advice on a simple mod, just for the experience.

[tonequester]

tonequester here.


This is more of a curiosity thing than anything else, but here goes. has anybody had the experience of adding a "bullit" tweeter(8 Ohms) to an amp to
try to get more top end ? I have a well used Ibanez IBZ10B(10W. Practice Bass amp) that was given me. As of now I've been doing some guitar practice on it as I am waiting on the delivery of a replacement(under warranty) Blackstar HT-1R. Under warranty they don't fix'em, they replace them. Anyway, as one would expect the Ibanez has great bass, but lacks treble. I have an orphan tweeter which could be fit in the cab without problem. I haven't found any specs on frequency response concerning the amp, and I realize that if it doesn't produce high enough frequencies, the tweeter can't "tweet".The amount of work to be done is nominal so that is something that i would take my chances on. The tweeter has no real value either, so if it blows, it blows. Any advice or tips are greatly welcome. I've heard that this has been done with mixed results, but usually the "chatter' is about using a piezo. I know that whether you hook up the two speakers in series, or in parallel is important. I can't remember off-hand which is the best way to go here, but i can easily find that out.
Thanks in advance for any input. tonequester.

[Enzo]

Your tweeter will be destroyed unless you use a crossover to keep bottom end out of it. Just like any other two way speaker - your home stereo speakers for example. You look at your tweeter, decide what the lowest frequency you want out of it might be, then buy or build a crossover for that frequency and the driver impedance. You would still run the woofers full range in most bass cabs, adding in the tweeter for sparkle.

Parts Express sells crossovers and parts. You can buy ready made crossovers. You can buy bare boards to add your own parts to. They have charts so you can look up the part values you need for whatever you plan to achieve. And they sell the parts.

[Tom Phillips]

Tweeter horns (With simple crossover networks using a capacitor to block the low frequencies from reaching the tweeter) were popular in the late 1960s and 1970's in some guitar amps. Tweeters that will have an effect are most likely more expensive and heavy duty than the one you mention. However, my feeling is that there is something else going on if the amp lacks high end. I think that it would be better to mod the circuit than add a tweeter to solve the problem.

[Chuck H]

It may help to simply use a guitar amp speaker with the amp. As noted, tweeters HAVE been used with guitar amps. But it's REALLY untypical. Two examples that come to mind are George Harrison, and more recently the "Edge" (U2). But these are unfair examples as they represent very experimental circumstances. Normal guitar tone shouldn't require a speaker capable of frequencies that high. Most bass amps aren't designed with attenuation of high end. But the speaker may be. Just try a guitar amp speaker that is known to be bright and you will probably need to turn down the treble control.

EDIT: The top end of any amp, such as would be covered by a tweeter, is at a frequency where most speakers have a relatively high impedance. If you did choose to try a tweeter I think a simple capacitor couple will be fine. The parallel load of the existing speaker and the tweeter isn't likely to be lower than the amps nominal impedance rating. The difference to the amp, operationally, should be small enough to ignore... I can hear the audiophile guys grumling as I write.

[JoeM]

Here's a tweeter for guitar amps, mainly for acoustic guitars:

Henriksen Guitar Amplifier: compact, solid state, small, inexpensive, powerful guitar amplifier

[tonequester]

tonequester here.


Hey Chuck ! Thanks for the informative reply. I was endeavoring to try this only because I have the amp(it was a give-away), and the tweeter(don't know how I came by it). I did find out that it's good down to 2000hz frequency wise. i knew that a crossover of some sort would be needed but had forgotten about the simple cap couple. If i ever get ny HT-1R back, I plan to replace the stock speaker with a Weber, so i'll have the 15W. Blackstar speaker to use. The old Ibanez amp doesn't tell output power, it says that it consumes 12W. I figure that it can't be over 10W. Rather than use the tweeter, I'll just wait for the blackstar to arrive. Thanks for the input my friend. All the best to you. tonequester.

[tonequester]

tonequester here.


I thank you for the advice in trying to keep me from frying anything Enzo. I had figured that I'd need to address that issue. I just hoped to find out if it was a viable way to get more top end out of the bass amp. You can sure adjust it for even less as it has bass,midrange, and treble controls. Just another hands on experiment. However, even when experimenting I always like to avoid smoke and fire. You sure have good intuition for when an eight-ball like me is about to blow something up ! have a great day. tonequester.

[olddawg]

I would just put a non- polarized 2uf cap on the positive lug of the tweeter and parallel the tweetercand cap to the speaker. You can ad a resistor or pot in series if you like. If you don't have a non-polarized cap, you can use 2 regular caps back to back. Be aware that tweeters hate distortion.

[Chuck H]

You can ad a resistor or pot in series if you like.

Good idea.

[J M Fahey]

The tweeter will sound horrible.
Replace your speaker with a guitar type, which covers 2 requirements:
1) it will typically have a 6/12 dB peak between 2000 and 3500Hz which is where electric guitar "highs" lie
2) just where the peak ends (between 3000 and 4500 Hz) response drops vertically, at over 24dB/octave.
Response at, say, 6KHz is already down by 15dB or more, and falling even more above that.
3) the tweeter complies with neither: it will not have the peak and response will extend reasonably flat to *at* least 12KHz, often *way* beyond if it's any good.

[Enzo]

TQ, I answered your question - or tried to - about adding a tweeter, but I also agree that it is not likely a good move to add one.

A few guitar amps may have had them, but mostly you find them in "acoustic" amps. AMps made to amplify acoustic guitars. The deal is that a regular guitar amplifier is a PART of your instrument, it is designed to add its own character to your guitar sound. That is why guys say "I play a Fender" or "I play a Marshall." The amp is a fundamental part of creating a sound. COntrast that to a PA system or a hifi stereo. The primary purpose of those systems is to REproduce some sound. They are designed to be utterly neutral and add nothing to the sound. And that is why all PA systems should sound alike. No one usually says he prefers the sound of a Crown amp over a QSC. (or whatever) The acoustic guitar amp is really a small PA system in a combo cab. It is designed to faithfully reproduce the soiund of an acoustic guitar. Now THAT can use a tweeter. Because acoustic includes not only the guitar strings, but also the pick sounds, percussiveness on the thing, etc.


Now having said that, in any players rig, the important factor is whether it pleases the owner. If YOU like the way something sounds, then it is right for you. Doesn't matter if someone like me comes along and says you ought to do it different.

[tonequester]

Greetings Chuck !


Thanks for your reply. I really didn't have much faith in the tweeter bring the answer, However, like the s.s. bass amp, I had one on hand. I have had a wierd occurance that left me with a new 15 W. guitar speaker to use instead. So, I'll be taking your advice(and that of others as well). I just got my THIRD Blackstar HT-1R, under their policy of replacing instead of fixing. My dealer friend assured that he put it through it's paces before i went to pick it up. I brought it home, but soon discovered that although it seemed to play fine, there was something rattling oround inside, and it was too big to be a loose screw or nut. I took the thing apart and founf the speaker attached by only one screw, and that only half tight. They had used super duty Locl-Tite on it and I had to use a Dremel cut-off wheel to slice the thing off. i couldn/t believe that the speaker dids not have 3 rips in it from the un-used screwa that protruded. I decided 6 months of jacking around was enough. I had actually purchases a Weber hand built Alnico spealer to use in it after the warranty was up. i went ahead and did the rep[lace ment and and screwed and glued some other things that werer badly built. I had also ordered a couple of tube for it because I didn't (and never have) liked the Sovtek tubes it came out with. I found that they had changed to TAD tubes in this last model. I put in my "gold pins" anyway, and now I have a sweet sounding amp that hopefully won't "blow" at 6 months.
Well, that left me with a 15 W. Blackbird, ribbed spealer that should be usable in the s.s. Fender bass amp. Always nice to have a spare. My experience with "hybrid" technology has concluded for the
present time. I intend to build the MOD 102 kit that I had prev iously posted about. I haven't checked to see what output power the finished kit will produce but I know that it's more than the 1 W. HT-1R's output. I will still look to again build a kit(s.s.) power amp to use in a re-amp configuration to get the possibility of between 230-30 W. output. It may end in smoke and fire but will be great fun and educational to boot. Thanks for 'chiming" in. I always appreciate hearing from you on any of my "debacles". Oh ! I finally have what I consider to be a great tip for you. DON'T UNDER ANY CIRCUMSTANCES, WASTE YOUR MONEY OR YOUR TIME ON A BLACKSTAR AMP. Once burned...shame on you. Twice burned...shame on me. Thrice burned.....
Just bend over and let them get on with it. tonequester .

[tonequester]

Greetings Enzo.


Thanks for your reply. I learned a thing or two from your reply. I didn't know that the tweeter thing was something employed to a degree with acoustic amplification.
The thing about the contrast between using an amp to "color" your sound, as opposed to using one to accurately re-produce your sound, is pretty much the thing that I am hopefully be able to do, without depending on a P.A. system. It may end up to be un-feasable, or it may not give the results that I hope for, but it's worth the try for me. If nothing else comes out if it, the experience will be educational and enjoyable. As for the tweeter, it's become un-necessary to even try it(plus, no-one thinks it's a good idea). I got my third HT-1R yesterday, and after almost 6 months of jacking around, this one had a "clunk" in it that I didn't notive untill I got it home. It played fine, but I actually thought after hearing the "clunk' when I would move the amp around, that someone might have left a tool inside it. After taking the chassis out carefully to have a look. The speaker was "all a kilter", attached only by one threaded stud which was onlky half way tightened. Three unused threaded studs had no nuts, anywhere in the cab. I had a Weber hand built speaker on hand, meant for use in the Ht-1R after the warranty expired. I just went ahead and did the swap, and repaired and beefed up the cab. I can't believe it ,but the speaker wasn't damaged by the three bare studs protruding, pointed at the cone. So now, I have the stock Blackbird 15 W. I'll put it in the s.s. Fender which is also a 15 W. amp. I won't crank it up though. Hopefully the Blackbird will handle the Fender.
Hey ! Thanks again for the advice. It's always good to here your opinions, based on much experience. tonequester.

[Chuck H]

Once burned...shame on you. Twice burned...shame on me. Thrice burned.....
Just bend over and let them get on with it.

actually LOL.

[tonequester]

tonequester here.


Greetings Chuck. You make a good point. Gotta take the good with the bad, and chalk it up to experience. I can't help but wonder if the first amp failed do to a heat related problem with the s.s. part of the "hybrid". The other two point to your quote by Brahms. The last one has already been "beefed up" with extra glue and screw. Now I'm thinking about improving the ventilation of it. I have to admit that I love the music too much to leave the equipment alone. It's always best to try to turn a negative into a positive. I'll also say that the
amp sure sounds great at lower volumes. There it does a pretty good tube amp impersonation. I do look forward to building the "kit' amp, and having one that is all-tube, even if I have to
get the good sound at high volume. I still have occasion to "crank it up. Always good to here from you, even if it's just...LOL. Have fun and be good ! tonequester.