PSU for 100w Veronica amp

[TGillies]

Purchased this on ebay the other day

https://www.ebay.co.uk/itm/80-100W-VHF- ... 2749.l2649

at £130, an absolute steal... however finding a psu for it doesnt seem easy. specs says it requires 13.8v 12a psu, not seeing many online

i have a 13.8v 7a psu, will that work? if not can anyone point me in the right direction.

cheers

[LeeCavanagh]

12v would work but you would get more power output from a 13.8v supply, which are very common for cb and ham radio, reason being it’s what a car battery gives out when it’s being revved.

How about this 30a for 25.99
https://www.ebay.co.uk/itm/401931779296

Or this 15a for 57.95
https://www.ebay.co.uk/itm/143629135866

Look here too, it says the unit requires 12amps (if you had two 7 amp power supply’s you could use both together to give you 14amp supply)
http://www.veronica-kits.co.uk/100wpa.htm

[nrgkits.nz]

You need a meanwell 15v supply and wind it down a little to 13.8, this is what I do for all the stuff I build that needs 13.8v

[MiXiN]

Purchased this on ebay the other day

https://www.ebay.co.uk/itm/80-100W-VHF- ... 2749.l2649

at £130, an absolute steal... however finding a psu for it doesnt seem easy. specs says it requires 13.8v 12a psu, not seeing many online

i have a 13.8v 7a psu, will that work? if not can anyone point me in the right direction.

cheers

I had my eye on that but was put off by the 25w input requirement. Very inefficient too, but rugged I'd think.

Please post a pic of the internals when it arrives.

[nrgkits.nz]

I’ve just seen the photo on eBay, it’s one of Hollings amps - no wonder it’s so inefficient.

[LeeCavanagh]

The insides of the Veronica 100w amp

31D7B9DC-586B-407B-8A87-26E3BD56C150.jpeg

D4CC9F3B-0BE5-4DC1-B45A-7F8EF7B09395.jpeg

A0A1360B-3746-441F-92E7-BC1BB081DA4D.jpeg

[Albert H]

Oh dear. That's a Hollings effort. The output "filters" won't filter anything as all the coils are in line. The huge numbers of resistors are an effort to try to prevent one board "current robbing" the other.....

25W in for 100W out is a joke. It's going to make more heat than RF, and the RF that you do get out of it will be on plenty of simultaneous frequencies.

If you want 100W, you really don't want to try to do it with a 12V (or even 13.8V) supply if you're using old transistors. The current required is ridiculous.

If you want to do 100 W these days, you need an MRF101 - 1 Watt in and 100 Watts out. The Dutch lads are selling nice little PA boards for this device for around £35.

My old bipolar transistor PAs used the MRF317, driven by a 2N3632. You needed 1 Watt in, a 28V supply, and the PA would (usually) give around 120 Watts. There were two trimmers to adjust for maximum output, and the harmonic suppression was excellent because of the correctly designed and constructed filter. The power supply needed to be rated for 7A (and would run cold).

[nrgkits.nz]

The proper way to do combine two amplifiers is to use a Wilkinson combiner with 100R balancing resistor - the phase shift along with the 100R resistor prevents the amplifiers from seeing each other on the two input ports. The only draw back is if one amp failed then the resistor will eat up 3db of power from the other resulting in only 1/2 the power of the working amp getting to the output.

[TGillies]

The proper way to do combine two amplifiers is to use a Wilkinson combiner with 100R balancing resistor - the phase shift along with the 100R resistor prevents the amplifiers from seeing each other on the two input ports. The only draw back is if one amp failed then the resistor will eat up 3db of power from the other resulting in only 1/2 the power of the working amp getting to the output.

Yeah is states on the the veronica site that it uses a wilkinson combiner, is this not the case here.. I have no idea who Hollings is, but am i right in thinking this is a clone build or.... ? i've always thought highly of Veronica stuff, the bread and butter so to speak along with with NRG for years

[TGillies]

12v would work but you would get more power output from a 13.8v supply

yeah i have a 13.8v supply but its current is 7amps - 5amps short of the required 12a... how would that affect the performance of the amp if i used this?

[radium98]

i did not understand anything from this combiner splitter

[tvtv]

12v would work but you would get more power output from a 13.8v supply

yeah i have a 13.8v supply but its current is 7amps - 5amps short of the required 12a... how would that affect the performance of the amp if i used this?

You would blow your power supply,
You can use more amps but never under rated, you must use one at least 12a, or as previously said you could use two 7 amp supplies if you can’t afford a new 13.8v supply but given one of them is £25 you can likely afford . They do differ in quality though , some are rfi filtered which helps keep your audio clean, that’s why some suggest the meanwell (it’s good but often expensive).

[nrgkits.nz]

The proper way to do combine two amplifiers is to use a Wilkinson combiner with 100R balancing resistor - the phase shift along with the 100R resistor prevents the amplifiers from seeing each other on the two input ports. The only draw back is if one amp failed then the resistor will eat up 3db of power from the other resulting in only 1/2 the power of the working amp getting to the output.

Yeah is states on the the veronica site that it uses a wilkinson combiner, is this not the case here.. I have no idea who Hollings is, but am i right in thinking this is a clone build or.... ? i've always thought highly of Veronica stuff, the bread and butter so to speak along with with NRG for years

You don’t know who Hollings is? Albert has put a lot of information on these forums about him, long story short steer clear of any gear he sells.

The combiner in this amp looks to be resistive so will waste a lot of energy, adding to the inefficiency and generating unnecessary heat. I use 75R 1/4 wave length pieces of ptfe coax with a 100R 250W resistor at the split end and bolted down to the heat sink. When both amplifiers are calibrated to have the same output power, the 100R resistor dissipates no power because it’s at a virtual ground point. If one amp drops a little in output power, there’s no longer a virtual ground and the resistor starts to dissipate power, balancing out the amplifiers in the process, but you lose some power at the combined output.

[TGillies]

12v would work but you would get more power output from a 13.8v supply

yeah i have a 13.8v supply but its current is 7amps - 5amps short of the required 12a... how would that affect the performance of the amp if i used this?

You would blow your power supply,
You can use more amps but never under rated, you must use one at least 12a, or as previously said you could use two 7 amp supplies if you can’t afford a new 13.8v supply but given one of them is £25 you can likely afford . They do differ in quality though , some are rfi filtered which helps keep your audio clean, that’s why some suggest the meanwell (it’s good but often expensive).

Thanks for the info people, I’m gonna at least get it up and running and give it a bash..

https://www.ebay.co.uk/itm/224057622497

^ would this psu be suitable, seems to me?

[TGillies]

The proper way to do combine two amplifiers is to use a Wilkinson combiner with 100R balancing resistor - the phase shift along with the 100R resistor prevents the amplifiers from seeing each other on the two input ports. The only draw back is if one amp failed then the resistor will eat up 3db of power from the other resulting in only 1/2 the power of the working amp getting to the output.

Yeah is states on the the veronica site that it uses a wilkinson combiner, is this not the case here.. I have no idea who Hollings is, but am i right in thinking this is a clone build or.... ? i've always thought highly of Veronica stuff, the bread and butter so to speak along with with NRG for years

You don’t know who Hollings is? Albert has put a lot of information on these forums about him, long story short steer clear of any gear he sells.

The combiner in this amp looks to be resistive so will waste a lot of energy, adding to the inefficiency and generating unnecessary heat. I use 75R 1/4 wave length pieces of ptfe coax with a 100R 250W resistor at the split end and bolted down to the heat sink. When both amplifiers are calibrated to have the same output power, the 100R resistor dissipates no power because it’s at a virtual ground point. If one amp drops a little in output power, there’s no longer a virtual ground and the resistor starts to dissipate power, balancing out the amplifiers in the process, but you lose some power at the combined output.

Did he work for Veronica tho, or simply pass his builds off as Veronica, slightly confused if I’m honest.

Regardless, he can’t be anyway worse than the guy I bought off eBay (unique electronics)

Yes... I’ve bought some shit hardware the last couple of years

[LeeCavanagh]

Paul hollings and Steven moss worked together, before hollings tried to steal the company that Steven had built up before hollings came on board. This is where NRG comes in, the company Steven started (I actually suggested the name to him which he went with) so he could continue his good work, Veronica and Nrg are both good names, but only because of Steven ... (and Nrg was subsequently split into two and the name lives on , some great new stuff coming out of New Zealand )

I actually heard from several people that this amp was sold by Steven , from people who have never met hollings, so I think there are some that exist. Pre/during split and post Steven’s death.

Your being warned against anything that Paul may have touched, because whilst he was trained by Steven , he only learned enough to get by, where as Steven was always learning and improving his products, you won’t see the same happening from hollings because he has nobody to steal from anymore!

[LeeCavanagh]

yeah i have a 13.8v supply but its current is 7amps - 5amps short of the required 12a... how would that affect the performance of the amp if i used this?

You would blow your power supply,
You can use more amps but never under rated, you must use one at least 12a, or as previously said you could use two 7 amp supplies if you can’t afford a new 13.8v supply but given one of them is £25 you can likely afford . They do differ in quality though , some are rfi filtered which helps keep your audio clean, that’s why some suggest the meanwell (it’s good but often expensive).

Thanks for the info people, I’m gonna at least get it up and running and give it a bash..

https://www.ebay.co.uk/itm/224057622497

^ would this psu be suitable, seems to me?

This one has me confused, the listing says “ .please note not for use with cb radios”, this isn’t a good sign, why not, possibly too noisy for rf? Just a guess. Did you look at the suggestions in the first reply?

https://www.ebay.co.uk/itm/143629135866

https://www.ebay.co.uk/itm/401931779296

[MiXiN]

I've got one of these and it's been really reliable - https://rover.ebay.com/rover/0/0/0?mpre ... 0986454092

It's capable of running over 2x the current you need so will just be cruising along without breaking out into a sweat.

The Dutch guys & Gareth (NRG NZ) sell much better gear, so I'd return that inefficient Hollings amplifier for a refund & look elsewhere.

This is the one Albert referred to & it's very efficient & small - https://dutchrfshop.nl/en/home/1032-100 ... tsink.html

[RF-Head]

@TGillies
I think the amp will work
the combiner that combines both amps using 2 pieces 75ohm cable and a balance resistor of 100ohm
only strane is that he use many 1W resistors to make a highpower 100E resistor
also the input use the same combiner only smaller resistors and a ATT on the input

[MiXiN]

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