6DJ8 Phono Amp Diagram

sled108

sled108

Super Member
Well, work's kinda slow...So, I guess that it's about time to get on with building a Companion for the 6LU8 Cake Pan Amp. So next up will be a Phono Amp. I'm going for the 6DJ8 Design from RJM. It will be a 8" Round Cake Pan, and use a 6X5G with a CLCRC PS...Here's the Prelim. Wiring Diagram...I hope that if any of You Guys see a Catastrophic Flaw in this Design, You'll let me know...Thanks..
 

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Well, the Amp's Up and Sounding Sweet...A Big Thanks Out to Bas at DiyAudio..And to RJM for the Circuit..It sounds Great, with just his Stock Design..
 

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I'm seriously thinking about building this one Keg, what do you think about the circuit.:scratch2:
 
I have not looked over the circuit, but 6DJ8's I would consider fine phono tubes.
(nice well selected quiet ones that is, I'm sure you have a decent stash) :)
 
6922, 6DJ8, pretty much the same thing as far as I'm concerned, those be a bit pricey..:screwy:

Some of those Russian tubes with similar specs can be quite nice performers an pricers..:thmbsp:
 
Well, after spending Too much time chasing a Hum on One channel of this...I found that One of my Vintage Amperex PQ Orange's was at Fault..So much for the Old Stuff...I Rolled it with a Jan Sylvania, which fixed the Hum, and now it Sounds Great..But..It still has a Bit less Gain then you might Want...So, I Plugged it into CMOY HeadPhone Amp with a OPA2227 Chip before the PreAmp...And Bamm!!..You can now Juice it from the Headphone Amp, or Your PreAmp...This way you can Press Your Amp and Speakers for all they're Worth on Vinyl...
 
This looks great!! I think I will try to build it.

Sled108, Do you have more exact specs for the parts used in the power supply???

Also how has it been performing for you?
 
It is working very Well and Often..I've swapped the 6DJ8's for CCCP 6N23P's which Sound Great..I have also Cleaned Up and Re-Routed the Wiring since Posting the Pics..Here's what's in the PS....Dayton PMPC 4.0uf 250V Precision Audio Cap.....22uf, 100uf and 220uf 250V Radial Mini Electrolytic Caps...2 1N4007 Diodes..All from Parts Express..Radio Daze 8H Choke & 100 Ohm 5W Resistor, and 2 Radio Shack 12.6V 3A Center Tap Xformers..
Have fun Building this, but plan the Part Placement Carefully. It gets Real Busy in there, and you have to watch for Crossing over Leads that can cause Inductive Hum. If you have any Questions, I'll be Glad to Help as best as I can...
 
It sounds Very Sweet and Natural, 'Wide & Deep Stage' and all that...I used a Multi-Turn Resistor for R5 so it can be 'Tuned' to Taste...The thing is...It Sounds Great, but Not Loud...You will Still need to Run it though a Pre-Amp, or as I do..A CMoy HeadPhone Amp. Doing that will give it all the Punch your Speakers can Handle..True..It is a bit of a Hybrid Setup, but your only other Option would be to make it with a Pair of Paralleled 6DJ8s on the Outputs...Which is what I'm thinking of doing Next..
 
I've been looking this over and I think I'm going to g ive it a go. I've been wanting to build a tube phono pre and this seems like I could get it done for pretty cheap. I have a couple of questions if anyone would be kind enough to answer for me.

Would a 6x4 be ok for the rectifier instead of the 6x5? I know the pinouts are not the same, but would it otherwise be ok?

Also, would the heater pins for the 6dj8's just come of of 2 and 7 on the 6x5?

Lastly could anyone explain what is going on with the two transformers and how it works. Is it 114v that is coming out of the second and into the plates of the 6x5?
 
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Believe or Not...It is just what it Shows..One 12.6v 3A Radio Shack Transformer run into the Output of Another...It works Fine and they never get Hot, and you get a B+ of +/- 134v. The Heaters for the 6DJ8's are run off of Pins 2 & 7.
 
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I got my version of this up and running last night finally. Plugged it in and it worked right off the bat. I usually miss something and have to troubleshoot a bit on all my builds so far.

For some reason I forgot to order the c4 coupling caps, so right now I'm using paralleled .22 and .47 auricaps. It seems a little shy on the bass and I hope 1uf caps will fix that.

Mine also got really crowded, especially with the parelleled cupling caps and Orange drops for the others. No hum introduced though. I still have a slight 60hz hum, but that was there before and I believe it to be the 12b4 preamp. I will try to take some pics tonight and post.

Thanks for posting this sled108. I've been looking to build a phono pre for a while and this was cheap enough.
 
That's Great Wianieq...I'm glad it to hear that it went Smoothly...I'm looking forward to your Pix...
 
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