The o-rings go on the EF86 tube V3.. The EF86 tube can be very microphonic it is also important to rubbermount the EF86 to limit vibrations.. It it's also a good idea to use a good quality EF86 NOS tube like a Dario Miniwatt or The Tesla EF806S

Like This
http://www.kcanostubes.com/content/nos-tesla-ef806s-not-jj-high-grade-ef86

Build a 5e7  you won't be disappointed  ....... such a great circuit..... Pete T. used a late 50's tweed with the  3 - 10's  on the Who's 'Who's Next' recording.... It has great chime and very clean and breaks up mid-point to get some good vintage crunch.....

Thanks!!!!! it's a very underrated circuit..... here's a shot of my Dizzy 30........

Built my 5e7 7/2008........ what a great amp.... in the last 3 years I have made a few changes like recapping with Sozo blue caps and AB carbon comp resistors which really warmed things up... also, smoothed out the higher volume gain placing a 470k grid stop resistor between  V3/p7 to the 1m resistor on the board.. also used shielded rg174  from the input's to V1/p2 and p7  and from V3/p2 to the treble pot. Last but not least added a buss bar and attached all pre-amp grounds to it cancelling at the chassis by the input jacks....

This amp took quite a bit of time to burn in and get shape... running Tung-Sol RI 5881's in V4 & V5 Jan GE NOS 12ax7's in V2 & V3 and a Brimar NOS 5751 IN V1.... currently running the head through a 2-12 cab loaded with a Celestion Alnico Blue and a G12H30...I Liked this circuit so much I have scratch built 2 more....

I gave bad info on the change from the .0047 to the .0022 cap on the brilliance circuit and have removed it ( it was late when I wrote it )  On my Dizzy 30 I went from a .0022 to  A .0047 not the other way as stated.. that said --- go up in value say to a .0068 or even try a .01.. and like I said it's easy to go back to the way it was if you don't like it... Sorry for the mis-info

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I checked my heater volt readings on all 4-5 and 9 pins and get 2.9v added together It gives me the 5.8v within the 10% +/- tolerance . I would like to know what is causing this and the comment's here make me think it is a universal issue... maybe nik will chime in.. As far as the fix I see in the pic shouldn't the standby switch be grounded??? Also, I just added  four 1n4007 diodes to the recto sockets as it shows on the new layout revision.. I guess it helps tame the current in-rush when switching standby to operate.. nik said they were having issues with the jj gz34's arching..

Heres what nic responded:

nik,  In this image you can see where the buss bar comes up short... it doesn't match the layout position? but we have it fixed and it made a huge difference. What value are the diodes on the new dc30 revision??

Thanks

On Jul 27, 2009, Nik S Azam <nik@ceriatone.com> wrote:

    
    Greg
     
    Thats great!
     
    As for the buss bar, I see. Is that to the last 25uf? Or maybe the way it is bent?
     
    Thats great then, glad you sorted it out.
     
    As for the diodes, 1N4007 would be good.
     
    I am afraid that the current JJ GZ34s are prone to arcing due to inrush current. Having this helps a bit.
     
    Standby switch for tube rectified amp isnt necessary, and in fact, hurts the amp, esp the tube recto itself.
     
    In turn, other things can be hurt like the PT etc if the tube recto fails, or if the surge gets too big on standby switch toggling.
     
    We will be updating the layout again, this time with more ways to help protect the amp.
     
    Other than diodes, a cap can be put on the plates of the GZ34 (0.01uf 3kV)
     
    Then, a resistor, say 100K, can be put across the standby switch pins, along with a cap, 0.047uf or 0.1uf, 630V.
     
    Then, a bleeder resistor from 1st filter cap to ground can be added as well.
     
    If you want to go the full shebang, a 100R 10W or 15W resistor can be put in line on each HT before recto tube socket, to provide some resistance which helps protect further. This is not necessary with the above, it's a way to over engineer it.
     
    Thanks!
    Nik
     

Cool thanks.. Got one major hurdle figured out... The Buss bar supplied in the kit was to short it did not connect the 2 25uf 25v caps together on the board it stopped a couple of turrets short, which left a gap and did not connect the ground to make a continuous path. Two major things occurred when I completed the path.. cathode volts dropped from over 100v to 1.5v and all noise is gone ...you can hear a pin drop>>>> I have a bad ef86 to replace and heater pins are only seeing 2.8v but, I think I might be measuring it wrong... nik is sending a voltage chart tomorrow I think I see light at the end of the tunnel.... Also.. this thing gained a huge amount of volume I can't believe how loud it's going to be.....

update: nik sent me the voltage chart and after the ground fix all my voltages are right there where they should be.... As it turns out the ef86 works fine and won't need to buy another one yet..... nik just responded again that they sent the right buss bar it's not noted on the layout yet

 
"ps. what was going on with mine was that the heating wire was only putting out about 5.8 volts instead of the 6.3 it should have, and the mains to the power amp section were hotplating the tubes once off standby. the wire change solved the mains and brought the heaters up to 6.15 which is still lower than should have been, but most likely the tollerance on the tranny was low, or there was a miniscule solder error."

How and where are you measuring the heater volts at??? I have my meter set to DC volts and checked at the 5&6 pins.... I get a reading of 2.8v ? confused even further now...


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Anyone recorded their voltages at the pins on their DC30 that they can share??... I have some Funky volt readings... I think what I suspected that my EF86 is bad is looking true.. But other voltages have me confused.. and would like to know what healthy voltages are???

I rewired the send/returns and now have the ch. 2 volume working proper through it's range.... Still have some hum to chase down and am not getting the level of volume I should out of ch. 2 .... I am thinking the lack of volume might be a bad ef86 bought off ebay.. ??

I built this from a kit it's my second build so I have a lot to learn about electronics ...Also, when plugged into channel 2 does your ch. 1 volume knob when turned affect the volume level of ch. 2???

With my channel 2 problem I am chasing down it appears that not much glow comes from that tube (ef86) all others appear to have more going on in the tube. Is this an ef86 trait or does it sound like a bad tube?? anyway to test the tube without a tube tester since I don't own one?? I get sound but only when channel 2's volume is all the way at zero.... would I get any sound if the tube was bad?? the tube shouldn't be creating the volume only works at zero issue right??? When using the shielded wire nik supplies with the kit does the braided shield need to be pig tailed to ground or just solder the core wire to the tabs stated on the layout... As I stated in a previous post all wires match the layout and all have continuity.... I'm CONFUSED
thanks

Got amp started up and channel 1 is sounding good but channel 2 is having issues..... The channel only gets sound if  volume knob is  turned to zero.. any other movement I get scratchy and pronounced hum and no sound from guitar.... Checked wiring against layout and it looks right ...... bad pot??? Kind of at a loss here and trying to avoid $50 per hr bench time......

Just as long as your iron gets hot enough for the romex you should be alright.. if you want to go the route with the 2 conductor shielded wire let me know and I will give you the source..... any questions you can get me at snookfam1@verizon .net

don't know if your in the USA but if so you can go to Radio Shack and buy a spool of buss wire for the jacks......

They supply all the wire you need except the buss wire (solid wire connecting jacks) I used 22g solid hook up wire for the buss I just stripped it to the bare wire. The smaller guage wire I supplied which is 22g teflon coated high heat hook up wire.. I did not use the supplied shielded wire. I fabricated the 2 white thick wires that run from jack to pots from 2 conductor shielded cable. But they supply enough except the said buss wire. I just chose to change a little.