Pilot tube amps!!!!

Quote:

---

Originally Posted by RonSSS

Well, from the photos, your amp looks mint. Probably untouched. A quick search on ebay etc revealed that it's quite valuable. Around a grand. So I would treat it nice!

First I'd test the tubes. All are common and easy to find. And it has a nice tube compliment. Dual rectifiers even. that's a bit rare.

Next I'd plug the tubes in,and power it up slow with a variac. This allows you to adjust the line voltage from 0-120 very slowly. Doing this will reform the electrolytic power supply caps if they aren't dead. While doing this, a 1khz sine wave is fed to the input jacks for both left and right channels. 100mV usually works well. The outputs are terminated into 8 ohm 100W resistors and that is monitored with a scope.
At the same time tha B+ (main supply voltage) and output tube bias voltage is monitored with a DVM.
once you get to about 60 volts on the power cord, the amp will begin to operate. At about 90v it will operate pretty much normally but with reduced power output. Once you get to 120v, it should be singing!

Along the way any issues would be found. Either the B+ doesn't work, or the bias is all messed up, or the output looks bad.
Any issues during the slow turn on can be fixed. As I said, if the transformers are good, the rest is easy.

The whole process takes a few hours if all is well, and when done you can check power output, freq response, check square wave operation, and measure distortion.

Once it's all up and running, you go back and test all resistors and caps for value and change as necessary.

I'm a tube head and have all of this test equipment. I have worked at Tektronix for 34 years as a tech, eng tech, and now am in project management. We make oscilloscopes. And all other kinds of high end electronic test equip etc.

My own system is all tube and I built the power amps myself from the best parts stolen from vintage equipment.

Anyway, that's what I'd do because I can.
You need to find a local guy like me, or even better like my buddy who basically does this for a living now since he was laid off from Tek a number of years ago. No one I know is more picky, anal and a downright perfectionest when it comes to this work.

Ron

---

Thanks, Ron this is very confusing to me! I have read some conflicting veiws about vintage tube amp care. Many say replace all the things that might fail, others say keep them as original as possible. I just want as much out of these amps as I can have. I wish you were closer or your friend. I contacted the local broadcast museum, hopefully they gave me a good recommendation as far as repair. I will use your advice when I speak with them. Thanks again

Quote:

---

Originally Posted by speakerdave

Nice score. I have been casually keeping an eye out for Pilot tube electronics since the seventies, but have not run across any.
Just out of curiosity, what speakers did they use in that console?

---

Speakerdave, I did a little research on the speakers there are 8 jensen speakers the largest ones only seems to have a little importance for guitar players.

I have an old Fisher console circa 1958 that uses three 8" Jensens per side. Pleasant sounding, if not real Hi-Fi.

Quote:

---

Originally Posted by Panomaniac

I have an old Fisher console circa 1958 that uses three 8" Jensens per side. Pleasant sounding, if not real Hi-Fi.

---

That's an odd configuration. What model of driver?

Quote:

---

Originally Posted by juniper

Speakerdave, I did a little research on the speakers there are 8 jensen speakers the largest ones only seems to have a little importance for guitar players.

---

I'm not following you sentence structure........ are you really saying that only the largest Jensen drivers have any value, although small? If so, that's incorrect. Some Jensen drivers go for quite a bit, and some don't. It has more to do with the model than the size, in my observation. The highest dollar Jensen drivers I've sold were P10R's........ one went to Germany, and the other to AZ, I think. I got over $200 for the one driver going to Germany, if I recall correctly. I've also done fairly well selling some of the 8" Jensen drivers.

P12N's sell well....... the P12NF's that I have don't :-(

On the other hand if you're comparing their value to 604's or 755A's, Jensen drivers are cheap.

ABG, All I was trying to convey is the info that I received from the local speaker shop. They said that the smaller speakers and crossover have little value, but the larger ones sell for around 130.00 a piece and some people put them in vintage guitar amps. They are Special Design p12ps sorry if my statement, sounded crass.....

Quote:

---

Originally Posted by juniper

ABG, All I was trying to convey is the info that I received from the local speaker shop. They said that the smaller speakers and crossover have little value, but the larger ones sell for around 130.00 a piece and some people put them in vintage guitar amps. They are Special Design p12ps sorry if my statement, sounded crass.....

---

It didn't sound crass, it just sounded, wrong....... if I was understanding what you were trying to convey. It sounds like the guy at the speaker shop only pays attention to new speaker sales, or can't be bothered with anything under $100. A friend of mine that did/does pro-sound places little value on anything Altec, because it's "old and isn't servicable".......... My point is that usually retailers aren't a good source for info on anything vintage, and don't know the difference's between what sells well, and what doesn't. For instance the blue frame in the auction below helped greatly with the price.

Vintage 1958 12

What tends to have very little if any value, in my experience are small cone mids and cone tweeters that I find in consoles. Most of my experience is with Magnavox and Fisher consoles, so that may not apply to other companies......... I've never even seen a Pilot console.

Quote:

---

Originally Posted by RonSSS

Well, from the photos, your amp looks mint. Probably untouched. A quick search on ebay etc revealed that it's quite valuable. Around a grand. So I would treat it nice!

First I'd test the tubes. All are common and easy to find. And it has a nice tube compliment. Dual rectifiers even. that's a bit rare.

Next I'd plug the tubes in,and power it up slow with a variac. This allows you to adjust the line voltage from 0-120 very slowly. Doing this will reform the electrolytic power supply caps if they aren't dead. While doing this, a 1khz sine wave is fed to the input jacks for both left and right channels. 100mV usually works well. The outputs are terminated into 8 ohm 100W resistors and that is monitored with a scope.
At the same time tha B+ (main supply voltage) and output tube bias voltage is monitored with a DVM.
once you get to about 60 volts on the power cord, the amp will begin to operate. At about 90v it will operate pretty much normally but with reduced power output. Once you get to 120v, it should be singing!

Along the way any issues would be found. Either the B+ doesn't work, or the bias is all messed up, or the output looks bad.
Any issues during the slow turn on can be fixed. As I said, if the transformers are good, the rest is easy.

The whole process takes a few hours if all is well, and when done you can check power output, freq response, check square wave operation, and measure distortion.

Once it's all up and running, you go back and test all resistors and caps for value and change as necessary.

I'm a tube head and have all of this test equipment. I have worked at Tektronix for 34 years as a tech, eng tech, and now am in project management. We make oscilloscopes. And all other kinds of high end electronic test equip etc.

My own system is all tube and I built the power amps myself from the best parts stolen from vintage equipment.

Anyway, that's what I'd do because I can.
You need to find a local guy like me, or even better like my buddy who basically does this for a living now since he was laid off from Tek a number of years ago. No one I know is more picky, anal and a downright perfectionest when it comes to this work.

Ron

---

Very Good Post Ron ! Nice explanation in getting that old tube amp hopefully up and running smoothly.

Quote:

---

Originally Posted by Audio_by_Goodwill

That's an odd configuration. What model of driver?

---

I don't remember. Will poke my head in there and check. They may not have model numbers. I do remember that it's 2 of one type, one of the other, all 8". No crossover, all wired parallel.
Have been thinking about putting my SABA green cones in there for mids.

Quote:

---

Originally Posted by Panomaniac

I don't remember. Will poke my head in there and check. They may not have model numbers. I do remember that it's 2 of one type, one of the other, all 8". No crossover, all wired parallel.
Have been thinking about putting my SABA green cones in there for mids.

---

They should have a P#x stamped on them some place, or something similar.