Modding Behringer T-1951 EQ Ultra-Q

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Maliq

Well-known member
Joined
Apr 23, 2012
Messages
65
Hey Folks, yes, I'm still using this Box and somehow I can't get rid of it.. I don't know what it is but sometimes I like to boost the low frequency band a lil bit (1-2dB) and cut 1-2dB around 10-12 khz on a mix, or when tracking with a Mic that might sound a lil Harsh on some Artists. So i don't do any dramatical, using the Tube Warmth (around 30% - which sound more like an exiter) to add some presence to some signals.

What i don't like is that I hear a lil humming noise around 113hz I think (I need to check it again on the Waves Analyzer), and also, its not the quietest box, compared to my SPL Tube amp or FMR RNLA.. swaping out tubes was the first think i did.. i know don't make that much sense.

I though about the idea that i could try to mod it, i know how to read cap values a lil bit and know how to solder..building a DIY EQ myself is way to much for me right now so i thought about the idea to mod this Box.

So first I found the Schematics of this unit here: http://elektrotanya.com/behringer_t1951.pdf/download.html

1: Somebody on gearslutz modded this Box with Ouptur trannys, scroll down for some pics: http://www.gearslutz.com/board/low-end-theory/656014-behringer-t1952-tube-composer-mod-modification-t1851-t1954-t1950.html

2: The Output Trannys can be found inside the Behringer (4 OT's) Di4000 and i guess 1 OT inside a Di100, i heard some jumper need to be cutted but i don't know which one?? I'm about to buy 2 Behringer Di100 to get those OT's..(if this make sense).

3: I heard some people replace the JRC4580's with AD8599 or LM4562 (I don't know nuthing about it just read it somewhere) some other say "Replace IC 4580 with TI # OPA2134 or TI # NE5532"

Last but not least:
4: Would it make sense to replace the power suply with a Carnhill power suply?? I'm even not sure if this is possible at all ??: http://www.audiomaintenance.com/acatalog/Power_Transformers_and_Chokes.html

5: Is it possible to use Jensen/Lundahl or Carnhill Output trannys instead of the Behringer OT's ?? might need schematics about the Output tranny to answer this right??

Hope some of you can help me to answer those Questions.. I don't want to throw this Box out the Window right now, sure i could get around 100$ for it, but I need an Analog EQ..and also i still like the kinda "Exiter" sounding function, i don't think i can get those many features that Cheap..  :-\

 
Ok, seems like the Schematics are not enough, so i try to take some high quality pictures from the behringer so maybe that makes it a little bit easier.  :p
 
I put high voltage on the tubes. I thought I documented that mod and posted it here somewhere, a search should find it. I noticed the "warmth" has increased effect.
 
Thanks Walter, yes i saw it, my major problem, i would need a step by step how to do it..i'm a noooob haha. Serious, i know how to read values, and how to desolder and solder new caps, but building something new, not gone work without a step by step. And I'm happy with the UAD plugins to make Sounds warmer.

My Major problem or the things are try to change in the Behringer T-1951 is:

1: Its a lil bit noisy, i guess the Opamps or IC (might be the same) in the Center of the Unit is causing this noise (New Opamps)
2: The Behringer is causing a huming electrical sound around 100hz (Waves Analyzer), might be to close to my screens or speakers..don't know yet need to figure it out,  maybe i need a better shielding inside the Behringer
3: I want to install the Output Trannys on the Output pcb, I know that you can find them inside a Di4000 or maybe di100 (will call Behringer to Figure it out).

I will upload some high quality pics later ok.. Thank you so far 8)
 
Here are some pictures.

Here is the Output Section with the missing Output Trannys (OT-1) and (OT-2)
fvln36.jpg



the backside of the Output PCB..as far as i understand, W1,2,3 and 4 (highlighted in Green) are bypassing the Transformers right?? so i guess i need to remove them to make the transformers work right??
1hwoll.jpg


Here is the Output tranny inside a Di4000 (took this pic from the original Gearslut thread)
y1pjt.jpg

 
Here are the last Pictures, so if someone got some ideas for a better shielding, or what i could do to reduce the noise, let me know.

Top Full
i2oj9d.jpg


Power Suply stage
px8xs.jpg

30j5jdt.jpg


Tube Stage
34zx9px.jpg

 
Some of the DI boxes had line transformers earlier, then behr used resistors. I dislike the way that device has the front circuit board mounted between the front panel and a chassis panel, difficult to get in, difficult to check during operation with it dismantled. You may want to consider how you are using this in your signal chain in order to address the noise issue. I recently had a problem with the noise floor on a field recording of a band under a freeway. The solution was to turn the volume up all the way and run that signal into my DAW. That effectively lowered the noise floor. My other option was to modify the Playskool cassette recorder to reduce hum from the motor. Consider the quality of the equipment, the quality of the source material, and the quality of the engineering for the desired end product. I was complimented on the live CD btw.
 
I would replace the lamps behind the tubes with some ulta low noise NOS diodes.


Seriously though, I would probably replace opamps with better ones, for less "hiss" and look at the power supply if your getting hum.

I would recap the whole thing too, with better caps, I had a beringer ultra fex that wasn't usable before, but replaced chips and caps and now its transparent and great...
 
Not sure about this unit, but Uli tends to save money on opamp decoupling and power bypass caps. You might want to check on this and add them if missing.
 
Thanks so far, yes replacing the lamps is something I would change but later, about the Noise, I guess the opamps on the Outboard PCB are causing it.. some people suggest that it make sense to replace the opamps with AD8599 and LM4562 in place of the JRC4580's. I hope that i can get them but I should wait what you say.

And yes Walter, the Front PCB is burried so deep inside the case, I'll not try to get it out I'm sure that i'll brake it

Bypassing is out of my knowledge, i would need a step by step (with pictures) to do this. So if i keep this Box I thought about to
1: Replace the Opamps on the Output PCB with better ones
2: Replace the Lamps
3: Try to get the OT-1 Transformers and Install them
4: Recapping as far as possible

Behringers webpage is confirming my guess that the DI4000 got OT'1 trannys inside
http://www.behringer.com/DE/Products/DI4000.aspx

Replacing with jensen or lundahl is impossible right?
http://www.jensen-transformers.com/datashts/123dbx.pdf
 
Sorry, I was kidding about the lamps ;D Always gets me how they add lamps to the tubes. List looks good though!

Also i would definitely recommend getting a hot air rework station if you don't already have one for this project, it will make things much easier as the pcbs are rather delicate if i remember correctly.
 
hahaha got you ;D ;D, but serious there was a guy who really replaced the lamps.. I thought about to put them out completely if thats possible cause they're producing some unwanted heat, or at least i put one out..

yap i might need a hot air rework station cause i allready heard and also see that Behringer is glueing a lot of there parts  :mad: :mad:.. I'll start as soon as i got the Output trannys

 
I bet with the extra current they had reserved for the lamps you might actually get the heaters glowing enough to be visible, might make for a better "tubey" sound.
 
will try and see what happen without the lamps.

So, as far as i can say, it will not be easy to replace the opamps..these parts are damn small and i need to make 8 good joints to solder them..thats difficult..also its not easy to get the AD8599 here in europe.. at least i found none. The only opamps i found are OPA 2134 PA , some replace the 4580 with it.

http://www.ebay.de/itm/Dual-FET-Input-OPA2134-UA-High-Performance-Burr-Brown-TI-Audio-OpAmp-SO-8-851533-/310563559524?pt=Bauteile&hash=item484f07d864

before i go into this opamp replacing (never did it before) Can somebody here confirm my presumption that the 4580 are causing the noise?? and does it make any sense to replace them with the opa 2134 (or any others you recommend)? Do i need to make any other changes to make them work correctly, (higher value caps etc).

Sorry I'm still a noob..
 
Maliq said:
will try and see what happen without the lamps.
Well, the unit will no longer shine like a Christmas tree  -- that's all that'll happen :)
And less heat inside.

Maliq said:
So, as far as i can say, it will not be easy to replace the opamps..these parts are damn small and i need to make 8 good joints to solder them..
Just hold the new IC down in place by applying pressure on the top and apply a blob of solder on all four pins at the same time. Do the same on the other side. Then heat up again and use a suction pump to remove excessive solder. Usually works like a charm. Soldering SMD ICs is quite easy, actually.

Maliq said:
and does it make any sense to replace them with the opa 2134 (or any others you recommend)? Do i need to make any other changes to make them work correctly, (higher value caps etc).
You might want to read this thread:
http://www.groupdiy.com/drawing-board/opamps-and-local-decoupling-of-rails-some-questions/

Maliq said:
Sorry I'm still a noob..
So am I :)
 
Thanks so far Script,
I've read half of the stuff and now my Head is full with Decoupling and bypassing ..also read so much on the net about it that the Headache is here again, seems like if i do it wrong i blow up the whole box :-\..damn, if I just had the Time things would be much easier..or the money to buy a decent Tube EQ...but not gone work yet.. ok back to it.. let me post this picture of the Circuit, there're 3 4580 opamps on the In/Out section..what should i do step by step to replace them with (whatever better opamps) to get rid of that noise. I guess i learn more when somebody tell me exactly what to do so I can think about it and ask Questions later.

1f788x.jpg




 
I would not recommend this as a first time project. The SMD PCB is far to fragile and will probably lead to much frustration if you try to do anything worthwhile. That being said, if you get the proper tools...it isnt THAT hard, I'm sure you could do it with some practice, its just the gain/cost/time/performance ratio isn't that great.

This is comming from someone that replaced all the SMD opamps in a delta 1010 WITHOUT an air rework station, and it was a great learning experience, but it was a very tedious job. and cost more than I want to mention...


Also your 2132's will work just fine, they are very well behaved op amps.

Its not going to make this thing a "tube" eq though, no matter what you do its not going to be that, because deep down in its soul its a chip based tube EQ.

Seriously, spend 15$ on a set of gyrafs Pultec EQ, some edcor transformers, and slowly get the parts...you will be much happier in the end I would think, but then again you mention your in a part of the world were parts are hard to get, so I don't know.

Don't want to discourage you, there is a charm in taking something and making it better, seriously I would recap one channel and you might be impressed with the clarity you gain. Me personally I don't mind crappy opamp distortion as much as crappy electrolytic distortion.

SO, basically look for the electrolytic caps, and count how many of each kind taking note of the uF values and voltage. then buy some panasonic FM or FC series capacitors of the same values and replace them.
 
Hope it's positive headache :)

Well, maybe this is not a good frist-time project indeed. Be very very careful and gentle when removing those glued ICs, otherwise you might end up ruining pads and traces or frying the board and other components. Traces can be fixed (bridged) but it's tedious indeed. I also had an eye on this unit a couple of years ago, but decided to build a Sontec EQ and mod an old Behringer comp (all through-hole components) instead.

I guess you already found the T1953 overhaul thread? Pretty comprehensive:
http://www.groupdiy.com/the-lab/behringer-mods-upgrades-my-findings-%28t1953-centric%29/
I assume the T1951 is somewhat similar in design. I'd start there and look at and replace some caps -- they don't cost an arm and a leg, and definitely less than an air rework station plus Jensen and Lundahl transformers ;)

You said parts are difficult to source in your area in Europe. Where are you located? Your profile doesn't show.
 
Thanks so far, I should carefully try to remove the Output pcb, and then decide if i'll replace the Opamps or not
My major problem is time and money right now, got to finish a Album real quick and you might laugh but i can't do it without the Behringer EQ, I know that it will never be a tube EQ but like I sayed the Tube stage is working a lil bit like an Exiter and it gives me a sound that i can't get otherwise, no API, UAD or SSL plugins could give me that sound. And i'm not joking here i got a guy that is intrested in my sound and he is from the major label EMI (If I'm lucky i get a chance to mix some stuff for this label).  Many Band and Artists allready recorded in my Studio and the Behringer Low Band with a lil tube exiter :D is giving my Analog Stems some nice round punch and fullness. I also use the FMR RnLA and an SPL Tube preamp alot. Other then that its all UAD plug ins and a touch of Waves SSL.

I only got 5 month left to finish writing and recording this Album then I'll be on my way to L.A to record with some major Artists outhere.

Its easy to get caps and resistors over here, but some other components seems to be difficult, sure i would love to build an Pultec EQ but honestyl, i would need a step by step with pictures to do this and since i dont know nothing bout how to meassure and all that, all those facts makes it very difficult for me to build a new piece.

I'm located in Germany..
 
Nothing to laugh about -- especially when budget is tight. And don't give up so easily ;)

2: Behringer OTs
If you already have them, why not.
Those two resistors look like zero ohm (please measure), if so, basically just a piece of wire. You'll have to remove them and the solder in the eigth holes to install the OTs.

3: OPA2134
Should work. However, looking at the schematic again, there are many 4580 ICs in the filtering sections too. Shouldn't those be swapped also? That's a lot of work (and money) for this unit. Here's how to remove the glued on SMD ICs:
http://www.groupdiy.com/the-lab/behringer-ada8000-modifications/msg478371/#msg478371
They sell similar knives at Conrad Elektronik.

4: Carnhill power suply
What do you mean? You want to swap the Behringer toroidal transformer for a Carnhill toroidal transformer? Doesn't make sense. You can get a much cheaper toroidal with Mouser, if you really need to. And rather than swapping the toroidal, better put money into a decent power supply board (that's the thing with the big caps in the middle of the unit -- advanced mod though).

5: Jensen/Lundahl or Carnhill Output trannys
Of course you can, but you've seen what they cost? And you'd have to pay shipping and import tax as well...  :-X

[quote author=Maliq]
I don't want to throw this Box out the Window right now, sure i could get around 100$ for it, but I need an Analog EQ..and also i still like the kinda "Exiter" sounding function, i don't think i can get those many features that Cheap..  :-\
[/quote]

Why would you throw it out? That label guy likes your sound, no? And maybe those 4580s (with their seemingly less than ideal implementation and their apparent slanting of the waveform to imitate "toobs") are an essential part of your particular sound ;)

Anyway, looking at what you asked in your first post, you seem prepared to throw some 150 EUR or more at the unit. Why not take those 150EUR, save up a bit more, and together with the 100$ you might get for selling the unit (some time in the future) you'd have the budget for a Pultec EQ. Five months gives you enough time to work on a new build from time to time and learn enough to be able to finish it. Or safe the above-mentioned 150EUR and go shopping in the States. ART gear is not too bad, especially when you're on a tight budget, and in the US those units sells for almost half the price, compared to Germany.

I don't have the T1951, but honestly I kind of doubt that the humming really comes from the ICs (please proof me wrong). If I were you I'd look into all caps, cabling and shielding first. If you can't fix it, you can always take a noise reduction plugin, take a "noise print" of the unit and filter that out of your tracks.

Anyway, if you really want to dive into modding gear, you need some free time, patience (Geduld) and a few "headache pills" and, very important, you will have to learn how to measure things (really not that difficult, just get a real cheapo multimeter for starters). And Germany is a great country for sourcing parts (Conrad, Reichelt, Musikding etc -- and then of course all online shops worldwide).

Viel Grlück mit dem Album  8)
 
Back
Top