mikeski's amp
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mikeski
I need input
Oh how plans change a. hahahahaha. Can't use my transformer. Have to look for a new one.
Triode has this one. http://www.triodeelectronics.com/mq060.html Exactly what I need. Even comes with a second 6.3v tap. I could split the heaters by channel.
This toroidal would be interesting. It's just lacking a bit of power. 365 at 250ma. And the 5v is only 3a. I need 4 for the two 5V4. It has a pair of 6.3v at 3.5a each. So that's a channel split there.
http://cgi.ebay.com/upgrade-Dynaco-...pt=Vintage_Electronics_R2&hash=item45f57aa3c5
I checked into that 5AU4. The heater draws 3.75a
What if I split this into two mono's? Could I get away with smaller power transformers and one rectifier? I could use the toroidal above. It would have more than enough power. It has an extra 6.3v tap. That would just dead end on each amp. There may be others that would work. I have been looking for 4a on the 5v.
Thoughts????
Triode has this one. http://www.triodeelectronics.com/mq060.html Exactly what I need. Even comes with a second 6.3v tap. I could split the heaters by channel.
This toroidal would be interesting. It's just lacking a bit of power. 365 at 250ma. And the 5v is only 3a. I need 4 for the two 5V4. It has a pair of 6.3v at 3.5a each. So that's a channel split there.
http://cgi.ebay.com/upgrade-Dynaco-...pt=Vintage_Electronics_R2&hash=item45f57aa3c5
I checked into that 5AU4. The heater draws 3.75a
What if I split this into two mono's? Could I get away with smaller power transformers and one rectifier? I could use the toroidal above. It would have more than enough power. It has an extra 6.3v tap. That would just dead end on each amp. There may be others that would work. I have been looking for 4a on the 5v.
Thoughts????
mikeski
I need input
Thoughts on tube brands???
6JB5's are CHEAP...... ~$5 each. Say $30 a quad. We can try a few different quads for that price.
Sylvania, Zenith, RCA, GE
5V4 could be cheaper. ~$60 a pair
That leaves the 6BL8.
6BL8's are all over the place price wise. And there are the European versions. I saw a pair of Amperex Bugle Boys. How much of a diff will changing this tube make compared to the others. That seems to be an important tube.
Mike....
6JB5's are CHEAP...... ~$5 each. Say $30 a quad. We can try a few different quads for that price.
Sylvania, Zenith, RCA, GE
5V4 could be cheaper. ~$60 a pair
That leaves the 6BL8.
6BL8's are all over the place price wise. And there are the European versions. I saw a pair of Amperex Bugle Boys. How much of a diff will changing this tube make compared to the others. That seems to be an important tube.
Mike....
jtnfoley
Well-Known Member
Don't we all?
My favorite search tool (and I've been doing this interwebs thing since LONG before Al Gore invented it) is to use the Google "site:" keyword.
Try this link:
http://www.google.com/search?q=site:audiokarma.org+"dual+5v4" (literal string "dual 5v4" on site:audiokarma.org)
Here's another, this time not literal:
http://www.google.com/search?q=site:audiokarma.org+dual+5v4
And because kegger used this phrase (string-literal)
http://www.google.com/search?q=site:audiokarma.org+"parallel+5v4" (spoiler alert: this turns up this thread only!)
Here's the same thing, not string-literal:
http://www.google.com/search?q=site:audiokarma.org+parallel+5v4
A string-literal search for "parallel rectifier" also turns up some interesting stuff...
Kegger
R.I.P. 1/12/1966 - 6/1/2017
Here is my rundown of the 6JC5/6JB5/6HE5 family of tubes as I presently know it.
(this is from some testing/using/examining plus net searching)..
The 6HE5 is the small bottle version with the small 12w plate.
(all the brands seem to make these, slightly smaller bottle then a 7868)
http://www.mif.pg.gda.pl/homepages/frank/sheets/123/6/6HE5.pdf
The 6JB5 is the larger bottle version and an larger 15w plate.
(these seem to all be GE, but re-branded as well)
http://www.mif.pg.gda.pl/homepages/frank/sheets/123/6/6JB5.pdf
The 6JC5 is also larger bottle version with a larger 19w plate.
(these seem to all be Sylvania, but re-branded as well)
http://www.mif.pg.gda.pl/homepages/frank/sheets/107/6/6JC5.pdf
Then there is the RCA 6HE5/6JB5, large bottle with small 12w plate.
(these seem to have the small 12w 6HE5 guts in that larger bottle)
I have ran them all, the Sylvania seem the beefiest an sound best, (to me at least)
(in Singled Ended UL I get 5-6w output, push pull pentode here you'd be say 23w)
The 6JA5 has the same pinout, but is not exactly the same tube an draw more PL
current to where they do not bias up anywhere near where the others do.
(I believe these are a 19w rated plate as well)
The tubes labeled with all 3, 6JC5/6JB5/6HE5 on them should be your large bottle
GE and Sylvania tubes, I would search those out..
Now to get funky, there is another set of tubes with a top cap plate connection an
with 17.5/18w plates, 6GV5/6GY5, if you look at the pinouts, you can see they can
be wired to use the same pinout/socket as the above just need the plate caps con.
(I have not used these so I don't know how they respond)
http://www.mif.pg.gda.pl/homepages/frank/sheets/123/6/6GY5.pdf
(I wouldn't pay more then $5 ea for these tubes, plenty out there for that price)
A couple places I have bought tubes from with good service and prices are here.
http://www.fourwater.com/compact/comp_c5.htm
http://www.esrcvacuumtubes.com/vacuumtubes_tubelist_tubes_5A5-5Z4G.html
======== These have also been referred to as 6V6's on steroids (not by me)
My camera isn't the best but here is a bit of comparison of how these tubes look
next to each other. (should give a decent example of there physical differences)
First pic shows left to right, 6HE5, GE 6JB5, Sylvania 6JC5
Second pic shows left to right, 6HE5, RCA 6HE5/6JB5
Third pic shows left to right, RCA 6HE5/6JB5, Sylvania 6JC5
Fourth pic shows left to right, GE 6JB5, Sylvania 6JC5
== (the Sylvania has a distinctive rectangular internal structure)
(this is from some testing/using/examining plus net searching)..
The 6HE5 is the small bottle version with the small 12w plate.
(all the brands seem to make these, slightly smaller bottle then a 7868)
http://www.mif.pg.gda.pl/homepages/frank/sheets/123/6/6HE5.pdf
The 6JB5 is the larger bottle version and an larger 15w plate.
(these seem to all be GE, but re-branded as well)
http://www.mif.pg.gda.pl/homepages/frank/sheets/123/6/6JB5.pdf
The 6JC5 is also larger bottle version with a larger 19w plate.
(these seem to all be Sylvania, but re-branded as well)
http://www.mif.pg.gda.pl/homepages/frank/sheets/107/6/6JC5.pdf
Then there is the RCA 6HE5/6JB5, large bottle with small 12w plate.
(these seem to have the small 12w 6HE5 guts in that larger bottle)
I have ran them all, the Sylvania seem the beefiest an sound best, (to me at least)
(in Singled Ended UL I get 5-6w output, push pull pentode here you'd be say 23w)
The 6JA5 has the same pinout, but is not exactly the same tube an draw more PL
current to where they do not bias up anywhere near where the others do.
(I believe these are a 19w rated plate as well)
The tubes labeled with all 3, 6JC5/6JB5/6HE5 on them should be your large bottle
GE and Sylvania tubes, I would search those out..
Now to get funky, there is another set of tubes with a top cap plate connection an
with 17.5/18w plates, 6GV5/6GY5, if you look at the pinouts, you can see they can
be wired to use the same pinout/socket as the above just need the plate caps con.
(I have not used these so I don't know how they respond)
http://www.mif.pg.gda.pl/homepages/frank/sheets/123/6/6GY5.pdf
(I wouldn't pay more then $5 ea for these tubes, plenty out there for that price)
A couple places I have bought tubes from with good service and prices are here.
http://www.fourwater.com/compact/comp_c5.htm
http://www.esrcvacuumtubes.com/vacuumtubes_tubelist_tubes_5A5-5Z4G.html
======== These have also been referred to as 6V6's on steroids (not by me)
My camera isn't the best but here is a bit of comparison of how these tubes look
next to each other. (should give a decent example of there physical differences)
First pic shows left to right, 6HE5, GE 6JB5, Sylvania 6JC5
Second pic shows left to right, 6HE5, RCA 6HE5/6JB5
Third pic shows left to right, RCA 6HE5/6JB5, Sylvania 6JC5
Fourth pic shows left to right, GE 6JB5, Sylvania 6JC5
== (the Sylvania has a distinctive rectangular internal structure)
Attachments
Kegger
R.I.P. 1/12/1966 - 6/1/2017
5V4's should be able to be purchased for $8-$15 ea. (I wouldn't pay more for them)
Yes 6BL8's are all over the place as far as price and brand, and yes they "should" have
the most effect on the sound of the amplifier, an I am also partial to the European brands
with say Amperex made in Holland my favorites, this goes the same for the 6GH8's as well.
Kegger
R.I.P. 1/12/1966 - 6/1/2017
As far as power transformers go, the 1 you linked from Triode for the ST70 is the
same 1 I linked and used in that PP triode 6AV5 amp with those parallel rectifiers.
Something to ponder, if you have an ST70 you "might" want to think about the PT
upgrade for use in it, then use the old one for a build like this, you could go with a
single 5AR4 rectifier or use a pair of damper diodes with the old 70 power tranny.
-----------
Other info/thoughts some may find useful, the replacement ST70 driver board that's
got the 6GH8 instead of the 7199 could VERY EASILY be turned into this circuit with
just using different resistors on the board(same place just different values) and then
strapping the pentodes screen to the plate, you could also use an old 70 chassis for
this amp build as the 12pin compactron sockets will go right in where the octals were.
same 1 I linked and used in that PP triode 6AV5 amp with those parallel rectifiers.
Something to ponder, if you have an ST70 you "might" want to think about the PT
upgrade for use in it, then use the old one for a build like this, you could go with a
single 5AR4 rectifier or use a pair of damper diodes with the old 70 power tranny.
-----------
Other info/thoughts some may find useful, the replacement ST70 driver board that's
got the 6GH8 instead of the 7199 could VERY EASILY be turned into this circuit with
just using different resistors on the board(same place just different values) and then
strapping the pentodes screen to the plate, you could also use an old 70 chassis for
this amp build as the 12pin compactron sockets will go right in where the octals were.
mikeski
I need input
Kegger your as bad as I am. Think, think, think.
For your photo's.... Try the macro focus for closeups.
Thanks for all the tube info. I will grind through the tube choices for a while. But the Sylvania sounds like the output to use. And I will be looking for a pair of Euro 6BL8's. Just cause I can.
I think I am still working on the PS and what to use for that. I am sure that plan will come together.
Mike...
For your photo's.... Try the macro focus for closeups.
Thanks for all the tube info. I will grind through the tube choices for a while. But the Sylvania sounds like the output to use. And I will be looking for a pair of Euro 6BL8's. Just cause I can.
I think I am still working on the PS and what to use for that. I am sure that plan will come together.
Mike...
mikeski
I need input
For the power transformer. Seeing as I do have an ST70. Will I get any gain in doing the swap?
Also, I am liking the dual 5V4 power supply. So unless the gain would be noticeable. I will probably keep the new amp setup as it has been discussed so far.
I do like a nice hand wired amp. I may do some sort of perf board to mount the small components to though.
Also, I am liking the dual 5V4 power supply. So unless the gain would be noticeable. I will probably keep the new amp setup as it has been discussed so far.
I do like a nice hand wired amp. I may do some sort of perf board to mount the small components to though.
mikeski
I need input
And the mail was glorious. Kegger and I have been communicating and it's all hammered out. He is actually providing me a kit from his stash. I will need only to acquire a handful of small parts like wire, tube sockets, output terminals and a chassis. Almost turn key.
The idea here was to build an amp with oddball tubes that are on the cheaper side.
5AR4 power with 6BL8 or 6GH8 input and 6JB5 output.
You can go cheap on the 5AR4 and input tubes. Or.... you can go global with Amperx and Mullard. The input tubes will be fun to roll. Output tubes are $5 a pop.
I believe we decided about 25wpc???
Now I'm just waiting on the mail now.
We also chatted about color. My son goes to Appalachian State. Their colors are Black and Gold. So I'm thinking flat black chassis with gold accents. Maybe paint the iron black and the bells gold. A yellow gold and not a flashy gold.
The idea here was to build an amp with oddball tubes that are on the cheaper side.
5AR4 power with 6BL8 or 6GH8 input and 6JB5 output.
You can go cheap on the 5AR4 and input tubes. Or.... you can go global with Amperx and Mullard. The input tubes will be fun to roll. Output tubes are $5 a pop.
I believe we decided about 25wpc???
Now I'm just waiting on the mail now.
We also chatted about color. My son goes to Appalachian State. Their colors are Black and Gold. So I'm thinking flat black chassis with gold accents. Maybe paint the iron black and the bells gold. A yellow gold and not a flashy gold.