Search found 4571 matches
- Fri Apr 26, 2024 9:19 pm
- Forum: Technical Discussion
- Topic: Add an HT Fuse?
- Replies: 7
- Views: 185
Re: Add an HT Fuse?
Just to be 100% clear, my reasoning for what I posted is grounded in many decades of replacing power transformers in amps that have only a mains Fuse. In terms of a vintage amp that’s seen 40 plus years of use ( effects of heat accumulation) and the situation of repetitive blowing of the mains fuse ...
- Fri Apr 26, 2024 7:51 pm
- Forum: Technical Discussion
- Topic: Add an HT Fuse?
- Replies: 7
- Views: 185
Re: Add an HT Fuse?
A HT fuss will cover the whole DC side of the amp, but you mainly have filters that can go bad and output tubes. Filters will give you notice before they go south enough to pop the main fuse, but output tubes do not when they short . In light of this I would be more inclined to place in line with th...
- Fri Apr 26, 2024 10:19 am
- Forum: Technical Discussion
- Topic: Does anyone recognize this amp design?
- Replies: 10
- Views: 375
Re: Does anyone recognize this amp design?
The chassis I would say is not a one of since the nuts that will tie it up into the cabinet are tack welled in, so the amp started life as something else.
- Thu Apr 25, 2024 10:07 am
- Forum: Technical Discussion
- Topic: Blackvibe 6L6 Strange behavior on tone pots
- Replies: 17
- Views: 511
Re: Blackvibe 6L6 Strange behavior on tone pots
If your looking for any mid boost with aFender type tonestack the only way to get any of that or even get a flat response out of it is to turn the volume way up, crank full up the middle and set the bass and treble very low.
- Tue Apr 23, 2024 10:51 pm
- Forum: Technical Discussion
- Topic: Does anyone recognize this amp design?
- Replies: 10
- Views: 375
Re: Does anyone recognize this amp design?
Well it’s got very hard to find knobs from a Heathkit from what I can tell. It’s got a T03 cased transistor mounted near the fuses so I would have to assume it’s DC powered heaters. It looks like it’s got a old paper cased filter in there and 2 other filters that could be old and out of a Highwatt o...
- Sun Apr 21, 2024 12:07 pm
- Forum: Technical Discussion
- Topic: '63 Selmer Treble n bass dilemma..
- Replies: 4
- Views: 167
Re: '63 Selmer Treble n bass dilemma..
I have used the jtm45 PT in a 65 Fender Bassman and one would be hard pressed to hear the difference with the slightly lesser B+ voltage.
If you can surmount the mechanical difference I say go for it, and you would likely save the owner 100 bucks in the end also.
If you can surmount the mechanical difference I say go for it, and you would likely save the owner 100 bucks in the end also.
- Fri Apr 19, 2024 10:07 am
- Forum: Marshall Discussion
- Topic: Bad case of ghosting...I've tried everything.
- Replies: 5
- Views: 398
Re: Bad case of ghosting...I've tried everything.
You did not mention if you tried different known good preamp tubes.
I have had a condition like that a few times that was due to a preamp tube.
Have you tried a different speaker?
I have had a condition like that a few times that was due to a preamp tube.
Have you tried a different speaker?
- Fri Apr 19, 2024 10:01 am
- Forum: Technical Discussion
- Topic: Illinois brand capacitors still bad?
- Replies: 10
- Views: 360
Re: Illinois brand capacitors still bad?
Yes they are not at the bottom of the ladder any more.
- Wed Apr 17, 2024 7:02 pm
- Forum: Technical Discussion
- Topic: Taming amp gain in single channel deluxe reverb build
- Replies: 52
- Views: 1158
Re: Taming amp gain in single channel deluxe reverb build
Note that 6BQ5 PP output stage needs 10 volts less of grid to grid drive signal then a 6V6 output stage does.
- Wed Apr 17, 2024 3:34 pm
- Forum: Technical Discussion
- Topic: Taming amp gain in single channel deluxe reverb build
- Replies: 52
- Views: 1158
Re: Taming amp gain in single channel deluxe reverb build
Please clarifie what your doing better. You can't be pumping in millamps ( MA ) of signal like you posted, millvolts yes. Interms of the MV level are you saying .037 volts or .137 volts, I use about .115 volts. (-10 DB ) which is about a single coil pick up output level, if your pumping in .137 then...
- Tue Apr 16, 2024 11:07 pm
- Forum: Technical Discussion
- Topic: Output Transformer formula?
- Replies: 13
- Views: 460
Re: Output Transformer formula?
Of special interest to you if you want to print them off would be pages 31 thru 38.
- Tue Apr 16, 2024 3:32 pm
- Forum: Technical Discussion
- Topic: Output Transformer formula?
- Replies: 13
- Views: 460
Re: Output Transformer formula?
Note that it only covers tubes that RCA made and there's quite a few that only GE made that will not be covered in detail if at all in the RC30 book.
- Mon Apr 15, 2024 10:15 am
- Forum: Technical Discussion
- Topic: Output Transformer formula?
- Replies: 13
- Views: 460
Re: Output Transformer formula?
That wattage rating of any tube is DC parameter, not AC voltage which is the audio output.
Go to the Tubes & more site a buy a copy of the RCA rc30 tube manual, it’s worth every penny as they say!
Here’s a example from the tube data section of the on line Duncan tube amp site.
Go to the Tubes & more site a buy a copy of the RCA rc30 tube manual, it’s worth every penny as they say!
Here’s a example from the tube data section of the on line Duncan tube amp site.
- Thu Apr 11, 2024 10:08 am
- Forum: Marshall Discussion
- Topic: Bias voltage range on JCM-800?
- Replies: 5
- Views: 202
Re: Bias voltage range on JCM-800?
With a -58 available I would also say that the amp was born with 6550s. With 34s in the amp you want to have the low end of the bias range go down to like-36. Start off with adding in series to the input side of the bias adjust pot a 10k to and then see what that gives you . Of course do this bias v...
- Sun Apr 07, 2024 7:00 pm
- Forum: Technical Discussion
- Topic: Stereo 6v6 amps in one cabinet - proximity considerations
- Replies: 6
- Views: 170
Re: Stereo 6v6 amps in one cabinet - proximity considerations
If the level of Genius that Designer McIntosh had in him was happy to make a stereo tube amp with its major components laid out like this then suffice to say that you would be fine to do the same for your build.