Magazine Archive

Home -> Magazines -> Issues -> Articles in this issue -> View

Once More Unto the Rack

Boss RPQ10 Parametric EQ

Article from Home & Studio Recording, July 1986

Another versatile addition to the ever growing Boss Micro-Rack series.

Boss have added a new product to their micro rack range and very useful it is too.

One of the problems often encountered when recording at home is that of direct injecting an electric guitar into the mixer and getting a decent sound. The problem arises because a guitar likes to work into a high impedance input if it isn't to lose an inordinate amount of treble and most mixer inputs have far too low an impedance to achieve this.

Assuming that you have managed to find a high impedance input, the chances are that the sound will still be less bright than you would like because guitar amps have a certain amount of high frequency boost built in as standard to produce the desired tone.

Wouldn't it be nice then if someone would produce a simple, inexpensive box that would present a high input impedance and include a decent EQ section. Well, just by coincidence, this is what Boss have come up with in the form of the RPQ-10. Like the other units in the system, this one measures a meagre 218 x 167 x 44mm which to you non-metric types is about the same size as a rack mounting box of Milk Tray chocolates.

Down To Details

The RPQ-10 is a single channel device with a choice of three inputs which enable it to accept signals at mic, line or instrument levels. The mic input has a sensitivity of -50dBm with an impedance of 1 kΩ, the line input accepts -10dBm at 50kΩ and the instrument input accepts -20dBm with an impedance of 1 MΩ which should keep most guitars happy. Following this input stage is an input level control with an LED overload indicator and this precedes the EQ section. A chunky bypass switch with accompanying status LED allow the equaliser to be switched in or out of circuit so that instant A/B checks can be made.


When most people advertise a parametric EQ section, they really mean a sweep EQ but this one is a true parametric and it has two bands. For those as yet unsure as to the difference between a parametric equaliser and a sweep equaliser, a parametric equaliser section has three controls, one to set the frequency, one to set the amount of cut or boost and one to set the bandwidth. This third control, bandwidth, is the one omitted on sweep designs and it is a useful feature to have as it allows you to tune in to a narrow or a wide section of the audio spectrum as needs dictate. For example, if you have an annoying resonance or perhaps a bit of mains hum that is giving you trouble, you could set the EQ to work over a narrow bandwidth and then cut the offending frequency without significantly affecting the sound in other parts of the spectrum.

This Boss design uses two equalisers to cover the audio spectrum and there's a little overlap between the ranges to ensure that there are no dead spots. The first section covers the range 40Hz to 1 kHz and allows up to 15dB of cut or boost to be applied. The Q factor is variable from 0.7 to 7 and for the inquisitive, Q is defined as being the centre frequency divided by the bandwidth.

Section two of the equaliser is identical except that the frequency range covers 600Hz to 15kHz. Apart from the input level control, all the controls are sliders and each one has a red, yellow or green LED mounted in the knob to induce a festive spirit into the proceedings.

Following the equaliser is another slider control which sets the output level and this is made necessary by the fact that the signal level may be radically altered by zealous use of the equaliser. To let you know if any frequency has been boosted to the point where it is clipping, another overload LED is fitted, this time in the knob of the Level slider though its operation is somewhat unconventional as it is normally lit and flashes when an overload is detected.

The mains power switch is quite conventional and a corresponding status LED is provided just in case you somehow manage to miss the seven LEDs mounted in the sliders.


All connections are made via the rear panel and there are two power sockets (in and out), power being provided by a Boss mains adaptor. The out socket is provided so that several units can be powered from One adaptor using a series of short daisy chain leads. Total power consumption is 60mA.

The Mic and Instrument inputs are on standard unbalanced ¼" jacks whilst the Line in is in the form of a phono connector. Both jack and phono output connectors are provided, the phono offering a -20dBm level and the jack a -10dBm level, each with an impedance of 2kΩ. Last and by every means least is a socket for a remote switch which can be use to bypass the EQ section at a distance.

In Use

The unit works well with a variety of inputs, the most demanding being low impedance microphones and electric guitars. Noise levels are reasonably low as long as the EQ is used sensibly and the overload LEDs are a great help in keeping a check on levels for least noise and distortion operation. The EQ covers a good range and allows you to scratch those itches at the bottom end that other equalisers can't reach (if you'll pardon the expression) and the range of cut and boost is more than adequate. Even if you have a mixer with a reasonable EQ section, you'll find that this one is a great deal more flexible when it comes to dealing with awkward problems and you can get quite gratifying results direct injecting a guitar if you just want a clean sound. If you want a more produced sound, you could plug in a compressor, a distortion box or a delay unit (or even all three) but at least you can get your guitar into the system unscathed using this box.


This is a very worthwhile addition to the Micro Rack range and it combines two very useful facilities, the flexible input stage and the two stage parametric EQ. True, it's a down to earth general purpose device and it won't astound your friends in the same way that the latest neutron powered anti-matter hyperflanger will, but you are sure to find a lot of uses for it. My only adverse comment concerns the profusion of jolly little LEDs which tend to detract from the seriousness of the product and make it look gimmicky.

Now that Boss have got their teeth firmly into the budget recording market, it will be interesting to see what they come up with next.

The RPQ10 costs £130 including VAT.

Further details from are available from: Roland UK, (Contact Details).

Also featuring gear in this article

Previous Article in this issue

Doing the Video

Next article in this issue

Monitor Special: Urei 809

Publisher: Home & Studio Recording - Music Maker Publications (UK), Future Publishing.

The current copyright owner/s of this content may differ from the originally published copyright notice.
More details on copyright ownership...


Home & Studio Recording - Jul 1986

Donated & scanned by: Mike Gorman

Gear in this article:

Studio/Rack FX > Boss > RPQ-10 PREAMP/EQ

Gear Tags:


Review by Paul White

Previous article in this issue:

> Doing the Video

Next article in this issue:

> Monitor Special: Urei 809

Help Support The Things You Love

mu:zines is the result of thousands of hours of effort, and will require many thousands more going forward to reach our goals of getting all this content online.

If you value this resource, you can support this project - it really helps!

Donations for June 2024
Issues donated this month: 0

New issues that have been donated or scanned for us this month.

Funds donated this month: £0.00

All donations and support are gratefully appreciated - thank you.

Magazines Needed - Can You Help?

Do you have any of these magazine issues?

> See all issues we need

If so, and you can donate, lend or scan them to help complete our archive, please get in touch via the Contribute page - thanks!

Please Contribute to mu:zines by supplying magazines, scanning or donating funds. Thanks!

Monetary donations go towards site running costs, and the occasional coffee for me if there's anything left over!

Small Print

Terms of usePrivacy