atsampson

Looks like a fun troubleshooting project! It's a nice tidy PCB, and the output transistors are cheap to replace if needed... Many multimeters won't measure low resistances very accurately, so I wouldn't be too concerned initially about the 0.33R resistors not reading correctly, especially if you're doing it in circuit. Some things to check: If you disconnect the transformer secondary from the board, it shouldn't draw much current. This rules out the transformer and the mains side. Check the power rails are OK - if one of them's present and one's very low, that'd suggest one side of the output has failed. Even better if you can find a way to temporarily break the circuit between the DC rectifier/regulator and the rest of the circuit. Those output transistors are meant to have their tabs insulated from the heatsink. Check that they actually are! (And that there isn't a stray nut trapped underneath, or something.) When you power it up, what's the voltage on the speaker output (before the output filter if it has one)? If it's stuck positive or negative then again that hints as to which side has failed... The electrolytic capacitors are all past their design life at this point - they may still be OK in practice, but you might want to think about replacing them (with 105C versions) once you've got it working.

Bought a mandolin from Andy - great communication, packed carefully and shipped next day. Thanks very much!

One band I play with uses AMPband as above. There's also Bryan James - https://www.musiciansinsurance.co.uk/ - we use them for PLI and equipment cover for a university music club that runs various kinds of events. We've never had to make a claim with them but they've always been very helpful in terms of renewals, updating equipment lists etc. Whenever I've tried to compare quotes from the two companies they've always been so close that it's not worth switching!

You feed white noise into the input, and look at the output with a spectrum analyser - I used JAAA on Linux here, but lots of tools can do the same job. White noise contains an equal amount of energy at each frequency, so it produces a flat line if you connect the generator directly to the analyser; put the pedal between them, and you can see what effect it's having at each frequency. As Jack says, pink noise is the same idea but it has an equal amount of energy in each octave; you could do the same thing with a pink noise generator, if you scale the graph in a different way. The BDI21 is a pretty simple device, and its frequency response shouldn't change (much) depending on the input - it'd be a different story for something like an envelope follower pedal where the equalisation it applies changes based on the amplitude of the input signal.

The BDI21 will always give you a mid scoop, unless the footswitch is pressed or the Blend control is at 0%. Here's what my BDI21's frequency response looks like with Blend at 100% and all the other controls at 50%: There are effectively two sections of the BDI21 - the amp simulator controlled by the Drive and Presence controls, and the EQ controlled by the Treble and Bass knobs. The Blend knob bypasses the amp simulator, and the footswitch bypasses the whole thing. The whole of the frequency response above, including the huge 800 Hz notch, comes from the amp simulator, so if you want less mid scoop, turning down the Blend control will do it. When Blend is at 0% and Treble and Bass are at 50%, the frequency response is more or less flat. Something I didn't realise until I measured it was that the Presence control's behaviour is a bit non-obvious - turning it up applies a few dB of treble boost, but it also significantly reduces the depth of the notch. Here are overlaid frequency responses with Blend at 100% and Presence at 0%, 25%, 50%, 75% and 100%: So if you like the drive effect but want less notch, another option is to turn Presence up all the way, then turn Treble down a little to compensate for the treble boost...

I'm not sure whether this is the case in Biggar, but there are parts of Scotland where the mains voltage is right at the top of the permissable range - here in Dundee my mains supply is typically 247V (the maximum is 253V, i.e. 230V + 10%), and I've seen 248V reported near Edinburgh. So any equipment using an unregulated power supply can end up with supply voltages rather higher than the typical values it was designed for...

There aren't a lot of small mixers with both builtin effects and multiple aux sends - here's a Thomann filtered search. Looks like the Alesis MultiMix 8 FX or the Behringer X1204 are about the smallest devices with that combination. I've not used the Alesis but I've used other Behringer mixers in that range - the build quality is a bit cheap and cheerful, but they work fine and the reverb effects are surprisingly good.

For further comparison, this site has internal pictures of the Trace Elliott ELF (I remember seeing pictures on here at one point but can't find them now - maybe from TheGreek?). Given that there's only centimetres of separation between mains inlet pins and pins on the front panel jacks on all three of these, I think I like the look of the TC design with the least internal wiring to flap around the best! I'm amazed the Trace one meets safety standards.

I wonder if they could do the 77 flatwounds without silks? I always seem to end up finding bits of red fluff everywhere when I fit a set of them...

Bought some used strings from Daniel - very easy transaction and arrived, very carefully packaged, by first class post the next morning. Thanks very much!

Jake Wildwood has made a few "banjo basses" like this using a big frame drum - here's one with a Precision neck and this one has a double bass neck. Seems like an interesting idea, and they don't sound too bad from his sample recordings...

No option for tapewounds? (That said, I put TI Jazz Flats on my Tokai Jazz a few weeks ago and am thoroughly enjoying them...)

Looks like Presto Jazzicatos.

The same video's on this page - Google Translate says the band's called はまち(Hamachi) and the song is 真っ赤な空 (Red Sky?).

You can - the four EQ bands are all parametric, and it's properly flat up to at least 20kHz when everything's zeroed. I bought an RH750 second-hand a few years ago, and I've used it for all sorts of things, both as an amp and as a preamp into PA or for recording. The EQ and tuner work well on acoustic guitar and mandola as well as bass, and you can set it up with presets for different instruments if you're switching between them. In addition to the treble shelving, the "Tweetertone" control is a gentler treble rolloff (about 12dB/octave above 2kHz).

If you haven't discovered it yet, the Grateful Dead allow noncommercial trading of live recordings of the band - you can find most of their live performances on archive.org (streaming or MP3 download) or etree.org (BitTorrent, lossless). The band's YouTube channel has quite a few full concert videos too. I'd second the recommendation of the 1990-03-29 show with Branford Marsalis above as a particularly good one for jamming, but all the Spring 1990 shows are worth checking out - the mid-1989 to mid-1990 shows are probably my favourite era for the band live, with Brent on keyboards, some fun experimentation with MIDI, and the whole band generally playing well. The 1989-10-09 "Formerly the Warlocks" show is another favourite of mine. For an early show, try 1968-02-14 which Phil Lesh recommends in his book - some lovely work by Pigpen in this one. Going even earlier, 1966-12-01 is also great. In terms of studio albums, I'd start with American Beauty and Workingman's Dead (both 1970). As live albums go, there are lots to pick from - Sunshine Daydream (1972) is great, and the accompanying film gives a good idea of what being at the concert was like; The Grateful Dead Movie captures them in their 1974 Wall of Sound configuration.

Here's what my settings look like, connnected to a server in London: Try turning off Auto Jitter Buffer and adjusting the sizes down until you're happy with the audio quality - it'll depend on how much jitter (variation in latency) there is between you and the server.

Lovely! When I was getting into jazz originally, my bass teacher gave me NHØP's "Those Who Were" to listen to - still one of my favourite albums.

Bought a camera from Brian - great communication, shipped next day, packed carefully. Thanks very much!

Perhaps it's intended for large touring bands to store all their spare drivers in safely? 🙂

Bought Shaun's TC Drip pedal - it arrived very carefully packed in as-new condition. Thanks very much!