No Vixen Deluxe? :(

[marmot]

Power does not increase in a linear fashion rather exponentially. After a certain point it doesn't matter. Mathematically speaking this translates to two times nothing is still nothing. Ten times the power is a different story.

I too am an engineer (well, actually a computer scientist who concentrated in computer architecture/digital design as an undergraduate student and digital communications at the graduate-level), so I understand this relationship well (e.g., a +9dB or an eight-fold increase in power is required to double the perceived volume). This relationship is why most low-resolution analog-to-digital converters use nonlinear encoding. By using a nonlinear transfer function that allocates more quantization levels to low-level signals and less to larger signals, we reduce the overall perceived quantization noise (i.e., quantization noise is more easily heard on small signals than it is on large signals).

By the way, I am also a tube-tube guitar amp hobbyist (my dad was an electronics technician back in the fifties). Here is a picture of the guts of one of my prototypes (minus the first gain stage):

[Tom]

HUH!!!!!!!!!!!!!

I am lost now ..... does anyone have my GPS ....... seem to be lost without it

[marmot]

Here's a picture of the front panel of one of my homemade ham radio transmitters. These are 833A vacuum tubes.

Holy smokes! Are the plates glowing on the 833As? I have very little experience with power triodes. I am pretty much a pentode and beam tetrode man when it comes to power tubes, and glowing plates is usually not a good sign in audio applications (i.e., it usually means that a tube is biased too hot). I am assuming that the control grid and the anode connections are made on top of the envelope and that the 833A is a directly heated tube. The 833A must be a robustly constructed tube.

[marmot]

HUH!!!!!!!!!!!!!

I am lost now ..... does anyone have my GPS ....... seem to be lost without it

I am sorry about the confusion Tom. This sort of thing happens when technical types communicate using a high-bandwidth channel.

[GaryL]

CQ.....CQ DX GL133

[GaryL]

CQ.....CQ DX GL133

Bring it back one time "C'Mawn"!

Hee,hee them were some good ole times back in the 70's early 80's playing radio, I got's a few albums full of QSL cards from all over the world

[Bill T]

I bet that you could get Dam Miller at 740 483 2312 to swap camo limbs and stock onto a Vix, but I don't know what he'd charge you for it......

[marmot]

I bet that you could get Dam Miller at 740 483 2312 to swap camo limbs and stock onto a Vix, but I don't know what he'd charge you for it......

Thanks for the suggestion, but I have already ordered a deerhide Vixen. Whitetail deer is the largest animal that I hunt, and, of all of the Excalibur crossbows that I have shot, my old Vixen Deluxe had the sweetest firing cycle. Heck, the Vixen is overkill for the sika deer that inhabit our lower Eastern Shore counties.

[marmot]

Nice looking work Marmot I am getting back into tube amps my self.

Thanks! I started building guitar amps for the technical challenge and because I was looking for a certain sound.

I got a old Silvertone 1472 (1962 vintage) I re cabineted in aged pine and it is in the shop now for a problem. It fades in and out in power Gets loud then soft I think it is the Tremlo circuit acting up as when I got the amp it never seemed to work right as even when you turned the pot off for the tremlo you still got some bleed through. So I could be wrong but I told the tech that I think the tremlo circuit is affecting the output of the amp. Just waiting to get it back he has some one working for him part time and the guy has not put that much time in lately as he is working on his house. So I am sitting and waiting for it to get done. They swapped the tube that controls the tremlo and that did not do it. I wish they would just replace the caps and the resistors to the whole circuit and get it done with there is not that many.

The problem probably lies in the power supply caps. From viewing the schematic, the second decoupling cap supplies both the screen grids on the power tubes and the plate on tremolo oscillator tube (the amp uses a multi-section can cap). If the amp has never been recapped, now is the time to replace all of the electrolytic caps. There is no need to replace any of the plastic, mica, or ceramic coupling caps unless they have gone microphonic. I would also get the guy to go over the plate supply resistors as carbon comps usually drift over time. I know it is heresy in the vintage world, but I usually replace carbon comp plate resistors with 1W 1% metal film resistors.

[marmot]

If worst comes to worst I may have to grab it and replace them my self. I can read a schematic I took a electronics course years ago and aware of the danger working with high votlage caps ect the only problem I would have would be bringing back up the voltage after replaceing the electrolitics. I do not have a variac to do that.

I can see that you have been spending too much time on the vintage gear forums. The only time I use my variac is when I bring a new amp up for the first time. I only use it to check for excessive current draw.

[marmot]

So your telling me you can replace the caps and fire up the amp ok?

Yes, that stuff about using a variac to form new caps is nothing but bull! All you need to worry about is getting the proper working voltage and wiring the caps into the circuit correctly (i.e., right polarity).