Varmint XL-250 on the bench
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- เผยแพร่เมื่อ 10 ต.ค. 2024
- Just going thru the Varmint XL-250 on the bench before I button it up and put it in the closet. 1 driving 2, three stage with Low, Hi, and Supermod. No preamp, but usually preamps on amps are trash anyway. Lot of folks say Varmints are noisy, trashy and junk, but after playing with a couple of them, with the supermod off, they are just normal grounded grid sweep tube amplifiers, like D+A or Palomar. The Supermod does turn the driver tube from grounded grid linear, to a modulator type driver though and probably what gives these amps a bad reputation. My thoughts are simple that you have to break a few eggs to make an omelet.
Nice job. Those amps used to be all over 50 years back. Happy New Year
Thanks!
That's why they drive a big amp so much better
Agreed!
Im renovating my radio room after 44yrs. In 1977 it had floresent light bulbs which caused noise in my HF reciever. I changed to incondesent bulbs. Im considering LED bulbs. Will it cause noise ?
I only get noise from my LEDs if I disconnect the antenna. Old-school incandescent bulbs are noiseless.
Yes, often worse than fluorescent's
good morning my friend we have talked on the phone before I have some sweet tubes amplifier that needs or some tubes for them
I don't have many left.
@tramdr I have Varmint Xl 250 That the relay sticks till powered off once keys. I also have no output at all on a watt meter. Tried new tubes. Heaters are working and have High voltage when keyed. Thanks for any help
relay sticking probably the keying transistor, Q2 on the schematic, a 2n3416, but could be a terrible harmonic or short on either the input or output side. Whats your input SWR? Is the driver tube getting hot? Are the final tubes getting hot? What I have seen with many amps lately that are putting out no power and have the voltage is the relay contacts are pitted or dirty, so either the amp is not getting power in to the driver from the radio (thru the relay) or the final tube power is not making it out to the antenna connector as it goes thru the relay. Clean the relay. Also there was a guy here on TH-cam who had a similar problem and it was his jumper.
@@tramdr Thanks I have transistors and caps on order, and yes tubes are getting hot. Both sets i tried. I will pull the relay out and clean it well and see what happens. Thanks for the Help and the swr is around 1.1.
Please explain "audio isn't free"
how about "Everything has a cost"? or to simply break it down, to get loud, to have that 'A-U-D-I-O' there are repercussions or costs. Harmonics, TVI, AGC overload, Clipping, Distortion, Feedback. Those problems can and should be addressed, but to address the problems with loud audio is not easy, and certainly is not simple.
trying to buy your linear left you a few messages with no reply
Don't know where you left me messages at. Try Tramdr@yahoo.com
hola amigo saludos desde valencia venezuela tengo un varmint XL450 Tiene el trancistor que activa el rele quemado y no tiene numero no tengo plano ud me puede decir el numetr del trancistosr creo que es 2sc3417
Translation anybody?
I need a schematic for one of these. Any ideas on where to get one? I’ve googled it and nothing
cbtricks.org/Amp/brewer_labs/graphics/xl-150-450_base.pdf
I have a buddy has one for sale I'm look for JB-12 or JB-150 if you have one let me know
th-cam.com/video/4Mg5XkmhD9A/w-d-xo.html
Can you see my post doc?
I didn't see a response to question curious rainmaker big apple.
A post about a transistor amp and drive? I remember something about that and thought I posted that transistors aren't 'my lane'. I am pretty much strictly a tube man.
Not seeing your original question, here are some general ideas about tube vs. transistor amps..
Tubes can handle being overdriven better than transistors. Transistors don't like heat for very long before they fail. Tubes are hot by nature so a little extra heat won't bother them, as long as the plates aren't turning red. That said...
All of our stuff is designed to ICAS, or Intermittent Commercial and Amateur Service. That means that it's not designed for long-duration service. Sweep tubes have a typical continuous power rating of less than 25 watts for B&W sets and less than 50 watts for color TV service.
The RCA tube manual has the 6LQ6 at 30 watts in TV service. It also shows a "temporary overload" of 200 watts input for no more than 40 seconds.
My Swan 350C was advertised as 550 watts of input. I could get the tubes to glow red by being long-winded or by sending slow CW, or by tuning up for too long. When I did that enough times, the maximum current that the radio would load to began dropping off.
I hope that I've answered some of your questions.
Do you repair tube amps?
Sorry , no. I do this as a hobby and am overwhelmed with it. Too much to do, too little time. What you got and whats your problem though.
Are you making any progress with fixing your Titan?
My Titan 4? Fixed it a while ago.