tubelab.com said:
I've come up with a classy DIY kinda use for metal 6H6's. Install an octal tube socket in each corner of your tube amplifier bottom plate. Fill each socket with a metal 6H6. Classy metal footers that expand the vacuum tube theme! This will rectify surface scratching problems suffered with other types of footer hardware like spikes, etc.
You can even hook up and power their filaments if you like to keep your feet warm!
Yeah, the loctals are cheap, and I have quite a few of them, but sockets are hard to find. Eventually the whole design will be laid out on a PC board. PC board loctal sockets are impossible to find.
I have a bunch of 6LU8 compactrons that would make a cool one tube per channel amp, but PC board sockets are not available.
Thanks for the thought
I have a bunch of 6LU8 compactrons that would make a cool one tube per channel amp, but PC board sockets are not available.
Thanks for the thought
I have thought about laying out a PCB for compactrons... I would use 12 individual .040 pin sockets from Mill-Max. They're in stock at DigiKey... Put them on a tube to align them for soldering. Suppose you could do with only the necessary pins and save a buck or two...
And since I also have about 50 6LU8s... I'm thinking about push-pull.
And since I also have about 50 6LU8s... I'm thinking about push-pull.
Lemme see if I´ve got this straight:
~300V plate-cathode, fixed bias, 5k OPT with 8 ohm secondary between cathode and ground, right?
I have some Sylvania 6AV5GA´s and a pair of Hammond 125CSE, if I wire those OPT´s for 5k/8ohm I have a 16 ohms tap available for the CFB, and I guess that´s a good thing.
I think I´ll run my output tubes a little cooler though, closer to the standard 2A3/6B4G op point.
Concerning driver tubes I have a preference for EC/PC86 ( don´t know what they´re called over there), a very nice little noval triode capable of driving any output tube I´ve encountered so far.
I´ll probably use Hammond 156C chokes as plate loads for the drivers, this is my standard concept when I need plenty of gain and swing from a limited B+.
Two of those chokes in series works even better, but then the DCR is getting seriously high (~7,5k)
~300V plate-cathode, fixed bias, 5k OPT with 8 ohm secondary between cathode and ground, right?
I have some Sylvania 6AV5GA´s and a pair of Hammond 125CSE, if I wire those OPT´s for 5k/8ohm I have a 16 ohms tap available for the CFB, and I guess that´s a good thing.
I think I´ll run my output tubes a little cooler though, closer to the standard 2A3/6B4G op point.
Concerning driver tubes I have a preference for EC/PC86 ( don´t know what they´re called over there), a very nice little noval triode capable of driving any output tube I´ve encountered so far.
I´ll probably use Hammond 156C chokes as plate loads for the drivers, this is my standard concept when I need plenty of gain and swing from a limited B+.
Two of those chokes in series works even better, but then the DCR is getting seriously high (~7,5k)
YAHOOoooo
I am sure glad you guys are developing some circuits for these severly overlooked Valves.
I also have several hundred of these babies and just could not part with them thinking there has to be a way.
Tubelab, I am watching this thread closely, When circuit boards become practical for production, I am about 90% sure I would rather just buy 1 rather than P to P it. This will make for a great conversation piece as well as something that I will truely enjoy using.
Your awesome!!
Thanks
Trout
I am sure glad you guys are developing some circuits for these severly overlooked Valves.
I also have several hundred of these babies and just could not part with them thinking there has to be a way.
Tubelab, I am watching this thread closely, When circuit boards become practical for production, I am about 90% sure I would rather just buy 1 rather than P to P it. This will make for a great conversation piece as well as something that I will truely enjoy using.
Your awesome!!
Thanks
Trout
I have been buying these every time that I can find them. They are cheap, but I have been told that there is no demand for them, so many tube sellers don't have them.
I haven't tried CFB with the Hammond's yet, but others report that this transformer responds well. They don't do UL though and I really like the sound of this amp with UL, and I am not a big fan of UL. The Sylvanias seemed to be the best constructed of the 6AV5's that I used, well up to abuse, but 15 watts dissipation seems safe with any of them except the slotted plate RCA's. 300 volts plate to cathode is no problem, the plate is specced to 550 volts, and I am running 550 in the P-P amp. The screen voltage is rated for 175 to 200 depending on which book you read.
I also have a pair connected up in screen driven P-P as per SY's instructions. I can get over 80 watts out of a pair of the crummy RCA's with no death glow. I have not played the guitar through it yet but I bet that it screams.
I think that there will be a SE board in the near future that makes a conservative 5 WPC. The idea is for a beginners amp that is plug and play using cathode bias. I may make provisions for using a more common tube as well since 6AV5's may not be available in some countries.
Down the road there might be a P-P board too.
I stopped at the warehouse today on the way back from my usual weekend trip to my fathers old house. I was looking to see which tube that I have plenty of to use for a driver tube. I didn't realize it until I did some digging, but I have a few hundred 6SL7's. These would do well for this project, but I need to find a good tube to replace the 5842 that I have used in all my previous projects. They have become too expensive. I have a long list of 7 and 9 pin triodes, and triode wired pentodes to try. I will set up a test to try them all with resistive load and PowerDrive (CCS + mosfet follower) load.
The testing itself won't happen until I get back from an upcomming trip (mid April).
The testing itself won't happen until I get back from an upcomming trip (mid April).
Personally time is not an issue with me, This is a project I plan on not rushing on. I have been busy building Tweed guitar amp head cabs the past week and still have several yet to finish.
But, as soon as a BOM is ready (again no rush) I will start gathering up the goodies to complete one .
This is sounding more fun all the time, I have plenty of 6SL7's here to.
But, as soon as a BOM is ready (again no rush) I will start gathering up the goodies to complete one .
This is sounding more fun all the time, I have plenty of 6SL7's here to.
Trout said:Personally time is not an issue with me, This is a project I plan on not rushing on. I have been busy building Tweed guitar amp head cabs the past week and still have several yet to finish.
But, as soon as a BOM is ready (again no rush) I will start gathering up the goodies to complete one .
This is sounding more fun all the time, I have plenty of 6SL7's here to.
Not to sound like a broken record, but 6sl7 tubes are also good in the fact that there is a 12 volt version of the tube that is readily available. I'm a big believer that one of the big advantages of DIY is that we have free access to all of the tubes that the amp manufacturers have left behind. 12 volt tubes are a haven for great sound on a budget... I have a stack of 12av5, 12sn7, 12j5, 12sl7, 14a4, 14n7, 1625, etc. All of which are great sounding tubes and can be bought for a fraction of the popular 6 volt versions. I'm hoping that, when possible, designers of DIY projects could keep this treasure trove in mind. Leave the expensive NOS stuff to those that are stuck buying amps
Isaac
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