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Yamaha B100-15 III

100 Watt Bass Combo

Never as successful with amplification as they have been in almost every other sphere, Yamaha have prepared afresh assault on the world's musicians with a new line of high-spec. amps. IT borrowed their brand new 100-watt bass combo to see if they've at last cracked it.

Amplifying bass frequencies is a science all of its own. Some makers dodge the unique acoustic and electronic demands imposed by a bass guitar, simply varying the tone controls of their standard guitar amps a little, fitting a tougher speaker and calling the result a 'bass combo'. As a result, many of the amps thus called are really rather poor - especially for the modern bass guitarist, who demands clean and powerful projection for his sound.

When Yamaha tackle product development on any subject - guitars, keyboards, effects - they do so backed by the resources of a company which must now be the world's biggest musical instrument combine. Thus they draw on resources which hardly any other maker can match. With that typical thoroughness, then, Yamaha's design team have apparently been looking hard at what today's bassist is calling for. You can tell this just by glancing across their new B100-15 III combo, and can tell even more from the accompanying handbook. They're by no means the first amp maker to have taken this professional approach to bass sound, of course; Peavey, Carlsbro and Trace Elliot (to mention just three) having already undertaken considerable research into the subject - but the handsome-looking B100-15 III shows some real thought on Yamaha's part.

The B100-15 III is a tough-looking combo, supplied with heavy-duty castors (an uncommon feature today, but one which more makers ought to think about - it certainly makes life easier for the player who has to double as his or her own road crew!). It measures some 22" x 30" x 14", but it does need those castors, being no featherweight at something like 94lbs - a lot of amp to have to shift around with only a top mounted carrying strap to help you!

There seem to be two definite keys to getting a good sound from a bass combo. Assuming that you have a good speaker, it must be fitted into a properly designed enclosure, and it must also have very fine control over tone - Eq. if you prefer. Yamaha's approach with this combo hasn't been to go for tremendously sophisticated porting of their speaker housing. In fact (in that respect) it's quite traditional, with a single' Japanese-produced 15" speaker having been fitted into a (well-sealed) housing with no particularly clever porting or ducting having been employed.

The Eq section, however, is a very different kettle of vultures - in fact the whole of the front panel is virtually festooned with small controls, governing an amazingly wide range of facilities and options.

Starting with a single jack input, the Yamaha proceeds to swamp you with an array of Eq. controls which endow this combo with enormous tonal versatility. Next in line (after the input) is a simple volume control, followed by the standard 'tone' controls governing treble, mid and bass. Then comes the first of two true parametric Eq. sections. Three controls per section cover the operation - each having 'level', 'frequency' and 'Q'. Gain on the selected frequency can be boosted or cut by ± 15dB (the usual range chosen by amp designers). 'Q' governs the frequency bandwidth around which the operation of the third ('frequency') control operates - i.e., how 'wide' the effect of the boost or cut is around the centre frequency selected - and 'frequency' itself selects which frequency is to be adjusted. The nice feature of this arrangement is that (with the use of two very sturdy metal footswitches) you can arrange things so that either or both parametric stages are on at any one time. Hence you can have either a lead/rhythm sound or - for a very complex tone - use the two sections at the same time.

Following these two parametric sections comes the next feature of this excellent array of options - a range of controls which enable you to bi-amp the output, using one bass extension speaker to handle the lowest frequencies alone, another (driven by another amp) to handle to highs alone. The theory of bi-amping is pretty obvious, of course - allowing two specifically designed enclosures to handle those sounds best suited to their capabilities, resulting in the cleanest possible sound.

What Yamaha offer on this combo is a built-in crossover enabling you to use a 'low pass filter' (settings running from 1-10) with 'crossover frequency' (regulating the point at which the output frequencies are divided; lows going to one speaker, highs to another). Crossover frequencies on the 'low pass filter" can be chosen from 100Hz to 5kHz, the 'high pass filter' also running from 0-10.

Of course you can't make use of this bi-amping facility with the Yamaha combo alone. You need an extra power amp (to handle one end of the frequency range) and an extra speaker or two, to take that amp's delivery of power.

All this is pretty clever stuff (although not unheard of on a top-flight modern bass combo) but it's followed by yet more facilities - a socket for headphones (also on the front panel) beneath which is the socket for the sturdy two-way footswitch's jack plug.

On the back, the Yamaha is equally impressive. An XLR socket is fitted, giving professional quality for an electronically balanced output which allows you to run a line-out to your P.A. mixer. A sliding switch governs 'on/off' for this feature, matched with an output level pot, so you can get the signal level exactly right for the mixer you're using. Pre-amp output, power amp input, 'high pass filter" output and 'low pass filter" jack sockets complete a range of facilities which make this Yamaha surely one of the very best-equipped bass combos around.

Of course, all this technical wizardry would be wasted if the combo sounded like a pig, but Yamaha, by tradition, don't go to all this trouble for nothing! The amp is superbly clean in sound at all but the very highest output levels, and the tonal ranges which you can get out of it - especially using the switchable parametric stages - are quite astounding. It's pointless just saying that this combo will deliver anything from whistle-clean top 'pulled' notes, down to deep, rounded bass tones - you've only got to read the specs, to see that for yourself. What no specs., however, can tell you is the quality of this amp's sound. The speaker handles the full range of Eq settings remarkably well, and if you use the bi-amp facility to stretch the amp's capabilities then it becomes the sort of combo that you could take on the road, from the smallest gigs and recording sessions right through to the biggest venues - making use of bi-amping and unlimited power amp options to get the volume and clarity you require, but still maintaining the Yamaha's exceptional range of pre-amp options. As such it truly is an 'amp for all seasons' and all potential uses.

About the only criticism we could have of this amp would lie in the lack of provision for easy transportation around, castors notwithstanding. Side-mounted carrying handles would really help the gigging player a lot - but if that's all we can find to grumble about, then how can we grumble?!

The price of the Yamaha B100-15 III isn't, perhaps, as low as it might be. Carlsbro's Stingray Pro-Bass combo offers it some definite competition, as does Laney's PB 100 unit - but, don't forget, the price we've quoted here is just the recommended retail price level, and these do vary from retailer to retailer. Given even a few pounds off, this Yamaha will represent not only superlative quality but also good value. Pro bassists, those needing the ultimate in versatility of both sound and use - in fact, every demanding bass player - should check this model out. It's superb!

RRP £539 inc. VAT with 12" speaker, £529

More details from Yamaha Musical Instruments, (Contact Details).

Previous Article in this issue

Manson Sandpiper Acoustic

Next article in this issue

V-Amp VA-60 Lead Combo

In Tune - Copyright: Moving Music Ltd.


In Tune - Apr 1985

Donated by: Gordon Reid

Gear in this article:

Amplifier (Combo) > Yamaha > B100-15 III

Gear Tags:

Bass Amp


Previous article in this issue:

> Manson Sandpiper Acoustic

Next article in this issue:

> V-Amp VA-60 Lead Combo

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