Thinking about ordering some lots of less expensive tubes to get started with on the µTracer. These often come from overseas and take time to ship so thinking maybe they will be here about the time this thing gets finished.
Someone looking for matched sets of tubes, or certain tubes to be tested?
We talkin pre, or power tubes? Seems like the 12AX7 and EL84/6BQ5 have many uses and are still available relatively cheap. Would those be able to combine for SET and PP options? I’m still ignorant of that stuff. Trying to learn.
Matched quads of EL84’s and 6V6’s.
Probably get some cheap 12**7 variants before getting into the more expensive ones. Thinking the el84 may be a bit more expensive and it may be a while before I feel comfortable with those. What kind of prices are the 6v6 fetching?
Quad ec88 tubes?
I bought a few of the NOS Russian equivalents (6N6C) before the Ukraine war started. They were only $4 each. I don’t know if those are even available now. New tubes from the Soviet block start in the low 20’s:
saw this:
Some AI output:
The 6KV8 is a dual-function vacuum tube combining a high-gain triode with good linearity and high transconductance and a frame-grid pentode, designed for use as a voltage amplifier and video output tube in television receivers.
It operates at 6.3 volts filament voltage and 0.775 amperes of current, with an indirect heating configuration.
Originally intended for television applications, the 6KV8 has found use in audio amplifier designs, particularly in push-pull driver circuits where its triode section functions as an active-loaded gain stage and its pentode section acts as a phase inverter and driver.
Some audio enthusiasts have used the 6KV8 in single-ended amplifier designs, with one builder noting that a pair of 6K6G tubes could complement the 6KV8 in a visually appealing setup.
Its high transconductance and favorable triode-mode characteristics make it suitable for high-fidelity audio applications, including emulation of triode behavior in output stages.
Seems like an interesting combo in one tube that could make for a somewhat unique design. If someone comes up with a circuit that uses readily available reasonably priced iron that would be sweet.
The 12v6 is still relatively cheap. Tube Depot has NOS for $7.00.
Those are great Tom! Don’t know how I missed seeing them. Bummer they only have seven in stock. The 12.6 V heaters are no big deal because a small 120V/12V transformer is pretty cheap. In fact I have a bunch of 24 Vac transformers. One of them could easiy power 2 or 4 of those tubes’ heaters (2 tubes in series). If anyone is interested I would be happy to ship one of those transformers for shipping cost only.
Looks like Amplified Parts has them too.
https://www.amplifiedparts.com/products/vacuum-tube-12v6gt-tetrode-beam-power
Great find!
Edit: this was a response to Drew’s post regarding the 6KV8 tubes:
Seems like a very similar tube to the 10GV8/LCL85 tube that was used in the K12G amplifier kit. I built one of those kits a long time ago. Still have it and it still sounds great. I bought 12 NOS RCA 10GV8 tubes when they were still available and dirt cheap ($1.50 ea).
Ouch, tube prices have gone up considerably since purchasing the Ukraine 6j1p tubes. Not seeing the lots of really affordable chinesium tubes either. Plus now have to pay import duties. Krap!
If you find some really good tube prices, especially the 12**7 tubes, clearing house, wholesaler, whatever, let me know.
You should check out the annual hamfests and swapfests in your area, as they can often be good sources of NOS or used pull-out type audio tubes. I usually attend 3 or 4 of these events every year. And I’ve scored many good, reasonalbly priced 12AX7, 6DJ8, and 6SN7 tubes over the years. Cash and carry. Also found some good 807 power tubes at very reasonable prices.
The biggest outdoor swapfest in SE Wisconsin is the one held in Oak Creek, Wisconsin each year, probably because it draws a big crowd from both the Milwaukee and Chicago areas. There are always several tube vendors there, in addition to arrl hamfest groups selling donated pull-outs at dirt cheap (1/8th retail) prices.
While you are at one of these fests, you will also probably end up buying lots of other electronic related stuff like transformers, tube sockets, used test equipment, etc. Like a kid in a candy store. In the link below, type in your zip code to see what swapfests are being held this next summer in you area. Parking for all the ones I attend is free and most only charge about $5 or so at the gate to get in.
Great suggestion Bill.
I need to get to Dayton Hamvention.
Unfortunately because of the resurgence of tube HiFi interest and the internet, a lot of those guys who are selling pull out tubes think they are selling a 1963 split window coupe! I get that if they are selling in the original box NOS Western Electric 300B tubes, but come on… a crusty pair of old EL34’s?
@PWRRYD you think you could design a circuit around 6KV8?
Just wondering if I were to have that lot of 100x sent to @Kornbread, if he would be willing to test em.
I think it would be cool to get a MAC design going for anyone here interested to build an amp. Besides providing tubes to the cause, I just don’t have the knowhow to input much.
I’m sure I could and would love to. Unfortunately my job/company situation just changed dramatically. My current EL84 tube amp project will just be a great “get away” escape for me when I can.
What lot of 6kv8? linky
Had a bad case of the don’twannado$hit today. Prob an issue with my flipping day/night since I work nights but flip certain off days so I can spend time with the fam. Sucks working nights but it pays the bills. Did manage to get some metal cut for the tube testing blocks. Pulled what I though it was just a piece of polished SS out of the scrap bin, but it don’t cut like any stainless I’ve dealt with before. Not sure I can drill it.
