Hi Stephe, I would keep the original paint on the vintage output transformers. I think that will help them to keep their value. It is great that somebody has made the replica stickers but that would be cool for restoring beaten up transformers.

I love the look of the old iron just the way it is! Don't change it - they are old and they should look it!

As a qualified electronics engineer with 30 years behind me and very experienced musician, I'm loving your channel because I'm learning so much. You're way ahead of most engineers becuase you have a practical approach and don't get weighed down by all the calculations. Love your work!

As an engineer with 40 years of industrial electronics experience I can honestly say I don't know the first thing about tube amps but I'm learning a lot from your videos. Keep up the great work.

I'm an electrical engineer with Ms. In controls and I have lots of fun with your projects! I'm sorry to hear about this ridiculous comments.. your channel is great!!

That patina took 50 years to create and has a lot more value than a 5 min spray paint job.

In the upper range of LineMagnetic they have a vertical amp, looks fantastic. Everything is on display.

OMG…🤦‍♂️ Everyone’s a damn expert in those forums. I’d personally leave those transformers alone. Wouldn’t touch em. The patina is just part of their story. Skunkie Designs Electronics. Best DIY channel, hands down. “I’m an engineer” 😂🤣 Ah, geez…I feel your pain and totally understand. Heard it plenty of times. 😂

Nice rant, don't paint.

Something that Janos on Real World Audio has found is that tube amps can punch much above their weight when driving speakers, compared to driving a test resistor. The key is to not skimp on the PSU or output transformer.. A few nominal tube watts can sound very generous when backed up by over sized iron and reservoir caps.

Many thanks for sharing another insightful video on your future build plans, Stephe. Wonderful to see the utilisation of KT88 and 6V6 tubes reintroduced, which also offer far more tube rolling options. For the vintage OT iron, I'd suggest hooking it all up first and seeing how you go with it. If you really like what you hear, then yes, proceed with the restoration process. I prefer the old vintage look anyway and would take functionality and performance over looks any day of the week.

Absolutely keep the original badges, it's the right thing to do. I fear new copies would taint the old-school vibes of the original badges. Love the vid, much gratitude. Eagerly waiting for you exploration with these pieces. I did some tube stuff back in the late 70s, but over time became a BJT guy, but now, are you ever swaying me into the magical world of tubes again! Stuff has gotten crazy spendy though, I used to drop about $18 for a KT88 back in the late 70s, and that was in Canadian Dollars! 12XA7 were almost giveaways, sigh.

cleaner wax for car finish is about all I'd do with them. Should shine them up a bit without going nuts.

I would keep the patin, it really fits with the look and just screams authentic. I really think the age adds character in this type of application.

Some great projects planned Stephe. I look forward to your builds - as usual. Regarding the transformers I suggest leave them looking vintage From Downunder

I'm an engineer. keep the irons the way they are to maximize performance.

I feel you, there’s a massive difference between following the numbers and using your intellect. I am pretty sure it’s called common sense.

I tune the NFB of a push=pull output amp by ear. The lead compensation can be tuned by using a square wave and/of looking at the frequency response.

Love KT-88's and who doesn't?

@Skunkie. Nice projects coming down the pike! I am definitely going to follow the KT-88 monoblock project. In terms of a tube push pull amp, well, I don't want to burst your bubble on that, but my first foray into tube amplifiers were with push pull amps. I had a vintage Bell labs (circa late 50's) stereo push pull 6V6 amplifier that I played around with and while it sounded good, I just felt it never really had that tube sound. I had tried tube rolling and that really didn't work. It was with this amp that I had entered the world of global negative feedback and learned more about push pull amps. While you probably already know this, but push pull amp designs inherently cancel out even order distortion, so learning this put a big damper on my initial push pull amp projects. So, then I have discovered that these amps use copious amounts of global negative feedback to deal with the odd order harmonic distortion that was left. In the end, you have a fairly sterile sounding tube amplifier which really only sounds marginally better than a transistor amp. Granted, perhaps it was just the Bell Labs design, but then again, doing more research, back in the day, when there weren't any transistor amps, designed were driven to make the amps have as low a distortion as possible, kind of like the transistor amps did in the 70's. Lower distortion meant more accurate reproduction of sound. So the correlation between push pull tube amp designs and push pull transistor amps became more clear. I knew that what I wanted was something that was going to preserve the all important 2nd harmonic, and the only way to do that was with a class A design. Now, I don't know if using a design with much less global negative feedback might help. Or if there is a way to reduce the canceling effect on the push pull outputs. That might be asking for more trouble than it is worth. For me, the only place where I would feel a push pull tube amp would be worth a look see, is with a guitar amp. Here is where you need lots of power and the amp can be driven into distortion, and with tubes, this is far more compressive, rather than a brick wall effect. Also, rectifier sag comes into play as well. So there is still a lot to be had with a push pull design on a guitar amp. But for hi-fi? Hmmmm, you might be wasting your time. Keep up the great work! I enjoy this channel very much and love what you do and what you have to say. Again, will definitely be looking at the KT-88 mono blocks and how the Musical Paradise project ends up. Cheers!

Really nice chassis for the KT88 Monoblocks!! I would keep the vintage patina on the transformers, i think that is cool. I'm not keen on the mint green color idea, but you do you....I'll still watch! I think you should stick to the single ended designs, if that interests you and you understand them. Its more about the sound quality of a tube amp than push-pull power output, IMHO. And if you need more power, there are some bigger SE tubes available to try, or maybe a more complicated design with more SE gain stages...? I'd love to see you do a comparison of the trendy Cryotone tubes vs your favorite PSVanes, head to head in one of your amps....just an idea for a future video. Thanks!

Hi Stephe. I worked with some old coke bottle style 6V6Gs. They may look cool, but their performance wasn't too good. Try them out, but I came to the conclusion that 6V6GT (most American brands) are better. Someone mentioned using a 6GH8 or 7199 as a voltage amplifier/phase splitter. The problem comes from using the tube the way it was intended. While the pentode voltage amplifier's cathode operates close to ground potential, the phase splitter operates at a high cathode potential; 90 volts or more. We have a compromise situation caused by the common heater. You can get nasty problems, not the least being hum and distortion when the heater operates at or near ground potential, that often gets worse over time.

I'm not a engineer,🚂I'm a bass player. Not professional. But good. I love tubes and reselecting tube amps in chassis of there own like RCA. Make guitar amps in industrial chassis of diff design. Do what you like. Right now I'm using 2 Nos Merit power transformers with pwr like 350-0-350 @250ma and 3 6 volt heater strings one 10A. Big stuff. Anyhoo. I've got 20 things going at once. Let ya know when I get one done. Thanks for all ya do.

I recommend you use a 6gh8 for the input amp/splitter. its just like a 7199 but different connections and lots cheaper. In 1970 I got a good acrosound (ultra linear) transformer and built a push pull 6l6 amp that sounded great.I used a 6sn7 2 stage driver/tone control with a push pull interstage transformer.built a base reflex enclosure for a 8 inch wide range speaker to go with it. made a good workshop system. the old 6v6 tubes are a good choice. you can get a easy 10watts

hi,the push-pull amp cancel pair harmonics and double impair harnonics distorsion, its the reason why you need global negative feedback .

Engineering is different from hobby DIY. A smart person can learn by himself or herself to gain the knowledge and hands on experiences, sometimes even more proficient than the formally educated engineers. However, engineers are trained to apply theory into actual design. In this process, modeling is a key and it needs a lot of math. We need a lot engineers to design the big machine right and at the same time we need a lot of technicians to maintain the running machine. The funny part is that engineers might be very stubborn as they are trained to be that way to stick to the rules. I think Boeing is typical example where engineers became flexible under the pressure from the top accountants.

my class T (texas instruments speak for class D)small amps are 8 watts/channel. which is plenty for me.

Seeing as you are making a 50s amp, I'd leave the age marks to reflect its heritage.....

Hey Steph, i am pumped for your upcoming build! I was in love with the idea of those 120 monoblocks. Have you ever thought about converting the amp designs to some pcb's, with gorgeous layouts, and selling those on Tindie or some other service? Or as kits straight from your website, even.

I definitely would keep the old original look

Exciting build! Thanks for doing it.... 🙂

call yourself a scientist. no degree is required for that.

Leave the patina. Buff them up and take what you get.

Steph don't mess with the OTs!!!! Leave them antiques. As you probably know the first thing an antique dealer will tell you is don't refinish antique furniture. Someone 100 years from now will thank you.

Keep em original!

Just leave them alone

Patina is only original once. I vote to keep them as is 🤠

Leave them they're perfect.

I'd just clean up the Acrosound xformers and leave the paint/sticker original.

12ax7 driving 6bq5/el84/7189 is the configuration my Cary sla-30 uses, but it's push pull with 4 output tubes on each side, but doesn't use ultralinear. I love that amplifier, so I'm curious to see what happens with these vintage output trafos. It's just different enough yet similar to what I've been working on. As far as leaving the patina on the trafos, I dunno. I've kinda always liked the retro-mod end of things, but I would certainly smack that one corner down with a 2x4 hehe

Hi , I am not am engineer, imo you got offended too much for you own good. Maybe the guy was stating what you found obvious or not paying attention to all you said but I don't think it was personal. Anyway, I appreciate your effort in these thorough analyses and sharing them on video

I agree with the others, keep the transformers as is. Being old and used isn't something to be ashamed of, lol.

Engineers who actually do shi$ get frustrated with those engineers too!

Leave 'em alone! They're only original once :-).

I think you should leave the transformers just as they are.

for the transformers, I prefer keeping original.

Leave patina Can you post the link for 5e chassis ? It’s beautiful. I am an engineer - I agree they can be a holes 😂 Love the channel keep up the great work!

The bottom looks great, but don't the slots limit mounting options for the components? 🙂

I only worked out how push-pull designs work by working on one - just like you have on your builds. I don't know much about global negative feedback either but if you are working to a known good design then you can make tweaks to it and measure/listen to evaluate it, just they way you have on your other builds! And try not to get down about the engineers that can't wait to tell you stuff that you already know. That happens to everybody and its frustrating but I've found that biting back puts off the people with the answers you seek and you suddenly only get people that want to side with you or people who want to bait you. Don't ask me why but just about every forum on every conceivable subject has a tendency to go this way.

I was wondering if the tube amp world makes any efforts in sound damping the chassis the tubes are mounted on. After all tubes come with the microphony effect, right? Putting car sound deadening material on the inside of the steel chassis - is that a thing?

Embrace their age.

Hey Skunkie. Today i bought some tube amplifier from marketplace. I can't use it because it is only a power amp. The sound is very low with my dac. What should i do? The thing weighs a ton or more.

I would keep the original look on those transformers - showing they're real deal vintage stuff. I think they'd look nice on a brushed aluminum chassis. Engineers trying too hard to use their engineer's degrees to out-engineer someone who does real deal engineering, just to show some class privilege or something... I think that at least some of them will also mansplain science and tech to you. The worst kind. Self-conceit and sense of superiority. Meh. I find it a no-brainer that people learn stuff throughout their whole lifetimes. Formal education never should be a limiting factor here, and just because someone could afford to spend a few years of their life at a college or uni and get a degree, doesn't mean they necessarily know more than someone who didn't but studied the area of expertise, often for decades. I love your work, keep that up

I think the "old" look would be nice... :-)

I am an engineer, but not in electronics, so what I know about software engineering has no value here.

Yep most Engineers have no clue. I started an engineering degree because i was getting tired of ecplaining to dumb engineer's how things work and how to fix them, while not getting any credit for my knowledge because i don't have the degree. Found out what a useless course an engineering degrree is and why engineers are useless. You dont have to be smart or have any clue of practical reality to pass an engineering degree. I quit after a year. Better to spend my time designing my own stuff and start a business than get a degree to work for some dum manager that will make all the money and bonuses from my good ideas

leave the transformers old

Do not paint them if they're old iron show off the old iron

Please don't paint the transformers.

LOL ... don't ever assume having a degree equals being smart. Especially in today's "lower the bar", easy A's universities. People buy their certificates today. Back in the day that used to be true but not now IMO. I've been around quite a few of these "engineers" that carried quite a bit more arrogance than brains. The problem is none of them do field work anymore and think that everything they've read is how it is. Most of what they read is wrote by people like them. See a problem here? Google engineers .... run for the search engine to get the answer. I'd take a Skunkie built amp over any other, because you have shown us that not only do you have the brains but also the skill to hang with the best amp builders ....... period

👍♥️🫂

Always great to explore some vintage components and circuit designs... but it would be great to go full "steam punk" or "rustic rat rod" with the overall design theme for a change!

Hi Stephe, been following your vids and was particularly interested in the little 6BM8 amp that you made. I have just aquired a pair of 6BM8/ECL82 monoblock amps rated at 8 watts/channel. Do you think these will be suitable for driving Klipsch RP600M speakers in a 16' x 10' room. AVREAVOX ARCANA 82 MONO POWER AMPLIFIERS Greetings from the UK