Author Topic: My First Tube Amp Build (Read 7887 times)

junkkk · « **on:** Mar 11, 2013 at 12:26 AM »

Here's my first tube amp project. PT and OT courtesy of Edrel Sison.

Project Details:

Based from Odd Watt
1st Stage - 12AU7 in SRPP configuration - B+ = 215V
2nd Stage - EL86 SEPP - B+ = 245V, CCS is LM317 at 125 mA
Used 16 ohm tap to drive 8ohm speakers to reduce primary imp to 4K which is better for EL86.

audiojunkie · « **Reply #1 on:** Mar 11, 2013 at 02:39 AM »

Ganda...!

Congrats...!

mbtorn · « **Reply #2 on:** Mar 11, 2013 at 07:17 AM »

Maganda at malinis...lalong gaganda tunog nito using Cal's signature IC.

ATJr. · « **Reply #3 on:** Mar 11, 2013 at 07:29 AM »

you may try the 6201/12at7 in the first hole, there are some who liked the higher gain it brings...

praktikal · « **Reply #4 on:** Mar 11, 2013 at 09:13 AM »

pwedeng manalamin... nice looking amp!

qwi · « **Reply #5 on:** Mar 11, 2013 at 09:15 AM »

linis sir ng gawa nyo.currently ipon mode to get irons from sir edrel also.

edrel sison · « **Reply #6 on:** Mar 11, 2013 at 03:27 PM »

congrats junkkk! nice to have been dealing with you. the OPTs are under right?

Abad Santos 7 · « **Reply #7 on:** Mar 11, 2013 at 06:21 PM »

Congrats....

junkkk · « **Reply #8 on:** Mar 11, 2013 at 08:32 PM »

Quote from: edrel sison on Mar 11, 2013 at 03:27 PM

congrats junkkk! nice to have been dealing with you. the OPTs are under right?

Thanks

Yes the OPTs are under, masyadong crowded kasi sa ibabaw tingnan.

junkkk · « **Reply #9 on:** Mar 11, 2013 at 08:33 PM »

Quote from: TonyT on Mar 11, 2013 at 07:29 AM

you may try the 6201/12at7 in the first hole, there are some who liked the higher gain it brings...

Subukan ko nga 12AT7,

Edrel, meron ka ba stock?

junkkk · « **Reply #10 on:** Mar 11, 2013 at 08:35 PM »

Quote from: mbtorn on Mar 11, 2013 at 07:17 AM

Maganda at malinis...lalong gaganda tunog nito using Cal's signature IC.

I'll try this one out when I have the 12AT7

stick · « **Reply #11 on:** Mar 11, 2013 at 08:46 PM »

Very nice build! Very shiny...

edrel sison · « **Reply #12 on:** Mar 11, 2013 at 08:53 PM »

hi junkkk, i have lots of NOS GE 12AT7s.

fishda · « **Reply #13 on:** Mar 11, 2013 at 09:23 PM »

very nice sir.

congrats

ATJr. · « **Reply #14 on:** Mar 12, 2013 at 07:18 AM »

Quote from: junkkk on Mar 11, 2013 at 08:33 PM

Subukan ko nga 12AT7,

Edrel, meron ka ba stock?

since your input stage in an srpp, this is one situation wherein switching from a lower mu to a higher mu is possible.........in other cases this should not be done....

for the 317 ccs, you may also try the dn2540 mosfet....http://doc.chipfind.ru/sutex/dn2540.htm

junkkk · « **Reply #15 on:** Mar 12, 2013 at 08:30 AM »

Quote from: TonyT on Mar 12, 2013 at 07:18 AM

since your input stage in an srpp, this is one situation wherein switching from a lower mu to a higher mu is possible.........in other cases this should not be done....

for the 317 ccs, you may also try the dn2540 mosfet....http://doc.chipfind.ru/sutex/dn2540.htm

Thanks for the tip Tony, ill try to make a dn2540 ccs and try it out as well.

junkkk · « **Reply #16 on:** Mar 12, 2013 at 08:05 PM »

Quote from: qwi on Mar 11, 2013 at 09:15 AM

linis sir ng gawa nyo.currently ipon mode to get irons from sir edrel also.

Ako nag ipon for 2 months, pag may pera buy ng parts sa ebay, di ko pa alam na may tubes si Edrel same price lang din at readily available pa unlike ebay wait ako 3 weeks to arrive.

Still got 2 6LU8 from ebay, I am planning for spud amp next, idea came from Edrel. He got OPTs for sana di pa nya na bebenta

nomad13 · « **Reply #17 on:** Mar 12, 2013 at 08:22 PM »

How much po kaya trafo ke sir edrel?

junkkk · « **Reply #18 on:** Mar 12, 2013 at 08:36 PM »

you can PM Edrel to get his contact number so you can discuss your options, tranny's cost will vary based on your requirements specially the type of tube you will be using. He can also guide you in your design.

JojoD818 · « **Reply #19 on:** Mar 12, 2013 at 10:18 PM »

congrats on your build sir!

stockHT · « **Reply #20 on:** Mar 13, 2013 at 01:04 AM »

ganda sir!!

ATJr. · « **Reply #21 on:** Mar 14, 2013 at 06:16 AM »

Quote from: junkkk on Mar 12, 2013 at 08:05 PM

Ako nag ipon for 2 months, pag may pera buy ng parts sa ebay, di ko pa alam na may tubes si Edrel same price lang din at readily available pa unlike ebay wait ako 3 weeks to arrive.

Still got 2 6LU8 from ebay, I am planning for spud amp next, idea came from Edrel. He got OPTs for sana di pa nya na bebenta

i got around 20pcs for U$1 each here.....http://www.vacuumtubes.net/?source=google&gclid=COeixdvb-rUCFQUl4godeAQAWw

the 6LU8 tube is a nice sounding tube, the only caveat is that you have to operate at lower screen voltage of about 120 to 150 volts, using a full wave voltage doubler in the psu, this is very easy...

junkkk · « **Reply #22 on:** Mar 14, 2013 at 07:16 PM »

Quote from: TonyT on Mar 14, 2013 at 06:16 AM

i got around 20pcs for U$1 each here.....http://www.vacuumtubes.net/?source=google&gclid=COeixdvb-rUCFQUl4godeAQAWw

the 6LU8 tube is a nice sounding tube, the only caveat is that you have to operate at lower screen voltage of about 120 to 150 volts, using a full wave voltage doubler in the psu, this is very easy...

Really! naku di na naman ako makakatulog nyan ... yaiks

ATJr. · « **Reply #23 on:** Mar 15, 2013 at 07:01 AM »

Quote from: junkkk on Mar 14, 2013 at 07:16 PM

Really! naku di na naman ako makakatulog nyan ... yaiks

talaga.....there are lots and lots of dollar tubes, kaya ako nakaipon ng 1000 tubes.....nukod pa dyan yung mga anik anik na napupulot namin ni Edrel sa paligid ligid ng metro manila...

and then there are Russian tubes, mura kasi hindi hyped....

junkkk · « **Reply #24 on:** Mar 15, 2013 at 02:11 PM »

Quote from: TonyT on Mar 15, 2013 at 07:01 AM

talaga.....there are lots and lots of dollar tubes, kaya ako nakaipon ng 1000 tubes.....nukod pa dyan yung mga anik anik na napupulot namin ni Edrel sa paligid ligid ng metro manila...

and then there are Russian tubes, mura kasi hindi hyped....

True Russian tubes are very cheap, I got 4 pcs EL86 in my project above for only PHP 140.00 each including shipping. Mas mahal pa yun cost ng chassis

I am building a serious CCS using DN2540 MOSFET, PN2222A Transistor and TLV431 IC. Ill replace the LM317 CCS and give you guys feedback of what I can observe. Then tube roll to 12AT7 afterwards.

junkkk · « **Reply #25 on:** Mar 24, 2013 at 01:00 AM »

Quote from: TonyT on Mar 12, 2013 at 07:18 AM

since your input stage in an srpp, this is one situation wherein switching from a lower mu to a higher mu is possible.........in other cases this should not be done....

for the 317 ccs, you may also try the dn2540 mosfet....http://doc.chipfind.ru/sutex/dn2540.htm

I modified the LM371 CCS into a TLV431 Boosted CCS at 75mA for each EL86 at UL mode and used 12AT7 on the first stage with no bypass caps. Sounds have greatly improved, can't explain it but this current setup gives the best sound!

Thanks Tony for the suggestions. Will keep it this way for a while.

ATJr. · « **Reply #26 on:** Mar 24, 2013 at 06:50 AM »

Quote from: junkkk on Mar 24, 2013 at 01:00 AM

I modified the LM371 CCS into a TLV431 Boosted CCS at 75mA for each EL86 at UL mode and used 12AT7 on the first stage with no bypass caps. Sounds have greatly improved, can't explain it but this current setup gives the best sound!

Thanks Tony for the suggestions. Will keep it this way for a while.

tubes are fun, we are here to help you and others in every way we can....

junkkk · « **Reply #27 on:** Mar 24, 2013 at 10:46 PM »

I got 2 pcs of 6LU8, I am now planning to make it a simple SET-UL amp. I will use the TLV431 to bias the 2nd stage at 60mA and use LED bias on the first stage, see how it will sound.

But I will need Edrel again for my PT and OPTs here.

ATJr. · « **Reply #28 on:** Mar 28, 2013 at 10:39 AM »

here is a good one...