manufacturer! BTW a very thorough walk through of the kit, nice job you're doing.

[@williamsquires3070]

Mark Tillotson - I’ve seen LEDs where the flat or notch is on the side of the case parallel to the leads; totally not helpful. I’ve also seen LEDs where the cathode is the long lead, and where the cathode is the short lead, as well as ones where the cathode is not the anvil (larger pedestal-like electrode inside the case where the die is mounted, while most do have the cathode as the anvil. The only true way to know is to test it! 😀

[@DeadKoby]

I did a kit amp a few months ago. I find these enjoyable. If it is engineered properly, it's a relaxing soldering experience.

[@jwren51]

Great video, can't wait for next episode. If it sounds good I think it will be my next project.

[@josephcote6120]

I think the transformers were OK as originally placed. It's not the direction of the laminations, but the magnetic axis of the windings. For the output transformers the axis goes, relative to the chassis, front and back; that is the windings would encircle a rod pointing from the front of the chassis to the back. If you made it into an electromagnet, that would be your north and south poles. On the other hand, the power transformer's magnetic axis points up and down relative to the chassis. The electromagnet would be vertical relative to the chassis. So there is already a 90-degree separation. Rotating the outputs 90-degrees in the horizontal plane to a side-to-side orientation maintained that 90-degree difference with the power transformer, so that's fine. If anything, rotating ONE of the output transformers would have decoupled all of them from each other.

[@SciPunk215]

This makes sense. At 5:50 in the video we get a good look at the transformers. It is clear that the windings run perpendicular to each other.

[@dhpbear2]

I do see how the output transformers could couple to each other.

[@mccoysguitars5535]

i was thinking the same thing

[@kane100574]

I enjoy your channel a lot. Look forward to more!!

[@jamesmdeluca]

Greetings: If the tube sockets are reasonably snug fitting in the chassis, I would loosely mount all of the sockets before committing their final positions with solder to avoid problems fitting all of the sockets if mounted first.

[@scratchback2001]

Hello. Andrew from Australia here. I own a Primaluna Integrated amp with 6 12AU7s for the pre-amp and 8 EL34s for the power amp. I've never liked printed circuit boards except in very low power areas. The heat alone has to affect the PCB sooner or later. On my Primaluna amp, all of the sockets are mounted to the chassis wiith pencil sized holes around them to vent heat from inside the amp and stop the the valves heat from adding to the problem.

[@Mosfet510]

I think that is 'Annual Holiday Man' on the packaging. I like kits like this, I get that time out I need. The only issue, like you pointed out, is the tube socket mounted directly to the pcb. It's to keep things simple and costs down, I get it, but the thermal cycling over time with have fun with the joints. Good video.

[@lowyoyo9961]

Built Elekit's (Japanese) amp and preamp kits a few years ago with outstanding results for my efforts. High quality components and CLEAR English instructions made the build experience even better. Next, is their 300B amp kit!

[@drdyna]

I generally agree on the LEDs under tube sockets, it seems a little silly, although, I did see one once where someone lit the tubes underneath with purple LEDs...they weren't super strong and the purple glow along with the orange of the filaments looked super cool.

[@eliadculcea7718]

I got it working. If you buy this kit from ebay, do not use the assembly instruction found on the ebay link, those instructions are not good. Instead ask the ebay seller to send you the most current assembly instructions, the most current is in Chinese but has lots of pictures and i think those pictures are self explanatory.

[@garybevis8691]

Hi Tony, I've never made a long video, and I'm sure that it is not easy for the avarage amature to , tape, produce and edit such a video. I just notice that there seems to be a lighting issue (dark) with this video that is usually not a problem with your vids. Also it would be helpful, as I'm sure you would agree, to be careful to keep the parts in the "shot" so we can see what it is you are talking about. Otherwise this is a very informative and a skilled build, please note that I am not complaining, just an observation from a longtime fan. Keep up the good work and thank you for sharing your skills and knowledge of electronics with the youtube community.

[@jonathancolling2284]

You're like a friendly uncle who's into cool stuff 😁

[@MrRobbyvent]

nice and fun project! My choice will be quite different: a nicer chassis and point-to-point connections for the circuit so to have a much more vintage feeling.

[@michaelaFlangee]

JUst to give you some history Philips , Mullard of old, sold their capacitors divisions off elcos to BC then Vishay bought a lot of them so they are what the seller said they were. Look up the part numbers on Mouser or Digikey et al to see

[@andydelle4509]

I would recommend putting the tube LEDs in but leave the resistor out. Reason is once the tube socket is soldered down, you can't go back and add the LED. But you add the resistor later on the accessible side of the board if you end up wanting the LEDS on.

[@danlevesque5486]

I know this is a few years old now and I didn't read all the comments, so please forgive me if this has been discussed... I believe those transformers were fine as originally laid out. Although I completely understand the visual of those laminations being oriented in the same direction throwing a red flag. It is easy to note here, with no end bells installed, that the PT and OT windings were already oriented at 90 degrees. The orientation of the windings determines the direction of the field around the transformer, not necessarily the direction of the laminations. If you had laid that PT on its side so the windings were oriented same as the OTs, then yeah, you'd have a coupling issue.

[@johnbellas490]

Looks like a fairly respectable amplifier !!

[@justme_2020]

@xraytonyb - the magic eye tubes are just for decoration, correct? If so, and I want to wire point-to-point without the PC board, can't I just omit them and the parts of the circuit associated with them? It would save some point-to-point wiring work, save the hassle and cost of tube replacement later, and save 2 tubes worth of power from the power supply transformer.

[@MaximRecoil]

It doesn't matter which side of the tube sockets that you solder from; the solder will flow to the other side of the through-hole as long as you feed it enough solder wire regardless of which side you do it from. If you don't like the look of the fillet on either side after soldering (such as if it's balled up excessively or there are voids), then just touch it up by swiping your iron across it while dabbing a little more solder (which adds flux, assuming you're using flux-core solder wire). If there's excess solder in the fillet then it will come off and stick to your iron (if you have the right technique), and if there are voids, they will get filled in (again, if you have the right technique).

[@mikeburch2998]

That was a very neat assembly job. Greetings from Arizona.

[@TY-ob7fz]

Hi Tony. I remembered watching one of Mr Carlson’s Lab when he talked about polarity concerning non polarized capacitors. Need to be concerned about that to avoid feedback and hum ?

[@robertkat]

Check the resistance of the output tube filaments, they should be identical, I had some 1.5 ohms, and some 2.5 ohms. Not matched.

[@_Ramen-Vac_]

some smartapple should invent a thingamajig that u just point at a device which tells ya the whole story on its health. hell, they got almost every other kind of meter. just takes a buttload of samples and then a feedback interface.. not like it's rocket science.

[@Sheevlord]

I use a multimeter in diode mode to find out the polarity of LEDs when unsure. The voltage/current supplied by my meter in that mode is enough for the LED to dimly glow if I get the polarity right.

[@w.rustylane5650]

Enjoyed part 1. Looking forward to part 2.

[@markironside430]

My experience with Audio kits and "cheap" audio components (Some not so cheap) from China/eBay is that the capacitors supplied have often turned out to be fake. I have seen many that have been resleeved to look like much better quality ones than they had actually supplied. I removed the sleeves from some to look at the can and found every cap in the power supply had dents in that had been filled with wax! Not only that but in one case three out of four supplied were found to be of different manufacturers. What initially made me suspicious was the end of the capacitors had a black plastic plate on it, I had some genuine caps the same make size and capacity I noticed they had aluminium ends with an manufacturers identification mark stamped in. The capacitors Looked perfect no blemishes were seen before I removed the sleeve's . When I then measured them the capacitance values were all over the place some higher than marked some lower. (Far away from the +- 20% norm Also the ESR was all over the show. I surmise from this that they were probably seconds had been damaged in manufacturing or when they were thrown in the bin! This experience has made me very suspicious of many parts purchased over the years. This is not an isolated case. I have some other capacitors supplied from a different shop at a different date these caps state Elna for audio they are 63v 10000uf I have looked through every Elna catalogue I can find and Elna caps of this rating are a different physical size! It was the stamping on the end of the can that drew my attention. It just didn't look quite right when compared to genuine Elna caps. This is just two instances I could go on with more examples. I will no longer purchase capacitors from eBay unless from a couple of suppliers who I trust. I know some people in the HiFi industry (Manufactures) who have told me that purchasing components has become a nightmare due to fakes coming out of China. If the components really matter in a build then the advice I received was to first check on the manufactures site. See who the official suppliers are and only purchase from them. Interestingly you can often see on the manufacturers site who has them in stock and how many. Apparently even purchasing from a good supplier isn't always fool proof. That's why I was told to check how many were in stock on the OEM's site. As the big boys have had their fingers burnt unwittingly purchasing fakes when components are in short supply. I have also come across fake power transistors. I hope this post may save someone time when trouble shooting a design that's not sounding or working how it should . As if we don't have enough to think about when playing around with this stuff. Its a good job its still fun and rewarding (that's when your not looking for where the smoke came from😤) .

[@tpb2]

Hey, I'm putting one of these together but I'm confused by the secondary wiring of the mains transformer. The transformer provided has 0, 275, 3.15, 0, 3.15, 0, 6.3 secondary taps from left to right. The picture of the wiring suggests the EL84 heater is taken from the 5th (3.15) and 7th (6.3) tap and that the 6th tap is wired to chassis ground. My guess is that the layout of the secondary has changed and that I should ignore the picture. If I'm right, I should use the 3.15, 0, 3.15 for the preamp tubes with the 0 center wired to chassis ground and use the 0, 6.3 taps for the EL84's. Would really appreciate any feedback. Thanks for you great videos.

[@fododude]

I think you're correct. The picture doesn't match. My amp's not working but probably for unrelated reasons.

[@bikematt5781]

FYI, Digi-key has $4.99 USPS shipping. I usually receive the order in 3 or 4 days from Minnesota to Los Angeles. Mouser is not so reasonable with shipping. I agree with you regarding the LED tube lighting, cheesey! :)

[@mlbabineaux]

Run it in ultra linear mode. It will sound better for a stereo amp. BC COmponents make good caps.

[@michaelclutton8446]

Thanks for the video, I am looking forward to how it works out

[@andymouse]

Took a nice piece out of the description for the amp " When playing string can show pine fragrance of the violin incisively and vividly " ...it does look like a nice kit, and well documented on eBay, I shall continue on with the build...cheers.

[@DAVIDGREGORYKERR]

This looks like a Power amp by ARION ACOUSTICS which is based in Dungannon, County Fermanagh, Northern Ireland.

[@adamwolfram6126]

I agree with you. I don't like it when manufacturers add LEDs to light up tubes. I'm a little disgusted that McIntosh is doing it with their current model tube amplifiers. They're a company with a distinguished heritage, and I find it tacky that they are doing that to their fine amplifiers. At least they included the option of turning them off.

[@YT32-16branch]

Exactly... option to turn it off, so not sure what you are crying about.

[@Dutchamp]

Don't even build that part it brings down the sound quality also the loudness BS, horrible I made my power Amp 6550we pp ul and preamp only entree sources Elna switch mounted in the back, adjustable in front connected with a rod. Volume 24step switch. Power switch on the back. That's it

[@freethinker1492]

Were did you download the instructions from? Mine came without any.

[@moodyga40]

You can test a led with diode test function on your meter to find the positive leg on the led

[@parilexisenfeuer9491]

I really enjoy your videos! Could someone please provide the assembly instructions for this amplifier? I got my kit without it.

[@almonzowilder4091]

Did you ever find the instructions? I need some too.

[@Nirky]

Set playback speed to 1.5 for all excellent xraytonyb vids. You're welcome.

[@1969CampEvans]

I would like to have the option to visit a audio outlet that markets hi- fi stereo equipment...so you could compare how the different brands sound

[@mfr58]

The transformers look worth the price of the amp alone. At least at UK prices. They look lvery conservatively rated and UL too, which gives more circuit options. I experimented with orienting x'fmr windings in different planes and it does result in noticeable coupling unless they are at 90deg. Screening will not eliminate magnetic coupling, unless you use mu metal and even then it's not perfect. Also the steel chassis is not ideal as it will carry eddy currents. Aluminum would be better. But it's a cheap kit for the quality of most parts, so you could always build a better case to house everything and mount the power resistors on the pcb topside. Thanks for posting. M

[@relaxvideomusic]

Wow! A lot of informations. Can you help me with problem, witch cable i should buy for my Fatman tube amplifier 13,5 w x2. I ordered Rogers LS 1 speakers. I have Wharfadele diamond 9.1. I am thinking about Rogers Ls5/9. Do I need expensive cable or more powerful tube like Yaqin, Nobsound 25- 40 w? But cables!?..... I am lost.Thanks. Mike

[@jeffcotton526]

You don't need fancy cables with uber inflated prices... get some good heavy gauge copper stranded cable; about a 16 or 14 gauge will do. If you want "Oxygen Free" copper cable then get it. Solder on your own connectors and you'll be good to go. The profit margin on those "monstrously priced" cables is upward of 600-700% and better. The only thing that can tell the difference is very expensive test equipment... certainly not the human ear.

[@robertcochran7103]

Thank you for posting this video, including the unboxing. I'm glad to see what to expect from beginning to end. This makes me think of a modernized Heathkit. I am learning the value of sorting and checking for all the necessary parts first, and then ordering any missing parts. Did you have to check that parts were within specification before building the kit? I've never done a project of this size and I think I need to start with a simpler project first. What are good containers for sorting parts into?

[@tomdewey9907]

Nice workmanship/build construction quality going on there Tony. I also agree about the Chinese having this "thing" for LED (blue or orange) underneath tubes; stupid IMO. Also, I agree that any heat producing components like 1-2watt+ resistors need to be on "top" for convection cooling.. At least that looks nice FR-4 circuit boards as opposed to cheapy phenolic crap.

[@Dutchamp]

Leave the glow tube part out of it. That will degree the quality of the output. Like leds underneath pre amp tubes. Stupid things has notting to do with audio. But looks like a desent amp. What a stupid thing about those transformers first rule of transformers they must be 90° up on each other. I find you made a good solution to this problem, the Amp would hum like hell. In my design I have a 25cm distance between power and output transformer. A bigger case ofcourse.

[@ExStaticBass]

How much well would an aluminum plate mounted between the transformers work for isolation?

[@HammyTechnoid]

Could more shielding around the power transformer be a solution? Like a shroud or something?

[@johnsweda2999]

Hammy Technoid yes I was thinking that I thought he would just rotate the power transformer leave the output transformers in their original positions just raised them up so you can get the wires underneath, if you had 2 L shaped pieces of metal using the fastenings for the Transformers there was a screw hole in the middle where it could be fastened as well. So both output Transformers would be shielded from each other and the power transformer, plus I don't like the idea of the connectors being so close to the shielded case not much room

[@williammcmanus7522]

Question. I've had a power tube go bad on this amp. At the same time the amp gave off a bad smell. Something obviously over heating. I traced this to the big resistor R1 on the power supply board (100 ohm 10w). Is it likely that a bad valve could cause this resistor to over heat? By the way I've been running this amp for over 3 years and love the sound. I'm using Russian 6P14 tubes which last better than the Chinese originals. I've also change the signal tubes for Mullard ECC85 which brings a big improvement.

[@xraytonyb]

My kit was one of the original old ones. It had a note for setting the screen grid, depending on what variant of EL84 tube you were using. There were two different settings, if I recall correctly. If you have the wrong voltage on the screen grid, it will draw excessive current and wear the tube out prematurely. There are several variants of 6P14. If memory serves me correctly (I could be wrong on the numbers), the 6P14P is similar to the 6BQ5, the 6P14P-E and 6P14P-EV were military grade tubes with higher ratings. There were also some chinese 6P14's floating around out there that were not as robust as the Russian versions. My build instructions had you install an extra Zener diode for one tube type and not for the other. I found the note in the (really poor) instructions and it said: "Parameters : If using 6P14, the regulator voltage should be 300V, If using EL84, the regulator voltage should be 320V(when it’s 300V can connect the 20V regulator diode via wire)" In addition, make sure you don't have any positive voltage on the control grids of any of the output tubes. I hope this helps.

[@williammcmanus7522]

Thanks for your reply Tony. From my research the grid voltage for both el84 and 6p14 tubes is 300v. Although the 6p14p-eV does seem to have a considerably higher tolerance, which I imagine is one of the reasons for its greater durability. The kit I purchased had no spare diodes and the instructions only came with details for the 320v power arrangememt. The power diagram is labelled el84 though the kit was supplied with Chinese 6p14 tubes. Interestingly the description on the Ebay listing describes it as a 6914/el84 Amp. On this basis the design will always result in early life failure of either of the intended tubes. I guess my options are to either use 6p14 p-eV tubes, fit another diode or put up with frequent tube replacements.

[@williammcmanus7522]

Update and correction. After some research it does seem there have been changes to the power board in this Amp over time. I've seen diagrams mentioning the 4th diode to produce 320v but my board only has 3 and is clearly marked 300v. I've measured and this is correct and from my research appropriate for either el84 or 6p14p tubes. So it seems I had a runaway tube that burnt out resistor R1. Fortunately after replacing the resistor and tube all seems to be well. I really do love the sound! The takeaway here is to keep an eye out for failing tubes and Replace sooner rather than later

[@rolfgerritzen1234]

Hello, I got the same amplifier but without loudness. Where can I get the board for it?🤔

[@russellesimonetta3835]

I,d switch out those cheap sockets for beltons. Make it alot higher quality. Also i think an alps pot would be an improvement.

[@tayro7265]

The led's under the tube is wrong. There should be no traces inside the pin hole/pads of the sockets. The area should be drilled out with a support ring pressed around the inner circumference. Standoffs should be in close proximity to provide support. The bass of the cabinet could as well be drilled for ventilation. But no. Not just no, but let's stuff an led in the way.

[@magnehaneberg8605]

Thanks for this very interesting video! All the best,

[@jeffmontenegro5318]

Pointing to Chi-fi with a chop stick is classic! You're info is great. Please point to Russian goods with a bear claw in the future. ;)

[@davidadada753]

Why aren’t you fluxing the solder joints?

[@mlbabineaux]

solder has flux in the middle.

[@TD402dd]

I'm surprised those old designed transformers. Monoprice already built hybrid 40watt/channel 8 ohms used a Toroidal transformer, and it is very quiet. They also have a pure tube amp.

[@deadfreightwest5956]

10:20 - The push-pull begins here. :P

[@sideswipe091976]

The shipping goes through the roof when it's an amp BECAUSE it's an amp. They are almost certainly folding in the cost of HTS duties into the "shipping" section. And, because it doesn't fall under 4lbs it doesn't qualify as "small parcel" and received subsidized rates.

[@KeritechElectronics]

SMD in tube tech? Meeeeeeh. Of course I'm an old school amp maker who does everything point-to-point, but I made a few PCB preamps, they all had THT components. None of that SMD rubbish, like Dave Jones says. I know it's been almost three years, but my personal tube recommendation here is NOS Soviet 6P14P-EV and 6N1P-EV. True about LEDs; I mostly recognize them by small vs large metal part inside, but always check the particular series of LEDs with a meter just in case I'm wrong. LEDs under the tube bases are just plain bullshit. I can't understand why anyone would want them. Good thing that you ditched them. I'd try aligning tube sockets with the chassis after putting them into the board, but before soldering them. Lay them on a flat surface too. Can save you a nasty surprise. I can't really see an advantege of using bell ends on transformers if they're to be covered with a box for all of them. They're there mostly for aesthetic and durability reasons, I like them a lot, but only when the design calls for them. Putting the mains transformer core in line with output transformers' is a major design flaw, but I'm glad you found a workaround. "That's how the resistor resists" is so on point that it should become your trademark catchphrase, haha! Speaking of these... quoting Dave again: "winner winner, chicken dinner!"

[@sarge27271]

Tony, great vids. I always learn new things. Love it. I have a question: I own a Pioneer VSX D1S. It has a slight buzz regardless of source. I think it's in dire need of recapping. I'm in Canada, so sending it to you is not really an option. How ever, I would like to know if you were to recap such a unit, (assuming it's just a cleaning and recap) approximately how much would it cost? (It'll help me figure out if I'm getting screwed or not on my end). Also, are there major differences between this unit and the Elite series? Different caps, power supply etc.Thanks. Cheers

[@johnb5519]

They are conning everyone with the shipping charges. They are used to bartering, so with some haggling, I'd bet they would sell it with free shipping.

[@jamesmdeluca]

Greetings: Use a 3v coin cell between the leads to establish LED polarity.

[@markdavies6950]

Did you route the 0V of the output transformer to the ground point or did you leave it floating? It wasn't clear from the instructions or the video. Also the supplied primary wire (P1/V/P2) is pretty thin. Assuming high voltage/low current so ok to use? I saw you had used pretty thick wire in there. Thanks!

[@cjbubeck]

I'm about 3/4 finished with the assembly (October 24, 2020), but I have two 100 ohm resistors left over that I can't find anywhere to install them. The boards appear fully stocked with parts, but those two orphan 100 ohm guys have me bugged. The 100 ohm resistors are on the parts list, so I know they are intended to go somewhere, but I'll be darned if I can find where. Any ideas! Thanks

[@cjbubeck]

Found apparently updated design feature where the two 100 ohm resistors are connected between the 0 and 6.3 pins on the power transformer and ground. Not sure what their function is, but that's why the two resistors were included in my kit (Oct 2020). Haven't yet completed and tested amp, but close.

[@MrRadar]

@@cjbubeck Those create a virtual center-tap between the filament lines and chassis ground to reduce hum. The channel Blueglow Electronics has a video explaining how it works: kzbin.info/www/bejne/h6Ssh3qEqpeMbc0

[@diabolicalartificer]

Cheap kit, not bad value. Agree with not putting LED's under the valve bases, apart from being a bit naff they might add noise. If folk are going to fit the LED's might be an idea to put a small cap across the LED's.

[@VintageSG]

I wonder what effect on the lifespan of an LED the heat of the valve will have and how naff it'd look with one dead LED, and one flickery, then the pain in the bejunker it'd be to remove the valve socket to replace an LED that has no right to be there in the first place. I like LED's, but not under valves. Naff, annoying and I suspect prone to failure.Valves look gorgeous when they're running in a darkened room.

[@DennisSantos]

I think that the heater wires were separate so that you can twist them and better isolate them from the rest of the circuit. Great choice with omitting the LEDs - bet they were blue.. Ugh!

[@BogdanWeiss]

Thanks for the highly detailed assembly videos - great for beginners :-) @ 1:03:40 You're NOT making a mountain out of a molehill - this would be a show stopper for a beginner & having a chassis that's too small for the supplied amplifier, & the transformers erroneously oriented & just packed in way too close, is not something that anyone should encounter when buying a "kit" I am wondering however, if in any future constructions, you could do a 2 min synopsis/overview ? what it is > basic specs & cost ? how it compares to XYZ ? your objective & subjective assessment of where the kit fits, parts quality,documentation is it "worth it" ? with literally 100's of Chinese audio kits available, it would be valuable to have some of the better ones highlighted... Elekit of Japan, has cancelled their much loved TU 8600 integrated amplifier kit in their line-up for reasons unknown to me.... Elekit existing offerings top out @ 8W/channel which unfortunately is just not enough for the types of loudspeakers I'ed be using them with.... cheers & respect

[@fododude]

Hey, I just noticed that you wired all your tube filaments together and my instructions say to wire the power tube filaments separate from the rest of the tubes and power them from different connections to the secondary. What gives?

[@verocola6335]

The power transformer voltage has been dropped to 250 Volts and and now the power output transformers ( 17:55 )... show a P1 and P2 connections for the plates and G1 and G2 connections for the output tube grids... totally different circuit.... or not ?

[@xraytonyb]

Sorry if there was any confusion, The output transformers that I received were different than the ones in the instructions. They were actually better. Although they did have the screen taps (G1 & G2), they weren't used in this amp and were left unconnected. I did make a comment that we could connect them to the screens, if we wanted to, for ultralinear mode. I did not connect them and the amp is the same as the schematic indicates. The voltages, when the amp was finished, were 350 volts on the center tap of the output transformer and 300 volts (from the regulated supply) to the screen grids, in accordance with the schematic. Hope that helps. Thanks for watching!

[@robertkat]

Yes we have come a long way since we used a hum bucking coil.

[@eliadculcea7718]

I just finished building it. When I turn it on I get a very high pitch and loud noise. the same noise is in both channels. When I disconnected the negative feedback from the board the noise is gone but it does not amplify the input. I took the preamp tubes out and the noise is gone too. I double checked my soldering and I did not see a problem. I must have made an error which is in both channels but I am scratching my head, I am lost. It looks i get a some audio signal if i place the input on the ground of the inputs. I figured perhaps I reversed the inputs wires, I took them out the noise still there even when is nothing connected to the inputs on the main board. I have enough knowledge to follow the PCB marking and do the soldering but I do not have enough knowledge to figure out what is wrong. Power supply seems to be fine, I get the correct voltage for the outputs. Any suggestion? Please.

[@basalt1900]

hello Eliad Culcea, i have the same problem, did you find out what the problem was? Thanks a lot

[@eliadculcea7718]

@@basalt1900 the pictures with instructions are very poor. For the speaker output transformer one end needs to go to the common ground and the other end to the red speaker output post. The black speaker output post is connected to the common ground. I hope this helps. For me i run into another problem, the power supply voltages are off by about 25V. I think is the power transformer output is 297V (should be 275V), I am in touch with the vendor to figure this out, it could be the power supply too. Frustrating.

[@eliadculcea7718]

Can you measure your power transformer 275V output? It will help me to figure out what is wrong with my power supply voltages.

[@basalt1900]

@@eliadculcea7718 First of all, many thanks for the good tip, that was the problem, now everything works fine :) The pictures are very bad, that's right .. What is your line voltage? 110V or 230V The output voltage of my transformer without a connected power supply is 278V. With connected power supply and amplifier 276V. The 350V output voltage from the power supply is at the beginning at 375V and then goes down to 345V. The 300V output slowly rises to 293V. The voltage supply for the EL84 is 6.25V and for the ECC85 6.3V. I hope I was able to help you with it, if I should still measure something, tell me ;)

[@eliadculcea7718]

@@basalt1900 I am glad the trick worked for you. My line voltage is 110V. I think the transformer is bad, for the 275V i get 298v with or without the power supply connected, then all the power supply output voltages are off by 25V, the filament voltages are correct which confirms I connected the 110V correct. I even tried another multimeter to make sure I am not wrong, At least the seller is willing to work with me on this, he thinks is the power supply board. I suspect the transformer is the culprit and you confirmed it by measuring your output voltages.

[@sc0or]

In which part this is an AB type? Sellers are so sellers...

[@tjasont1]

Dont you get more power in ultra linear?

[@widecast]

Why are you having to wait for resistors. I don’t recall you mentioning any problem with resistors being missing or what ever earlier in your description of the build.

[@almonzowilder4091]

Could you make a video explaining how to download the instructions. I can't seem to do it!

[@xraytonyb]

Send me an e-mail (listed under the description) and I'll send you what I have.

[@robertcalkjr.8325]

Pretty cool, Thanks. How much did the kit cost? I'm a new subscriber.

[@buildstoys]

He literally spent time in the video going over the listing and the prices.

[@robertcalkjr.8325]

I guess I was multi-tasking and missed the price, thanks.

[@blackdog.6398]

Cathode-tube. I love those old webcor reel too reel machines and even some helix rafters receivers had the infamous CAT EYE TUBE ,,, I would plug my Guitar into it sweet sound cam out I hooked up two classic c60’s speakers sorry ,,,and do what Jimmy H would take a razor and make small cuts here and there too give it a distorted sound I read it somewhere,,, old plexi heads ,,, warm sweet and ball blisters razor sharp!,,

[@ColocasiaCorm]

Could you put a metal plate between the trafos?

[@thermionic1234567]

What is that device called that you have you’re circuit board clamped into?

[@tombryan1]

10K on the OT primary, for El84s?

[@akdenyer]

do you have a link for this amp?

[@tomstanley7773]

If my memory serves me right, the filter caps are Philips, kind of, Mullard - Philips - BC - Vishay BC.

[@Aswaguespack]

They left out the bag of smoke! How will it work if there is no smoke? 😉😂

[@5argetech56]

Ahh, the old Push-Pull... Push-pull.... Giggity, Giggity... :)

[@russellesimonetta3835]

I think duok is the manufacturer or distributer.

[@tjasont1]

Just Add some shielding plates in between each transformer

[@sunnysun6086]

Very good, I have some too, and I select comment from German or Russian and Japan .

[@GeorgeChristofi]

Putting the heater wires in the same loom as those other signal wires is asking for hum..... Its a neat enough board but I always felt those kits were too expensive for what they are. Still, the video was enjoyable.

[@almonzowilder4091]

Oh boy. On mine there is no loudness switch. And a very simplified volume board. Well, I guess that makes it easier. :)

[@deadfreightwest5956]

I agree on the tube LEDs, so very tasteless and guache.

[@MichaelBeeny]

I have made a follow up video of an up dated version of this amplifier, it can be seen here. kzbin.info/www/bejne/aoipdJmCq7GNp9U

[@AlexK-vy3tt]

Hi Tony, 6N1P does not have an analog. Russian replacement for ECC88 is 6N23P. Here is a data sheet for 6N1P: istok2.com/data/553/ , but in Russian language. For russian tubes is better to find an -EV versions, it's a military grade (6N1P-EV or originally 6H1П-ЕВ).

[@69eddieD]

When swapping electrolytic capacitors in a power supply, you have to check ripple current. Bigger ripple current = bigger physical size, as a rule of thumb. The Nichicons are probably fine. The included capacitor is probably very old technology, which means they're physically large for their capacitance and voltage rating and ripple current. Plus you'd probably be hard pressed to find a datasheet on them anyway. As a rule of thumb, Nichicon capacitors are very high quality, and affordable. I keep lots of them around.

[@unique_amps_electronics]

26:42... so don't install LEDs, or install the color you like, hahaha!

[@TheFunkman]

unboxing... I just don't get it. forward to 3:10 for the meat

[@dennislarson9560]

No schematic?

[@54tristin]

Re :the fake lights. I think MccIntosh does it but for functional reasonsI may be wrong

[@smstiao-tecnologia]

Hi friend! Please, your have the name this model for sale in the eBay ? Tnx for response!

[@roscozone8092]

Hi Seb, I couldn't find it on eBay. X-Ray mentions in the video that he purchased from the doukstore on Ali Express. I posted a link below.

[@buildstoys]

www.ebay.com/itm/6P14-EL84-Push-pull-HiFi-Class-AB-Stereo-Tube-Integrated-Amplifier-DIY-KIT-13W-2-/272970610465?hash=item3f8e50f721

[@williamsquires3070]

At least they didn’t use blue LEDs under the tube sockets - that’s truly unnatural!

[@ΑλέξανδροςΓεκίλης]

6n1 aren't the same as ecc88. 6n11 are. Be careful.