DIY Phono Pre-amp: Final Assembly

[@OpossumPiper]

Yeah, I definitely am in the camp that the tubes sticking out a little more makes it look nicer, and easier to change. Nice build!

[@ShawnWrona]

Thanks for all of the videos! I’m putting together a shopping cart for components tonight to order tomorrow!

[@zefrog7482]

Awesome build series, as usual.🙂 You've got me wanting to build all of this stuff.

[@insurrectionindustries1706]

I like the tubes sticking out like the new build as it does make tubes easier to change. I don’t think more would be better but I would not prefer them being as low as the previous build.

[@SkunkieDesignsElectronics]

Thanks and I agree.

[@gregwilliams2746]

Definitely prefer seeing the tubes and it makes it easier to change them. I would prefer to see them all the way out - they are proper eye candy and make it obvious what this phono preamp is all about! I definitely would like to build one of these. Nice work, Stephe!

[@SkunkieDesignsElectronics]

I'm just concerned about microphonics with this much gain.

[@gregwilliams2746]

@@SkunkieDesignsElectronics - cheap and easily reversed mod, right?

[@kbeast98]

Just ordered my board. I'm a new ham radio operator and this is right up my alley, thanks for this series!

[@SkunkieDesignsElectronics]

Have fun!

[@kbeast98]

Having trouble finding these rca jacks on mouser,

[@SkunkieDesignsElectronics]

Got those off ebay.

[@kbeast98]

@@SkunkieDesignsElectronics thank you Stephe, believe i found them but from a different seller, and found the Mundorfs and some of the other ones that are discontinued. Almost went with the higher price mundorfs but will start here first. Can't wait to get started, this is going to be a huge upgrade for me!

[@SkunkieDesignsElectronics]

I don't think the higher priced Mundorfs sound as good, you made the right choice!

[@FredSchill]

Found your channel while looking for a new phono Pre. My Little Bear Pre Amp does hum and as I love the actual sound quality I wanted to build a better version of the Ear834 circuit. Anyway, after you mentioned how important the twisted AC wires are I took a look at my amp and off course I had almost an inch of parallel running AC wires coming out of the transformer! Fixed it and my amp is completely silent now, thank you so much! And keep up the great work, I continue watching your channel. lots of love from Austria!

[@SkunkieDesignsElectronics]

That is awesome!!! And yeah, that little bear when setup right is a really decent sounding phono-pre IMHO.

[@kbeast98]

I am up and running! Needed the .25A slow blow. Ran into a dead channel but think it was a cold solder joint on one of the terminals. I'm using tungsols 12ax7s and this is a night and day upgrade from my bellari vp130. I'm officially all pure tube. Sounds insane. If it takes a half hour to sound good Im in for a real treat. Curious even once these tubes break in. Thank you again for these videos and your support building! The chassis work which i was fearful about was honestly really easy with the tools u recommended. Could probably build one now with my eyes closed. Thanks Stephe!

[@SkunkieDesignsElectronics]

Yeah people are intimidated by the chassis fab, with the right tools it's not that hard!

[@kbeast98]

@@SkunkieDesignsElectronics and i suck at measuring and everything lines up great! That chassis punch was the deal though

[@brokkur7629]

I assembled it with the valves completely outside, by - mounting all the big stuff, capacitors, on the underside of the board - using "socket savers" in the sockets. I had some microphonics on V1 with the first valves I tried, but found one that was silent in my stash. I also use damping rings. Sounds great!

[@cobar5342]

Thank you Stephe. It is a really good result and the tips help

[@VinylRescue]

Looks great! I like the tubes sticking further up, but I'd build mine with them higher up. But that's me. I'd use a different ground post like the one I put on my Little Bear T11 so I can use a banana plug connector. One of these days I'll build one 😊

[@SkunkieDesignsElectronics]

The fat copper ground wire 100% helped!

[@terryife8823]

Hi Everyone I've finally finished this Phono Amp, thank you Steph for all your hard work 👍 It does sound fantastic apart from I have a bad hum. I went with the extra thick ground wire that was suggested also i twisted the wires that came out of the transformer, any ideas ?

[@SkunkieDesignsElectronics]

Some of the later boards don't have the front ground pad actually connected to anything. Shoot me an email and I'll try to help.

[@terryife8823]

@SkunkieDesignsElectronics where can I find your email address, Steph ?

[@SkunkieDesignsElectronics]

[e-mail]

[@cured808]

The amp is slightly favoring the right channel. This happens on two boards I did. I checked and switched out the caps; also checked all the connections. Switched the tubes. Any ideas?

[@SkunkieDesignsElectronics]

You tried swapping rca cables/signals from left to right?

[@cured808]

yes I swapped cables,@@SkunkieDesignsElectronics

[@cured808]

I'm at a loss. Next I'm changing out the wire and RCAs.

[@only1stefan]

intresting i just finished mine i upgraded all the parts and it does sound amazing i also made a custom case.The only question i have is when i first switch it on after being off for a long time the front valve glows realy bright then iminiatly settles down any ideas ?

[@SkunkieDesignsElectronics]

Try another tube in the spot? There is nothing different about the heater circuit for that one tube.

[@only1stefan]

@@SkunkieDesignsElectronics your right its that one tube doing it where ever i place it

[@only1stefan]

@@SkunkieDesignsElectronics i also wonder if they do a subsonic filter for that amplifier and a way to make it work with moving coil as im soooo super impressed with it

[@SkunkieDesignsElectronics]

You need a Step Up Transformer or a SUT. And yeah, that's just a "bad" tube heater. I've seen them do this yet still work fine and last a long time. If you need a subsonic filter, there are external RCA inline types out there.

[@only1stefan]

@@SkunkieDesignsElectronics thankyou i do love it it honestly sounds amazing

[@Expedition18]

Do you have a link for the pcb? Thanks awesome series👍

[@SkunkieDesignsElectronics]

Look for them on ebay.

[@aquaescape411]

Hi Stephe, in this video series you connect the white wire to the switch, and the black wire to the plug. In your first edition of the EAR834 from years ago, you connect the black wire to the switch, and the white wire to the plug. I have been trying to troubleshoot my build and switched to the new videos wiring and now get no power whatsoever. No heater current, nothing on caps, no output at all. I am new to this and have hit a wall. Also, when I was looking for shorts my multi meter buzzes when I touch the two 6.3v taps. Is this normal? I’d appreciate any help I can get. Thanks!

[@SkunkieDesignsElectronics]

Those are AC wires to the primary. It really doesn't matter which one goes where as there is no polarity at this point. Are you sure the fuse is installed and not blown?

[@aquaescape411]

@@SkunkieDesignsElectronics Thanks for such a fast response! You’re the best! Brand new fuse. 250V 250mA.

[@terryife8823]

Hi Everyone I've completed the board but have one capacitor left over, it's a nichicon film capacitor 6x15x26.5, 0.047uf 630 vdc. Any ideas ? It's in the original BOM and it's a flat one. Thanks

[@SkunkieDesignsElectronics]

It's to go across the power switch

[@terryife8823]

@SkunkieDesignsElectronics to stop the pop ? Thanks Steph.

[@kbeast98]

Me again, for the iec connector, are you wiring the line and neutral reversed intentionally, because it seems the neutral is wired for the fused terminal. I'm just about done!!

[@SkunkieDesignsElectronics]

The switch goes on the fused side, the transformer has no hot or neutral.

[@kingarthur1953]

I prefer the tubes sticking out more better. I like the brass details on the front.

[@SkunkieDesignsElectronics]

Thanks!

[@moodyga40]

do you have a series globe for testing

[@SkunkieDesignsElectronics]

??

[@OTO_45]

Great finish for this outstanding serie! One question. The ground-knob (Turntable) wired to the PCB. Has it also connection to the chassis or is it isolated there like the RCA-Inputs? Looking forward for your Monoblock serie to be continued and the serie about SUTs Thanx and cheers Stefan from Germany

[@SkunkieDesignsElectronics]

Connected to the chassis there.

[@chelillingworth9466]

What would you estimate the ballpark would be for the total parts cost for this build?

[@SkunkieDesignsElectronics]

Total all in with good tubes, paint, hardware, shipping etc. about $500, maybe a bit less if you shop carefully.

[@chelillingworth9466]

@@SkunkieDesignsElectronics That's very reasonable!!

[@mddawson1]

I like them sticking out a little more. It would be interesting to see an amp painted in 'Black 3.0'. This paint is so black that objects painted with it lose all surface detail becoming almost two dimensional.

[@DustinWatts]

Very nice build! Edit: I was commenting on the 3rd terminal of the power switch. But, looking at it again, there seems to be no 3rd terminal. So you are save. Sorry for that and this does not apply to you but I'll leave my original comment here for when you have a switch with 3 terminals.. One very important tip I can give you. When you solder the power switch, use one of the outer wires for the incoming live voltage and the middle pin for the switched output. If you do it like you did it, when you switch the power of, the other (not used) terminal of the switch becomes live. So remember, live outside, switched inside. If do it like that you are save! 👍

[@MashBill]

Great job as always. What hardware do you use for the turntable ground lug near the input RCAs?

[@SkunkieDesignsElectronics]

Some brass hardware I got at the hardware store. Going to get some stainless for the silver theme one.

[@aquaescape411]

Could you recommend an appropriate fuse please?

[@1mctous]

She's going to try a 1/8 amp fuse after nearly burning up the big Hammond choke with the 1 A fuse.

[@aquaescape411]

@@1mctous How many Volts? 250V?

[@1mctous]

@@aquaescape411 Probably, since the current matters more than the voltage.

[@aquaescape411]

@@1mctous Appreciate it, thanks!

[@aquaescape411]

@@1mctous also looked like a 30mh choke in the video, not a 20?

[@cured808]

With Mundorf EVO SGO caps and Telefunkens, with casual A/B listening, I'm not hearing a huge difference between the clone and my Modwright PH9.0. Sumiko Talisman LOMC going into some Hashimoto HM-7s. Between the clone and Darlington Labs MP-7, it's the difference between SS and tubes. The clone will get you to the 90th percentile. I did the first version, now converting to the 'small box' version.

[@SkunkieDesignsElectronics]

And that's my goal, 90th percentile is fine wi5th me, especially if it's at DIY prices!

[@stevegorkowski3246]

The tubes in the case are going to heat the parts. They made wire tube clips/sockets in the past to hold tubes in place. It was common in old portable tube equipment. The tube sockets with the clips are tall coming out of the case . Place an expanded metal cover over the tubes. The parts and PC boards used in this new stuff will not stand up to heat so keep the heat far from the capacitors and resistors. My Heathkit amp in the past was designed much better to hold up to heat by using point to point wiring. Just a few things to think about.

[@SkunkieDesignsElectronics]

These pre-amp tubes just don't get that hot, not like output tubes do. Many commercial tube pre-amps sold for decades actually have the tubes inside the case. In my build, the large hole with the top of the tube exposed allows the heat to rise up, cause heat rises. Yes, output tubes put off a lot of heat and need better ventilation. www.mcintoshlabs.com/products/preamplifiers/C22-Mk-V

[@stevegorkowski3246]

@@SkunkieDesignsElectronics Each tube places 2-3 watts of heat . I just don't see it being a problem in most cases. It isn't likely that the heat will cause many problems . Overtime the tube sockets pins get weak from the heat localized on the heater pins and the PC boards can start to get brittle over time. All of this takes years of constant use. It has been the 90s when I built a RF amp using a tube ( 4-1000) that would put out 1500 watts with 2000 vdc plate voltage and the parts I would use are not made. Enjoy your project!

[@1mctous]

Big iron and big copper = quiet circuit.

[@ywsx6489]

18:00 Maybe they live in an area with alot of EM interference.

[@SkunkieDesignsElectronics]

But they are describing 60 or 120hz hum.

[@jacksyful]

I like sticky outers ,for convenience