Has anyone made an Excitron audio amp? - Page 1
Forum section: electronics / projects

author: Deactivated-1
author_rank: Frequent Contributor
timestamp: October 14, 2022, 04:15:57 am
content: Using excitrons as output tubes, I reckon they'd work pretty alright as ones.seems impossible to find them today so I don't think I'll be making my own 10kW excitron power audio amp

author: CaptDon
author_rank: Super Contributor
timestamp: October 14, 2022, 02:20:12 pm
content: Still pretty easy to find Ignitrons used in welders as well as grid controlled rectifier tubes like thyratrons used in radar 'hard pulse' modulators. A friend of mine has a bunch of 615's but I forget if they have a control grid. You could use thyratrons in a class D amplifier but the switch frequency would be limited to avoid a 'shoot through' short circuit due to the arc not fully quenching in either tube. I would suspect you could build a subwoofer amplifier that worked up to about 80hz and 10kw would be easily obtained.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 14, 2022, 03:13:06 pm
content: Think I recall conversations with friends, or on dA or RAT, about making an infrasonic amp like that.Not that anyone would have the power available to run it, or the transformers or speakers to make use of it, let alone the program matter to amplify with it.I suppose hydrogen thyratrons could do reasonable audio-range output, but an OPT is still required -- the pulsed current ratings might be high, but continuous ratings matter here, and the voltage is quite high (~kV) too. To get high efficiency and power output while still meeting ratings, you need about the same load impedance as any other tube (i.e. a kohm or thereabouts). So it's not really all that interesting.Tim

author: CaptDon
author_rank: Super Contributor
timestamp: October 15, 2022, 02:07:56 am
content: Set up those Ignitrons in class D and all you need is an output inductor, not a transformer. 1kv and up at a couple of hundred amps. WOW!!!! As stated, 10Kw would be child's play. Just got to make sure that arc has quenched before firing the opposite bottle or BANG in a big way. Those ignitrons worked great for phase controlled rectifiers to control speed and power in the old GG1 locomotives!!! used to see them every day along the Susquehanna River!!! They are nearly silent when one or two are coming down the track in light power configuration, hence my nearly being killed by a pair!!! Interesting note, the catanary power was 25hz and so was my friend's party line ringer frequency!!!! The phone would rattle and lightly ring whenever those GG1's were pulling freight along the river, also caused weird ghost images shifting on the T.V. with the outdoor antenna!!!! He lived on 'River Road' near the Accomac Inn. I once toured the Safe Harbor Hydro Dam where some of the 25Hz was generated.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: October 15, 2022, 02:24:44 am
content: I like these tubes and they can switch quickly... but don't they have a lot of trigger jjitter? Also, you can turn them on, but they only turn off when the anode current goes below some amount... There's no off grid, right?I don't know, just musing.

author: jonpaul
author_rank: Super Contributor
timestamp: October 15, 2022, 05:42:01 am
content: OP please post links, spec sheet, photo od Excitrons.web search yields very little.Jon

author: jonpaul
author_rank: Super Contributor
timestamp: October 15, 2022, 09:31:23 am
content: Rebonjour à tousThe arc drop of any mercury arc is 15..22 VGrid control determines the start of the arc, but cannot affect the current afterwardsThe extinguish of arc is when current is zero.All mercury arcs exhibit a de ionization time of 20..300 uSec.The excitrons seems to be a thyratron with a keep alive auxiliary electrode.Without a circuit and better description of the intended audio use, hard to see how it worksFinally ignitrons are metal/céramique high current version, but theory like a glass thyratron.Je vous souhaite une bonne weekendJonJon

author: CaptDon
author_rank: Super Contributor
timestamp: October 15, 2022, 06:20:28 pm
content: So buy a pair of Excitrons (The other guys found them) and let us know how it works. I would say that by the way the glow dances during his steady state experiments the signal would have a lot of Excitron induced noise mixed into the desired signal and it appeared that the grid voltage vs. current flow was not a particularly linear function. It would seem you would have to have some idling current flow to get away from the zero crossing distortion since the 'start-of-glow' didn't appear at exactly the same grid voltage every time. That would surely suck for push-pull operation where the glow extinguished. Maybe suited to a single tube class-A??? Try and tell us.

author: james_s
author_rank: Super Contributor
timestamp: October 15, 2022, 06:40:06 pm
content: Quote from: ELS122 on October 15, 2022, 09:59:26 amThyratron is a broad category of tubes comprised of numerous subtypes. Likewise "Thyristor" is used to describe both SCRs and triacs. I'm not familiar with an Exitron, but if it is a gas discharge tube with a trigger electrode then it's probably fair to call it a type of thyratron.