I recall playing thru this exact model amp when I was younger and fully recall being very unimpressed with it!
In fact it did not even sound as good as my very beat up Deluxe with 6V6 tubes and only one speaker.
It may not be true to the original, but I would leave that choke out!
It’s a odd thing because there really should not be a over abundance of low end with those .01uf caps feeding the output grids.
It’s also interesting that the implementation of the standby switch in this amp is the same as a Silvertone 1484 model,
Airline 62-9015-A
Moderators: pompeiisneaks, Colossal
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Stevem
- Posts: 5144
- Joined: Fri Jan 24, 2014 3:01 pm
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Re: Airline 62-9015-A
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Airline 62-9015-A
The parafeed choke lets the OT be small as the OT doesn't have to carry the DC current to the tube, just the audio signal.
Tube junkie that aspires to become a tri-state bidirectional buss driver.
Re: Airline 62-9015-A
Found this... makes sense now.
Inductor basics...
Inductive reactance or the impedance of an inductor describes the opposition to ac current flow in an inductor as a function of frequency. If a choke is added across the speaker terminals it will act as a high pass filter. At low(er) frequencies the choke will act as a resistor (R~the resistance of the wire) largely shunting the speaker. Connected this way the choke will reduce the LF content (a.k.a. boosting treble) delivered to the speaker at the rate of 6dB/octave. This is analogous to putting a bypass cap across a tweeter to reduce its exposure to HF content.
In a power supply the choke may be used to limit transient current according to the differential equation L*di/dt. Slow changes (large dt) in current are passed, rapid changes (small dt) are attenuated.
Inductor basics...
Inductive reactance or the impedance of an inductor describes the opposition to ac current flow in an inductor as a function of frequency. If a choke is added across the speaker terminals it will act as a high pass filter. At low(er) frequencies the choke will act as a resistor (R~the resistance of the wire) largely shunting the speaker. Connected this way the choke will reduce the LF content (a.k.a. boosting treble) delivered to the speaker at the rate of 6dB/octave. This is analogous to putting a bypass cap across a tweeter to reduce its exposure to HF content.
In a power supply the choke may be used to limit transient current according to the differential equation L*di/dt. Slow changes (large dt) in current are passed, rapid changes (small dt) are attenuated.
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Stevem
- Posts: 5144
- Joined: Fri Jan 24, 2014 3:01 pm
- Location: 1/3rd the way out one of the arms of the Milkyway.
Re: Airline 62-9015-A
Parafeed?
Wait a minute now, unless there’s a internal issue with the OT there’s no dc on the secondary side of the OT anyway!
Wait a minute now, unless there’s a internal issue with the OT there’s no dc on the secondary side of the OT anyway!
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Airline 62-9015-A
Sorry, brain fart. I was thinking primary. Failure of reading comprehension.
Tube junkie that aspires to become a tri-state bidirectional buss driver.
Re: Airline 62-9015-A
I have yet to hear the amp. So far I have changed out the AC input with a three prong plug and set it up per the usual sequence... Fuse, switch, primary. I have the speakers cleaned up, but they are 8 ohm each so not to original specs, but very nice speakers....one Jensen C12Q and one C12NA. This is a mismatch. I'll listen with one of the speakers and figure out if I want to source 2 16 ohm speakers.
There is a 50/50 electrolytic across the power cathode resistor, not on the schematic, not sure if that will stay.
It came with some good tubes as well. I brought it up on a variac, through a bulb limiter without tubes so far and no shorts. Will report as I proceed. I have read several reports that are not stellar at all with regard to tone. I may be looking for a roadmap to getting a bit more character from this amp... we'll see/hear.
A
There is a 50/50 electrolytic across the power cathode resistor, not on the schematic, not sure if that will stay.
It came with some good tubes as well. I brought it up on a variac, through a bulb limiter without tubes so far and no shorts. Will report as I proceed. I have read several reports that are not stellar at all with regard to tone. I may be looking for a roadmap to getting a bit more character from this amp... we'll see/hear.
A
Re: Airline 62-9015-A
I have yet to hear the amp. So far I have changed out the AC input with a three prong plug and set it up per the usual sequence... Fuse, switch, primary. I have the speakers cleaned up, but they are 8 ohm each so not to original specs, but very nice speakers....one Jensen C12Q and one C12NA. This is a mismatch. I'll listen with one of the speakers and figure out if I want to source 2 16 ohm speakers.
There is a 50/50 electrolytic across the power cathode resistor, not on the schematic, not sure if that will stay.
It came with some good tubes as well. I brought it up on a variac, through a bulb limiter without tubes so far and no shorts. Will report as I proceed. I have read several reports that are not stellar at all with regard to tone. I may be looking for a roadmap to getting a bit more character from this amp... we'll see/hear.
A
There is a 50/50 electrolytic across the power cathode resistor, not on the schematic, not sure if that will stay.
It came with some good tubes as well. I brought it up on a variac, through a bulb limiter without tubes so far and no shorts. Will report as I proceed. I have read several reports that are not stellar at all with regard to tone. I may be looking for a roadmap to getting a bit more character from this amp... we'll see/hear.
A
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Stevem
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- Joined: Fri Jan 24, 2014 3:01 pm
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Re: Airline 62-9015-A
You will probably be hearing more of the 12n then the 12q since the 12N is much more efficient then the 12q!
Also while your out & about in there I would up that 5 watt cathode resistor to 7 watts, or maybe for 10 cents more and even better stability go for 10 watts.
Gez, even a blk or silver faced Champ with one darn 6V6 uses a 5 watt resistor!
Also while your out & about in there I would up that 5 watt cathode resistor to 7 watts, or maybe for 10 cents more and even better stability go for 10 watts.
Gez, even a blk or silver faced Champ with one darn 6V6 uses a 5 watt resistor!
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Airline 62-9015-A
Thanks man. So its up and running. I managed to find a couple of 6L6's (Peavey branded) that are pretty close on PD. I am getting .049 on one side for current and .042 on the other. PD is 14.5w & 14.1w. Sounds passable but not anything special. The Tremolo is not working and the Reverb is also kaput. I understand that these things have a piezo device in the reverb box and tough to get going again. I see that the trem can be tackled by swapping out the .02 caps for fresh ones. I don't think this amp has been turned on in twenty years. I tried the choke in parallel but did not hear much difference at all. I do not have the foot pedal, but I read tha without the pedal the trem and reverb are on all the time?? I am running one speaker right now at 8ohms, its on its back (magnet side) down
on the bench.
OT is pretty punny... any thoughts on what might take this up a notch? Plenty of ability to alter tone stack with treble and bass but its the basic tone that is unremarkable.
One other tis bit, as I was working with the amp, checking voltages and such, when I went to play the amp it was quite low and almost no sound. As I switch the standby off it came up loud, amp was off. Then I realized that the standby had been, somehow, altered in terms of the bat. Its on, the opposite of the bat position for the on/off. Thats was weird. I put a dymo label on for on/off on the standby for now. I suppose I should flip it 180.
on the bench.
OT is pretty punny... any thoughts on what might take this up a notch? Plenty of ability to alter tone stack with treble and bass but its the basic tone that is unremarkable.
One other tis bit, as I was working with the amp, checking voltages and such, when I went to play the amp it was quite low and almost no sound. As I switch the standby off it came up loud, amp was off. Then I realized that the standby had been, somehow, altered in terms of the bat. Its on, the opposite of the bat position for the on/off. Thats was weird. I put a dymo label on for on/off on the standby for now. I suppose I should flip it 180.
Last edited by angelodp on Mon Apr 25, 2022 8:46 pm, edited 1 time in total.
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Stevem
- Posts: 5144
- Joined: Fri Jan 24, 2014 3:01 pm
- Location: 1/3rd the way out one of the arms of the Milkyway.
Re: Airline 62-9015-A
Forget the stock reverb!
It’s like my Sears 1484 reverb tank with its ceramic phono cartridge at each end of what amounts to a back door return spring!
Get yourself a SS reverb block that powers up with 5 volts if you want the verb to work.
Just replace c21,24,25 and 26 and then with a good tube the trem should pump again.
It’s like my Sears 1484 reverb tank with its ceramic phono cartridge at each end of what amounts to a back door return spring!
Get yourself a SS reverb block that powers up with 5 volts if you want the verb to work.
Just replace c21,24,25 and 26 and then with a good tube the trem should pump again.
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Airline 62-9015-A
Steve, I am curious about this reverb, before I chuck it. I opened up and fixed up the piezo, per Uncle Doug vid. I think someone has messed with the components. As you look a to the schematic, I cannot find the second 1M that forms a voltage divider at R35.... I take it that the reverb won't work without that second 1M in there. I just don't see that additional 1M.
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A
Re: Airline 62-9015-A
R35 and R36 do not form a voltage divider. R35 is the grid leak for V5A and R36 is the grid leak for V5B. The center point where the two resistors are connected together is GROUND, and that means the two resistors may not be physically connected. Both resistors are needed. You should be able to look at V5 pin 7 and trace a path to R35. The resistor may even be connected directly to pin 7. Then you should be able to look at V5 pin 2 and trace a path to R36. The resistor may even be connected directly to pin 7. If you still can't find a 1M connected from V5 pin 2 to ground, then put one there.
Re: Airline 62-9015-A
Ah, slaps head. So yes 1M's are there. It appears that one of the leads from one end of the reverb box was not grounded, so I did connect that to ground. Still no reverb. I tried shorting the pedal switch but still no reverb? As I mentioned I went in and re-did the piezo spring setup. I isolated the spring at the ends where it gets tensioned with tape, so now does not conduct to the spring on either end. The little piezo's appear to be behind paper tape and mounted to a bolt and screw that goes to the leads. The other leads go to the metal armature. I followed an Uncle Doug vid including a three to hold the spring down in the middle. Tube Tests good. Any suggestions on what I can further test.
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Stevem
- Posts: 5144
- Joined: Fri Jan 24, 2014 3:01 pm
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Re: Airline 62-9015-A
When you excite the piezo’s do you read any Voltage out of them?
If any of the grounds for this circuit are landed on the hold down of any terminal strip that this amp is made with be sure to do a resistance check as many times the rivites that hold them to the chassis loosen up over the years and the ground you think you have is crap!
If any of the grounds for this circuit are landed on the hold down of any terminal strip that this amp is made with be sure to do a resistance check as many times the rivites that hold them to the chassis loosen up over the years and the ground you think you have is crap!
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!