Andy Peters
Well-known member
Kingston said:
Blech.
-a
How to Build the Bruce Swedien Bass Box with vintage UTC LS10x
- Thread starter Cocoman
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Blech.
-a
Winetree
Well-known member
there's one on e-bay, buy it now, for $400.00
Two non accepted offers.
Two non accepted offers.
it is not just a DI box, it is a bass boosting di box.
the jensen transformer will work if you want a generic git center pro co di,
i believe we are trying to build a di with a different sound, correct?
you should get what you are after with the LS-10, just hook it up the way the kind man has it on his pic with the red wires and stuff.
that big utc case probably has about 5 layers of steel inside it, 3 nested cans and maybe some copper in between, don't know for sure, never had the money to buy one for "experimentation"
if the large inductance of the utc ls-10 sec. does not do it, try the WE 111c,
people put there stuff thru that one for more bass, ask Soundguy, if he is still alive,
probably out rock climbing somewhere with NY Dave.
or not.
wonder what happened with the new UTC the guy ordered, Magnetica not using the same materials or winding technique?
or, maybe it is the 40 year break in period, i do not know.
if you inject a huge 60 hz signal into a new trans, a signal large enuff to saturate the core 5 times over, you will get more inductance with no break in period.
but this seems to work better on steel lams, not as great as effect as the alloy stuff.
the jensen transformer will work if you want a generic git center pro co di,
i believe we are trying to build a di with a different sound, correct?
you should get what you are after with the LS-10, just hook it up the way the kind man has it on his pic with the red wires and stuff.
that big utc case probably has about 5 layers of steel inside it, 3 nested cans and maybe some copper in between, don't know for sure, never had the money to buy one for "experimentation"
if the large inductance of the utc ls-10 sec. does not do it, try the WE 111c,
people put there stuff thru that one for more bass, ask Soundguy, if he is still alive,
probably out rock climbing somewhere with NY Dave.
or not.
wonder what happened with the new UTC the guy ordered, Magnetica not using the same materials or winding technique?
or, maybe it is the 40 year break in period, i do not know.
if you inject a huge 60 hz signal into a new trans, a signal large enuff to saturate the core 5 times over, you will get more inductance with no break in period.
but this seems to work better on steel lams, not as great as effect as the alloy stuff.
CJ said:it is not just a DI box, it is a bass boosting di box.
the jensen transformer will work if you want a generic git center pro co di,
i believe we are trying to build a di with a different sound, correct?
you should get what you are after with the LS-10, just hook it up the way the kind man has it on his pic with the red wires and stuff.
that big utc case probably has about 5 layers of steel inside it, 3 nested cans and maybe some copper in between, don't know for sure, never had the money to buy one for "experimentation"
if the large inductance of the utc ls-10 sec. does not do it, try the WE 111c,
people put there stuff thru that one for more bass, ask Soundguy, if he is still alive,
probably out rock climbing somewhere with NY Dave.
or not.
wonder what happened with the new UTC the guy ordered, Magnetica not using the same materials or winding technique?
or, maybe it is the 40 year break in period, i do not know.
if you inject a huge 60 hz signal into a new trans, a signal large enuff to saturate the core 5 times over, you will get more inductance with no break in period.
but this seems to work better on steel lams, not as great as effect as the alloy stuff.
I'm staying away from the theory here, like how could a well designed active transformerless DI box not have better extension on the bottom than any transformer could - even if it's just the last octave.
On matters of L and distortion/saturation effects, from what CJ has said, then you should add to the list: UTC A, HA, Triad's equivalents, Peerless eqv, and I don't see why Jensen would not be there. Cinemag CMMI-10 should be there too based on what's been stated re pri L. I'll measure the sec L when mine get here in the mail and confirm. Said another way, they should all be in the same ballpark on sec L. If level handling is critical to this claim, then why not use the iron with a smaller core and lower level handling capability for more saturation? Just posing some logical questions here.
WE111C L is way lower than sec L on any of the above. What is source L of typical bass guitar? Bass synth source L should be low though, but isn't mini moog funky enough on it's own?
At least make sure the mic pre you run into after you build this box has bandwidth wide enough not to spoil said effects . . .
For 350.00, I'd buy a Fender MusicMaster Bass. That's a bass sound you can bank on. 8)
what is the ratio on those jensen di box transformers?
put the musicman bass thru the bass booster, thats what we need,
now brother michael had brother johnson try 30 different basses befoe he found the mojo he was after, so even with the transformer, you still need that bass, the line is easy enuff to where you could fake a brothers johnson,
now the ls-10 is probably built on L lams,
the a-10 sec. has 400 henries per coil, so 1200 henries total depending on level and all that,
31 UI lam has 0.08 times turns squared times constant K,
Henries = 0.08N^2k
L lam will have maybe 0.12N^2k
so figure if the a-10 has 1200 H, multiply that by 12/8 = 1.5 * 1200 = 1800
so call it 2000 henries for the LS 10, that is getting up there,
now dcr will probably be less with the ls-10, because the same turns go on a bigger core, you can use bigger wire.
so you have more henries and less dcr than most 1:10 transformers, plus humbucking operation, probably why the audio geeks like em so much,
best way to find out is to give them a try,
we111c would be more for line level stuff, so i had the wrong application there,
now brother michael had brother johnson try 30 different basses befoe he found the mojo he was after, so even with the transformer, you still need that bass, the line is easy enuff to where you could fake a brothers johnson,
now the ls-10 is probably built on L lams,
the a-10 sec. has 400 henries per coil, so 1200 henries total depending on level and all that,
31 UI lam has 0.08 times turns squared times constant K,
Henries = 0.08N^2k
L lam will have maybe 0.12N^2k
so figure if the a-10 has 1200 H, multiply that by 12/8 = 1.5 * 1200 = 1800
so call it 2000 henries for the LS 10, that is getting up there,
now dcr will probably be less with the ls-10, because the same turns go on a bigger core, you can use bigger wire.
so you have more henries and less dcr than most 1:10 transformers, plus humbucking operation, probably why the audio geeks like em so much,
best way to find out is to give them a try,
we111c would be more for line level stuff, so i had the wrong application there,
Good breakdown on the UTC. Thanks.
Some other aspect having to do with "phantom harmonics" and elliptical response patterns that are way over my head. They do something there that's nice to have on some things but hard to describe exactly what it is. When there's an excess of bass going in it sometimes comes out like a small delay had been put on it.
Some other aspect having to do with "phantom harmonics" and elliptical response patterns that are way over my head. They do something there that's nice to have on some things but hard to describe exactly what it is. When there's an excess of bass going in it sometimes comes out like a small delay had been put on it.
ok i went back over some LS dissections and it is possible that the LS-10x is the same transformer that is inside the HA-100x, which is the same transformer as the A-10 only with a few more lams,
the LS-68 splitter transformer has the 31 UI just like the A-10 and 100-X,
but i believe the LS-140 had the L lams,
the LS-10X has four mu cans inside plus the case, plus you can buy another mu shield to slip over it, just like on the fairchild, only bigger.
some times the extra shielding can chew up a few lines of flux, so they might jack up the input level for the same transformer as some of the level will go into the 4 cans,
so you could use the HA-100x inplace of the LS 10x and save some money,
or even the a-10 and save more money ang get about the same sound.
the LS-68 splitter transformer has the 31 UI just like the A-10 and 100-X,
but i believe the LS-140 had the L lams,
the LS-10X has four mu cans inside plus the case, plus you can buy another mu shield to slip over it, just like on the fairchild, only bigger.
some times the extra shielding can chew up a few lines of flux, so they might jack up the input level for the same transformer as some of the level will go into the 4 cans,
so you could use the HA-100x inplace of the LS 10x and save some money,
or even the a-10 and save more money ang get about the same sound.
If I understand correctly this is a passive step down transformer box? The one picture looks like two connectors and a transformer, is there anything else besides the case?
How predictable is this circuit? Is this to add bass to a source like the output of an active gain stage or for a passive bass or is it for all of that? As note before in this thread the transformer will interact with the source(z and level) and loading
How predictable is this circuit? Is this to add bass to a source like the output of an active gain stage or for a passive bass or is it for all of that? As note before in this thread the transformer will interact with the source(z and level) and loading
Gus said:
I had also wondered if a strapping resistor was used on either side to set the impedances.
On theory question I had was: If no strapping resistor is used, and you have a bass or synth output connected to the Hi Z side (used as "pri" in this case), and the low Z side connected to what could be any number of secnarios at a mic pre input, how would it behave? It may be better to ask as an example:
Let's say the source is a synth with an output Z of ~ 100ohms, and the mic pre is a Mackie mixer with an input Z of ~5K.
So, you have output Z of 100r going into the transformer's "50K" side, and the 5K input of the mixer is being fed by the transformer's low Z side which for LS could be any one of 5 values, let's say it is strapped for the "125 ohm" ratio.
Would the transformer then behave as if it's 50K side was terminated by a 100r resistor and it's low Z side terminated by a 125r resistor? Would one dominate the other in terms of what impedances are reflected and how the transformers freq response is altered? Seems like it would be complex and it makes my head hurt thinking about it.
pucho812
Well-known member
From the photo of the inside no resistors can be seen
brute force will again work here,
assign an input voltage,
figure current
tranfer voltage and current to sec
look at load on sec
see how it affects voltage and current on sec
i can sell it out with numbers, but you try first
assign an input voltage,
figure current
tranfer voltage and current to sec
look at load on sec
see how it affects voltage and current on sec
i can sell it out with numbers, but you try first
bockaudio
Well-known member
I have no concern or interest in what Mr. Swedien may or may not have done, ever. Comparing the J*nsen and any UTC DI will reveal the lack of bass in the former. I gain nothing from this, it just is what it is.pucho812 said:bockaudio said:
Well sir I cannot comment on using that particular transformer as a D.I. or anything else as I never used them. More over I have never used any utc as a d.i. so I can only comment on one of my experiences which happen to be using the Jensen D.I. transformer and building the design off the data sheet. I have used utc in other applications and to be honest it did sound pleasing to my ear but then again that's all perspective, opinion and using the right tool(in this case a transformer) for the job. Reality is this thread started because someone wants to build a d.i. In fact, he/she wishes to build an exact copy of a d.i. Bruce Swedien has built and used. There are too much variables in the recorded sound to say this magic d.i. is responsible for every bass sound on thriller or any other album Mr. Swedien has done. More over we know from the data sheets that the UTC in question may be better suited in other applications. There is a part of smoke and mirrors to the story in the fact that he built one and then couldn't build a second one because it never worked the same? Sounds a little like P.T. barnum combined with actual fact and sonics.
bernbrue said:Hi,
this thread is funny! If I only knew what Bruce had eaten when he was mixing "Thriller" I would eat the same meal everyday. Seems to make the mixes somehow better. I don´t know why, but it sounds more like .......... Chilly con Carne.
Take a Bo Hansen, G9 or REDD 47/Rude Tube with good iron as DI and then there is no need to eat Chilly con Carne everyday.
bon appetit
Bernd
Well Spoken. There are many passive and active d.i. designs out there, what works for Mr. Swedien may or may not work for cocoman.
Anybody have a Jensen JT-DB-E direct box transformer that they could measure the L on?
They quote it as less than 1db, 20Hz-20KHz , and as being designed for use with guitars (basses, High source impedance)
http://www.jensen-transformers.com/datashts/dbe.pdf
DCR looks closer to a "60-70K:600" vintage iron.
They quote it as less than 1db, 20Hz-20KHz , and as being designed for use with guitars (basses, High source impedance)
http://www.jensen-transformers.com/datashts/dbe.pdf
DCR looks closer to a "60-70K:600" vintage iron.
My jensen JT-DB-E Di traffo box primary measured 4.73K on dc resistance and 'OL' on the 20H inductance range.
So I guess it is > 20H by way of a cheap inductance meter.
It has been ball park accurate for inductance in past measurements.
The jensen di traffo in my experience is better than any other I've tried.
Except, as it seems, an LS10x
(but it sure doesn't boost nothin!)
So I guess it is > 20H by way of a cheap inductance meter.
It has been ball park accurate for inductance in past measurements.
The jensen di traffo in my experience is better than any other I've tried.
Except, as it seems, an LS10x
(but it sure doesn't boost nothin!)
not too many meters go past 20H.
you need the old gen rad bridge for that,
or you can create a resonant circuit by adding a cap in series, find the res freq, you know the value of the cap so you use math to find L.
how do you find the peak?
either add a series resistor to the cap and xfmr and look for the highest voltage across it as you sweep it with your signal generator,
or measure the ac voltages on the cap and inductor with a dual trace scope or a DMM, when the voltages are equal, you have the res freq.
you need the old gen rad bridge for that,
or you can create a resonant circuit by adding a cap in series, find the res freq, you know the value of the cap so you use math to find L.
how do you find the peak?
either add a series resistor to the cap and xfmr and look for the highest voltage across it as you sweep it with your signal generator,
or measure the ac voltages on the cap and inductor with a dual trace scope or a DMM, when the voltages are equal, you have the res freq.
I emailed Jensen for their L numbers on the DI and mic input. I haven't gotten a reply yet but I'll throw in my early guess based on standard calculations.
My guess for the DI is that the input side has L of around 175H or greater.
My guess for the DI is that the input side has L of around 175H or greater.
pucho812
Well-known member
one would think that would be in the transformer datasheet ???
They don't specify it directly. I hardly ever see manufacturers listing L figures, only indirectly as response for a given source impedance. Sometimes the measured L deviates from what the quoted response suggests for vintage units. Probably marketing related
http://www.jensen-transformers.com/datashts/dbe.pdf
It sounds like they are expecting about a 10-15K source impedance for typical use. What isn't clear to me is what source impedance was used to generate the low freq response chart. Maybe I'm missing it. I've gotten used to it being stated directly. When speaking with David Geren at Cinemag, he will state what source Z was used for the various sweeps he supplies for their iron.
http://www.jensen-transformers.com/datashts/dbe.pdf
It sounds like they are expecting about a 10-15K source impedance for typical use. What isn't clear to me is what source impedance was used to generate the low freq response chart. Maybe I'm missing it. I've gotten used to it being stated directly. When speaking with David Geren at Cinemag, he will state what source Z was used for the various sweeps he supplies for their iron.
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