Mindsets Low-Noise Stereo Pre-amplified Kit

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Quoting product code: N47FL

£5.99

About this product

Overview

  • Boost weak stereo sound from your audio devices
  • Amplify two channels to improve sound or output to an amplifier
  • Fun to solder with 22 parts

Product overview

• Boost weak stereo sound from your audio devices
• Amplify two channels to improve sound or output to an amplifier
• Fun to solder with 22 parts
• Requires a 3-25V power supply (not included)

What can I do with this kit?
Use this kit to boost your stereo audio devices output to an amplifier or increase the sound. Amplify two channels with individual adjustable output levels – great for level matching. The stereo pre-amp uses the NE5532 chip, which is high output, low noise amplifier. With a compact 49mm x 35mm circuit board, you can fit this kit in almost anything. This is a great kit for those looking to improve their soldering skills, and comes with 22 parts.

What can I learn from this kit?
Practise soldering and learn about electronics and circuits in a practical way. The kit uses resistors, capacitors, potentiometers and a microchip to create a circuit that amplifies two audio inputs – strengthening the signal without altering the pattern. The two potentiometers allow you to independently change the gain on each channel, letting you match the level on the inputs. The audio output will be dependent on the incoming signal, the adjustable level and the power supply connected. This kit requires a soldering iron and solder, and may require wire cutters.

How easy is this kit to solder?
This kit is simple to solder and ideal for those looking to move on from beginners kits. Once you’ve put the kit together you could add to your project with additional gear and build an enclosure to protect your circuit, or add jacks or screw terminals for easy attachment and detachment from the board. This kit required a DC 3-25V power supply (not included).

Rated 3 out of 5 by from needs modifying I'm using one of these as a microphone pre-amp; it works reasonably OK, but only after modification. The main culprits for the poor low frequency response are the input capacitors. These need to be 10uF or more (-ve end to the input pin); 22uF is better. Changing the resistors to metal film ones did cut the noise level, but I would still not call the design 'low noise'. Word of warning to anyone making modifications after assembly - the PCB is single-sided and the pads are very vulnerable to damage from the stress of removing a component (even more so with the higher temperature needed for Lead-free solder).
Date published: 2015-07-27
Rated 3 out of 5 by from I'd love to report this is a great kit - and the NE5535 is a fairly neat chip so it's a good choice and the use of single-rail biasing is convenient. Things go downhill from there though. I've come to trust designers and when I first built one of these I was disappointed by the performance; particularly at the low end. Turns out this amp - simply down to poor component choice - rolls off at around 160Hz - making it pretty useless for music. Simply increase the 1K resistors to 10K (dropping the gain to x10) and a more respectable 16Hz rolloff is achieved; together with a more respectable 10K input impedance. Worse perhaps, is the choice of carbon film resistors - while these are easier to read than the metal film ones sold by Maplin (the blue body ones) they are noisy! Swap them for the stock Maplin metal film and presto, you have yourself the beginnings of a decent audio amp - for little extra cost. Six off D100K and two of D10K will do nicely! If you need more gain, just chain two together or increase the value of the feedback resistor - but beware that the NE5535 is prone to oscillations; and this board is no exception.
Date published: 2014-11-11
Rated 3 out of 5 by from Good but... "It is an educational kit....", or so says the packaging. If so, why is there no schematic circuit diagram with the blurb? Just put bits [1,2,3,4 etc] into places [here,here and here...] and hope it works. OK, I might learn how to bend resistor wires and solder things together but there is much more to be learned surely? Middlesex University Teaching Resources could help more with this I think. [Yes, I know there are generic articles on Wikipedia etc, but an explanation for the learner of what the bits do and how they are connected together would make a 'good' kit 'excellent' at almost no additional cost - just better presentation].
Date published: 2017-01-17
Rated 4 out of 5 by from Great little kit , bought this to boost the output from a TosLink to Phono adapter, from TV to House Stereo , needed that little bit more as Stereo was nearly on full to get good volume ...now I can turn it down to half way and get great volume. Agree totally with Marc's review and have swapped the resistors for metal film and changed the input values from 1K to 10K ( R1 and R5 ) , this worked brilliant and only needed this on half boost for both channels to get the volume right , eg : same as Tuner /CD Player. Note however , my kit came with 2 Ceramic Capacitors replacing 2 of the Polyesters , and the paper add in did not make it at all clear as it only mentions C2 and C4 nothing about C1 or C5 , to clarify this I used the DOWNLOAD available and looked at the Circuit Diagram , so to help those less knowledgeable here is the answer C4/C5 are Ceramic (Small brown disc stamped 104) , C1/C2 are Polyester ( Yellow and Rectangular ) , also NOTE the IC chip in the picture shown is fitted the wrong way around , the DOT should be at the other end with the NOTCH on the 8 pin DIL Socket. I also used a 12v 1A ( 500mA would be OK ) wall wart to supply the power to this . One last thing , if you buy the 6 extra resistors at the same time you get free delivery , as it goes just over ?ъ10 ,and you save the ?ъ2.99 delivery, so you can upgrade this kit for free almost :)
Date published: 2014-11-11
Rated 3 out of 5 by from Looking at the previous reviews I traced the circuit tracks and it appears the component list values for C2 and C4 are switched so the right input capacitor is 100n rather than 1uF-the picture shows the board made up this way. IMHO this is a good reason to have a schematic with component values as this would indicate what was going on. I have seen other application circuits take this to 10u electrolytic (+v end toward the IC).
Date published: 2014-11-11
Rated 3 out of 5 by from I agree with the previous reviewer; bass roll off at such high frequency is a serious problem for this type of pre-amp. Also with the noise comment but the correct replacement components would be M10k and M100k which are 0.6W rated as opposed to the 2W components in the previous review. Those would be difficult or impossible to fit. Overall an easy kit to assemble and use.
Date published: 2014-11-11
Rated 5 out of 5 by from I have built one of these, taking into account comments by Marc, Dave and Peter in earlier reviews, changing resistor values/types accordingly. It was easy to assemble and worked straight away. I use it as an intermediate amplifier between my Nokia mobile phone (MP3 player) and a ghetto blaster. It is first-rate in this role; I am very pleased with it.
Date published: 2014-11-11
Rated 5 out of 5 by from Stereo Pre-amplifier kit I sorry to see that this very useful and reliable kit has been discontinued. I have used several in various sound systems.
Date published: 2017-02-25
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Specification

Operating Specifications

Impedance:

1000 ΩΩ

Product Specifications

Soldering Required:

Yes

Dimensions & Weight

Width:

49mm

Depth:

35mm

Height:

1.5mm

Hi I have noticed on the circuit diagram that the capacitors on the left and right channels differ i.e C1 and C2 are 1uf and C4 and C5 are 100n is this correct?

Asked by: Alan
The circuit diagram will be correct.
Answered by: Dominic
Date published: 2017-05-12

What is the Max input Sensitivity in mv

Asked by: Alan
I am sorry but the manufacturer has not provided this level of information.
Answered by: Russell
Date published: 2017-04-28

hi can i ask please what is the gain of the mindsets preamp.

Asked by: richard
This info is in the instruction provided on the listing https://maplindownloads.s3-eu-west-1.amazonaws.com/n47fl-5967.pdf " A low noise stereo preamp based on the NE5532 chip with independently adjustable output levels (gain typically 100). • Operating voltage 3V to 25V."
Answered by: Les
Date published: 2017-03-02

Can I use this for a record turntable ?

Asked by: TSGB
Unfortunately we are unable to guarantee full compatibility for this item in your intended application I am sorry for any inconvenience this may cause you.
Answered by: darren cordon
Date published: 2017-02-07

Does the input signal under go a phase reversal on the output? Thanks.

Asked by: Gord
Sorry NO Full details of the kit as well as a circuit diagram are provided on the listing. https://maplindownloads.s3-eu-west-1.amazonaws.com/n47fl-5967.pdf
Answered by: Les
Date published: 2016-12-08

could you use this to amplify the phono output on a record player

Asked by: has29
A Phono output on a record player needs RIAA compensation. That is Bass boost and Treble cut to specific requirements. So no this amplifier would NOT be suitable without the RIAA correction.
Answered by: Elecjon
Date published: 2016-12-04

Hi I'd like to use some pcb mounting blocks to connect these. Can you tell me if that's possible and what pitch I'd need please?

Asked by: Andy
Unfortunately we are unable to advise on the modification or redesign of units. If you choose to make any modification to the kit and or design it would be at you own behest using components you select, we cannot assist with this I'm afraid.
Answered by: Les
Date published: 2016-11-29

I'm looking to build a spring reverb unit operating in mono. Can I use the Left and right channel on this individually as pre amp and recovery amp?

Asked by: some freaky guy
It is important to note that as a retail only company we are unable to assist with any design projects or queries, or advise on specific products that may be required for your purpose.
Answered by: Dominic
Date published: 2015-07-17
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