Mottlefeeder

I have to say that I have never understood the reason for setting intonation at the 12th fret, other than the ease of comparing a fretted octave note with the harmonic octave note. Apart from fanned fret designs, surely minimising the error at the 1/2 open string length (12th fret) means that you will maximise the error at 1/4 and 3/4 of the open string length, and 1/4 open string length is where I spend most of my time. On that basis would it not be better to set the intonation to by right at about fret 7? What am I missing? David

Is that the yellow and purple one that's really noisy? David

If it should ever fail with a spectacular puff of smoke, the lack of a power switch might be regretted. That will also be the day it is so close to something else that you cannot easily disconnect the power lead. I would also suggest that you should be able to power down when you are having a break between sets. David

Channel B has the option of a line in or Hi-Z input for an instrument - so far so good. If you connect the 'through' output to your mixer and your tone changes, then you will know that option does not work for you. However, if you are only using channel B, could you use the active-speaker mixer-output as the feed to your FOH mixer? David

I have a PDF circuit diagram for a 2005 HA 1200 which shows no plug/socket connections between pre and power amps, but all 120 watts pass through the headphone switching contacts. That would be my starting point. With regard to the more powerful amplifiers, I have had both a Samson and a Hartke with intermittent faults that turned out to be the output relay. This one doesn't have an output relay. David Hartke Kickback HS1200 schematic.pdf

I posted a design for a one by 10 here, using the Eminence Basslite S2010 10 inch Neo speaker. The box is 30.5 x 32.5 x 39.5 cm, but could probably to tweaked to give you either a footprint or a baffle that matched your speaker: The cab plans were in a March 30th post. If you are anywhere near Manchester/Warrington, you are welcome to come and check it out. David

Bought Alex's BDI 21. Item was as described, communication was good and delivery was fast - thanks Alex. David

Most of those measurements are given at 3 m distance from the instrument - having several of them 1 m behind you must be horrendous. David

A more expensive mixer may well have higher quality opamps in it, or input circuits with discrete transistors as well as opamps, both of which would give you a better sound. Also, if you try and design a cheaper mixer with fewer opamps, some of them will be providing lots of gain, and may struggle to do so compared with a more conservative design using more opamps. That can also degrade the sound. I have small mixers by Behringer, Soundcraft, Mackie and Gear4music, and the Soundcraft and Mackie sound better. David

Mixer microphone inputs are designed for microphones of 200 ohms to 600 ohms impedance, so connecting an instrument to that (XLR) input will not work without a DI box. However, if that channel also has a line input, that is likely to have an input impedance of 10-30 thousand ohms, and a guitar or bass with a built-in preamp will feed into that without loss of tone. A passive bass or solid bodied guitar may work well, or may lose some treble feeding into that impedance - hence the 'Hi-Z' guitar input option on some mixer channels. A passive piezo pickup on an acoustic guitar will probably sound better feeding into an input impedance of about 1 million ohms (and using a short cable). In my experience, line inputs on mixers tend to be in the 10-30 thousand ohms impedance range, so if they have enough gain, they should work with any pre-amped instrument, but possibly not with passive ones. David

One point worth considering is that most guitars operate at about -20dB or -10dB, and most line inputs are intended for inputs at 0dB, so your guitar input could be x3 to x10 times too low. The cheaper the mixer, the less likely it is too have extra gain on the line-in channel to accomodate lower level inputs. David

Stripboard layout for the FDeck HPF Mk3 - note the first version has errors, corrected in the second version later in the thread. http://guitar-fx-layouts.42897.x6.nabble.com/F-deck-HPF-Series-3-td44880.html David

A bit of an unusual one for us - playing at the opening of the first part of Manchester airport's revamped Terminal 2 - first flight out 06:00. Went to bed at 21:30, got up at 01:15. On the road by 02:40. The new car park was apparently opened/signposted about an hour before we got there. Spent about an hour getting visitors' passes and getting our gear through airport security. Started playing at about 04:30. Played two short sets with a break for speeches and then packed up, handed in the passes and headed home. Got in at about 07:00. Nice audience (nothing else going on) and lots of money donated for Cancer Research UK. David

The Bulgin mains connector may not have the clearance distances between the terminals inside as specified for modern connectors, but that does not make it dangerous. For a device that will not be used by children, and will be treated with respect by its owner, 'replace as soon as possible' is a bit of an over-reaction. David

We are both routing the earpiece cables to the back of the neck. The problem I had with taking the cable up my spine was that it was then clamped by the bass strap. If you didn't get the amount of slack right, the earpiece pulls out when you turn your head. Having the slack on the side of your neck keeps it away from the strap, and dropping it down the left front keeps it away from the bass, so it doesn't get clamped except by the clip at your collar. Like you, I use belt loops to feed it to the umbilical connector, but mine is at the bridge end of my bass strap, because it gives me easier access to adjust the controls. There is no right or wrong, just different options to consider. David

I've found that a single rubber cup on an earpiece does not give me sufficient isolation, but a multiple cup (Xmas tree) works better. I'm not sure what yours are, but that might be worth checking. As far as the earpiece cable run is concerned, my cables go from the earpiece to the back of my neck, then round the left side of my neck to be clipped to my shirt at the front, then down the left side of my front. This is the only path I have found which keeps the cable away from the bass strap (assuming you are a RH player). Finally, if you take a feed from the PA, either through a DI designed for speaker use, or from the output (headphone oputput?) of the PA mixer, you can balance the PA and ambient feeds with your bass feed to get the mix you want. David

Heat shrink sleeving is not compatible with all cables. I tried to add extra protection to a microphone cable where it entered the plug, but the heat caused the conductor insulation to shrink, leaving nearly a centimeter of bare wires in the plug. I didn't find out until the cable stopped working during a gig. That particular cable had a polythene type insulation, as against the normal PVC or rubber based ones. Best to check before you start work. Daivid

We put acoustic guitars and vocals through a fairly basic PA, with keys, electric guitar and bass through backline amps. I use resistive DIs to take a feed from the PA speaker, and the speaker lead of my amp, and a Maplins/Tandy electret mic to pick up ambient signals. I feed this to a simple 3-channel mixer, with bass panned left and everything else panned right. The headphone output feeds a belt-mounted junction-box that gives me separate volumes on left and right, and a mono/stereo switch to blend everything together. I'm using shure SE215's. The combination of PA feed and mic feed means I can usually get a good mix of the band sound, and I don't have to fiddle with a separate monitor mix on the main mixer that is not within reach. I can give further details if anyone thinks a similar system would work for them. David

Have you tried tilting the cab back to the angle you want - that will tell you whether you need a wedge under the front or a prop at the back. I needed a prop at the back and I found a s/h 'Standback'. It works well provided no one tries to move your rig. https://www.thomann.de/gb/standback_ampstand.htm David

It is not a 200 W amp. The spec in mathlang's post states a maximum of 200 W, so its 'RMS' power could be 100 W - or it may be that they have got the power supply reserves right this time and it limits at 200 W without objectionable distortion, so it still sounds louder than the competition. Who knows. David

My Ashdown MyBass was fried by a faulty generator at an out-door event. Ashdown talked me through the diagnostic checks I had done/needed to do and then sent me a new amplifier/PSU circcuit board with the agreement that if it worked I would send them the faulty one and £80 and if it didn't work I would send the amp back and they would check it out. No complaints here. David