Pickup load impedance (Z) and thoughts on Tom Brumley's tone

Brad Sarno · From: St. Louis, MO USA

I recall years ago when I got a vintage, gear-driven ZB volume pedal that came from Brumley's ZB company. Then I recall years ago at Scotty's convention talking to Noel Anstead the maker of Brumley's Anapeg pedal steel and a LDR (light dependent resistor or "optical") volume pedal I believe Tom was using at the time too.

What's interesting to me is that the ZB pedal I got had a 100k pot in it, not the normal 500k. And Noel's optical pedal was also at about 100k Ohms of resistance. We know how variable-impedance (vari-Z) affects the treble peak of a pickup, often in the 2-4kHz range. 500k is the standard we all know and expect, that treble quality at 500k is the "normal".

But it seems Brumley may have spent quite a span of time working with a load of 100k, a MUCH darker, mellower tone, and then that was addressed at the amp to find the right tone. Peavey understood this impedance loading factor very well, and when they designed the Nashville 400 with the input patch where they wanted us to plug the guitar straight in, and THEN do a send/return to our volume pedal, they decided 220k Ohms was the right tone for a pickup, darker than a pot pedal.

So, for those out there with variable impedance controls (FreeLoader, Black Box, Revelation, etc.) maybe play around with a darker tone up front with the Vari-Z control and then compensate at the amp to bring back some treble. It won't be the same sound, it's different, smoother, just an interesting experiment. I'd love to hear what people find.

On a FreeLoader, about 4.5 on the dial gives you 100k Ohms of loading. About 6.5 on the dial gives you the Peavey 220k Ohms, that tends to be my normal go-to setting. And about 7.5 on the dial gives you 500k, the standard pot pedal value we're most used to.

Brad

Lee Baucum · From: McAllen, Texas (Extreme South) The Final Frontier

Hmm. Food for thought.

I'll try it this evening.

Thanks for all you do, Brad!
_________________
Lee, from South Texas - Down On The Rio Grande

There are only two options as I see it.
Either I'm right, or there is a sinister conspiracy to conceal the fact that I'm right.

Williams Keyless S-10, BMI S-10, Evans FET-500LV, Fender Steel King, 2 Roland Cube 80XL's,
Sarno FreeLoader, Goodrich Passive Volume Pedals, Vintage ACE Pack-A-Seat

George Macdonald · From: Vancouver Island BC Canada

Brad, I always use my Black Box here at home, but I took my Freeloader out of my seat and saw that it was set on 4.5 from the last time I played out. [recording for you tube service from our Church]. That was through a Fender Tonemaster Twin with an Omni pedal

Dennis Detweiler · From: Solon, Iowa, US

I haven't had the Freeloader very long. I gravitated to the 7.5 setting soon after I got it. I'll experiment with your suggestions. My amp lately has been the Quilter 201 and using a Boss 59 Bassman pedal for a preamp. I'm getting a good tube amp replication with this setup. Brumley liked the 59 Bassman and I was told that he played through two of them. Interesting experiment.
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1976 Birdseye U-12 MSA with Telonics 427 pickup, 1975 Birdseye U-12 MSA with Telonics X-12 pickup, Boss 59 Fender pedal for preamp, NDR-5 Atlantic Delay & Reverb, two Quilter 201 amps, 2- 12" Eminence EPS-12C speakers, ShoBud Pedal, 1949 Epiphone D-8. Revelation preamp into a Crown XLS 1002 power amp.

Georg Sørtun · From: Mandal, Agder, Norway

The old "rule of thumb" was to set input impedance (load) at, or higher than, 10 times the outpot impedance of source (PU) for optimal result. For most single coil PSG PU's that would be around 100Kohm, or higher, and for most humbuckers it would be aroind 180Kohm, or higher.

Modifying a PU's sound by varying the load, is quicker, and often produce better results, than buying and testing lots of different PUs for testing in ones more or less "fixed" sound-chains. As shorting passive PUs does not cause permanent problems, any value/type of linear, or non-linear, load can be tested to see if one likes the resulting sound.

I used to perform such testing by "clamping" a 1Mohm pot across the 1Mohm input of an input stage, resulting in 500Kohm as highest (lightest) resistive load and below 1Kohm (shorting) as lowest. Most PUs actually sound fine, warm and pretty linear (to me) into a 1Mohm load – no particular frequency ranges get excited over the others, so these days I use such a 1Mohm buffer, and roll back slightly on the highs in the active stages to suit my taste.

Glenn Demichele · From: (20mi N of) Chicago Illinois, USA

I was curious too, and did freq sweeps on my Franklin pickup loaded with a resistor driving a cable when excited by a magnetic loop driven by a signal generator. A 220k load R gave me the flattest (â€œButterworthâ€) response. A higher R gave me more high end, but with peaking (underdamped) because of the pickupâ€™s L and cable C. Lower R resulted in a less drastic (overdamped) response that started at a lower freq.
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Franklin D10 8&5, Excel D10 8&5, homemade buffer/overdrive, Moyo pedal, GT-001 effects, 2x BAM200 for stereo. 2x GW8003 8" driver in homemade closed-box. Also NV400 etc. etc...

Dustin Rhodes · From: Owasso OK

Would it be accurate to say that he spent a long time playing into JBL loaded fenders with much more high frequencies than most current steel speakers?

Donny Hinson · From: Glen Burnie, Md. U.S.A.

Single coil low-res pickups (in the 8-14K range) tolerate lower loads far better than than higher-wound single coil pickups or humbuckers. Winking

Lee Baucum · From: McAllen, Texas (Extreme South) The Final Frontier

This is good reading for the FreeLoader/Black Box users on the Forum.

It gives a description of what is happening at different settings, giving a good starting point to use before adjusting the amp's tone controls.

~Lee

Bud Angelotti · From: Larryville, NJ, USA

Donny Hinson · From: Glen Burnie, Md. U.S.A.

Jake DeJongh · From: Idaho, USA

My Freeloader is the ultimate tone shape tool - it is crucial to me now. I have a steeltronics Z-10 (ZB Style) pickup in my show pro and I play through either a headstrong lil king s or a milkman pedal steel mini. My Freeloader allows me to achieve diverse tones, which I find so useful for padding, soloing or just trying to emulate classic players tone, it can be warm butter or bright twang. I wish any of my guitars had such a sensitive tone control that reacted as intimately with the pickup as my freeloader does. I'll often EQ the amp so it gives me more treble and bite and use the freeloader to roll off when needed. I'm usually between 5-8 on the dial. It is my favorite tool.

tom anderson · From: leawood, ks., usa

Many years ago I ordered an Anapeg from Noel Anstead after hearing the story of Al Perkins having found the guitar and maker on an Australian tour and his convincing Tom Brumley to get one. I had come across one of Noel’s earlier Anstead guitars while I was waiting for my Anapeg. One day I packed it up and drove down to Branson to visit with Tom and look at his Anapeg. He had me set up my Anstead next to his Anapeg and I plugged into his Bassman. As I started to play I thought to myself OMG the tone on my guitar sounds just like Tom Brumley! It may have been Noels pickup but I think Tom’s tone had a lot to do with that amp. Now I also have Noels volume pedal and I’m not sure if I had it at that time.
On another note, a friend of mine in KC bought Tom’s second Anapeg from Rolene. I went by the day he got it and it hadn’t been played since Tom died. When he plugged it in and started playing the tone and the melding of notes in chords and intervals sounded like Tom. I told him to write down all those values from his strobe tuner so he couldmaintain that tuning.

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