JHS wrote:In the Mk1.5/Mk2pro are 2 R (1k/8,2k) connected in series to the collector of the 2nd transistor, though some units have 470E instead of the 1K.
The 47k is connected to the collector of the 1st trannie and I recommend to subs the R with a 50k trimpot for biasing Q1.
If you set the value of the trimpot lower than 33k you have to decrease the FB-resister too or Q2 will be misbiased.
JHS
JHS wrote:The org. TB MK2Pro circuit was designed for the use of the weak OC81D (hfe max. 40, and made for the use in driver and phasesplitter stages in radios).
OC76/44 and similar trannies (hfe app. 70-80) don't match the 2pro circuit specs. as perfect as OC81D, yielding in an dist. sound even at min. gain. and an overcompressed fuzz when maxed. Sola never adapted the circuit for trannies with higher hfe but used them in the later made TBs.
JHS
bobo wrote:Torchy wrote:http://fuzzcentral.ssguitar.com/mkII.phpThe transistor gains for the MKII should be something like 70 for Q1 and Q2 and 100 for Q3.
Thank I already tried Q1, Q2 = 70 and Q3 = 100. The sound is not so good. Someone said Q1& Q2 must have high Hfe than Q3. What's the correct statement.? I tried many hfe of OC-75 but it could not complete with AC-128.
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