Ad Widget

Collapse

Announcement

Collapse
No announcement yet.

Bassman 70 maintainance

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Bassman 70 maintainance

    Hello all!

    I wanted to ask about my Bassman 70. It is still in the original Silverface specs so I thought to upgrade it a bit as I have done to my Fender Silverface Twin. My idea is to alter the phase inverter to blackface specs and to change the bias to a blackface bias next to normal ELCO and tube replacement.

    Now I was wondering; the unit is rated at 70W (hence the 70 in the name)...... does this require a special bias / bias setting? As a 6L6GC is rated at 30W max you could'nt reach the 70W specs, right?

    Schematic

  • #2
    You are mixing up the amplifier output spec (70W) with the output tube's max plate dissipation spec (30W). Have a read through the Aiken articles to see if they clarify the distinction for you.
    http://www.aikenamps.com/Advanced.gif
    Re blackfacing, what are you hoping to achieve? It's got an ultralinear output stage and so is fundemantally different to a BF type amp, it's never going to respond the same no matter how many resistors/caps you tweak.
    Best to make sure the tubes and caps are good, and enjoy it for what it is - a powerful clean amp.
    Keep the output tube balance as it's useful, but add a bias pot. Peter.
    Last edited by pdf64; 11-25-2008, 10:24 AM.
    My band:- http://www.youtube.com/user/RedwingBand

    Comment


    • #3
      Thanks for the advice! As I am just browsing around the world of amps and amp tweaks I still need to learn a lot....... the link is pretty usefull (well, the link is to a GIF file but you know)

      As for the phase inverter, I noticed a great difference when I changed it in my Silverface Twin. The amp was a lot more direct and open sounding, something it lacked before. I hoped this change in this amp would do the same.

      As for the bias, would a bias pot + balance pot be a big advantage over a simple blackface bias set?

      Comment


      • #4
        bias supply

        Using the balance PLUS bias adjust allows you to more evenly balance unevenl matched tubes. Not a big deal in todays world of matching everything but if you have REALLY unmatched tubes(more than 10mA apart) it gets you there. Tone won't change, just versatility. A good feature if you're trying to use up singles that aren't matched. Mike.

        Comment


        • #5
          Ah, I though that..........

          But it can be omitted if one should use matched tubes, right? As I know I would never use unmatched tubes

          Comment


          • #6
            bias adjustment

            No NEED for it at all with matched tubes. HOWEVER, if those tubes drift at different rates, it allows you to adjust for it, if you wish.

            Comment


            • #7
              Thanks!

              I'll check into this then!

              How about the phase inverter; I know from my Twin that the altering of this little circuit resulted in a brighter, more biting tone...... more openness. Would this also happen with the UL output?

              Comment


              • #8
                Sorry about the link, I should have checked it - doh.
                Altering the component values in the phase splitter to typical BF won't cause a problem, so if you've done it before and like the results then go for it. I was just hoping to get across to you that it's a different amp than a BF bassman, more powerful, and with lower output impedance and distortion due to UL configuration. Also due to UL it will need those first power supply filter / reservoir caps working well, so check the B+ ripple at high signal levels. Peter.
                My band:- http://www.youtube.com/user/RedwingBand

                Comment

                gebze escort kurtköy escort maltepe escort
                pendik escort
                betticket istanbulbahis zbahis
                deneme bonusu veren siteler deneme bonusu veren siteler
                mobile casino no deposit bonus
                deneme bonusu veren siteler bonus veren
                deneme bonusu veren siteler deneme bonusu veren siteler
                bahis siteleri
                deneme bonusu deneme bonusu veren siteler Canlı casino siteleri
                mobilbahis rokubet
                güncel deneme bonusu
                deneme bonusu veren siteler bonus veren siteler
                bonus veren siteler
                deneme bonusu veren siteler
                deneme bonusu
                casino siteleri
                bodrum escort
                atv-youth.org Deneme Bonusu Veren Siteler Deneme Bonusu Veren Siteler sherlockimmersive.com
                onwin
                alanya escort gaziantep escort gaziantep escort gaziantep escort mersin escort
                deneme bonusu
                deneme bonusu veren siteler
                deneme bonusu veren siteler grandpashabet
                url shortener betturkey
                Working...