Running a F-1X Pre Into BGW 500D Power Amp

[Mostlow]

Ok, I'm a newbie here and not overly technical, and just recently purchased a F-1X for the first time. I also just acquired an early 70's BGW 500D stereo power amp that runs approx 200w per channel @ 8ohms, and goes down to 2ohms. I'm using the crossover on the F-1X to send the lows into a 8ohm cab with a single 150w JBL K140, and the highs into a '68 Fender Dual Showman cab @ 4ohms with two 125w JBL K130's (8ohms each). This thing is strictly a power amp with no volume knob (the only switch is on/off), so 1) I'm a bit leery of frying the K140, and 2) can the F-1X handle putting out a mixed load into separate channels (I would think yes, but thought I should check).

The 500D manual can be read online here: http://e.manualretriever.com/lect.php?ID=307421&lg=E&h=d41d8cd98f00b204e9800998ecf8427e

Thanks.


   

[JimmyJ]

That should be a lovely combination!  I believe the BGW does have gain controls near the input jacks, they're not knobs but screwdriver trim pots. In addition you have the "HF Level" control on the F-1X which will allow you to trim or boost the High Pass output level.

Your 4 ohm cabinet may be louder than the 8 ohm but you can use the above mentioned controls to balance things the way you want.  The F-1X will not care about the different speaker loads as it is only talking to the amp's inputs.

Plug it all in, turn it on, and see what you've got.  I predict you're gonna like it!

Jimmy J

[JimmyJ]

PS:

The power amp should be the LAST thing in the chain that you turn on after everything is plugged in, including the bass or guitar, and the F-1X is powered up.

Then the power amp should be the FIRST thing in the chain you turn off, before you change any patch cables, unplug the bass or guitar, or shut off the F-1X. 

Jimmy J

[lembic76450]

This brings back some memories. I used a BGW-500 with an F-2B back in the day.  It has a nice sound, just make sure you follow
Jimmy's advice for turning on and shutting off.  The wrong order can create a very loud pop that can really stress your speakers.
We used BGW amps in our PA for years and I used them in a club install that ran for a number of years and never had a failure.
You may want, as normal maintenance, to open it up and blow out the dust with canned air every 6 months to a year. They can get
quite funky inside. Also, I found that the modules inside needed to be re-seated now and then,  they can get loose from hauling
your rack around.  I may have an old manual around if you need it, let me know.
Good luck with the rig.

[StephenR]

I used BGW power amps for about 32 years. I had a 750 and a 250, both sounded great and were rock solid, never had a problem running each side into a cabinet with different a speaker load. You should be quite happy with your rig! The advice about what order to turn everything on and off is well worth heeding.

[bigredbass]

Yes, be careful with your gains.  K-series JBL's were the thing in their day, but are not meant to take lots of power relative to today's offerings.

[Mostlow]

Great. Thanks for the input, folks.

I'm well aware of the power limitations on the JBL's. I initially had a 900w per channel QSC PLX 1804, but was strongly advised against using it. I also recently snagged an early 70s Sunn Concert Slave, which will go well with the F-1X (Similar to Entwistle's rig in '76) once I clean the pots on it. I also have a SWR Interstellar Overdrive pre, so I should be able to do some interesting mixing & matching.