Upgrading my SWR Baby Baby Blue II 110 Combo (long w/pics)

[MuthaFunk]

I've had my SWR Baby Blue combo since 2005. I've always found it to be a very versatile combo for practice, studio, and even some gigs. Over the years it's proven to be very well built but I remember it needed some minor modifications right from the day I bought it.



The first thing I had to do was pull the panel off of the back of the cab and silicone around both switches and seal the whole panel back to the cab with silicone. In addition to that I had to seal the speaker cable protruding from inside the cabinet to to the head to prevent a whistling when really pushing the 10" speaker.

I remember although the amp sounded great through other cabs I wasn't super happy about the tone of the combo. It did give a lot of value for the money and sounded good enough, so I kept it. It later proved to have an exceptional D.I. for recording and a wealth of other studio features I didn't know I'd be using down the road.

I found myself using it with a drummer on a regular basis and pushing it pretty hard. I wanted to run it at 2 ohms like the old Electric Blue heads could do. I thought I'd give it a try and install some fans to keep the amp cool.


Interior photo from TB member Duff2





This seemed to be the best location for the fans and two little ones spread out would serve the combo best as the vent on top was about the same width of the two fans. I was concerned about the fans inducing noise in the perfectly quiet studio quality pre-amp so wired them up to an independent supply out the back polarized to accept standard boss adapters.





They work exceptionally well. I tested them out with smoke to observe the air flow. They seem to draw air from the back venting on the amp and right out the top vents on the combo. I immediately noticed the amp running cooler with more headroom and 2 ohms hasn't been a problem. I think the old Electric Blue documentation states the amp to put out 220 W RMS at 2 ohms but I haven't confirmed that on mine. I can say the basic design and output transistors on the old ones vs the Fender ones were the same.

I happily used and abused this combo for years and then I came across this thread here on TB. I LOVE THIS SITE!

SWR Aural Enhancer Bypass

If you follow through the thread you'll find details and how I performed the AE bypass mod on this amp. This mod was an amazing transformation of this combo. It was a prolific change for me and rekindled my love for this combo. It had been previously displaced by a Mesa Walkabout Scout.

Because the Baby Blue head has push pull pots all over I used a on/off/on switch to perform the bypass mod. This gave the mod one more dimension as I now have 3 separate voicings to choose from. The standard AE, the flat setting, and something in-between both. I'm finding I prefer the in-between setting most but I still use all three depending on what sound or function I'm using the amp for. I'll often use it as a powered P.A. monitor and the flat setting is great for that.




Switch down is stock AE, middle position is the in-between, and up is the flat setting.

As I found myself enjoying the Baby Baby Blue II combo so much more after this mod I began to think about what else I could do to it to improve on. Like I sad before, I was never really happy with the sound of the combo but it worked well enough. I started to look into replacing the stock P.A.S. speaker with something that could handle more excursion and perhaps lighten things up. A quick thread here in the amps forum and the brilliant minds of Talkbass directed me to use Linear Teams program WinISD.

There was a little bit of a learning curve with that program but I had successfully used it when searching for new speakers for my Traynor YC-610. I tried modeling any speaker I could find until I found an appropriate curve given the combos dimensions and port size. The best curve by far was given by the Eminence Deltalite 2510. It showed a flat response down to about 80 Hz and 65 Hz at -3 dB. The software said the cab would be tuned to 60 Hz but the plot didn't really depict a bump at 60 Hz or anything. I'm a little lost when it came to deciphering the data from WinISD but it was clear that the Deltalite 2510 was the best 10" available for this box so I ordered one.

*edit- using a car audio port tuning program on-line showed the port in this box being tuned to 48.5 Hz.





Let me tell you. This thing sounds good! I was blown away. Not only is it lighter (slightly) it's much more powerful, deeper, and more articulate. Pretty much better in any way I can conceive of. The stock driver struggled with the anything on the low b string. Not anymore. I was hammering this speaker and it just pounded out the deep end. I couldn't believe that little box could produce lows like that without some kind of trickery like the passive woofer on my Scout cabs.

Just to make perfectly sure my ears didn't deceive me I put the stock PAS driver back in....



It was at this time I realized that Fenders marketing group must have been behind the creation of this combo and without anybody who cares about the reputation of SWR on the team, this combo was thrown together without any R&D. Although I think they were a little ahead of their time, I don't think they ever modeled this cab with the driver specs from PAS. If they did, they would have seen it's not properly matched at all. The PAS driver info from the Golliath III series is not available on line but I'd love to get my hands on it just to see what it would plot out to be.

In comparison, the PAS driver seemed like a mid driver with subtle low end. With the stock setting, SWR's AE circuit always in place, there was always a 250 Hz mid reduction. This just seemed to pit the amp against the combo and the resulting sound had some audible low end bass only because of the mid reduction. The AE bypass mod allowed the PAS drivers natural tones to come out which is why I may have liked the AE bypass mod so much. The Delta 2510 really brought this cab into the bass guitar world. It's no surprise to me that this amp has been discontinued and the Spellbinder has replaced it loaded with an Eminence speaker and an AE bypass function.



If you are one of the happy owners of these fine amps and not so fine combos, you can perform a few mods to the combo and end up with a world class portable rig. The used market doesn't call much for these and I can kind of see why now. The price of a Eminence Deltalite 2510 is a little hard to swallow these days however, IMO it was worth every penny.

Next I'd like to look into replacing the tweeter as the LeSon was IMO the weak link in the chain from the first day I bought it. I had no idea the PAS driver was the real weak link. If any of you have any suggestions for a good tweeter that would fit in this combo please let me know. If you've got down this far thanks for reading!

[LeonD]

Nice write up. Thanks.

I've got a Baby Blue II and it's the center point of my recording and practice space.

[gerryjazzman]

Nice little combo there, and nice work. From what I've read, I believe the Le-Son tweeter is a piezo unit (TLX-1). If that's the case, I can believe that it's marginal at best. I've tried piezos before in melded arrays in BFM Omni 10.5's and I did not like them even in arrays for bass guitar. Sounded OK for recorded music though.

I think you'd get a very noticeable improvement with a standard compression driver/horn. Problem from looking at the pictures is room. The better horns are about 4" x 4" or larger and it looks like your tweeter is less than 3" on a side. Is that right? Don't know how much wiggle room you have but something like this:

Eminence APT-80 Super Tweeter with 80° Conical Horn 290-532

or this:

Pioneer AHE60-51F 3-1/2" Horn Tweeter 270-050

or this (I've actually used this one in a 1x12 cab years ago which I still have. Sounds pretty good crossed over around 3.5K with a full-range Eminence Beta12 even though I'm sure there is an upper midrange dip in there somewhere )

3-3/8" Bullet Tweeter 270-055

Since your existing tweeter seems to be a piezo, you'll need to add a crossover, or at least a high pass for the tweeter. You're woofer I suspect is running full range now, so a just a high pass on the tweet would suffice. This is of course not optimum but working with what you've got it looks hard to do much better. You could possibly cut off a corner or two to make something fit.

My personal preference that I've found works quite well is one of these:

Selenium DH200E-E 1" Titanium Horn Driver 1-3/8"-18 TPI 264-225

with one of these:

Selenium HM11-25 1" Exponential Horn 60x60 1-3/8"-18 TPI 264-306

with a full 2-way crossover at 2KHz with Deltalite II 2512's or 2510's but you need to accomodate a 4.5" x 4.5" horn.

Good luck.

[MuthaFunk]

Thanks for the helpful reply Gerryjazzman!

I think I'd have a hard time getting any of those tweeters you suggested to fit but can you tell me what you think of this one?

Morel MDT 22 1-1/8" Neodymium Tweeter 277-062

It looks like it will fit right in and then I just have to design a crossover for it based on the upper frequency response of the Deltalite 2510. I can turn the Le-Son tweeter off and run a sweep through the amp using true RTA software to observe the drop off point and choose my crossover point there.

My only concern is that it is a dome tweeter and perhaps not as robust?? I got the idea of looking for a neo dome tweeter from Genz Benz as they use them on their 110 cab.

Here's a potential Ribbon tweeter I may get to fit:
Beston RT003C

Any thoughts?

[gerryjazzman]

Well, the problem with the Morel is that it's sensitivity is only 89dB, fine for home audio, but the Deltalite 2510 has a midband sensitivity of around 96dB and it rises from there between 1KHz and 2Khz to over 100dB. Not a very good match sensitivity-wise so you probably won't hear much of a boost in treble.

The Beson is a bit better in sensitivity (93dB) but still not the best match for the 2510. Also at 15 watts power handling, I'd be afraid of blowing it at higher volume levels with cranking the treble to compensate for lower sensitivity.

That's why the horn-loaded tweets would work better. Even if they don't have a lot of power handling, their high sensitivity would give you the response needed without excessive treble boosting and the chance of blowing it.

What are the max dimensions that you can handle?

[gerryjazzman]

BTW, here's a picture of the parts express horn in my cabinet with the Beta 12:

http://i841.photobucket.com/albums/z...orn_in_cab.jpg

As you can see I cut off one of the corners to make it fit and drilled another mounting hole. There is enough mounting surface to trim it that it might fit.

[MuthaFunk]

It looks to me like I have just over 3" for a horn and the existing hole is about 2-1/8"



Here's some phone camera pics.





I noticed the back of the le son tweeter says dome tweeter model lj. I all documentation says this is a piezo tweeter model TLX-1 but the tweeter isn't labeled as such. Is this still a piezo tweeter?

[gerryjazzman]

Wow, that is tight. Do you have an ohm meter? Check the resistance of the tweeter. If it is a standard compression tweeter it should have a low ohm reading, like less than 10 ohms (if it is an 8-ohm unit, probably will read 6 - 8 ohms). If it is a piezo, it will read infinity (look like an open circuit at DC since it looks like a pure capacitance).

As far as retrofitting a horn, here is a shot of the back of the Parts express horn with the driver unscrewed:



Looks like it could be easily trimmed to be less than 3 inches on a side so you could probably shoe-horn it in. The driver diameter is about 2 3/4 inches so it won't fit through the baffle hole. However, you could unscrew it from the horn and assemble it in-situ with the horn from the front and the driver from the back. You'd have to remove the woofer to do that.

Not sure what else to tell you unless you want to try one of the dome tweeters. Ain't much available in small horns. Besides, small horns are going to have a high cutoff frequency (super tweeter category) so the ones that I showed you are probably the smallest you could find Whatever you decide, I would try it outside of the cabinet with whatever crossover you use to get an idea of how it would work before you make any modifications.

EDIT: On further inspection, you'd probably have to enlarge the hole a bit anyway to make room for the horn flare, probably to 2.5 inches.

[MuthaFunk]

I've been trying to do a little research on the existing crossover and tweeter in this thread Speaker system gurus. Help. SWR content. but will still be on the look out for a tweeter locally so If I can't get it in the combo I'll be able to return it.

I'll get into designing the appropriate crossover after I've found a horn to fit. Ideally I'd like to get it down to under 4KHz as I like boosting 4K for a zinngy slap tone every now and then but the crossover point will be decided by the tweeter's design.

[Stephen05301]

I'm planning on doing the same speaker replacement on mine. Any idea as to how the Deltalite 2510 would work with upright bass?

[MuthaFunk]

Originally Posted by Stephen05301

I'm planning on doing the same speaker replacement on mine. Any idea as to how the Deltalite 2510 would work with upright bass?

I can't see it not being better. It's a superior driver in every way to the P.A.S. and matches the box and port size well.

You may find the AE bypass will get you a better double bass sound as it really allows the punch to come through...

I don't play upright so I don't really know much about using an amp with an upright so take my comments with a grain of salt. I do play jazz with a FBass though and found the AE bypass did wonders for that situation. It shouldn't cost you as much as the Deltalite either but you'll need some soldier experience or know someone who can do it for you.

Let us know what you decided and how you like it.

[Stephen05301]

Replaced the stock speaker with the eminence deltalite and it does sound better. Also seems to be able to play louder without the distortion of the stock speaker. BTW the stock speaker was not a PAS but an eminence 101444 4ohm. Upright also sounds better. Not sure the AE mod would be beneficial for the upright. Using a realist pickup I need to turn down low mids. With the AE in the off position the graph that is in the AE mod thread displays the mids as being scooped which is what the Realist needs.

[MuthaFunk]

Interesting note on the speaker difference. Was yours bought new? If so, when? I can tell you that mine was indeed a matching PAS driver to the spare I had out of an old Golliath III which looks very similar to the slightly lower power and heavier magnet PAS drivers out of my Golliath Jr. II.

If yours was bought used it might explain the changed driver. I thought I remembered the marketing blurb for the Baby Baby Blue combo toting the use of the 8 ohm PAS driver... I'll have to check that again.

Glad to hear you like the Deltalite 2510 better as well. I too found it to be cleaner, louder, and deeper sounding.

[MuthaFunk]

Here's what I remembered reading when I bought mine. I just pulled this off of google.

www.zzounds.com/item--SWR4420500000
Rating: 4.5 - 3 reviews
SWR Baby Baby Blue Bass Combo Amplifier (120 Watts, 1x10 in.). 120 Watts ... ( 1) 1/4" Extension Speaker Output Speaker ... (1) 10 in. custom-designed PAS driver, P/N 0067077000, ...

I don't believe they ever shipped from SWR with a 4 ohm driver either as that's technically the minimum recommended impedance and would prevent the use of an extension cab.

[Stephen05301]

I did buy mine used but it came with all manuals and papers and looked like it had not been used at all. Seller told me that it was purchased and not used. Maybe he replaced the speaker with the eminence.