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JohnH89

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Posts posted by JohnH89

  1. 30 minutes ago, Frank Blank said:


    Sorry Sir, you appear to have stumbled unwittingly into an Internet forum rather than the sensible and rational destination you were headed for. If you'd just turn the light off on your way out we can resume our endless circular pointless arguments until Mum brings us jelly and squash. :hi:

    Light turned off . Dogs let out . Off to bed . I'll let mum sort breakfast out 😃

    • Haha 2
  2. 9 minutes ago, Downunderwonder said:

    You would enjoy the air guitar YouTube guy. He started off with changing guitar body for no name body then lump of 4x2, then literal air by stretching strings between two solid workbenches and propping the pickups underneath. 

    Oh good grief . Here we go again ....................................................................................

    Does anybody actually get the joy of just playing the bass with some like minded idiots for the hell of it . Instead of just pointlessly arguing about the minutiae of stuff that literally nobody other than us cares about . We will all end up in the same place eventually . Enjoy the ride while we can . 

    • Like 1
    • Haha 2
    • Confused 1
  3. 5 hours ago, Happy Jack said:

    That's a very cool micro-rig. 

     

    Do you offer a build service? 😉

    No mate . Life is too busy . If you can solder a jack plug together and drill a hole it is not beyond you .

     

    5 hours ago, tauzero said:

     

    I think this may be the widget you want: https://www.electronics-lab.com/simple-adapter-board-turns-usb-c-power-supply-variable-voltage-source/

     

    So it would be possible to fit a USB-C power bank, one of these boards, and a TPA3118 into a micro cab, with a USB connector and a jack socket on the back panel, and have a portable powered speaker. And a switch to allow switching between active and passive.

    I do have a plan for the future that is similar to this . I was going to build a micro version of my Markbass 801 , using a 6in speaker , DIY rear ported cabinet and a class D board . I was going to stick with the power tool battery as they can be changed quickly , are easily replaced and I have a load of them . A spare can be tucked in a pocket . I reckon 4 of them would do you for 24 hrs play time .

    I fed the original into a high efficiency 12in 4ohm cab and was astounded by the volume . I think a 4ohm 6in driver with 95dB at 1W/m would be more than loud enough . 

    Regarding the active/passive switch , I have found it to be unnecessary . The amp will work fine with a passive . If active overloads it , which it didn't when I tried it , just back off the volume on the bass .

    • Like 1
  4. Original build was with TDA8932 . Mk2 was built with TPA3118 which is 60W at 24v into 4ohm . I think it was 35w at 18v into 8ohm . On recommendation from contributors , mk2 was built with fused power supply . Output is bridge tied load so needs to be an insulated jack . I used my PJB HA1 as a preamp and later the Hotone nano bass . Now I use it straight from the bass as it appears not to need a preamp . 

    Here are a few photos .

    nano class D.jpg

    Mk2 hotone.jpg

    mk1 with bighead.jpg

    JCB bighead mk1.jpg

    TDA8932.jpg

    • Like 4
  5. I am using , when needed , a 35W class D module from ebay for a fiver , from an 18v power tool battery , intlo a PJB C2 cabinet . I bought a Hotone nano bass to use as a preamp but there was no need . A fine sounding little amp that is easily transportable . A 2000mah battery has been tested and was still working 4 hours later . To change the battery takes seconds . This has nowhere near the power of the Briefcase but the battery lasts a hell of a lot longer . This was designed to play a gig that is about an hours walk from the public highway , so the fact that it is a quarter of the weight of the Briefcase is a bonus . I will see if I can dig out some photos and post them here if I find them .

    • Like 1
  6. As above , card scrapers are my go to for finishing fingerboards on uprights and fretless . Take your time and learn how to put an edge on them . Its not hard . Also hand planes are fine tools but again , learn how to put an edge on the iron properly . After plenty of practice and patience , I can level a fretless fingerboard so you can balance a ball bearing on it without it rolling off  .

    Also a decent (not cheap ) japanese saw .

    • Like 2
  7. Welcome the wonderful world of tapewounds . Been using Roto88s almost exclusively for 5 years . Epiphone Jack Casady , piezo jazz fretless and P bass bitsa fretless . The only bass that does not have them is my latest . A Yamaha BB734 with LaBella Jamerson flats . 

    They have a sound to die for on the fretlesses and in my opinion are perfect on the JCB .

    • Like 2
  8. 4 hours ago, fretmeister said:

     

     

    While I love the sound of Roto flats, it turns out I'm allergic to the Monel wrap used. After only a short playing time they leave my finger tips red and painful.

     

     

    Blimey mate ! thats a new one on me . At least the cost of flats and tapes are less than rounds , if you factor in the length of time they last . Put some Labellas on my new BB734 a few months ago , and expect them to last the distance . (mine and the basses )

  9. Absolutely love mine . I have had it for 4 years and it will go in the coffin with me when I croak . They do have their little weirdnesses but well worth the effort of putting up with . Hipshot ultralites on mine cos I had them sitting around and a supertone bridge from Hipshot cos I am not a fanboy of the Gibson 3 point bridge . Strung with Roto tapes and used for everything from folk to punk . A very versatile bass . Not much of a neckdiver but that doesn't bother me that much . With the strap button on the neck heel it can lean away from you , but a long strap and a slight change in technique fixed that . The button can be moved to the top horn with a little work . 

    Buy one and be openminded and adaptable enough to appreciate it .

    • Like 2
  10. A quick update for you who may be interested . Played my Yamaha BB734 through the amp for 2 hours at a rehersal tonight . Sounded great to me and compliments from other band members . Had it up way too loud and made the point it was to stress test the amp . It coped with the above plus 20 minutes or so idling between songs . A couple of quieter tunes to give the ears a rest and finished up with a full on hammering . Now here is the thing ......

    No noticeable heat at all . Played with it on its side for a couple of minutes at the end , and no noticeable heat from the upper reflex port . Not even detectable above ambient temperature . I couldn't tell you if the fan even ran as it would be impossible to hear unless cabinet was dismantled . The rehersal space is centrally heated to 21 degrees (70 F) . 

    Very pleased all round , the only possible casualties are the windows which got rattled a bit .

    Thank you all for your help , assistance and ideas . Any further reports or problems in the future I will post it here .

    • Like 5
  11. 'My calculations show that with 25 degrees C ambient, a 31cm x 31cm x 31cm wood box with nominal 12mm thickness, the final temperature after "forever" (called the asymptotic limit) will be 33 degrees C with an 8 degrees C total temperature rise. This is about what I would expect worst case, pretty much trivial.

     

    Here's one handy enclosure calculator, there are several. These sorts of formulas are also used in the heating and air conditioning industry too, the walls will have a thermal resistance, and if playing in the sun there will also be heat gain due to radiation.'

     

    Cheers for that . Way beyond my comprehension but I have confidence in the design . For info , cabinet measures 395mm on each side of the cube (internal measurement ) . 2 x 75mm ports in the lower part of the rear plate . Cabinet is built from 9mm ply , laminated to 18mm across approx 65% of surface area . Baffle and rear panel from 18mm MDF . 

    I will really try and destruction test it tomorrow . If it survives ( it will ) I will buy myself a beer . And those that have helped can have one on me .  😀

    #downunderwonder . Just what is your obsession with the sideways thing ? I said I would do it just to please you . Just wait for some empirical evidence . Not long now .......

    • Like 1
  12. The BQ250 has a thermal cutout . Let me try a real world scenario later this week and I promise I will get back to you . To please #downunderwonder I will even turn it on its side and check the temperature of the upper port . 

    • Like 2
  13. Because , my learned friend , I am , maybe optimistically , confident that the original design , all things considered , has a far better than even chance of being absolutely fine . 

    If you can wait until thursday late evening or more likely Friday morning GMT , then we will know for sure . 

    I think you may have misunderstood #agedhorse and his very well informed opinions but I will leave that between the two of you . He has quite a background in design and development of bass amplification .

    Be assured that I will post the results of a test and will willingly admit if my assumptions/calculations prove inaccurate .

    • Like 1
  14. IMG_6102.thumb.jpeg.24f6fd594bcca502ff27db7c2e3ed6e6.jpeg

    1 hour ago, Downunderwonder said:

    Please explain. Ime micro amps all get nicely warm to hot enough to be properly glad it's got a fan.

    The BQ250 is a lot bigger than the BAM200/Warwick gnome/TE Elf with better heatsinking and considerably more venting and bigger fan . 

  15. As pointed out , the case and heatsinking on the BQ250 is a lot larger than the Warwick . I have also come across the following from TC electronics

    COMBO750_P0CIS_Front_XL.thumb.png.d3c0531ec60328ffe5e05a88bcdb09b6.png

     

    Which is a 750 combo using this head

    RH750_P0CIV_Left_XL.thumb.png.3500da49f80f96bfbf1ab83dfe38d10c.png

    Also vented from the side and a lot less airflow than the BQ250 .

    My money is still on the little BQ having adequate cooling .

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