Search found 143 matches
- 04 Apr 2021, 07:25
- Forum: Amplifiers
- Topic: Valveste 8080 copy EXPERIMENTAL tube gain stage mod
- Replies: 19
- Views: 5259
Re: Valveste 8080 copy EXPERIMENTAL tube gain stage mod
Did you try removing the feedback? Cathode bypassing and changing plate resistor have lesser effects when the stage gain is largely determined by negative feedback loop: 1uF bypass makes open loop gain higher at higher frequencies but does not alter closed loop gain much. 100k to 220k plate load inc...
- 01 Apr 2021, 13:22
- Forum: Amplifiers
- Topic: Valveste 8080 copy EXPERIMENTAL tube gain stage mod
- Replies: 19
- Views: 5259
Re: Valveste 8080 copy EXPERIMENTAL tube gain stage mod
You could also experiment with just removing the global negative feedback loop around tube stages of the original design. It's what keeps the gain so low that the stages run clean with the given input signal range (limited by clipping LEDs). The solid state input stages are also already introducing ...
- 01 Apr 2021, 12:57
- Forum: Vintage Stompbox Corner ( ... - 1975)
- Topic: MusicMan Phasor
- Replies: 9
- Views: 4545
Re: MusicMan Phasor
Peavey introduced the VTX series around the same time so it's difficult to say who copied who. Both likely took the design from some electronics journal of the days. As a side note, Peavey also added a solid-state tube amp emulation circuit to their version of the circuit so that this tube amp would...
- 09 Nov 2020, 09:22
- Forum: Amplifiers
- Topic: Requesting Laney Klipp circuit analysis.
- Replies: 6
- Views: 2664
Re: Requesting Laney Klipp circuit analysis.
It's a basic differential amplifier circuit (yes, similar to LTP phase splitters) sans negative feedback, very low impedance plate load and (very importantly) with only 80VDC plate supply to lower headroom and clipping threshold. Because two opposite-phase outputs are not needed (like in a phase spl...
- 19 Oct 2020, 15:07
- Forum: Amplifiers
- Topic: amp differences
- Replies: 5
- Views: 2528
Re: amp differences
You could compare circuit diagrams of, say, those Mesa and Fender amps and see plenty of differences in them. Those differences are largely the answer to your questions of "what" and "how".
- 14 Sep 2020, 08:33
- Forum: Printed/Published Online Designs
- Topic: Guitar Distortion Pedal, Popular Electronics, September 1999
- Replies: 4
- Views: 4282
Re: Guitar Distortion Pedal, Popular Electronics, September 1999
10K input impedance, no low-pass after clipping, output "ground" referenced to half-supply bias, etc.
Next please.
Next please.
- 03 Sep 2020, 09:54
- Forum: Amplifiers
- Topic: Peavey amp
- Replies: 33
- Views: 7906
Re: Peavey amp
The "Supersaturation" generation of Peavey amps didn't generally have any notch EQ after the tonestack - except for the effects of current feedback in power amp that emphasizes high and low end response. The Bottom/Body/Punch tone controls (featured in later amps) provided level response w...
- 01 Sep 2020, 10:56
- Forum: Amplifiers
- Topic: Peavey amp
- Replies: 33
- Views: 7906
- 31 Aug 2020, 10:47
- Forum: Amplifiers
- Topic: Peavey amp
- Replies: 33
- Views: 7906
Re: Peavey amp
Consult the manual. It probably says tone controls are inoperational on gain channel (that's "feature" of several Peavey amps of the era, sometimes implemented to a "Thick" switch). Yes, as explained the tone stack is bypassed with signal path that swamps impedance of tone contro...
- 07 Jul 2020, 07:14
- Forum: Vintage Stompbox Corner ( ... - 1975)
- Topic: Victory Electronics - Sizzle Tone
- Replies: 5
- Views: 2114
Re: Victory Electronics - Sizzle Tone
I agree. I also recognise seeing this font type in several different places, such as album covers. It's probably some fairly "common" type. Someone with graphic design background could probably tell exactly what it is. E.g. Electro-harmonix logo uses font called "Skjall" but it i...
- 18 Oct 2018, 15:25
- Forum: DIY Projects
- Topic: Friedman BE-100 JFET emu [documentation]
- Replies: 33
- Views: 17911
Re: Friedman BE-100 JFET emu [documentation]
These things are never going to nail the tone of the original tube design because a JFET simply isn't a "drop in" substitute for a 12AX7 triode tube. Key elements that create "tone" of a circuit are overdrive characteristics and "voicing". These JFET "emulation&quo...
- 06 Feb 2018, 15:44
- Forum: Amplifiers
- Topic: Funky distortion circuit on this fender 'super twin' amp
- Replies: 31
- Views: 18297
Re: Funky distortion circuit on this fender 'super twin' amp
Zombie thread resurrected I see... :D Yes, this is definitely a weird circuit since cathode follower likely isn't a first choice when you want to produce "tube distortion". This one "brickwall" clips very asymmetrically and very "hard", with abrupt clipping onset. Aside...
- 06 Feb 2018, 14:58
- Forum: Amplifiers
- Topic: Strange Phase Inverter in Geloso tube amps?
- Replies: 7
- Views: 4681
Re: Strange Phase Inverter in Geloso tube amps?
Yes, nothing but a generic "cathodyne" phase inverter there. ...And overall the setup is pretty generic too: Since cathodyne does not have voltage gain (only insertion losses) there is a common cathode amp input stage for voltage amplification. The same stage also receives negative voltage...
- 19 Aug 2017, 07:59
- Forum: Amplifiers
- Topic: Seymour Duncan - Powerstage
- Replies: 3
- Views: 2768
Re: Seymour duncan Powerstage
Seems like they jumped the bandwagon of "micro" amp products. Everyone seems to have one now. What comes to overall compactness, keep in mind that these "pedal" -type amps often tend to require an external power supply unit, which is about equal in size and weight with the actual...
- 12 May 2017, 17:19
- Forum: Printed/Published Online Designs
- Topic: Speaker and Cab simulators
- Replies: 122
- Views: 84275
Re: Speaker and Cab simulators
You're right about what a speaker sim actually does, it's "just a filter" and I wish there was a simple (stomp)box with a filter inside that was modelled after a really good sounding example of one of those digital cab impulses. The virtue od digital signal processing (like "impulse ...
- 13 Nov 2016, 10:05
- Forum: Amplifiers
- Topic: PEARCE G2R schematic - channel 1, what's happening here?
- Replies: 2
- Views: 2955
Re: PEARCE G2R schematic - channel 1, what's happening here?
For "modern" high-gain designs it is customary to attenuate / filter out majority of lower frequency signal content in order to decrease intermodulation distortion. Yes, many modern high gain design have a significant gain peak around lower mid-range frequencies, e.g. 1 kHz. Yes, it sounds...
- 30 Apr 2016, 09:43
- Forum: Multi-Effects
- Topic: Digital components in analog circuits?
- Replies: 5
- Views: 6452
Re: Digital components in analog circuits?
Concerning "digital potentiometers"... They are actually somewhat broad product category with different types of arrangements for control and different types of arrangements for attenuation. Most complex "digital potentiometers" actually run the signal through Analog-Digital-Anal...
- 30 Apr 2016, 09:15
- Forum: Multi-Effects
- Topic: Digital components in analog circuits?
- Replies: 5
- Views: 6452
Re: Digital components in analog circuits?
You may not always need a "digital potentiometer" if you can substitute it with OTA, LDR, FET or multiplexer IC. All can be used for various purposes of "gain controlling", whether frequency-selectively or at full bandwidth, and you can generate an analog control signal to them w...
- 20 Aug 2015, 16:38
- Forum: Amplifiers
- Topic: Add Three Prong Cord to Japanese SS Amp?
- Replies: 4
- Views: 2919
Re: Add Three Prong Cord to Japanese SS Amp?
Pignose in a much bigger box is what I'd say...mictester wrote:Of course if you drive this thing hard, it'll be a big germanium fuzz box!
- 07 Aug 2015, 15:19
- Forum: Amplifiers
- Topic: Add Three Prong Cord to Japanese SS Amp?
- Replies: 4
- Views: 2919
Re: Add Three Prong Cord to Japanese SS Amp?
Yes, replace with a 3-prong coord, and yes add fuse. Preferably on both mains and secondary side.
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On a completely another topic though, I wonder what could be built to the "unused sections" of the circuit board.
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On a completely another topic though, I wonder what could be built to the "unused sections" of the circuit board.