PAL Electronics 750B Tube Amp........Help Please.

[honeybunn1]

I have recently purchased a PAL Electronics 750B Ttube amplifier. I have had a great deal of trouble finding any info of any kind on this amp. Has anyone seen, owned, or heard of this amp. Any info would be appreciated.

73's to all.
thanks.

 

[fnkycoldmedina]

if it has 3 transformers in it and about 10 tubes then i,d say it closely resembles the phantom line of amplifiers.if i remember right thats what yours should look like ......4 knobs,lots of switches........couple on back too?is this the one??

 

[nomadradio]

I've seen a lot of sweep-tube amplifiers, but never that one. Biggest Pal I remember seeing has four tubes.

Never knew they got that ambitious. Can't imagine they sold too many of that one. No trace if it anywhere I know to look, either.

Makes me wonder if the Firestik Antenna company kept any of the old files from the "Pal" days. Nothing on their web site, anyway.

73

 

[honeybunn1]

More info on Pal 750b

This amp has a black case, tan front. Switchs are as follows. Power on/off, ssb, rec on/off, 150/750, standby/transmit. It has nine 6lr6 tubes, six on the plate. Two adjustment knobs, Ant and Plate. Any help on what kind of swing and deadkey this amp will handle would be appreciated, as well as any advice on the best way to tune it. I can post a pic if anyone would like to see it. It is a Ham master ten series, if that helps.


73's
Thanks.

 

[fnkycoldmedina]

i believe i have seen one of those befor .with good tubes your looking at about 1200 peak watts or more out that monster.get it tuned in to the highest swing by turning the load n tune knobs while giving it some audio...when you reach max swing your pretty much done .i tune my tube boxes for max swing ,then whatever dead key you get after doing this is what your left with .dont tune it for max dead key,this only hurts the tubes ,tune for max swing then let it alone.

 

[nomadradio]

Like the man said. Max modulated swing. Every time. Unless you have a garage full of tubes.

Are you sure there isn't a third knob on the rear panel, too? There's usually one for the driver stage. Same rule for that one. Max modulated power.


73

 

[Toll_Free]

The PAL Ham 10 series came about later, after the CB amp crackdown was "coming".

Before that, PAL electronics used to market their amps as multi-band by selling different plate coils.

Yeah, I'm going to pull over and replace the plate coil in my 350MDX while going cross country. What a lame idea in a multiband amp.

The HAM-10's, if memory serves me well, where designed as "mono-band".

Your amp can do a LOT of PEP power. Keep it around 900 watts PEP, and you won't be digging into the wallet all the time Tube replacement sucks.

The 150/750 switch is the hi-low switch. It removes a stage, but for the life of me, I can't remember if it kicks the finals out, or the driver, ah la Palomar 300A/350Z. Most of the PAL amps where pretty much direct copies of something Palomar, but ...... If it removed the driver, that would be GREAT, enabling you to use a 2970 type 100 watt radio to drive it.... But be careful, some of them only removed the finals (like the big Glen, Golden Falcon and Loudmouth amps).... If that's the case, then your hitting the drivers with full power, instead of just the final chain.

Firestick (about 5 - 10 years ago) was still VERY responsive about PAL electronics requests. I have a lot of them... San Diego had a LOT of PAL and Palomar tube stuff running around, they where local (pretty much) companies. Give Firestick a call and see if you can find someone willing to dig through the archives... If that doesn't work, send in a written request. Mine have always been answered... Sometimes it took months, but I at least got a "sorry, we couldn't do it for reason xxx"... Good people. No wonder they are still in business.


Hope you like that amp. Good box, VERY heavy duty, and a direct clone of the Palomar 1000.... Now, how many people have seen THAT amp... Looked like the Skipper line, but was a 9 or 10 (depending on vintage... they only made it for a short time) tuber

**edit** Forgot to add... Sometimes the driver control is located inside the amp... Very nice way to do it, lol. So, if you can't locate a cap adjustment on the back of the amp, pop the covers off and look around inside for a cap around the drive tubes that you can adjust... Sometimes (rarely this long do they still exist) they have a thumb screw type knob on them, but usually not... A compression cap is what you will more than likely be looking for, like dulaney used in his amps.

--Toll_Free

 

[bgosper]

I just picked up one these 750B's

I cannot find ANYTHING online about these amps! Unbelievable! No specs, no schematics, no manuals.
It has 9 tubes and is super heavy.
I am getting about 750 out with very low drive. Not sure if that is about right as the high switch is labeled "750". Although the low switch says "150" and I am getting about 500 from that setting.
The drive tune control is INSIDE near the single drive tube. It is a small hex thumb screw but I need to use a small socket since it is a bit tough to turn probably due to age. I have no idea where to set it to get best performance and protect the tubes. I think 900-1200 like other posters have said is ambitious. Again, another reason I need a manual or specs on this.
If anyone knows where I could get one, let me know!
Thanks....
73's

 

[bgosper]

Still Looking for Info on this Amp? Go here!

Pal Electronics

I emailed the guys at Firestik and they did great work tracking down the manual and schematic for this amp!

Take care...

 

[Spooner454]

The svhematics on the firestick link does not appear to be the same amp it is only a 5 tuber not NINE or am i missing something?

 

[paws264]

The svhematics on the firestick link does not appear to be the same amp it is only a 5 tuber not NINE or am i missing something?

What is the problem with your amp?

.

 

[dudmuck]

The manual on the firestik site says 9 tube, but the schematic shows 5 tubes.

Cant be right, but their site said many of the original documents were lost due to storm damage.
Its par for the course, when you are working with a product coming on 40 years old which wasn't legal in the first place. And likely few of these units were produced.

At some point you have to say these are museum pieces or collectors items rather than units for actual use.

 

[Spooner454]

I was just looking for the schematics for the Pal 750 B amplifier

 

[bgosper]

You are not missing anything. To save printing space, they simply eliminated the drawing of tubes 6-9. The schematic shows one 8950 (v1) driving two more 8950's (v2, v3) and those driving six more 8950's (v4-v9) but it only shows v4 and v5 in pic. Circuitry for the other 4 not shown is just a repeat of circuitry of v4 and v5.
Hope that helps...I own this amp so I am quite familiar with it.

 

[bgosper]

These are perfectly usable amps until something major goes wrong or you need to replace the tubes. At that point, I would retire it as it will cost you alot more to fix it--especially replacing 9 tubes-- than you probably paid for it used in the first place. I use mine almost day for DX and I get great results with it. It still does the projected 750-850 watts (the manual says 1500 on SSB--not a chance!) it is rated for with 2 watts in. Not bad for a 40 year old amp! Again, the day it blows or the tubes fail, I will pitch it...