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Palomar Elite 400 amp

F

Freddy Texidor

Member
Jun 22, 2021
11
1
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60
Does anyone know the values of the resistors R7 and R8 and if so, where can I buy them?
They look heavy duty to me.
also I seen on this site different people saying that the 400 only needs 1.5 - 5 watts dead key into it.
Should I input 1.5W, 3W or 5W into the amp?

Any and All Information will be greatly appreciated.
 

27 and 100 ohm non inductive and my guess is 2 watt rating.
That is the padding for the high/med/low switch on those amps.
To be honest I would leave it on high and adjust the radio.
AM no more than what ever gives you a 75/80 watt dead key out of the amp on high and I would limit peak input to 20 watts swing.
These usually have 4 sd1446 transistors in them.
SSB I would also limit to 20 watts peak input.
Put a fan on the heatsink.

73
Jeff
 
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Jeff,
Thank you for the information.
The amp has 4 MRF 455 9245 Malaysia F Transistors. If I'm only getting 150 watts out @ 2 watt dk swinging to 20 watts, is that ok or is there something wrong with it?
Greatly appreciate your help.

By the way someone had a 39 ohm resistor soldered to the Med side of switch.
 
Freddy Texidor said:
Jeff,
Thank you for the information.
The amp has 4 MRF 455 9245 Malaysia F Transistors. If I'm only getting 150 watts out @ 2 watt dk swinging to 20 watts, is that ok or is there something wrong with it?
Greatly appreciate your help.

By the way someone had a 39 ohm resistor soldered to the Med side of switch.
Click to expand...

I guess that would depend on what kind of watt meter you have. If you have a true peak reading meter then you should see a bit more. If it's not a peak reading meter then your probably fine.If you click on the data sheet above you will see the MRF455 is a 60 watt device @12.5 volts.
 
9C1Driver posted:
"the MRF455 is a 60 watt device @12.5 volts."

@ a minimum of 13 dB. gain (20X) will produce
60 watts output with 3 watts (modulated) drive
per device in the high power (less input padding)
position. 12 watts of unmodulated carrier input
should produce +or- 240 watts, if not then the
gain of the device/s has been degraded, usually
due to excessive drive.

that is NOT a 400w. amplifier.
 
Last edited:
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All the above.

150 watt dead key is too much for that amp, roll the power back to a 75/80 watt dead key.


I don't even run a 150 watt dead key out of 4 2879's for a daily driver setup.

I just seen your other post, there is really nothing you can change to make it produce more power.
Those little 455's are working hard enough.

73
Jeff
 
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9C1Driver posted:
"If I'm only getting 150 watts out @ 2 watt dk swinging to 20 watts...."

dB. gain = 10 log (power out / power in)
dB. gain = 10 log (150 w. out / 20w. in)
dB. gain = 10 log (7.5)
dB. gain = 8.75
7.5X

based on your input it's time for some new
devices as the gain has dropped at least
4.25 dB. below the minimum rated 13 dB..
 
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@freecell,
So if I change out the 455's for some 1446's would that be better?

@9C1 Driver
I am using a Dose TFB 3001 meter

Radio is a Stryker 955HP
Low power @ 2watts with a 20 watt swing.

I am not able to lower dk to 75-80 watts

I think the radio is too much for the amp?
 
Just getting back to this thread. The Stryker 955 is a pretty hot radio for that amp. Remember to always have the RF power dialed way down before you key it up.

Good catch Shockwave, I assumed the 150 watts was peak but if it was dead key wow.
 
Just to let you guys know, The Stryker was too much power for the amp.
I hooked up my Cobra 29LTD and was able to adjust the radio with amp on high to a 80w dead key and 200w out. I am Happy with these results.
Thank you everyone for all the information and most importantly your help.
73's
 

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