I bought an old Heathkit amp and wasn't confident in the way it was built so I used a copy of the original assembly manual to redo it. I recently built an Akitika SS amp and the instructions reminded me very much of the old Heathkit ones; albeit with circuit boards for much of it.
I haven't done any of the tube amp kits that are out there for comparison.
I haven't done any of the tube amp kits that are out there for comparison.
JoeAlders,
What were the years of your manuals that did not live up to that standard?
What were the years of your kits that did not recommend that the wires be wrapped around the terminal or eyelet hole?
Was there never an "old standard"?
Perhaps I am not understanding what you said.
I also remember wiring up Harmon Kardon kits, and Dyna kits.
Same good manuals and techniques.
I know . . .
"Standards are such a wonderful thing that everyone has his own" - Me
I am still waiting for my next car to have 17.5 inch wheels.
So much for standards.
What were the years of your manuals that did not live up to that standard?
What were the years of your kits that did not recommend that the wires be wrapped around the terminal or eyelet hole?
Was there never an "old standard"?
Perhaps I am not understanding what you said.
I also remember wiring up Harmon Kardon kits, and Dyna kits.
Same good manuals and techniques.
I know . . .
"Standards are such a wonderful thing that everyone has his own" - Me
I am still waiting for my next car to have 17.5 inch wheels.
So much for standards.
Those were all Tung Sol. Since that amplifier I had two other ones and they went, a third one is in use and a fourth one is contemplated.
I regretted selling the cream EL84 SE one to fund a third one - a clone of an Audio Note PP amplifier (no cost spared) that was ultimately not satisfying.
The one I am using is a SE EL84 with 5670 as driver. I'm embarking on another SE EL84 build with SRPP drive and the EL84 in UL with CFB in order to have even more flexibility in output impedance.
Hopefully the OPT won't give me grief: too much leakage inductance and if too much it might become a nice oscillator (although it depends on how much CFB there is and the power tube. Would not think about using anything else except for the EL84 and the EL34.)
Cabling is important: too long or too close to other cables (especially if they are flopping around and get too close to some tubes' input but do not underestimate the length of the wires to the OPT, especially with UL) and you might introduce unwanted coupling. I am using what Philips taught me rather than listening to what someone on the internet says (and which is why he is on my ignore list with his critism and knowing it better - NOT! ) YMMV.
Peace.
AM
Attachments
Last edited:
A couple photos of an all valve stereo guitar amp I finished early 2015.
It is all point to point with terminal strips located as necessary. Lots of hours. Scratch build with bare chassis to start. No hum, buzz or hiss. Star ground scheme - glad I did. Excellent sound. Sharing in this thread on point to point.
Attachments
If you really believe that DIY Audio is a "hassle" instead of a labor of love, you shouldn't even BE on this website, pal.
Amadeus Mozart,
I see you have many more great looking amplifiers!
Were those output tubes in your Post # 27 EL34 tubes?
And were the 6BQ5/EL84 tubes in Post # 64, Beam Power construction or Pentode construction?
If you only use EL34 and EL84 for your output tubes, and if they are True to the original tube specifications,
that means you only use Pentodes.
Thanks for sharing!
I see you have many more great looking amplifiers!
Were those output tubes in your Post # 27 EL34 tubes?
And were the 6BQ5/EL84 tubes in Post # 64, Beam Power construction or Pentode construction?
If you only use EL34 and EL84 for your output tubes, and if they are True to the original tube specifications,
that means you only use Pentodes.
Thanks for sharing!
Underside and top view of one of my point-to-point wired 833C mono amps. Some PCBs sprinkled in for dedicated circuits like the soft start (really needed at 2300V B+) and the 10V, 10A filament supplies.
Space, corona dope and careful construction has kept it safely sounding great for 6 years now.
Space, corona dope and careful construction has kept it safely sounding great for 6 years now.
Attachments
In #27 it are 6L6GC Tung Sol.
I've got about 28 NOS EL84, various brands: Polam, Telam (the last Philips vacuum tube factory, which was located in Poland), Tesla, Radiotronic (Australia, often bought the inner parts from Mullard and Philips) and Russian 6P14P-EV's. I use new EH for initial power up before swapping over to the more expensive NOS.
I have not checked but suspect some of the Russian might be beam.
Similarly I have about 15 5670's, GE, Philips (2C51) and again some Russian 6N3P (-E, -EV) the latter are used in first instance.
Transformers are all custom wound with 22.4% UL with proper interleaving to get the best compromise of quality versus output for the EL84. (not all tubes work best at the same 40 odd percent UL, see Rudolf Moers - UL Investigation and also check Langford with the KT66 and 6V6).
AM
Amadeus
Thanks for the idea!
After the lockdown opens up again, I need to drive down the street and purchase a pair of JJ EL84 to try.
I have a push pull Dyna A470 that has had the laminations pulled out, and re-stacked with all the Es on one side, a paper "air gap", and all the Is on the other side.
Now it is for single ended operation.
A470's 100-40-0-40-100 can easily be wired to be 0-20-100 by picking the 3 appropriate wires . . . one end, 40% tap, the other end.
. . . EL84 at 20%, it is worth a try.
Too many projects.
Thanks for the idea!
After the lockdown opens up again, I need to drive down the street and purchase a pair of JJ EL84 to try.
I have a push pull Dyna A470 that has had the laminations pulled out, and re-stacked with all the Es on one side, a paper "air gap", and all the Is on the other side.
Now it is for single ended operation.
A470's 100-40-0-40-100 can easily be wired to be 0-20-100 by picking the 3 appropriate wires . . . one end, 40% tap, the other end.
. . . EL84 at 20%, it is worth a try.
Too many projects.
Last edited:
Tony,
Nice 13FM7 amp.
I have a friend with a similar 13EM7 amp.
I am getting old. Confused a couple of who did which posts.
I keep seeing dual-marked 6BQ5 and EL84 tubes.
Some have Suppressor grids, g3.
Some have Beam Formers, no g3.
You have to look to be sure which kind you have when they are dual-marked.
I miss the Philippines (I left in 1974, after 2 years there).
I used to know a little Tagalog, and even less Pampangan.
Nice 13FM7 amp.
I have a friend with a similar 13EM7 amp.
I am getting old. Confused a couple of who did which posts.
I keep seeing dual-marked 6BQ5 and EL84 tubes.
Some have Suppressor grids, g3.
Some have Beam Formers, no g3.
You have to look to be sure which kind you have when they are dual-marked.
I miss the Philippines (I left in 1974, after 2 years there).
I used to know a little Tagalog, and even less Pampangan.
Last edited:
Tried a cathode winding on your OT? Reinhöfer 53.1S52 for instance is derived from an old Revox EL84 tube amp.
For me its not the most amusing part of the process. Its labour that has to be done. If you love labour, me not.
The more interesting part is the design, planning and purchasing of parts.
And in the end, ones own ideas become a reality.
But to construct, design and build something that has been already done makes no sense, at least to me. Thats why some of the models here share construction ideas that are not ordinary and that couldn't be purchases anywhere in the world.
But the idea of DIY could be different. Some may love to build gear for the building aspect, some love to build gear for the goal to hear and interpret music through it. If you are one of the first type of persons, than we may have different goals and aims in DIY. But for everyone who is into DIY, no matter for what reasons, this forum is an open place to share his ideas and believes.
Last edited: