Search found 758 matches
- Thu Jun 15, 2017 11:53 pm
- Forum: Trainwreck Discussion
- Topic: Express Startup Issues
- Replies: 15
- Views: 1823
Re: Express Startup Issues
Double check the measured value of the cathode resistor on v1a. If it is high those voltages would move in that direction.
- Sun Apr 30, 2017 11:27 pm
- Forum: Trainwreck Discussion
- Topic: Phase inverter issue on express build
- Replies: 1
- Views: 643
Re: Phase inverter issue on express build
Is B3 supposed to be that high? Are the power tubes installed? Did you double check the plate resistor values with a good meter?
- Thu Mar 30, 2017 11:56 pm
- Forum: Technical Discussion
- Topic: New amp build from old pa - transformer question...
- Replies: 24
- Views: 2329
Re: New amp build from old pa - transformer question...
Some use the CT as one end. Many say it's taboo. Most talk about an "air gap" being needed. I think the issue is "saturation." (A bad kind.) Don't do it unless you know how to employ it that way.
- Wed Mar 29, 2017 1:51 am
- Forum: Fender Discussion
- Topic: VibroChamp / Pro Junior Boxy; Suggestions?
- Replies: 11
- Views: 2092
Re: VibroChamp / Pro Junior Boxy; Suggestions?
The trem on the homebrew provides the "ground" connection to a Larmar Post PIMV on a ~5E3~ output.
- Tue Mar 28, 2017 1:48 am
- Forum: Technical Discussion
- Topic: 1974 Traynor YGM-3 Guitar Mate Reverb
- Replies: 17
- Views: 3226
Re: 1974 Traynor YGM-3 Guitar Mate Reverb
PR Trem is an AC signal thru a cap to the bias, so it pushes the bias up and down. I think all non-photo-resistor trems push and pull. Photos just pull down.
- Sun Mar 26, 2017 5:21 pm
- Forum: Fender Discussion
- Topic: twin reverb bias question
- Replies: 28
- Views: 3203
Re: twin reverb bias question
I made that mistake once. Very frustrating. The internets tell us to use the bulb for initial startups but fail to remind us that we must stop using the bulb for any quantitative testing.
- Sun Mar 26, 2017 5:11 pm
- Forum: Fender Discussion
- Topic: VibroChamp / Pro Junior Boxy; Suggestions?
- Replies: 11
- Views: 2092
Re: VibroChamp / Pro Junior Boxy; Suggestions?
Tremolux AA763 trem is the roach type. You won't have the negative bias to send to the trem, to keep it "off," which is only one "issue" with using that trem in a VC type build. I like all Fender trems. The only drawback with the VC trem is the fact its intensity control also changes the bias of the...
- Fri Mar 24, 2017 11:49 pm
- Forum: Fender Discussion
- Topic: twin reverb bias question
- Replies: 28
- Views: 3203
Re: twin reverb bias question
How is the heater voltage during these tests. Does it change measurably?
- Sat Mar 11, 2017 4:38 pm
- Forum: Technical Discussion
- Topic: 6SJ7 Pentode Operating Conditions
- Replies: 51
- Views: 15061
Re: 6SJ7 Pentode Operating Conditions
With the original goal of allowing for better pedal response I wonder if addressing the load on the pedals, while preserving the grid-leak bias, should be considered? My Silvertone 1451 has a single stage grid-leak-biased pentode preamp into the power tube. And it presents very close to a 1meg load ...
- Sat Feb 25, 2017 3:56 pm
- Forum: Fender Discussion
- Topic: 1967 "Fender" Double Bassmaster Custom Amp
- Replies: 34
- Views: 5477
Re: 1967 "Fender" Double Bassmaster Custom Amp
Looks like a great platform for whatever you want to do with it. The only concern I see is the gauge of the orange heater wire looks a little thin.
- Tue Oct 25, 2016 12:40 am
- Forum: Fender Discussion
- Topic: Fender BF Tremolo Disconnect
- Replies: 11
- Views: 3438
Re: Fender BF Tremolo Disconnect
If one experiments with master volumes before and after the LTP, it might be preceived that moving the ratio of distortion away from the pre-amp towards the power amp is a good thing. The reverb channel of a 2 channel BF Fender sounds awful when it overdrives, as the 1st point of the pre-amp to ove...
- Thu Sep 29, 2016 12:05 am
- Forum: Technical Discussion
- Topic: Spark on reverb transformer.
- Replies: 8
- Views: 1195
Re: Spark on reverb transformer.
Looking at a scheme I never thought that this is the same as an OT, as mentioned, regarding flyback. Why have the internets not warned us on this like with that other tranny?
- Sun Sep 25, 2016 3:54 pm
- Forum: Technical Discussion
- Topic: 1st mod = learning the hard way
- Replies: 27
- Views: 3449
Re: 1st mod = learning the hard way
Using mixing resistors will weaken the voltage of each signal 50% from the voltage division. (This is less then a 50% reduction in "volume.") Injecting each preamp in to opposite sides of a LTPI preserves the full strengths. Look at an 18watt Marshall on how to do it. If using pre PI MVs, it won't m...
- Tue Aug 09, 2016 11:44 pm
- Forum: Technical Discussion
- Topic: Installing Strain Relief. Your method please!
- Replies: 14
- Views: 1767
Re: Installing Strain Relief. Your method please!
I place the relief, with the cord in it, into my bench vise. I leave it tight for a while, rotating it a few times. Then I use vise grips to keep it closed and transfer it for installation.
- Wed Jul 06, 2016 11:36 pm
- Forum: Fender Discussion
- Topic: Bandmaster reverb (i think 1974)
- Replies: 5
- Views: 1386
Re: Bandmaster reverb (i think 1974)
I think the 100wt Fenders had a Master in 1971. Drawing # 010182 Rev F is dated 11/17/71 and was not the 1st MV series since it has the boost. Drawing ver C would be earlier, does not have the boost, DOES have the MV, but is not dated: