All Tube Phono Stage, Moving Magnet Pre-amp Part 1

[@NickP333]

Fantastic vid! Great choice of parts. I built an EAR834 clone but from a different PCB about a year ago. I used all top notch parts and a toroidal transformer. Also separated the PSU from the main PCB with a separation “wall” inside the chassis. Also used copper tape throughout the inside. It turned out to have no hum or hiss. It sounds great! Thanks again for the great video! 🙂🎶🔊

[@SkunkieDesignsElectronics]

Very cool! Where did you get the copper tape?

[@NickP333]

@@SkunkieDesignsElectronics Hi there. I found the copper tape at my local hardware store, but if you can’t find it there, you can easily find it on eBay.

[@The-Spotlight-Kid]

I totally agree with the importance of the phono-stage's quality as being vital to bring out the best of what's actually on our L.P.s. I bought my own & very first s/h stereo at around 19'yrs old in 1980'ish after i moved into my first flat, it was a Thorens 150 t/table with it's original buyer's- fitted SME tonearm & KEF 3-way f/standers (Concertos) & a some make of integrated amp, from local s/h ad's ...way back when pre-eBay vintage hi-fi prices were dirt cheap & handy for an apprenticeship wage'd person as I was. After buying a 2'nd & then a 3'rd s/h integrated amp, out of sheer frustration because i'd heard my new s/h speakers & t/table combo both sound very good by the seller's home demo big-but, i kept remembering my own L.P.s tone sounding far better via a adopted clunky BSR auto'drop t/table plugged into the "Gram" input of an adopted old & large mono valved table-radio during my parent's bedroom listening -days. I quickly learned how varied & mostly unsatisfactory were the internal phono-stage circuits in the budget integrated amps that i'd bought tho their line-stages were all far more similar, by miles. The sound of that, my first stereo totally stood or fell by how the integrated amp's phono-stage performed & all varied greatly while most fell flat on their face, at least in my price range. Then I saw a cheap s/h Quad fully valved stereo pre-amp with 2 dedicated Quad II mono power amps for sale in a local ad & tho of a much older vintage, I bought it unheard (with a loose "bring it back if...", but all units worked well & my L.P. collection suddenly came alive like never before. A year or so later, i tried & then bought a s/h 3-box modular P.S. Audio dedicated phono-stage to play into the Quad valve pre tuner (or tape) line input... even better! & I felt i'd achieved something extra good for the first time & it was all down to the phono-stages i.m.firm.o. That was 35+ years ago & a decent phono stage has been a very important decision ever since. I now have a 2-box fully valved phono-stage / power supply (Ming'Da) I bought 12 to 15'ish yrs ago & it beat all previous contenders but it's not silent on M.C. setting (which a peak inside told me it uses extra valve gain for & not step-up trannies (& so hissy it seems a silly design but it sounds excellent on any good M.M. As an answer to that M.C. hiss (even on higher 0.5'mv MC's) So I later bought a Dynavector solid state phono stage for no hiss from my mono-M.C. fitted tonearm. Gr8 video. I'd love a fully valved phono stage that doesn't hiss on M.C.s but step-up trannies may not do it & home trials are out of the question here in Cambridgeshire, u.k.

[@DennisSantos]

Tell it like it is, Steph! Don't hold back 😎

[@gene8933]

best sounding phono preamp i had a separate power supply with a long umbilical cord it was dead quite. I put preamp on self power supply on floor.

[@everTriumph]

I built a EAR834p clone. I scratched my head about loading of the MM cartridge. That required 47k and a capacitance of 200pF to 300pF. The phono lead could account for 125pF, but what did the phono input contribute? Studying how to calculate the Miller capacitance for a stage with a gain of about 50x gave a figure around 100pF. For a circuit with passive equalisation that would be it. Simulation of the circuit showed the gain of the first stage was only about 5x. This is because the feedback is summed at the point between the anode of valve 1 and the grid of valve 2. This reduces the voltage gain of the first stage. This in turn reduces the Miller effect by the same proportion. So the input capacitance is of the order of 15-25pF. Clever that! So strapping a 100pF across the 47k load gives me a cartridge loading of approximately 250pF. At last I can close the box.

[@SkunkieDesignsElectronics]

I would experiment using cables, and also measure the wiring in the table. Very few carts would actually benefit adding capacitance inside the box

[@crimsonghost6454]

Nice. I'm interested in this very much. I will follow to the end no doubt. Keep up the great content

[@SkunkieDesignsElectronics]

Awesome, thank you!

[@andrewm1894]

Looking forward to this 👍

[@joemartin6439]

Johnnie back again . You still are great video lady . What is the total cost of parts and where to get it all

[@moodyga40]

good to revisit old projects don't use the chassis as you're electronics ground, couple you're electronics ground to the chassis via 10 ohm 4 watt resistor and a 100 NF condenser to the main cassis this will stop the 60 cycle hum and run DC heaters

[@joemartin6439]

Love your thought, I have always played vinyl as my main front, Thorens modified TD160 TT. Many tube amps though quiet had not the speed needed to bring music to life. I have huge horn speakers and a great integrated tube amp. Poor components creation jitter, hum, and low life. Used great capacities,great resistors . China stuff I have tried and been very disappointed.

[@ELDecano1971]

I would love to compare a EAR834 clone to my Hagerman Cornet 2 .

[@kb6dxn]

Having a schematic would be nice of what your are building would be great.. Where did you get the parts in this build?

[@SkunkieDesignsElectronics]

I'll get one uploaded to my website soon!

[@sonhouse9636]

Great ! Thanks

[@MichaelLivingston-me]

I must have missed the kit name or the specific one you ordered off eBay. I'm intrigued to build one myself.

[@SkunkieDesignsElectronics]

Search EAR834 phono on Ebay and look for the long black board model. The green board model doesn't include the power supply.

[@jm_1214]

Id be willing to buy 9ne from you. I don't have the time to build one

[@jerryandlisa27]

Do you sell them ?

[@SkunkieDesignsElectronics]

I've built and sold a few of them for close friends, but don't have any plans for public sale.

[@gnoter2]

What little I know, I'd separate the granny from the circuit & place in a separate from the main chassis. Upgraded parts is a plus! Also, how much is this project total cost? I wish you success!

[@gnoter2]

Typo: transformer in separate cab.

[@SkunkieDesignsElectronics]

I'll post a BOM when I am done. The main reason I changed my mind on two chassis, I couldn't find 2 premade chassis in the right sizes, so gonna try this one with bulkheads inside.

[@SpinnerPaddlefoot]

Can anyone assist in identifying the correct circuit board and/or kit to buy on ebay that matches what is being discussed in this series of videos? Thank you.

[@SkunkieDesignsElectronics]

This link might not be valid long but this is the board. www.ebay.com/itm/353077232768?hash=item52350b0480

[@SpinnerPaddlefoot]

@@SkunkieDesignsElectronics You are so kind with your rapid response. Got it.

[@Dutchamp]

Vinyl rules despite of kracking or plopping or wow and flutter. My phone and vinyl doesn't do that at all. The soundstage is much wider and more depth then my teac vrds10se and seperated dac. I use a phono tubestage passive riaa correction. I use direct current to the 12ax7 's for heater. Then you won't get any hum. It is too delicate to heat with ac. I use one 12ax7 per channel not more tubes less is better.

[@SkunkieDesignsElectronics]

This does used DC to heaters, I think the very minor hiss/hum I hear (ear up to the speaker) is due to component quality and possibly PS shielding :) We will see!

[@Dutchamp]

@@SkunkieDesignsElectronics I packed my tubes with Mu metal that improves a lot but it isn't cheap metal.

[@stevelueb7787]

Oh NO !! An Lp will sound a million times better than a CD if you have a 1/2 ass decent System

[@joetaylor5078]

A Chinese 834 knock off isn't the way to start. The values and circuit design are not close to the original $2500 design. Adding somewhat decent parts to a flawed circuit isn't going to add anything of value. I suggest that you seek out a decent phono preamp to examine and discuss.

[@SkunkieDesignsElectronics]

The one I build sounds good or I wouldn't be doing this. I A/B compared this to a well respected/reviewed $400+ SS phono-stage and I preferred this clone. If using better parts doesn't improve anything, that's what I will report when I am done :)

[@ceylonmooney]

how many of these have you built and listened to?

[@everTriumph]

Lenco Heaven has some suggested modifications in its forum. The mods I used were based on those, and checked using LTspice. Between the sim and real world frequency sweeps a nice flat RIAA response was obtained. No sags in the middle, just a gentle roll off towards the extremities. I added a 50K stepped attenuator and a 470nF capacitor to provide DC isolation from my power amps, and a low frequency roll-off 3db at 15Hz approx. I threw it into an aluminium box with the power supply and transformer. I added a sprinkling of filter caps to the power supply to catch any spikes. Tucked the cables in the best places I could find. Result: the preamp has very, very little noise, and I cannot hear any mains breakthrough. Substituting it for my Self Elektor 2012 (feeding the power amps directly), there is a difference in presentation. The sound-stage of, say, John Williams is more 'spacious'. but maybe less precise. The circuitry apparently doesn't realise it is a cheap 834 knock-off. I didn't use any magic caps or resistors either.