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 Post subject: Updates
PostPosted: Tue Oct 03, 2017 5:44 pm 

Joined: Fri Aug 16, 2013 6:37 pm
Posts: 2

I have a HR50 s/n 1135 and I'm interested in adding any additions / corrections that have been discovered since I have originally built the amp. I have read about the bias current change, input / output terminal changes, the 6m cap mod, and the T2 replacement.

Are there any other changes I should be aware of? Is there a parts kit for the updates available? What are the specs for the changed components? Is there a consolidated list of mods / changes that I should check out?


 Post subject: Re: Updates
PostPosted: Wed Oct 04, 2017 5:34 am 

Joined: Mon Jul 23, 2012 6:25 am
Posts: 1143
Hi Kevin,

The majority of component changes in the amplifier have been is response to supply chain issues and as long as you already have the parts, do not need to be changed. I'll address them one-by-one

1. Bias current increase. Yes the amp has better gain and linearity by increasing the bias from 50mA per device to 150mA per device.

2. Change from internal RCA jacks to terminal blocks. We can no longer get that type of RCA jack and they prevent the installation of the ATU. You do not need to make the change unless you plan on installing the ATU and if you do, we'll send a retrofit kit.

3. Adding two 33pF 50V NPO/G0G cap across the RLY_OUT and AMP_IN connections lowers the SWR on 6M. If you plan on operating on 6M you can add the two caps, either leaded or SMT will work fine.

4. We changed from a RF Parts supplied transformer core to one supplied by Communications Concepts for supply chain issues, thee is no technical reason to make the change.

5. We redesigned the rear panel board with an isolated, FTDI based USB-TTL converter. This allows 'no driver' installation since Windows 'knows' about FTDI. This mod will also eliminate ground loop issues with SDRs like the Flex-1500 and Softrocks by removing the amp-computer ground connection. It also eliminates the need for a 12 MHz crystal. We plan to offer then new board for sale stand-alone for anyone interested in upgrading.

6. There are a handful of other changes that are needed on older amps to accommodate the ATU, a parts kit and instructions are available if/when you buy the ATU.

There are FW updates the current version is 3.0D for the amp and 1.4 for the ATU. These are reported by the amp, on the LCD when the amp is first powered on. So if you don't have the latest, follow the procedure in the manual for updating the FW.


 Post subject: Re: Updates
PostPosted: Thu Oct 05, 2017 9:40 pm 

Joined: Fri Aug 16, 2013 6:37 pm
Posts: 2
Hi Jim,

Thanks for the detailed response! It's good to know I don't really have to do much. I do use 6m occasionally, so I'll do that mod.

I am interested in the updated rear panel. I noticed that when I connected to the amp via USB for cat control, I heard RFI from the mCU. I didn't notice the ground loop, but it's been a while since I've used it with my 1500. I now have a KX3 and will be using the amp with that radio.

I am strongly considering the tuner in the near future.

Thanks again,

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