Transcript
DU67 Tube Microphone
M ai n PCB. Don 't i n stal the fol l owin g parts yet: R1 5,R1 3,R9,R1 2,C7,C4,C2 and C1 7 **** Don 't u se th e h ol es m aked i n red Start By I nstallin g the parts that are shown to the left. I like to stuff all the parts, bend in g the l ead s on the bottom su ch that they are not overlappin g other traces to avoid any brid ging. Cl i p al l of th e l ead s of th e i n stal l ed parts, th en sol d er.
Th e n ext few parts wil l be i nstall ed so th at th e H i gh Z (i mped ance) i s bu i l t i n the air. Th i s wil l ensure a l ow noi se bu i l d . I n stal l C7 Leave th e top l ead strai g h t an d u n -sol d ered
I n stal l C4 Leave th e top l ead strai g h t an d u n -sol d ered
I n stal l C2 Leave th e top l ead strai g h t an d u n soldered
I n stal l R1 5 Leave th e top l ead strai g h t an d u n sol d ered
Ben d th e lead of R13
Tri m th e lead of R1 3. Do th i s to both si d es.
Sol d er R1 3 to C4 an d R1 5
I n stall R9 i n th e h ol e with th e circle arou nd i t then sol der. Bend th e l ead towards C7
Form a Hook on R9
Hook the one end of R9 to the end of C7 and solder.
Do the same for R1 2 an d sol der the hooked end to C4
Use the drawing below to install tube socket parts. The silkscreen may confuse you. Notice that the colors match the colors on the schematic on the following page.
I n stal l th e insulated tu rrets by pressi n g th em i n to th e h ol e circled i n red
When installing th e parts on th e top si d e of th e Tube Socket PCB, be sure to l eave en ou g h room
(¼” or 6mm ) to solder the tube socket. *** N ote: Tu be socket sh own for reference on l y. Don’t in stal l tu be socket yet.
I n stal l C8 an d R1 clip the leads and solder
Prepare R2 by form i n g a h ook on one en d . Leave The Other en d l on g
Solder th e hook to th e Turret as shown
Prepare C1 Leave the other end long. This will get conn ected to the Tu be socket
Install R1 6 but leave one end long. This long lead is coded red on the schematic
Prepare R8 by forming a loop on one end around the other turret. Leave the other end long.
I f you plan on cleaning off the flux, don't in stall C1 0 (styroflex) cap u ntil after clean ing the flux off is d one
I n stal l tu be socket an d sol d er
Form a 90 d eg re an g l e of C1 toward s the grid pi n
Bend th e lead down towards the tube socket pi n
Cl i p the lead of C1 and solder to the tube socket pin
Form a 90 degree angle of R8 towards the grid pin. Form a hook. trim and solder
BLU E
RED
YELLOW
RED BLU E YELLOW
BLU E RED
YELLOW G REEN
G REEN
I n sert th e Tu be Socket PCB i n to th e sl ot on th e main PCB
Sol d er on e set of pad s su ch th at th e two PCBs form a ri g h t an g l e. ****Don 't try to "ben d " th e ang l e with ou t reflowin g th e sold er j oi n t.
Now solder th e two remaining joints circled i n red
Form a 90 d eg re an g l e with R2 toward s C4 (yellow n et)
Form a hook. trim and solder
Form a 90 d eg re an g l e of C2 toward s th e Backpl ate tu rret.
Form a hook around the Backplate tu rret (g reen n et) Tri m an d sol d er
Con n ect C7 (bl u e n et) an d R8 by form i n g inter connecting h ooks. Trim an d sol d er.
Form a ri g h t an g l e wi th th e l on g l ead of R1 6 toward s R1 5. J oi n R1 5 an d R16 (red n et) by form i n g i n tercon n ecti n g h ooks. Tri m an d sol d er.
Solder To Link
HZ Bridge Reference
Install C10 Solder from top Pad on tube Socket PCB and then to grid turret
Find the three position switch and install in the "PAT“ position and solder. Take care to solder the Switches so they are flush to the PCB and aligned to the silkscreen
I n stal l th e rem ai n g swi tch es (two posi \tion ) an d sol d er. Test fi t th e swi tch PCB i n th e assembled m i c bod y. M ake su re th e pattern swi tch i n not obstructed by th e m i c bod y
Sol d er si x d i fferen t col ored wi res as sh own . (abou t 3 i n ch es l on g )
Solder the rear diaphragm wire to the other side.
REFERENCE PAD SWI TCH REAR CAPSU LE
M ODI FI ED RAI L LOW CU T SWI TCH COM PON EN T SI DE OF PCB
PATTERN SWI TCH
FRON T CAPSU LE
Backplate
Back
Feed th e rear capsule wi re through the si n g l e one of th e center h ol es. Attach switch PCB With the 3 screws and standoffs.
Install m ai n m i c PCBs i n to m i c bod y on th e Same side of th e rai l th at h as been modified to fit AM I T67 tran sform er.
Feed the backplate wire from the Switch PCB and tri m to length . Leave some slack. Strip the en d , tin with solder, an d form a hook.
Solder Backplate wire to the insulated turret.
Feed th e PAD wi re from th e Swi tch PCB an d tri m to l en g th . Leave som e sl ack. Stri p th e en d , ti n wi th sol d er, an d i n stal l , an d sol d er to PCB
Trim the Low Cut wires to length. Strip the ends back, tin with solder. Solder to two pin header labeled "LC"
Trim the Omni wire from the "PAT" switch to length. Form a hook and install to the Front diaphragm turret.
Tri m th e Bl u e Fi g u re 8 wi re to l en g th . Stri p th e en d s back, tin wi th sol d er. I n stal l an d sol d er to the h ol e ci rcl ed i n red bel ow.
Cu t two m ore wi res to abou t 2 -3 i n ch es l on g . Sol der one to th e Front d i aph ram capsule tu rret an d ru n u p th rou g h the capsule m ou n ti n g base. Do th i s th e same for th e backplate wi re an d rear capsule wi re. Carefu l l y I n stal l th e capsu l e. Cover the d i aph ram to protect it from th e sol d eri n g process. H eat an d fl u x can ru i n a capsu l e. Th i s i s very important.
Now Careful l y sol d er th e three wires to th e capsu l e.
Remove the 7 pin XLR connector from the bottom of the mic body by turning the screw clockwise. You may have to push it out from the inside of the mic.
You can cut a section from your tube mic cable for the internal wiring. Teflon insulation wire is better because the insulation won' t melt when soldering. Use this wiring chart for XLR pin-out. to tube mic. Cut about 3 inches of wire. Strip, tin and solder to Male XLR connector.
It should look similar to this after soldering .
I t's a g ood i d ea to h eatsh ri n k th e wi res.
The AMI T67 transformer is a tad too big for the mic rails. Remove the head basket . Remove the bottom four screws to remove the XLR/ shock mount base.
Use your favorite tool (My favorite is a 4 Inch angle grinder) or Dremel to grind away part of the rail . Test fit the T67 transformer and PCB to the Mic rails. Make sure there is clearance between the laminations and the rails.
Install the T67 transformer to the adapter PCB. Be sure to align the black mark on the transformer to the marking circled in red on the PCB.
Verify that the black making on the transformer and the marking on the PCB are located inside the red circle. Solder the transformer to the PCB.
Screw the transformer PCB to the rails. Feed the wires between the transformer and PCB as shown. Attach the base to the rails with the four screws.
Trim and Solder the XLR wires to the Mic PCB
Sol d er wi res as sh own ~2 i n ch es l on g to th e tran sform er PCB. Solder "1 " on the transf. PCB to "T44" on M ain PCB Solder "7" to "T1 01 0" Solder "5" to "T1 21 2" Solder "1 2" to "T55" Solder "1 0" to "T77" Sol d er "4" to "T1 1 "
N ow you shoul d have eveyth in g soldered on the PSU and the M ic. En su re th at th e m i c i s u n pl u g g ed from th e PSU . Appl y power to th e PSU . Ch eck vol tag es at th e AC i n pu t of th e PSU PCB. 20VAC for th e h eater ~270VAC at th e H T i n pu t
N ow Ch eck DC vol tag es. U nl oaded, my mic meau sres -1 6VDC at H - and 250VDC at B+
I f your Voltages check out, power d own the PSU, plu g in the M ic
Do not install the tube. Tu rn on the PSU. Check Voltages at H - B+ on the mic. U se the screw mounting holes as G nd ref. Voltages should be very close to the read in gs at the PSU.
Verify that there is less than one ohm between the mic body and the chassis of the PSU
Turn off the PSU. turn down the pots on the PSU to the highest resistance settings.
I n stall the EF86 tu be (you can use a cheap one for settin g vol tages. Be carefu l l to n ot disturb the wiring at n ear the
Check the voltages at the mic with the tube in stalled and the PSU turn ed on.
The voltage wil l start high and d rop as the tube warms u p. Ch eck th e B+ Vol tag e. I t sh ou l d be j u st u n d er 21 0VDC Check the H - Voltage. I t should be arou nd -6. 3V (negative)
I t's a g ood i d ea to be u n d er vol tag e by a few vol ts. Let the tube warm u p for about 20 minutes N ow ad j u st th e vol tag es u si n g th e pots i n th e PSU . Ad just Rtrim H - until you reach -6. 3VDC
Ad j u st Rtri m Pl ate u n ti l B+ read s 21 0VDC Con ti n u e to m on i tor th e vol tag es an d peri od i cl y sm el l th e el ectron i cs for an yth i n g th at sm el l s. Don 't l et th e m ag i c sm oke out!
Power off th e m i c. In stall th e bod y
Power on the mic and check the LC, Pad , and pattern switches by listen ing through a mic preamp and headphones as you toggle the switches.
You shoul d now be pleasantly suprised with the great sound of your voice through a tu be mic, Enj oy!
