It would be possible, it’s a similar scenario to Fender’s 6G series, eg https://el34world.com/charts/Schematics ... _schem.pdf
But the design and layout will probably need amending to keep things stable and usable.
Search found 2707 matches
- Wed Jan 17, 2024 10:47 am
- Forum: Vox/Hiwatt Discussion
- Topic: Can Top Boost Be Added to the Vib/Trem Channel?
- Replies: 5
- Views: 771
- Fri Jan 12, 2024 12:25 pm
- Forum: Speakers and Cabinets
- Topic: 1920s vintage speaker with a guitar amp (Impedance problem)
- Replies: 4
- Views: 2433
Re: 1920s vintage speaker with a guitar amp (Impedance problem)
A photo clearly showing the component that the wires connect to would be beneficial. Are there definitely only 2 wires from the speaker assembly? Are any of the components magnetic? I get the impression that it’s not the standard magnet / polepiece / voicecoil / former / cone design. Maybe more akin...
- Wed Jan 10, 2024 12:09 am
- Forum: Technical Discussion
- Topic: 6L6 vs KT66
- Replies: 26
- Views: 30978
Re: 6L6 vs KT66
Would I use the same Screen and Input Grid Resistors from the 6L6 when switching to KT66? The amp I have uses 470R for the Screens and 2.2K at G1.. hardly, since a real kt66 draws more screen current than a 6L6 … I never even seen a real MOV KT66, nevermind tested an amp with them to see how they p...
- Tue Jan 09, 2024 12:09 pm
- Forum: Technical Discussion
- Topic: Odd behavior regarding variable NFB, presence, and volume in a Plexi clone
- Replies: 20
- Views: 16961
Re: Odd behavior regarding variable NFB, presence, and volume in a Plexi clone
… if the presence knob is not cranked to maximum (or slightly below maxium), I have some pretty obnoxious 120hz buzz. Additionally, switching in the additional gainstage in front of the plexi topology leads to some strange oscillations unless the presence knob is at MAX. How about if the NFB is dis...
- Sun Jan 07, 2024 12:07 am
- Forum: Technical Discussion
- Topic: Stumped by Silverface Twin Reverb...PT?
- Replies: 11
- Views: 6995
Re: Stumped by Silverface Twin Reverb...PT?
It seems like the mains transformer is fine then.palomarsound wrote: ↑Sat Jan 06, 2024 11:43 pm … I'm getting 0v across the primary. I do see continuity across the primary. …
With no voltage across the primary, you can’t expect any voltage out of it.
- Sat Jan 06, 2024 1:31 am
- Forum: Technical Discussion
- Topic: Odd behavior regarding variable NFB, presence, and volume in a Plexi clone
- Replies: 20
- Views: 16961
Re: Odd behavior regarding variable NFB, presence, and volume in a Plexi clone
I suspect that the amp is oscillating; the hum is indicating that, you’ll probably find that the cathode voltage is increasing and HT voltages are reducing alongside it. It may be that the OT is very low spec, has too much phase shift to accommodate a feedback loop. But it also may be that the amp i...
- Thu Jan 04, 2024 7:48 pm
- Forum: Technical Discussion
- Topic: Odd behavior regarding variable NFB, presence, and volume in a Plexi clone
- Replies: 20
- Views: 16961
Re: Odd behavior regarding variable NFB, presence, and volume in a Plexi clone
People sometimes flip the signal polarity when fitting a LarMar, they don’t realise that the polarity has to be maintained.
If the power amp gain reduces when the feedback loop is opened, then the feedback is positive.
If the power amp gain reduces when the feedback loop is opened, then the feedback is positive.
- Thu Jan 04, 2024 7:42 pm
- Forum: Technical Discussion
- Topic: Replacing a tube rectifier with solid state?
- Replies: 10
- Views: 7323
Re: Replacing a tube rectifier with solid state?
… To stabilize the bias voltage I used a Z-diode. https://ampgarage.com/forum/download/file.php?id=72380&mode=view … I can’t see a zener in the bias supply? Anyway, my thinking is that it’d be a bad idea to regulate the bias voltage. It seems better to allow the bias and HT supplies to track the ma...
- Wed Dec 20, 2023 4:53 pm
- Forum: Fender Discussion
- Topic: Curious about original fender layout\build
- Replies: 5
- Views: 3439
Re: Curious about original fender layout\build
Also Fender typically made more than a few soldered connections to the chassis. Those tend to not be not feasible for DIYers to do, unless they’ve got a big bertha iron and the skills to use it.
- Wed Dec 06, 2023 11:57 am
- Forum: Technical Discussion
- Topic: Rebuilt Transformers
- Replies: 24
- Views: 18180
Re: Rebuilt Transformers
Maybe @wpaulvogel would be interested in taking this on?
- Sun Nov 26, 2023 11:23 pm
- Forum: Trainwreck Discussion
- Topic: Changed the Input Grid Stopper to 68K
- Replies: 6
- Views: 3505
Re: Changed the Input Grid Stopper to 68K
Maybe use a higher value cap? eg 1nF.leadfootdriver wrote: ↑Sun Nov 26, 2023 10:01 pm … I actually removed that very arrangement to add the 68K.
For me the extended highs are to much glaze on the sound...
They work out to 34k.leadfootdriver wrote: ↑Sun Nov 26, 2023 10:01 pm … Whatever hiss that's there is still good enough for nearly every Fender and Marshall worth hearing..
- Sun Nov 26, 2023 9:46 pm
- Forum: Trainwreck Discussion
- Topic: Changed the Input Grid Stopper to 68K
- Replies: 6
- Views: 3505
Re: Changed the Input Grid Stopper to 68K
68k grid stopper will introduce hiss.
Merlin suggests to use 10k and add a cap to obtain the desired high frequency response / RF rejection.
http://www.valvewizard.co.uk/gridstopper.html
Merlin suggests to use 10k and add a cap to obtain the desired high frequency response / RF rejection.
http://www.valvewizard.co.uk/gridstopper.html
- Sat Nov 18, 2023 1:30 pm
- Forum: Trainwreck Discussion
- Topic: Weird note decay - Express build
- Replies: 41
- Views: 16550
Re: Weird note decay - Express build
My guess is that’s it’s unstable.
It’s to get the scope out, verify that, and identify what stages are included in the pfb loop.
It’s to get the scope out, verify that, and identify what stages are included in the pfb loop.
- Wed Nov 15, 2023 6:33 pm
- Forum: Technical Discussion
- Topic: Does a 'bright cap' really boost highs?
- Replies: 21
- Views: 4974
Re: Does a 'bright cap' really boost highs?
… Does a so called "Bright Cap" on a volume control … actually boost highs, or does it really act as a HPF and rip out lows … The distinction between those 2 options might be seen as something of a matter of perspective really. What matters is that unless the volume is set really high, the amp soun...
- Sat Nov 11, 2023 12:26 am
- Forum: Fender Discussion
- Topic: 5V4 recifier with 6L6WGB pair
- Replies: 12
- Views: 4043
Re: 5V4 recifier with 6L6WGB pair
… I'm wondering if I could get away with using a 5V4 rectifier considering the low to lower-medium volumes I play at in the small to medium size bars and restaurants I gig frequently at… I suggest to use a GZ34 with a sag resistor, eg 100R, in series with the rectifier output. By that you’ll get al...