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Replacement driver for Yamaha PA cabs

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  • Replacement driver for Yamaha PA cabs

    Dear all,

    If there's a better place for discussion about loudspeakers, do let me know: happy to post there instead!

    I've been working on a Yamaha Stagepas 300 powered mixer and speakers. The amp's working well ( if you're interested!) and I'm now turning my attention to the 2 way cabs.

    I've glued the broken bits and reattached the crossovers, which look visually to be in good condition. These cabs have had a hard life, and I think a trip down a flight of stairs might have been a feature at some point. The tweeters test OK (impedance check) and pass audio (I'm not sure yet how well) but the 8" woofers have had it. One tests approx 1 ohm, the other tests OK impedance wise (5.8 ish) but both have that horrid rubbing noise when you gently push the cone, and they either pass little or no audio.

    So I'm looking for some replacements. Yamaha seems to be a little coy about sharing specs, but I *think* they're 6 ohm. OEM replacements are available (e.g. here ) but at over £70 a pop it's too much money to throw at this beaten up system, so I'm looking for alternatives...

    6 ohm units are not common - what's the implication (e.g. adjustment to the crossover) of sticking an 8 ohm unit in?
    What differences should I be aware of about drivers aimed at the hi-fi market rather than PA?
    What should I know about units labelled as mid/low, low, or sub woofer? Some have the frequency range defined, which is helpful, but not all...
    Any recommended units or brands?
    Anything else I should know?!

    Thank you!

  • #2
    IMO, most any 8 ohm full range speaker rated at 150 watts or more would work just fine providing it fits in the cabinet. You wouldn't want a foam edge woofer. I'd offer suggestions, but I'm not sure what's available in the UK.
    "Yeah, well, you know, that's just, like, your opinion, man."


    • #3
      Thanks, The Dude, good to know. Last night after posting I did try an old (8", 8 ohm) speaker out of a old Carlsbro amp. It worked OK. Not a long term solution (wattage rating not sufficient, I've only got one of them, and I wonder if I can do a little better on the quality...

      I suspect that we can get most of the cheap units over here that you can. The brand names might differ over here, of course... some of the names that turn up after a search are:

      However, I'm tempted to give these a try: What do you think?

      It would be good to support a family firm, they're reasonably priced and look to have the potential to sound just fine. Funnily enough, Andrew Bishop was associated with Carlsbro for some years!

      Thank you.


      • #4
        Originally posted by Rhod View Post
        6 ohm units are not common - what's the implication (e.g. adjustment to the crossover) of sticking an 8 ohm unit in?
        Implication of 8 ohms vs 6, not much. Perhaps a small loss of power delivered from amp to speaker. Also, be aware that DC resistance of speaker voice coils often is lower than speaker's rated impedance and a resistance measurement of 5.8 ohms isn't out of line for an 8 ohm rated speaker.

        Out of your list of speaker manufacturers, SICA is the only one I recognize. They do build some quality products. I ran across a video "factory tour" and only 15 seconds in, there's a tech holding one of their speakers, looks to be a pokey 8 that would likely work a treat in your Yamahas. FWIW SICA also builds the "Italian Jensen" speakers we have come to know and like (well some of us anyway) over the last 20 years or so.

        The Bishopsound speaker you linked to looks to be a downright bargain, quoted at US$ 27. For a quality 150W rated speaker, that is a giveaway price. It's unlikely Bishop is manufacturing them. The usual thing is to stick a house brand label on a speaker supplied by an existing manufacturer. Fender "Special Design" for instance, seen on millions of OEM amps & cabs. But relabeling doesn't mean it's a dodgy speaker, just that the seller doesn't want to reveal their source.

        OEM, maybe expensive but the advantage is it will fit the baffle cutout perfectly. No guarantee of that with other speakers. I've run across this headache more than once. Who wants to fiddle faddle with modifying the cab to fit the speaker.

        It's a shame Yamaha isn't forthcoming with specs on their OEM speaker. All those Thiele-Small parameters SHOULD be closely matched in a replacement, as they really do matter, if you care about achieving the same frequency and power response. Without that info, you're limited to a "best guess" choice.

        I hope you can revive your 300's. I've run across only a few of them and I'm impressed with their tone quality and compact size. IMHO it's an item Yamaha should have continued to manufacture and support, a clear winner in a world of mediocrity.

        This isn't the future I signed up for.


        • #5
          SICA is a highest quality PRO speaker brand, and made in Italy.

          FWIW they were chosen to manufacture modern Jensen Guitar speakers, I take that as an endorsement.

          Never herd about the others and suppose they are rebadged Chinese speakers.

          5.8 ohm speaker resistance means an 8 ohm speaker.

          Post a link to the shop selling SICA so we can suggest some model but in principle one standing 80W RMS or higher will do.

          I mean real RMS of course, might be branded "500W max" or some other misleading label, though I trust SICA in that respect.

          PS: being in UK, perhaps a >80W RMS 8" Celestion speaker might fit the bill.

          Juan Manuel Fahey


          • #6
            Leo_Gnardo. Yes, I used to use a 300 some years ago and I was surprised at how good it was, even for an outdoor gig. And I’ve just been running this current Yamaha amp through some old Yamaha S12e cabs and it sounds really good. With these cabs you lose the portability though, so I’m keen to get the originals up and running.

            I’m under no illusion about the provenance of the Bishopsound cabs - at this price! Although they do mention “British” cones, I reckon that’s a reference to their paper construction i.e. no new fangled polypropylene or the like rather than their place of manufacture. On the other hand, you hope that their quality control might be more active than a nameless corporation behind an Amazon storefront or the like...

            J M Fahey - thank you - a Celestion would be nice, and I’ve got a nice Celestion driver in a guitar cab - but I suspect prices might be up towards the Yamaha OEMs! Good intel about Sica - I’ll see if I can find where I saw those, although on a quick search I can only see 6” drivers at my sort of price point...


            • #7
              Be advised that Celestion has moved most if not all of its manufacturing to China. The battle rages among guitarists who believe their China Celestions are perfectly OK vs those who swear the quality isn't there anymore. BUT for Celestion, the profit sure is sweet! Their manufacturing discount is NOT passed on to the buyer.

              It's entirely likely that Bishop speakers are re badged Chinese. At that price, what else could they be? But who knows they might work out just fine. Can't beat the price.

              Hard to say what will fit the low budget AND sound terrific. We're back to a "best guess" compromise. Let us know what you get & how you like them. And a year or more later, how have they been holding up?
              This isn't the future I signed up for.


              • #8
                I’ve no doubt that the Bishopsound speakers are Chinese, just as the Celestions are. And you’re right - you suspect that some off brand Chinese made units will be every bit as good as the well known brands, and indeed as the original Yamahas which were, of course, built in a Chinese factory too!

                I may give them a whirl, and, rest assured, I will keep you in touch with what I find.

                Still looking at Sicas - they seem to have some units perfect in every way except being 2” too small!


                • #9
                  There´s Chinese and Chinese.
                  Typical unknown cheap low quality ones are all over the place and you get what you pay for, now a product from a serious Company, such as Sony, Yamaha, Celestion, etc. is quite Country independent.

                  product will be GOOD, with no qualifications, as long as the Company:
                  * knows their job
                  * has good product design
                  * has necessary machinery and access to raw materials
                  * hires competent Industrial Engineers who will design a well distributed and functional Factory but most important: train employees, follow and control their work,ensure proper and efficient use of resources, and most important:
                  **** has good quality control ****

                  I can COUNT on serious Companies meeting those 5 important aspects, and if so Factory can be anywhere: Stuttgart, Oklahoma, Shanghai or the Moon, that will not affect product quality in a bad way.

                  Say, a Sony product will be exact same no matter where it´s made, they keep a tight control on manufacturing.

                  In a particular case, Celestion was bought by Chinese over 20 years ago ... but not "current" Chinese, instead Hong Kong ones.
                  Yes, afterwards they also built factories in PRC ... like anybody else, but kept quaity.

                  I hear no difference between old UK made and HK/China ones.

                  ]As long as they use same blueprints, cones, magnets, etc. ... why would sound change?

                  Workers can be trained to any necessary degree and then controlled so they do not deviate from the norm.

                  Absolute worst case, first few Months might be iffy or have more rejects (at Factory, of course) but then they learn and production line smooths up.

                  Now if it´s a local company, with inexperienced local "talent" ... anything can happen.
                  Juan Manuel Fahey


                  • #10
                    Wise words! I’ve sent a message asking for some dimensions info to Bishopsound- I’ll let you know how we get on...


                    • #11
                      Well, so far, so good. Received a reply to my enquiry about dimensions directing me to the info on the website. I pointed out that the dimensions quoted weren't the ones I needed, and they responded really quickly, having measured the driver, and including a diagram of the unit to confirm what they had measured. Looks like almost identical measurements to the original, so I've placed an order. Included a pair of speaker cables which took me up to the free shipping threshold - happy days.
                      I would be surprised if many of the eBay/Amazon sellers etc would have been able to respond in this way, and this encouraged me to place an order. If they hadn't responded and having done some more research I probably would have spent a bit more and gone for the Celestions or a pair of Fanes, but I'm intrigued to give these a go now!
                      I'll let you know what they sound like when they arrive...


                      • #12
                        Order placed Tues evening
                        Personal acknowledgement of order on Weds and package shipped.
                        Thurs: package arrived but only one driver included. Email sent to company, reply received within half an hour, and 2nd speaker despatched.
                        Fri morning or early afternoon- 2nd speaker arrived.

                        Speakers look good, not that you can tell much from the appearance - at least I can’t! But the quality of finish looks good. Much bigger magnets on these than on the ones I’m replacing. The company warns of a mislabelling - the units labelled as 100w rather than 150w and these were relabelled on the first driver but not the second. Raises some questions but I’m inclined to give them the benefit of the doubt here. Time will tell whether I will be claiming on the lifetime guarantee!

                        Now installed in the cabs. Have to say that they sound good. They’re not hifi speakers of course, but for reproducing music with clarity for live vocals and enough meat to the bass line/bass drum they’re absolutely fine. Balance between these mid/low units and the original tweeters seems fine with no major eq adjustment necessary. How do they compare to the originals? Don’t know, as it’s been years since I listened to one of these stock and this one was broken when I got it.
                        If I get an opportunity, though, I’ll AB it with a stock cab...

                        All in all - I’m happy. I bought a system for less than £60. It was more broken than I hoped but after £10 on new fans for the amp, £50 on new drivers and some glue for the shattered insides I’ve got a decent quality system ready for a small gig on Jubilee weekend coming up. (Also bought 2 top hat adapters as these cabs annoyingly don’t include these - £5 each + postage. Just need a pair of stands now.)

                        My experience with BishopSound was good - sometimes you don’t know what a
                        company is like until something goes wrong, and they sorted out the order error really quickly. I’m pleased with the quality of the speakers, especially at the price.

                        Thanks for all your helpful input. Much appreciated.