I find it elevating and exhilarating to discover that we live in a universe which permits the evolution of molecular machines as intricate and subtle as we. - Carl Sagan Rock 'n' Roll... It's got nothing to do with journalists, and it hasn't really even got anything to do with musicians, either. - Pete Townsend
Bench tone stack? - not sure what that means.... it's a Baxandall type with dual inductor driven midranges - same as on my other preamp. It really works well for me, and seems to for others as well.
Bench tone stack? - not sure what that means.... it's a Baxandall type with dual inductor driven midranges - same as on my other preamp. It really works well for me, and seems to for others as well.
Bench is Steve Bench. He designed a 3-band eq that uses inductors. Pretty simple in design but seems like it would perform well...if you can get the right size inductors.
Bench is Steve Bench. He designed a 3-band eq that uses inductors. Pretty simple in design but seems like it would perform well...if you can get the right size inductors.
Foz has been testing the prototype. Wanted to share some of his insights for folks not on the GB forum - he rocks a Sadowsky 5 string through a FF 151566!
A couple of his posts from this past week:
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Much tamer than I thought it'd be - has a real nice tube edge when cranked [see pic and sound sample] but stays clear and airy not at all like guitard toob/gain distortion - this is a bass pre and you can tell you designed to be one from the ground up.
5 stars - I'm already in love - can't wait to hear it with drums and congas and my 66.
sound clip is a custom Sadowsky 5 with EMG's and Circle K strings into the JGR_6SL7 into a Yammy board into BFM omni tops with GB headcase mic'd with an EV RE20
I'm done... this thing is the cat's pajamas - its the preamp I've been looking for.
Tons of gain - ample output to drive anything including the 1.4v sensitivity 20 k-ohm impedance input of a Crown iTech. The DI set to pre-EQ works just as you'd expect / set to post-EQ does a great job of moving your tone to the PA.
The basic tonal profile is FFFFAAAAAAAAATTTT. I had no desire to honk on the bass EQ knob - at noon there is plenty going on down there and the 40 Hz boost only shelf EQ on my bass never got more than cracked open for a couple of tunes that call for big bottom. Most of the night I was flat on the EQ save a touch of boost on the hi-mid [was getting to the grind - maybe a bit too much - but what the hell eh?] and a roll off down to 10:30-ish on the highs [new strings = a bit bright - this will probably go back closer to flat as they wear in].
EQ is very useful and obviously done for and by a bass player - exceeds the utility of your average bass amp or even your average channel strip. It aint an Avalon 737 [a $2k EQ with a free compressor] but for a bass player its actually more useful because the treble knob seems to shelf at a more rational frequency for bass than anything I have ever used before [4k?] and the hi-mid seems perfect for dialing sizzle/grind into the tone [1.5k?].
What frequencies do the EQ's work at?
At modest gain its is clean and fat - reminiscent of early the Ampeg - capable of bell like piano tones with superlative note articulation with no shimmer or bloom. At above noon on the input gain it does just that shimmer and bloom with a refined grind - but never loses articulation. I don't use distortion - I don't like it - until now.
Bench is Steve Bench. He designed a 3-band eq that uses inductors. Pretty simple in design but seems like it would perform well...if you can get the right size inductors.
It performs very well
@jgr, sorry assumed you'd used it since i saw a post of yours on another forum asking about it!
Winding up my beta test on this unit and the bottom line is I like it... a lot... so, I ordered one. The units is not cheap [nothing with equal quality jacks, pots, transformers, et cetera could be], but in my honest opinion if the face plate had a famous name on it the price would be double what JGR is doing and it wouldn't be hand crafted point-to-point construction. I will miss the prototype when I ship it out later this week and eagerly await my production unit.
Its default voice is a warm tube tone without any haywire instability or tendency to choke on strong notes. It is capable of a very polite clean voicing or when the input gain is driven yields an extraordinarily articulate take on vintage bloom and chime.
The EQ is bass player friendly and idiot proof. The DI is at a perfect output for both boards I tried it on [A Mackie VLZ3 and a Yamaha MG24] = set the channel gain at unity and you get 0 dB peaks when you solo the meter and gives a very close mimic of my fEARful rig through the PA. The balanced main out works just as expected - I have no trouble driving a 1.4v sensitivity power amp and the unbalanced main out worked fine driving the loop return on the Mesa 400+ [nice combo BTW = super tooby if a bit low powered at only 275 watts].
The unit is very, very quiet - amazingly so for a tube pre - and there is no LF woof wobbling foolishness [even with all HPF'ing turned off].
The only thing I can come up with to pick at is that it will not do a 100% transparent pass through [like a ultra-polite channel strip]. The unit does has inherent tube character and while it can be dialed down to subtle, its always there. You might say that aint a bug, its a feature, and if you did, I would agree - but it is a limitation / something the unit won't do.
he's probably talking about this: http://music-electronics-forum.com/t2029/
from five years ago..... no wonder you don't remember asking. you were asking about preamp inductor mids, and that was the answer someone gave.
I just googled it up.
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24 ov 25. We are Mothman.
Last edited by eyeballkid : 12-12-2012 at 09:33 PM.
Blast from the past! It's kind of cool to have Internet artifacts - how time flies! I started toying with the idea of doing a bass preamp around 2006 and IIRC had a preliminary design and parts by 2007. Everything got shelved when we relocated cross country in 2007, started new jobs, marriage, etc. I picked it up again in the fall of 2010 as a much needed diversion from home improvement and the thread for the first pre got started around then. The latest design evolved from the original this summer which then served as the foundation for the latest 6SL7 build.
That's a great forum with a lot of really sharp cats, and a great resource if folks are serious about DIY. As Eyeballkid mentioned, that info wasn't really what I was looking for at the time, and wasn't the approach I used when I finally picked it back up. Cool stuff though.
he's probably talking about this: http://music-electronics-forum.com/t2029/
from five years ago..... no wonder you don't remember asking. you were asking about preamp inductor mids, and that was the answer someone gave.
I just googled it up.
Haha wow, maybe i should've checked the date on the thread! Guess someone could accuse me of being a necromancer now haha.
In addition to tweaking circuitry, I like to look for new methods of improving mechanical construction, and spend a lot of time cruising the McMaster Carr website. I found some spiffy wire clamps that can be mechanically fastened to the chassis which I'll show when I get to it. Other improvement is a new method for mounting the Jensen DI transformer - they come with an L-bracket, but I'm going to a clamp mount that should be more bomb-proof. The Jensen is held nice and tight with a couple of compressed layers of gasket tape in between the tranny and clamp, and the clamp hardware has been replaced with a SS screw and nylock nut.
If you look at the hardware to the right of the transformer, the PEC pots come with the tiny lockwasher on the left which I replace with a larger SS one seen in the middle, and add a SS washer on the right to go between the nut and faceplate. The mini switches come with a kind of ugly washer seen on the bottom left - it's OK for the rear panel, but I want the front to be clean - couldn't find any washers in the right size, so I ended up with some kind of "bearing shim" which translates to a really, really expensive washer for this application, but it looks really nice.
I also try to add lock washers to other stuff like the lamp and fuse holder even though they don't come with it.
Good call. I used a similar method to mount the transformer in my last DIY direct box. Jensen also offers an optional threaded stud mount on some of their can transformers that I prefer to the old L-bracket format. Not sure if it's available for the DI ones yet. Moot if you're not using the L-bracket, I guess...
I've got a Cinemag DI transformer to mount up, same deal as Jensen, tapped for 4-40 screws but they don't supply the L bracket. Rolling up a clamp like yours looks so much more elegant, plus that makes for one less round of "ship in a bottle" tricks for me.
