escholl

Given the amount of dislike and confusion displayed here over people who name their basses, I'm going to say that, err, no of course I've not named my bass. Don't be silly. *looks around shiftily* ....*runs*

[quote name='LukeFRC' post='809863' date='Apr 17 2010, 09:18 PM']added the wire to my P bass (why dont they earth through the amp's earth, surely that would make more sense?)[/quote] To stop you from being electrocuted in case the signal ground goes live for whatever reason, or in the more likely event you touch something else live while holding the strings. If you put a 47nf or 100nF cap between the bridge and the ground, instead of a straight wire, then you should be alright, as the cap will limit the AC current that can flow through -- give you a sharp jolt but nothing that will do any damage.

[quote name='JackLondon' post='806219' date='Apr 14 2010, 04:35 PM']I did follow the signal through with a probe and it goes everywhere, the problem is there's no wah sound. I've taken off all the mods and taken the circuit out and wired it directly to jacks without a switch, my voltages are getting close to where they should be but there's still nothing happening.[/quote] I've never worked with these chips before, am not familiar with the circuit, and don't have it in front of me to work on. Having said that, and based off of what you said above, this is my best guess, and this is what I would try: Take out IC3, and directly connect where pins 11 and 10 were in the socket with a jumper wire. Do the same to pins 9 and 8. Don't worry about any other pins for now. Run audio through the pedal. The wah effect should now be hard on. If there is still no wah, start by diagnosing the audio filter, which is the top part of the circuit. If there is a wah sound now, the problem lies either with IC3, or with the control voltage generator, which is the large, bottom portion of the circuit diagram. Whichever of these two outcomes it is, let me know, and I'll help you the best I can.

My BDDI and Blackfinger are always on when I have them, but if I don't have them I can usually live without them. I wish parallel compression effects were more common :[

[quote name='Clarky' post='794982' date='Apr 3 2010, 12:33 PM']Thanks Etienne! Its more of a background interference type noise, like a hissing/crackling when that pickup is selected and on full.[/quote] Does it happen only when you turn the knob? Or constantly?

[url="http://www.maplin.co.uk/Module.aspx?moduleno=50"]This[/url] is all you need for the internal wiring. Fairly cheap, easy to get, works perfect. No need to spend more.

[quote name='essexbasscat' post='793796' date='Apr 1 2010, 10:18 PM']Class B cuts the current cycle at the valve, so it has to be regenerated another way. Still one valve (simply).[/quote] Class B will always be an even number of valves or transistors, similar to AB. Never only one valve (exceptions may be, theoretically, where one valve might have two gain stages, such as dual-triodes). [quote]Then copied from alien's post: "Most of these only have valves in the preamp, which more or less by definition runs as class A. When amp manufacturers call their amps class A, class D etc. they're referring to the power amp stage." I'm fine with the first bit, as that concurs with jack's explaination or valves in the pre - amp stage, but the second sentance throws me, as it seems fundamentally at odds with jack's explaination of the classes being described in terms of how the pre- amp operates. Q. Can anyone shed any light here please ?[/quote] The two stages of amplification are not related to one another. Preamps run exclusively in class A for audio (or at least I've not encountered any that don't), as they don't really dissipate any power and thus efficiency is not a concern, however they present simplicity, lower distortion, better linearity, and better stability than other classes -- hence they make good input stages. The topology of the power amplifier stage, whether it is class, A, AB, etc is unrelated to the preamp, and as Alien says, when manufacturer's talk about the class of their amp, they are referring to the power amplifier stage. [quote]Q. What's an H class ?[/quote] The power rails of the amplifier supply are continuously variable. By keeping the rails just a bit higher than what is required by the output waveform at that moment, the output stage of a class AB can be run more efficiently and will waste less power, at the cost of higher THD and increased complexity of design. Class G is similar in concept with the exception of having discrete power rails that the amplifier switches between, instead of a continuously variable supply. [quote]"class ab2 amps have a less linear response than class ab1". I understand that Linear gain is uniform progressive while Logarithmic gain follows a curve when charted. Q. Can anyone explain what this means in real terms to the ear ? Q. If someone like trace etc develop pre-amps with greater numbers of valves, is this a way of promoting greater efficiency in the current modulation stages of the pre-amp?[/quote] In answer to your first question, it really depends on what the non-linearity is caused by. It could be a distortion of the waveform, or it could be something like compression (or expansion) of the signal. Basically anything where the waveform going in is not linearly proportional to the waveform coming out, but there's not a specific "sound" as it can be due to a multitude of things. I'm not really sure what you mean by your second question, but there are never really ever any concerns with preamp efficiency, at least not in bass amps. In large circuits with many, many small signal amplification stages, such as mixing consoles, the power consumption of each gain stage can be a concern, at least in terms of designing the power supply (but even then they are always class A, regardless). But this is largely irrelevant to small systems such as musical instrument amplifiers. If they add more preamp valves, it is likely just to obtain a better, different, or more flexible sound. To summarise, the only topologies used for audio pre-amps is class A, at least as far as I'm aware. The only topologies used for audio power amps are Class A (including single ended and push-pull), Class AB (including AB1 and AB2), Class D, and Classes G and H, which are basically Class AB. Class B does have some limited uses in audio, such as in mobile phones, where audio quality can be traded for efficiency while keeping to a simplistic design. In general, you may safely ignore Classes C, E, and F entirely for audio. Class T, if anyone ever mentions is, is not a real class -- just the marketing term for a (incidentally very good, and now sadly defunct) type of Class D. Just remember the general differences between A, AB, and D, and you'll be fine. :]

[quote name='Rimskidog' post='789925' date='Mar 29 2010, 08:55 PM']Adam s3a.[/quote] Ooh nice, I love the Adam tweeters, definitely some of the best out there.

In a VW golf: -HH Bass Machine head -Two HH Unit Bass III cabs -bass -pedalboard -22" bass drum, softcased -One floor tom, two rack toms, softcased -cymbals -hardware bag -two people The best I've ever seen though was: -double bed, mattress and frame -tv corner cabinet -two people ...in a Clio!

Nice. What are you using for nearfields?

[quote name='SS73' post='788552' date='Mar 28 2010, 03:12 PM']I have put Alps pot's in guitars before now[/quote] haha, I knew I'd forgotten one make!

According to the datasheets you are right about the max plate voltage being 600 volts for a 6550, for the KT88 the plate voltage max is 800 volts. If they can be interchanged in the circuit, as they often can be, then I would go for the KT88's. Can't recommend any specific brands though, as I've not much experience there.

[quote name='HarryPotter' post='784993' date='Mar 24 2010, 06:55 PM']Bit of an update and a result - spoke with Ashdown, carried out all the checks they asked me to, they decided it was broken, and although out of warranty they would repair it gratis as a good will gesture, all I had to do was ship it to them. Sent it to them Thursday, they got it Friday, I got it back Today. They'd replaced the rear PCB as it was faulty (and they have, the Speakons are diff colours and the board looks different). Works fine, fingers crossed its 'fixed' for good now. Another good result for Ashdown Customer service.[/quote] Customer service -- one of the many reasons why I have always liked Ashdown. This is great to hear

As far as I'm aware, Alpha, Bourns, and CTS are the three most common. I've never had problems with either, although the concept of plastic pot shafts, and the use of conductive polymer, in a guitar does appeal to me -- I think next time I'll probably try Omeg or someone like that.

I've always really liked the Visualsound V2, guitarist of the band I used to be in had an H2O, which has the V2 in it, and the chorus is really lovely on bass. Would be my choice above any of the others I've tried, but hardly anyone I've ever seen uses it.

[quote name='JackLondon' post='784628' date='Mar 24 2010, 01:04 PM']What would you suggest for the volume drop? Bear in mind that this effect will be used for guitar only! I'll check all the solder points later on and see if it's all good! But if there are any badsolder points would the signal still go through? I'm still thinking about the power supply, just doing a bit if research at the moment and trying to get an idea of what is going to work best![/quote] Glad to read you got it working, if you've still got the volume drop problem there are two resistors near IC1b, a 10k and a 33k. Raise the value of the 33k. The ratio between them will determine the gain of that final output stage (33k/10k) and by changing the 33k instead of the 10k, hopefully the de-emphasis network which is also there (comprising of the 0.01uF cap and 6.8k resistor) won't be affected too much. As far as power supplies go, for a linear supply the extra complexity of an LM317 circuit is worth it I think, as they have nearly 10dB better typical ripple rejection when properly set up. I personally like switch mode supplies for pedal boards however as they are multi-voltage and generally smaller. Most of them are properly filtered as well nowadays so no worries there -- if I was to do it on the cheap and wanted to build it myself, what I would probably do is find a small power supply off of a disused laptop, smaller is better as they should all easily be able to meet your needs in terms of current. This should output around 19 volts, feed that into a LM317 circuit, and there you go. I suppose it depends how far you want to go, you could always try something like an op-amp regulated supply, if you really wanted to go crazy... Although unless you are really set on having separate regulated outputs for cheap, or on building it yourself, I would probably just buy one -- it will work out about the same price or possibly less.

[quote name='chris_b' post='784605' date='Mar 24 2010, 12:43 PM']Some tell us that you can't successfully mix speaker sizes, that cables are all the same and that power conditioners don't do what the manufacturers claim.[/quote] Mixing speaker sizes won't lead to an early death or global warming, but there are objective reasons why it is not an ideal solution. Cables are not all the same but once you pass a certain quality threshold (generally speaking, around 20-30 quid) the differences between makes becomes irrelevant. Furthermore, there are actually times when a higher capacitance cable may be the favourable tonal solution, however shielding and connector quality are always important. For speaker cables, it is important to simply have decent sized copper conductors well soldered to connectors which will provide a good, firm contact, thus providing as low an overall cable resistance as possible. Once you reach that point, your money is better spent elsewhere. In the studio and in hi-fi systems the same principle applies, regardless of what manufacturers say. Psychoacoustics is a powerful thing. Power conditioners do, often, do in operation what the manufacturers claim. The will remove high frequency noise and harmonics above 50/60 Hz, and provide a measure of surge protection. In my experience, they are also unable to remove most of the things which are truly disruptive, such as transients caused by lights being turned on or off, or the mains noise generated by a high-current AC motor. As such, their necessity, given that any well made electronic equipment will have a power supply which does a similar or better job of this, and why they should be chosen over a simple RCD and surge protector, is debatable. In my own personal objective view, short of upgrading to a rather expensive balanced power conditioner (for studio use, not live), there is no need in the UK to use a conditioner on the mains supply. They *do* tend to be useful, however, as they will also likely incorporate built-in rack lighting and convenient power distribution functionality.

[quote name='JackLondon' post='784545' date='Mar 24 2010, 11:40 AM']Right, I finished putting the small clone together but there seems to be 2 problems! Number one there's a small volume drop when the effect is on which isn't that big of an issue to be honest. The second problem is there's not enough chorus in it, it doesn't affect the sound that much, I fiddled with the trim pot and it does almost f*ck all as well as the pots don't change the sound at all! Any ideas where to start?[/quote] The volume drop is normal, there is a way around it though. As for the chorus part not being loud enough, the first thing I would would be to double and then triple check all solder connections, and the same with component orientation and values. By the way, did you ever decide on a power supply design?

[quote name='cheddatom' post='776021' date='Mar 16 2010, 09:51 AM']If you have the option to mix two signals together, it would be worth trying the two channels in parallel, or better yet... Set one channel to punchy compression, then mix this around 50% with clean, then feed that into the limiter![/quote] Try putting the limiter before the parallel compression. Set the threshold above the compressor threshold (obviously), that way the compressor doesn't have to deal with the signal peaks and can really work more effectively on shaping the dynamics. Otherwise you are still caning the compressor with the peaks, which you don't limit till afterwards, when it's too late!

[quote name='cheddatom' post='783451' date='Mar 23 2010, 02:08 PM']Good idea![/quote] I can't find the SPL circuit in the usual places, but if anyone manages to find it let me know, I will add this to my short list of concepts I'd like to play with and will some day -- honestly -- get round to.

[quote name='cheddatom' post='783398' date='Mar 23 2010, 01:31 PM']Random idea: High gain distortion reduces all dynamics from the input signal. What if a pedal "read" the dynamics of the clean signal, then obliterated it, then used the "reading" to vary the volume of the output?[/quote] Interesting idea. What if something like the envelope follower of an SPL Transient Designer was used to control the envelope of the distorted signal, thus allowing you to adjust the attack and sustain of the distorted signal as well, similar to the way that unit works?

[quote name='JackLondon' post='783357' date='Mar 23 2010, 01:01 PM']You're not wrong there. The lead stuff is more harmfull, few years ago I've worked in a steel factory that was dealing with loads of lead stuff and after about 2 hours of being close to the fumes it gets a bit funny [/quote] If you were in a steel factory, were you not using acid flux then? As far a I know, for electronics, leaded and non-leaded solder use the same rosin based flux. Acid flux, thankfully, is never used. Have used aluminium solder a few times, don't know what the flux is but it's got to be pretty potent to cut through the aluminium oxide -- ughh, one of the worst things I've ever smelled.

[quote name='JackLondon' post='783198' date='Mar 23 2010, 11:19 AM']Inhaling the fumes for a long time can cause headaches, fainting, upset stomach and prolonged inhaling can damage your lungs! F*ck it I say, I prefer proper solder joints [/quote] This is true of all solder though, not just leaded stuff. The smoke and fumes are caused by the flux, not the solder itself. [quote name='LukeFRC' post='783316' date='Mar 23 2010, 12:42 PM']To be honest that SFT is amazing, it would be worth having two of them in a box for two different channels![/quote] Where did you get the SFT circuit diagram from? I would be interested in it.

I've had one of those EHX pedal bags and a Johnny Shredfreak 9V supply for my pedals together for about almost two years now, never let me down and only set me back about 50 quid in total for the two.

[quote name='bobbass4k' post='782293' date='Mar 22 2010, 12:24 AM']I have far too many opinions on solder[/quote] I thought I was the only one who suffered from this