Superior Amp's 2 X 8 MOSFET

[Unit 148]

Is anyone familiar with JD's MOSFET anp's and if they are still available in the market?

I've watched his video's on YT and the numbers look good:

Are there any other similar 2 driving 8 MOSFET mobile amp's out there? I've searched and Palomar/Magnum is about it and limited to 4 FET boxs.

Unit 148 Mobile

 

[9C1Driver]

Only watched maybe a minute of that, wonder what mosfets he's using? It would be nice if he would give more information. Off hand I thought it was funny how he had a TnT amplifier under his speaker, and sorry but a Cobra 2000 is not a 25 watt radio. It seemed odd how the needle would swing as he tried to keep saying AUDEEEEOOO.

 

[tecnicoloco]

Those amps are made by a tech in Ontario,Ca

 

[Unit 148]

Hey 9C1,

Thanks for your input.

Can the Cobra's PA be modified for higher output? There seems a number of mod kits out there however I hear what you say and it would of maybe been more educational to have seen an accurate measurement of this radio.

Tecnicoloco,

Do you know if this Canadian tech has a website or Facebook page up? I'd like to get in touch to possibly order one of these boxes for my mobile export radio? I have commercial website which he can contact me through if you know him personally.
I'm from London, England but now live out here in sunny Cyprus in the Eastern Med.

148 Mobile

BTW, just found another MOSFET amp able to produce similar numbers so same questions for DC in San Antonio, TX if anyone knows him?

 

[rabbiporkchop]

I'm assuming that if Chris Holland made those amplifiers they are probably not something worth purchasing.

 

[Unit 148]

Hi Rabbi,

After that statement I have to ask you to elaborate and not be cryptic in your clues

Are we talking here about the person or the product because I'm really very interested in the product?

Where's PEAKABOO when you need him? I met him and many others when I visited Tyler, TX back in the 80's.

Tnx

148 Mobile

 

[rabbiporkchop]

Hi Rabbi,

After that statement I have to ask you to elaborate and not be cryptic in your clues

Are we talking here about the person or the product because I'm really very interested in the product?

Where's PEAKABOO when you need him? I met him and many others when I visited Tyler, TX back in the 80's.

Tnx

148 Mobile

Chris Holland is the king of Southern California splatter boxes. That's the same guy that supposedly designed the rfx 75. I'm not saying don't buy it I'm just saying I'd be highly skeptical of anything he had his hands involved in.

 

[Unit 148]

Hi Rabbi,

Thanks for your input.

In my experience much if not all splatter is caused by amplifiers being over-driven. If a box is designed for 10W drive then that does not equate to 'all controls to 11', it means you or your tech sets your drive level to 10W max, if not a little less to keep things clean
The above of course excludes operation on CH-6!

Unit 148

 

[Onelasttime]

A decent amp only amplifies what u input. So a clean radio should not make any decent not great not perfect just decent amp to produce harmonics at insane levels. On the other hand the best amplifier in the world cannot be expected to produce a clean signal if the signal source aka the radio is a splattering mess of harmonics. Unfortunately, most of the amps we see in the CB world are poorly designed, poorly executed with cheap parts. Not a great starting point. The radios are even worse!

So exactly what it is about amplifiers made with garbage non-rf mosfets that has you so interested? Are you hopping to get one cheap or do you just not understand how much garbage these particular fet's are for rf?

All kinds of people thought the pet rock was a good idea and where willing to bash peoples heads in for a cheaplymade Cabage Patch Doll or willing to kill a person for their Air Jordan shoes. Desire and common demand or acceptance does not make a highly polished turd worth owning it is still just a polished turd. Maybe you will recall all the idiots that thought they where going to put their kid's through college speculating on the prices of Beanie-Babies?????

Non-rf mosfets are garbage no matter what you hear on this site and other CB sites. If you want a non-bjt amp than at least look at rf-specific LDMOS type amps like but not limited to the BLF188XR. Not only is it a more cost-effective solution but it will likely outlast you if you do not overdrive it since it can withstand something like a 68:1 swr mismatch at all phase angles continuously but it will not survive being overdriven! You can easily get 1000 watts out of a single device if you have the power to run it and use it int he right mode and freq. range for the device you might need 2 just to play it safe for 1500 watts. Did I mention they take a lot less current to make that power and generate far less heat?

If you want fet's so badly just buy 2 4 fet or 1 8 fet RCI amplifier board and roll your own.

7530's, 520's, 530's, 13N10 etc.....are known to let go with just the slightest abuse of swr above 1.5:1 even for just a short while. As long as you do not overdrive the BLF188XR it is almost idiot proof. You need far fewer combiners and transformers etc.....even to do a multi-transistor setup compared to bjt's. Also most people that are used to building with bjt's completly screw up when it comes to mosfet amp design.

 

[rabbiporkchop]

Hi Rabbi,

Thanks for your input.

In my experience much if not all splatter is caused by amplifiers being over-driven. If a box is designed for 10W drive then that does not equate to 'all controls to 11', it means you or your tech sets your drive level to 10W max, if not a little less to keep things clean
The above of course excludes operation on CH-6!

Unit 148

IMD is caused by mismatched devices. Clean signal in equals dirty signal out. Only fix would be a teardown and rebuild with
beta-matched devices.

 

[Onelasttime]

Loved the "all controls to 11" I take it you are a Spinal Tap fan.....The Guitar Cabinet/Amp went to "11" instead of "10" so it had to be better!