JapanAxe

Another vote for OBBM, especially for speaker cables.

I have a Neo D single coil installed in my Taylor. I will measure it when I get home. Btw I did have to modify it to make it fit, but that was because it was too close to the strings - I removed the top set of cork pads and replaced them with pieces of thin (1mm?) cork sheet.

So many amps, so little time!

Just ordered a PF-50T from Kenny's. 😎

The manual online says it's 400W at 4 ohms - and that's an old-school MOSFET power amp, should be plenty loud through a decent cab.

Leave the soldering iron alone for now. Assuming a passive bass, select one pickup only, connect your meter across the output. Slowly turn the appropriate volume pot through its range and note the maximum reading, which will be somewhere in the middle of the sweep. Double that for the approximate pot value. The nominal resistance of the pot will be a 'round' figure, so if you get 257k, that would indicate a 250k pot.

I am very conscious of this, but the Demeter has no top vents. I usually hang my bar towel on my guitar stand. I do occasionally have a problem with drummers putting their mobile phone on my amp or speaker, with inevitable ray-gun noises when it communicates in any way.

Rather fun actually. Regular gig at a large chain pub, which can get a bit over-lively. Slightly quieter tonight, but lots of young people dancing enthusiastically. Apparently there were quite a few 'freshers' out on the town. I was somewhat mortified to think that it is 39 years since I was a fresher myself! Anyway, I took my Mustang rather than the usual Precision, to give my fretting hand a bit of a rest. It sounded superb - I think it is probably the rockingest bass that I own. Here's me (looking like the BFG's nephew) and my rig:

Thanks! Another option was the AC30 output stage - I found the schematic for the 'bass' version on the Dr Tube website.

Just had a quick look at that schematic. The PI/driver is a 12AU7, and it will probably be simplest if I keep that in and follow the circuit from the wiper of the volume pot - before that will be my 6SL7-based B15-style pre-amp. Solid state rectifier for the HT - works for me, as I have no 5V secondary on my PT, and there is enough power available on the 6V heater secondary for four EL84s and four 12AX7s. Am I right in thinking that is cathode biased like an AC30? Yes there will, but first there will be a design-based thread in the Repairs & Technical forum, and in the Tube Amp DIY Builders Facebook group to which I subscribe (where you get people like Rob Robinette and Bruce Egnater chipping in with advice!)

Thanks @Bigwan, you are a star!

You may! I have just acquired (as scrap) a Carvin Vintage 33 combo. The cabinet is more than a little distressed, the speaker is blown, but both transformers work. My plan is to take the existing chassis and transformers (and some other useful working parts e.g. switches, pilot light) and convert it to a 30W bass head with the following features: Output section based around four EL84 valves, because that's what the OT is suited for - hence my interest in the LB30 schematic; Preamp based on a 1964 Amped B15 channel; That's about it! I need to make sure that the pre-amp will work with the power amp (i.e. that phase splitter has enough beans to drive all the EL84s), so I will be working on my understanding of push-pull amps and hitting up the forums . Here's the innards as I got the amp, and the almost-gutted chassis:

Thanks @Bigwan

Does anyone have a schematic for the Ashdown Little Bastard 30? Or at least the output section. I have a project in mind...

OK, so no need for me to snag a used big-iron Class AB head then. D'oh!

That's an utterly brilliant justification for GAS! Just off to enquire about a big f-off head that might still be for sale...

That does make sense for the bass guitar, as a clean bass note starts with an amplitude peak which falls away to a much lower sustained level, then decays away. The TC Active Power Management blurb describes how the system heavily limits the initial peak, so that they effectively only have to amplify the remainder of each note. EDIT: Although we should all probably stop worrying about power, and listen to how loud an amp is and whether we like the sound, inevitably we are always going to want numbers to compare.

That's the point, there is no logic to GAS. I have a killer amp and cab yet I still find myself browsing eBay and the BC Marketplace for another amp!

I am the lucky owner of a lovely hybrid bass head, with a valve pre-amp and Class D power amp. Recently I had to carry out a repair on the pre-amp, and it got me thinking about other amps - could an all-valve head be EVEN BETTER? For a while I had been ogling an EBS T90 Classic on Absolute Music's website. I had a gig in Longham on Tuesday night (only 3 miles from the shop), so Mrs Axe and I drove down early and I took a bass and cab in to try it out. It's fair to say I didn't feel the love; it sounded quite nice, but was a bit hissy, and I didn't think it went loud enough before running into distortion - I tried it in their big Live Room, you can't really tell in a demo booth! No sale. Then I toddled off to my gig. My own rig sounded truly wonderful So no more amp GAS then? No, I'm now thinking about building/repairing/modding a 'big iron' conventional transistor amp... And that, folks, nicely demonstrates the illogic of GAS

For only £199.99 you can be the proud owner of this not-very-highly-sought-after Marshall Bass State combo. Except it's 'for spares or not working'. And if you want it posted it's another £39.99. Huh?

Welcome Giulio, from another AVRI 63 Fender Precision owner!