Questions for Brian Brown - Part 4

strangedesign · April 16, 2008, 11:03:44 PM

I have emailed some new questions and hopefully we will have some answeres shortly. Stay tuned!

1. What brand of tubes is Trey running in the Deluxe Reverb, specifically v1-v6
Trey tubes/ 12ax7, 12at7, 12at7, 12ax7, 12at7, (2) RCA (1940's) 6v6gt, GZ34

2. What kind of Leslie did Trey used to play? The one that sat on top of his rack for a few years. Why did he switch to the 122?
Goff custom leslie top (unpowered)/ he switched because it didn't sound as cool as a Leslie 122

3. Why did Trey switch from the Groove Tube D-75 to the Deluxe Reverbs?
too loud for phish songs

4. "I would like to know the specifics of the vibrato circuit conversion -- that is, what he calls the "mid boost" in Trey's DR? I'm thinking it's something a little more involved than merely changing the value of the mid resistor in the tone stack from 6.8 to 10, or even installing a 25k pot. I thnk it might be an *actual* mid boost (cf. "BASS and TREBLE CUT (MID BOOST)" http://www.harpamps.com/micKcircuits/Tone-Circuits.html)."
we removed vibrato circuit and researched and developed midrange boost with Trey involved (I don't remember frequency)

Poster · April 18, 2008, 10:57:51 AM

where is part 3? lol whups, you should ask him what type of power strips trey uses with his conditioner? or does it even plug into the conditioner? now ive pretty much got the same rig most of noise is the result of power issues. cactus pointed out some time ago that iso power supplies are uber expensive, if trey doesnt have something similar, how is it so quite? Even with a true bypass looper covering all the noisy digital pedals, powering that much shit will cause some hum. I ask because some people have suggested he has regular batteries in his rig at different points. Also, I was wondering who built his old 2 12 cabinets that he toured with up through 96? 97? and what kind of speakers were in there? What is that huge white rack that takes up like 4 rack spaces during that same window of touring circa 93-96? What kind of vocal mics does trey like to record with? What vocal mic has he been using most recently to gig with? And what kind of direct box does he use on the XLR line?

cactuskeeb · April 20, 2008, 01:58:44 AM

I've seen the power strips trey plugs his wah+ts9 and whammy into and they're nothing special -- straight from the local hardware store variety. It sounds like you're having pretty serious issues with your noise floor level. I plug my rack equipment into a furman power conditioner, and everything else goes into a APC power strip -- absolutely everything sources the same wall outlet, ultimately. At any rate, here's got to be another reason for your noise. If I were you, I would check *everything* -- I mean cables and all. I would inspect the ground solder connections inside your guitar and even A/B all your pedals one by one and in small combos. I have next to no noise at all, and it doesn't get any louder as I turn up the volume, but most of that is due to good cable selection, as well as knowing the pedals I get have the best capacitors and resistors, and circuit designs, on the market (this isn't 100% true, but I try). Also, I would swap out your tubes, especially the first preamp stage, until you get a lower noise floor -- this is *crucial," as it's usually where the big problems occur, at least in my experience. If you want to get into the finer details, check *all* solder joints (I mean, every pedal, cable, and especially inside your amp chassis), and look up the cap an resistor values for your pedals and then replace key areas in the circuit board with quieter components. Trey doesn't use batteries; anyone who does *not* look for a power adapter for everyting is being stupid, wasting money on over-priced 9 volt batteries.

Paul built Trey's old 2x12 cabs back in '87. They're loaded with EV (Electro Voice) speakers. The white thing in the rack...the CAE SE+ preamp, perhaps?

strangedesign · April 24, 2008, 03:02:55 PM

answers are in!

scroll to the top...

cactuskeeb · April 24, 2008, 10:17:18 PM

Hey Strange, is there any way to get Brian to be a little more specific about his answer to question #4? Perhaps he could provide some insight into the research materials that were consulted during the conversion process, and at least tell us whether the circuit incorporated active elements or was one-hundred percent passive design? Thanks. -ck

Happyorange27 · February 24, 2011, 10:35:00 AM

Gents, I've been studying the tone stack circuits lately. I bet cactus can help me out too. Anyway I'm trying to see what will give me a superior mid hump. According to the tone calculator which I posted a link to here http://strangedesign.org/forums/index.php?topic=709.msg1883#msg1883 you will find that the Fender circuit has limitations. I like what is posted above ^ where the link talks about the Baxandall tone stack circuits. Google it if you want. It has so much more possibilities for a huge mid hump but also a super mid scoop. Your drawback is there are more components and it would take some work to install. Any thoughts on this?

FYI if you are using the calculator, use the James tab for Baxandall.

Happyorange27 · February 24, 2011, 12:59:34 PM

To navigate to parts 1-4:
Part 1 http://strangedesign.org/forums/index.php?topic=712.msg1886#msg1886
Part 2 http://strangedesign.org/forums/index.php?topic=711.0
Part 3 http://strangedesign.org/forums/index.php?topic=553.0
Part 4 http://strangedesign.org/forums/index.php?topic=709.0

cactuskeeb · February 24, 2011, 07:55:40 PM

Quote from: Happyorange27 on February 24, 2011, 10:35:00 AM
Gents, I've been studying the tone stack circuits lately. I bet cactus can help me out too. Anyway I'm trying to see what will give me a superior mid hump. According to the tone calculator which I posted a link to here http://strangedesign.org/forums/index.php?topic=709.msg1883#msg1883 you will find that the Fender circuit has limitations. I like what is posted above ^ where the link talks about the Baxandall tone stack circuits. Google it if you want. It has so much more possibilities for a huge mid hump but also a super mid scoop. Your drawback is there are more components and it would take some work to install. Any thoughts on this?

FYI if you are using the calculator, use the James tab for Baxandall.

That last question is a quote from me. I asked the question (and provided a link to the discussion of the Baxandall tone stack). The answer Brian provided led me to researching the possibilities inherent in removing the vibrato circuit and replacing it with something else. I never found a mid-boost replacement, per se, but I did eventually go with Gerald Weber's "Converting Your Normal Channel to British" idea, which uses the vibrato tube to add an extra gain stage to the normal channel, and involves adding about five or six components to the board (the empty space left over from removing all the vibrato components) and involves rewiring. In doing this, I definitely added a boost to the midrange (Weber describes it as a British-y [i.e., Marshall-eque] "bark"). But replacing the 6.8K resistor with a 25K pot on both channels--something Trey has as well, although his pots could be 10K--is the simplest way to boost the midrange because adding the pot gives you an actual mid-range control.

EDIT: I guess my response would only help you if you were using a vintage Fender. But most amps have very similar tone stacks and doing things like changing the bass and mid caps (usually .1 and .047) to .022 would give a more mid-rangy tone...kind of like the difference between a blackface and a tweed fender (or marshall). I did that to my normal channel as well. Additionally, I lowered the value of the slope resistor (normally 100K) to 56K, because this also imparts a more mid-rangy tone.

Happyorange27 · March 07, 2011, 11:50:45 AM

Cactus, you are so the man, I knew you would come through for me on this. The only difference between the Fender and Marshall circuit (other than the stock component values) is routing of the mid cap to the mid pot (wiper versus end lead). Fortunately on the Blues Jr. it's a simple adding of a jumper wire to go between the two types of stacks. I'm going to experiment with some of the values you suggested. You are an asset this site.

Currently I have the amp in "Fender" mode but I'm considering going back to "Marshall" mode so I can get more of a mid hump. Again the tone calculator is where I'm getting all my planning.

cactuskeeb · March 16, 2011, 02:08:34 PM

Quote from: Happyorange27 on March 07, 2011, 11:50:45 AM
Cactus, you are so the man, I knew you would come through for me on this. The only difference between the Fender and Marshall circuit (other than the stock component values) is routing of the mid cap to the mid pot (wiper versus end lead). Fortunately on the Blues Jr. it's a simple adding of a jumper wire to go between the two types of stacks. I'm going to experiment with some of the values you suggested. You are an asset this site.

Currently I have the amp in "Fender" mode but I'm considering going back to "Marshall" mode so I can get more of a mid hump. Again the tone calculator is where I'm getting all my planning.

Be careful that you don't overheat the circuit board, especially those copper traces that mark the connection points. If they peal off, depending on where they are, you might need a whole new circuit board.

The good thing about the vintage amps, at least in this respect, is that you can heat and re-heat the shit out of practically everything in there and nothing bad will happen.

Happyorange27 · March 16, 2011, 02:32:57 PM

Thanks for the advice.

I think I've got the hand of soldering on pcb's. I've done a good amount of this work and not really any problems. I try to keep a hot tip and get on it fast and get off fast. Keeps the heat localizes.