ampeg m12 6v6

[Tom_Hull]

hi

I put together a m12 6v6 ,and with many posts read from everyone,,, it works .first startup using a light limiter

thanks for your posts and ramblings that make me have the understanding what works .i sanded and leaded all  the resistor and capacitors  leads first ,and then put it together .old world style

well its not tweaked but it sounds real nice .
but
the tubes rattle inside .6sl7s
and the first tube humms like crazy without a sheild.

i can get a good variance in sound .but just starting out on the guitar so what do i realy know . seems nice to me  


i bought my first guitar 4 weeks ago  ,, at 56 years old, lol ,,,, epiphone 100  les paul model.and put some black beauties in ,,,

i junked out some parts . black beauties in the trem area.
old ceramic capacitor at the pots ..

old transformers from a 1956 lowery organ .

the organ was a wreck
mice nests,coffee syrup on the chassis and then painted inside with white wash.

well ill maybe invest in making a new m12  ,,seems worth it .but

maybe with 12ax7 or nine pin tubes . so i can mount it in a skeaker cab .. the rattleing 6sl7s bug me .. and should i buy some more nice used  6sl7s instead . i have a source with good prices or nos for real money  but if the rattle not sure ??

anyone know of any old tube brands that rattle less or something  for 6sl7 s..??

tom


ps and now ill try a untested vox AC30 posted

[sluckey]

I just built a J12B which is identical to the M12 except only one preamp. My old 6SL7s don't rattle or hum. I wouldn't give up on the 6SL7s just yet. Not sure how you would shield an octal tube, but I don't think you will have to.

[Jack_Hester]

Not sure how you would shield an octal tube, but I don't think you will have to.

Here's a shielded 6SL7 on the far left of the picture:



This is a Harmony H-200, Valco in origin.  This is the first shield that I've seen for an octal.

Jack

[TubeGeek]

I too am dealing with rattling octal preamp tubes in my latest project, they rattle like crazy!  Mine are 6SC7 which is very similar to 6SL7, just different pinout.

I think it may just be that we need to find good tubes.  I have ordered a set of the new production 6SL7 tubes and will report back to you if they rattle or not. It may help you out if you decide to purchase new tubes for your amp.

Have a listen:  http://soundcloud.com/glacier/5c3-bounce-no-clamp-on-tube

Excuse the crappy guitar playing please

[Tom_Hull]

hi

yes i do indeed enjoy the sound the tubes are making . a fullness..

and i like the two preamps conected




and ill check into the hum from the tube but its very loud  without the sheild ..

and ill tweak

the amp  out.



tremolo speeds not working just a nice constant rate and no change in speed ??


i' ll be ordering some tubes 6sl7 s  used $3.00 each and up to nos $70..

$3 is my price range plus shipping  and yes it would be nice to here about your order ..

thanks for posting

 

[Tom_Hull]

Hi

I am so happy .
I chopsticked it and there was the problem ...

the sheilded wire slipped down the wire and  was shorting to the soldered  connection. i simply slid the ground  from the connection .
there were two wires shorted that way. the second volume pot and the tremolo speed wire .

i ll make my sheilded wire as in an organ . and use shrinkwrap to hold the wire more secure .

now

there is no hum
no sheild for the tubes and no rattleing sounding tubes .

the tremolo works . everything works

except the power light .

thanks for the heads up on no tube sheild .

sounds so so  sweet now .thanks ampeg.

tom


  

[HotBluePlates]

Not sure how you would shield an octal tube ...

His picture showed the input tube with the shield in place.

It's the one like the old-school radios... a shield that's just waiting to cut your finger to the bone.

But it's nice that he doesn't need it now.

[darryl]

... a shield that's just waiting to cut your finger to the bone.

These were good for doing exactly that . . .

[sluckey]

Not sure how you would shield an octal tube ...

His picture showed the input tube with the shield in place.

Yes, but there was no picture when I made that statement. After seeing the pic the cobwebs fell away and I remembered seeing octal shields with wires attached to chassis for grounds. But that was in old radios. I can't recall ever seeing an audio circuit with a shielded octal. 'course, that could be the cobwebs again.

[Jack_Hester]

As a number of my finds are in antique shops/malls, I will pay more attention to the old radios, for shields.  I'm sure that I've seen them.  But, I didn't pay enough attention to know them for what they were.  I'll pay attention, now.

I got cobwebs, too.  Plenty to go around.

Jack

[Tom_Hull]

hi

that sheild..... is the sheild i leave around .for instant use .

the preamp tube hums only if i almost touch it .

the lowery organ had nice larger sheilds  for the 6sl7 ,,6n 7 s, on the preamp area but the tubes were very close side by side .so they were used there.

i put them away , lost away ...lol..and now good thing its not needed.


there was one thing I did not like ..
one yellow new cap ,,the lead just slipped out of the capacitor after it was installed ,....good thing i found that right off or part of the preamp would not work well.


now to order 6sl7 tubes ,,,,,,,hummm silver  ,grey. black plate?????  round and other shaped plates??    may just buy all types??? ....hummmmmm...then what rca or tungsol or ??????
 

tom


ps one of the tubes was rattleing abit so i change that one

[Tom_Hull]

here are  the voltages in this,,,,,,,,,,,,,,, ampeg m12_6v6


http://www.el34world.com/charts/valve/ValveData.php?e=view&f=14082

[sluckey]

Looks like maybe V3 grid (1,4) and cathode (3,6) voltages are reversed???

[Tom_Hull]

thanks


 

i tried so carefully as well and still mistakes and still wondering    

 rechecked
pin 1 4 grid 1.1  ac
pin 3 6  ,,7.7    dc

[Tom_Hull]

h

so my order is in one dozen 6sl7 s..  few brands  GE >sylvania   national union philco a few more ..grey plates,,, black plates and one silver plate  all about 90 to 110 %

So when i tested out the amp my wife was sleeping so i did not turn it up.
it humms in the acc jack it humms loud

 and in the inst jack there is less humm .
 
 so i put a better sheilded cable in place of the, double line,  sheilded one i used helps .

the jacks seem to be my humming area and i am checking through it all..  

i turned the volumes at full.. plugged a vibracaster pedal in ,,turn that on full,,,, tremolo full

,Blasted for a few minutes which may have been a hour lol  and

now the speakers burnt lol..

buzzy speaker lol,,now i have a black organ speaker to use as a replacement. and a leslie ..

my daughter is having agreat time recording her song BIG JOHN  ,,and its cheaper to do an album almost  then to make only a few songs ..

the asking is $110,000  to record an album and he is doing it for free . thats about the nicest man around ,

except for most people  and moderators on this forum ..

tom

[sluckey]

it humms in the acc jack it humms loud

Did you use a 5.6M resistor on the Accordion jacks? If so, change it to 1M.

[Tom_Hull]

hi steve

yes and will do

your just great thanks ..

i play the harp abit.... so that was the reason for the build . i plug a mic in that jack




tom

[Tom_Hull]

hi  and thank you



So this is what i did . about time ..

ok so
all numbers added sayes that i am getting a nice sounding 17 watts from one 6v6.. lol.
thats of course for how long ..lol

now let me fix this
the 250 ohm 10 watts bias resistor is warm os now its a 300 ohm 20 watt cement resistor
i change the first power resistor to,,,,,,,,,,, two cement resistors in sieries 500 ohm  600 ohms

 that is 1100 ohms instead of the 1000 ohms

i change the jack resistor from 5.6 m t0 1 million .

started it up .

here are the numbers for the 6v6gt s  

 pin 4 .....380 volts
pin 5 ...... 25 volts with a 300 ohm resistor

maybe thats 15 watss from the 6v6gt each ..

the tremolo had a missing resistor  not marked i used 270k resistor .

the humm has gone way down to quiet........ unless cranked up .
but maybe there is a sortof high note in the humm.

1   i think its the jack setup that makes that humm

2   and the output tranny thats there seems small  ,,,,,,,,,,,,

     i have an organ tranny 16 ohms  for 6l6gt maybe change that..

3   so i can put a leslie and a 12 inch speaker,,,, in...series

4  also my bias capacitor is rated for 25 volts and thats whats there now 25 volts i have a new 25 uf 50 volts ,maybe put that there

and maybe a choke for the power supply not sure though .

thats it thanks
 

the

added    the voltages after a long warmup

pin 3....368
pin 4 ...375

25 volts with a 300 ohm capacitor

.043 amps running per tube 
thats 14. 7 watts ??each

[Tom_Hull]

hi

so i am completly confused here.

now i put in a large new choke from Doug
it read like 100  ohms

so i put that in and now the humming has gone gone lots .. it seems very quiet running

and volume is not so blasting . but i i would run it like it was . and cope with what ever .

now the volume is less but stiil has good sound ,different .

the voltages are now

373
379
 and 17  volts and a 300 ohm resitor .

so is this ok  .????

tom

[sluckey]

now i put in a large new choke from Doug

How did you connect it? I would have replaced R31 with the choke.

[Tom_Hull]

hi

i put the choke after the rectifier tube before everything ,thats all '

tom

[sluckey]

i put the choke after the rectifier tube before everything ,thats all '

Doug's chokes are meant to be used between the plate and screen nodes. For your amp that would be between node C and B, ie, replace R31 with the choke. Give it a try.

[Tom_Hull]

hi steve thanks

done
replaced choke with r31  i believe your saying change1000ohms for the choke done

so here I am with

388 volts
371 volts

26 volt with a 300 ohm resistor .

15 watts per 6v6 gt,,,, i believe   minus whatever
well i like the sound of this ,,,,
it reminds me of 6l6 gt tubes ..

 the hum is only at the  very high volume levels  ..quiet amp  

well poor tubes tung sol 6v6 gt ,,

tom

thanks tom

ps just wrote a song on testing for sound ..i cannot wait till i learn to play lol been only a few weeks with this guitar and wrote three songs

one is being recorded,, lol,,,,,,,,, like ////who let the dogs out,,,, an easy song .. had 15 dogs at that time ..lol

[sluckey]

15 watts per 6v6

That's hotter than I like to run 6V6s. I had to increase the cathode resistor up to 500Ω to get the static dissipation down to 9.6W (my comfort zone) on my J12. See schematic...

    http://home.comcast.net/~seluckey/amps/RCA/Ampeg_J12B.pdf

You may want to consider adding some 470Ω screen resistors, especially if you're gonna run the tubes hot.

[Tom_Hull]

hi Steve

very nice of you ..

perfect ..
 
thanks so much
tom

[Tom_Hull]

hi

the bias

so the capacitor is now rated for 50 volts.
and with a 500 ohm resistor.

well scratch my head thinking ,,,,,now ..omy

403 volts
393
volts

31 volts with a 515 ohms cold ,,500 ohm resistor

now thats 11.2 to 11.5 watts per tube .. they still sound as nice .but

this amp is so quiet now

thanks tom

ps. 6l6 gt tubes next build well almost

[Tom_Hull]

hi

steve thanks for the schematic .

I put in a 5y3 as the rectifier .
i looked at the lowery power trans and found that its 2mp for the 5 volts .so thats part of my toubles ..i had  a 5u4 there........... but it was a 5v4,,and i tried it .. that gave me a 409 volts .

and a flash  to the heater wire as i was probing  ,, electrical jump,,  telsa coil stuff .turned it off immediently ..change the two magnavox tubes 6v6gt . hummie humm

well the amp still works lol...

now with a 5y3 untested nos

375 volts
365 volts
 
26 volts with a 500 ohm resistor .

but now tweaking the humm  .. by following the posts

like i said thats so much Steve ..


tom

PS

i was playing my new song here in the living room ,,, and ermine,, WEASEL,,white and grey just turn white for the winter

just sneaked up to the speaker . to have a listen ,,
now this must be a sweeet sounding amp amp LOL
well hes still there .lol

[Tom_Hull]

hi

all is well .

my order of tubes is in
there are diferent heights o 6sl7s but for now

 there are silver plates grey plates and black plates .
i found that they really make a difference in the sound.

i like this lineup .
black plate for the preamp then silver plate  and grey plated for tremolo.
seems right .

 but different plate colours really change the sound . so i might just change the 6sl7s  color plates for sound changes .


my son inlaw can play a bit of guitar and it does sound great,,,, beside his solid state amp but the reverb in his amp helps the transistor to have ok sound and he has a tube pedal booster to help with that tube sound . but nowwhere near the great full sound this amp gives .. .

now does any one KNOW what skeaker should go with this amp.\???

 i was thinking about a new  cheaper legend 50 watts speaker  ,,it has a blues sound ,that he likes ..

this sounds close to what my sounds like with old organ speakers ....i have a great fullness of sound from this amp in the bass 

 http://www.eminence.com/speakers/speaker-detail/?model=Legend_GB128

Is that an ok size speaker ??


tom

[Tom_Hull]

hi

 so i ended up buying a recone speaker  for guitar ,,, conn organ speaker  ... 12  inches .

It handles 20 25 watts

now i had this fleetwood extention speaker cab.
 a little paint from a garage sale and this is what i have for a setup .


i really like this sound ..it  can blast bass ,,for sure ..i found out about fret  power cords on the guitar ,, and overdrive pedal and amp volume at 2  treble up full   wow,,,,,,.  ..just a few months into playing guitar and I just cannot stop. my first amp for me  

 i need to do some more work ,,,, .light bulb and computer plug in setup  afew things .
the curcuit is  . back to normal .

here is a look of it ..

I am working on a vox and i have a great cab for it ,but no pictures yet ,in case i  change my mind.

tom

[J Rindt]

I built an M12 about 2 years ago. I used an old PA Head. Space was tight, so I had to use both sides of the chassis AND the sides. Sounds really nice though. Just a single input jack.
I like your chassis much better.
Nice Job.!!!!!

http://i111.photobucket.com/albums/n143/zzmoore/AmpegMercury004.jpg
http://i111.photobucket.com/albums/n143/zzmoore/AmpegMercury003.jpg
http://i111.photobucket.com/albums/n143/zzmoore/AmpegMercury002.jpg
http://i111.photobucket.com/albums/n143/zzmoore/AmpegMercury001.jpg
http://i111.photobucket.com/albums/n143/zzmoore/ampeg.jpg

[Tom_Hull]

hi

Thankyou

tight ;
like the vox 30 ,,,the  chassis i am building in now smaller  ..

it turn out with a choke coil fitted in the emtpy space opposite the ot at the back . \
they are both the same size ..lol

i looks balanced now ..

one tube blew when  i put the amp in the speaker box .. it ran hot .
put the amp in the cab and not working  ohhhhhhhhhhhhh


so i was worried for a mniute,,,,,,,,,, i checked the amp and could find nothing wrong /.
so i thought to change tubes ..lucky it was the tube . the tremolo tube .. i need to check that out later .why..??

any way
 need to build my son inlaws amp before he gets back in feb from 8 month military tour ..
another different ampeg with reverb  ..
i have most of the larger parts .
but i have a vox 30 on the bench .

its neat with a switch for ,,,,the 4 power tube working or....... 2 on and 2 stand by ,,,,and and   

tom