DIY Audio Projects Forum

First time I heard about compactron, or to be precise, heard the term compactron was when I found the 6T9 tube kit on SpareTimeGizmos website.
I already had laid my hands on compactron tubes as I had bough a pair of exotic 50CA10, the power triodes found in Luxman amps, but didn't have the "technical title" at that time.
As this forum have full knowledge of the 6T9 and we happened to slip into compactron discussions elsewhere I saw a need for a thread exclusively aimed for discussion the many-pinned tubes. I have checked some tubes (data sheets) and have become slightly interested in some of them.
So here we go here are some links:
http://www.junkbox.com/electronics/CompactronTubesIndex.shtml A list of various tubes and their proposed use
http://www.angelfire.com/vt/audio/compactron.html Cheap TV-bube amp with tube suggestions.
http://www.pmillett.com/midget.htm Millett's 6T10 amp.
http://www.angelfire.com/mech/beansamps/ Bean's hard to find schematics

Of the various tubes I have some 6T9s but I don't think they will go into a project. Then there is the 50CA10. Also I would like to try the 6D10 in Rosenblit's Grounded Grid preamp.

More ideas or good links?!

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Magnus

The ponies run, the girls are young
The odds are there to beat ...

Thanks for starting this tread Magnus.

Here are links to the various 6T9 tube amp projects on the site:

• Single-Ended 6T9 Tube Amplifier Project
• Single-Ended Ultra-Linear6T9 Tube Amplifier
• Push-Pull 6T9 Tube Amplifier Project
• Bill's point to point SE UL 6T9 tube tmplifier build (thread)

Cheers

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[ DIY Mains AC Power Cable Cord ] - [ K-12 Tube Amp Kit ] - [ Tang Band D4-1 Horn Speaker Kit ] - [ Monoblock Push-Pull KT88 Tube Amp Kit ]

The majority of compactrons I have owned in the past (I have dispensed with them) were sweep tubes. These were power tubes (normally beam tetrodes and sometimes pentodes) that served the dual purpose of linearly controlled the horizontal motion of the TV's beam and dealing with the flyback that generated the EHT for the final anode. I may have my facts a little off but I think that's the way it was.

Some of the tubes such as 6DQ6A were especially sought after as guitar output stages (although the 6DQ6 was an octal with a plate cap). If you can get your hands on a matched pair they may make an interesting output stage. Aside from 6L6, EL34, KT88 and the like, there may be a whole new world of powerful output devices.

I never got into compactrons because I wasn't willing to buy yet another type of socket. Three types are enough (normally I don't use the 7-pins, except when I want to make some radios. As a result I have a veritable surplus of them).

Ed

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Completed Projects:

6L6G / 12AX7 25W Guitar Amplifier
TLC272CP/2N3904/3906 Headphone Amp (Can Man)
MPF102/IRF630 Headphone Amp (FETZilla)
12AU7 / IRFX Headphone Amp (x2)
TIP31C/32C 5W Stereo
More to come...

Bow to Ed!!

This is a popular compactron amp
http://www.pmillett.com/DCPP.htm
Pete sells the circuit boards on ebay.

George from Tubelab.com got 500W out of one with 4 35LR6 compactron output tubes.

I have a plan to use a 6C10 (a compactron containing 3 hi-mu triodes) in a phono-preamp stage, as well as plans to use the 6T9 in a PP stereo amp. I have several 6T9s (my avatar is one of those). I have also picked up a few compactrons containing a med-mu, hi-mu and pentode in a single package (a true single tube amp ). I have an idea for a "flea-power" guitar amp for those (SE, about 1w).

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The key to a successful build is to keep the smoke IN the circuit.
-Les

Science without religion is lame, religion without science is blind. - Albert Einstien
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LM380 Bridged Guitar Amp, Oatley K301 Phono Pre-amp, Oatley K272 Headphone Amp, Tube proto-board
Current project: 6V6 "pseudo Champ" prototype
Still to come (On hold): 6CG7/12AX7 Guitar amp (modified FireFly)

When checking the first link on my list, Jeff's tubelist, I find a lot of heavy tubes with a Pa of 20 ... 30 ... 40W. Are any of those useful in audioapplications or do they need tons of FB? Tubes like EL504/509/519 have found their way into audio amps and they were intented for other purposes. Not to mention tubes like the Russian 6S33S.

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Magnus

The ponies run, the girls are young
The odds are there to beat ...

The 6LF6 is useful in audio applications. I built a cathode follower output amp with it's octal cousin. Also great for making high power screen driven PP amps. When triode trapped it has a low Rp. The 6LR6 is also another tube good for audio, at least for PP, I haven't tried it in SE yet.