K4poz accepts PayPal, USPS Money Order or personal check. Learn more 18+, T&C apply, Credit subject to status. Shipping Costs or cheap with financing Make 3 payments of 58.00. All product info 174.00 1 Each Add to Cart incl. Email me at the address below and ask for a quote on shipping to your address. The Tube Amp Doctor BM4 Bias Master measures the BIAS current of any 6L6GC, 6550, E元4, 6V6GT, 5881, KT66, KT88, KT90, KT100. Outside the continental USA including Mexico and Canada. No longer available from w4zt.Bias Board is available from k4poz.
Tube amp doctor bias master free#
I have no plans to switch to lead free solder in any of my projects. My Bias Board is built using Kester #44 60/40 solder and is NOT RoHS (Restriction of Hazardous Substances) compliant. K4POZ SB-200 retrofit to a single GI-7B.K4POZ homebrew pair of GI-7B's desktop amp.Bias Board Documentation including schematic and parts layout.Having your bias adjustable from the front or rear of the amp is GREAT! I suggest you leave about 100 to 500 ohms resistance in the trimpot which will only effect the low bias end of your adjustment. Then set trimpot R1 to the MINIMUM bias, least resistance, end and your panel mounted pot will work just fine. Solder the leads to your panel mounted 10K linear pot between the cut end of R5 and the pad it was connected to. Simply clip one end of R5, the 100 Ohm 1/4 Watt resistor next to the trimpot R1. If you wish to remote the bias adjustment to the front or back panel of your amp, you can do so easily.
Tube amp doctor bias master series#
Also be sure to include the fuse in series with your bias board (or bias zener diode or diode string if you aren't using this board) so that should there be any failure of the bias board or system, the fuse will keep the tube from drawing excessive plate current due to the cathode being connected directly to B.
If you do not bypass these lines adequately you may experience a bias board failure. 1 uF 200V capacitor across the cutoff resistor. Be sure that you have good bypassing on the B- and cathode lines. Everything functioned properly in idle with no drive but as drive was added a point was reached where the transistor failed. This caused a failure of the TIP-147 transistor with increased drive. There have been a couple of cases where guys did not have the cathode and B- leads bypassed for RF well enough. The B- and cathode leads must be bypassed as shown below to insure that there is no RF reaching the bias board. You MUST insulate the tab of the transistor from the heat sink using the thermo pad and shoulder washer provided. The transistor MUST be bolted directly to a large (preferably aluminum) surface or a good heatsink that receives good air flow to take the heat away from the transistor. There is no need to mount the board with additional hardware but a hole is provided for that purpose if you use a heatsink other than the chassis and prefer to mount it that way. The board can be mounted and supported by the tab of the transistor ( hardware and thermo-pad are included). An additional 10 to 15 volts is available on the high end by cutting a single jumper (at the expense of the low end) and adding the zener and capacitor shown on the schematic. The bias voltage is variable over a range of about 3.5 to 39 Volts. It is built as a direct two wire replacement for the typical zener diode bias regulator or series string of silicon diodes found in thousands of commercially manufactured and home brew triode amplifiers.
Setting the bias correctly is essential for achieving optimal tone and performance, and keeping your amp running safely. The VHT Tube Tester lets you see how current (measured in milliamps or mA) is affecting your tubes and where to set the bias on your amp. Tubes don't have a predictable life, but you can measure how they are performing in your amp. View All WOODSTAX - Shop Tonewood by the Piece.View All All Hardware + Parts by Instrument.
0 kommentar(er)
