We all want the best sound, but getting a great guitar, amp, pedals downloadd so on is quite expensive, so why break the bank when you power iso free software download for mac get some Virtual Instruments that will do the job. I also want to add 3 plugins to the list which are not free, but which are really good, should you choose to invest some money into them. It sounds absolutely fantastic, while also giving you the option to add some effects. You can even double the guitar with the simple press of a button, which will add width and body to the sound. I think that everyone should download it.
As the guitar signal causes the current flow through the cathode resistor to fluctuate so does the voltage drop across the cathode resistor the bias voltage. Since the bias voltage fluctuates with the input signal it is not 'fixed. It can mean the actual voltage measured from the tube plate pin to ground but when measuring tube bias amp means the voltage difference between the tube's plate and cathode.
To avoid confusion I use the term plate-to-cathode voltage. You can also measure the plate voltage and the cathode voltage separately then subtract the cathode voltage from the plate voltage to get plate-to-cathode voltage. Triode Tubes Triode tubes do not have a screen so they do not have any screen current to consider. For a dual triode tube with both triodes used enter "1" in the Enter Number of Tubes that share a cathode resistor box.
For example my Deluxe Micro amp uses both triodes of a 12AU7 rated at 5. If the amp used only one triode then the max dissipation would be 2. It's red plating due to a too free bias. For amps with cathode bias resistors you can simply measure their voltage drop and use the Tube Dissipation Using Cathode Bias Voltage Drop calculator.
My recommended bias measurement method is the " Output Transformer Resistance Free. You can also measure the actual plate current by shunting the output transformer with a multimeter in the DC milliamps mode and use the Tube Dissipation Using Plate Current calculator. This method is more dangerous because when your meter probe touches high voltage your other meter probe will also carry that high voltage so you must be very careful what those probes touch.
If your amp has 1 ohm bias setting resistors then enter '1' into the Cathode Resistor's Ohm Value field. You can get an accurate resistance measurement of cathode resistors by turning the amp off download simply measuring resistance across the cathode resistor. It's more accurate to actually measure the resistor's ohm value rather than relying on its marked rating. The calculator subtracts 5. To measure voltage drop across the cathode resistor set your multimeter for DC Volt measurement, clip the black probe to chassis ground so you can use just one hand to do the measurement and put the red probe on the tube socket cathode pin.
You can also put one probe on each leg of download cathode resistor. The voltage shown on the meter is the 'voltage drop' disregard any minus sign. Note that voltage measured at the cathode pin is the same as the voltage drop across the cathode resistor so you don't have to actually put your meter pins on the legs of the cathode resistor to measure its voltage drop. In a practical application one encounters a significant difficulty: unless the capacitor C is periodically discharged, the output voltage will eventually drift outside of the operational amplifier's operating range.
This can be due to any combination of:. A slightly more complex circuit can ameliorate bias second two problems, and in some cases, the first as well. Here, the feedback resistor R f provides a discharge path for capacitor C fwhile the series resistor at the non-inverting input R nwhen of the correct value, alleviates input bias current and common-mode problems. That value is the parallel resistance of R i and R for using the shorthand notation :.
Differentiates the inverted signal over time:. The transfer function of the inverting differentiator has a single zero in the origin i. The high-pass characteristics of a differentiating amplifier can lead to stability challenges when the circuit is used in an analog servo loop e. In particular, as a root locus analysis would show, increasing feedback gain will drive a closed-loop pole toward marginal stability at the DC zero introduced by the differentiator.
Simulates an inductor i. The circuit exploits the fact that the current flowing through a capacitor behaves through time as the voltage across an inductor. The capacitor used in this circuit is smaller than the inductor it simulates and its capacitance is less subject to changes in value due to environmental changes. Applications where this circuit may be superior to a physical inductor are simulating a variable inductance or simulating a very large inductance.
This circuit is of limited use in applications relying on the back EMF property of an inductor as this effect will be limited in a gyrator circuit to the voltage supplies of the op-amp. Creates a resistor having a negative value for any signal generator. In this case, the ratio between the input voltage and the input current thus the input resistance is given by:. The amp drop V F across the forward biased diode in the circuit of a passive rectifier is undesired.
In this active version, the problem is solved by connecting the diode in the negative feedback loop. The op-amp compares the output voltage across the load with the input voltage and increases its own output voltage with the value of V F. The circuit has speed limitations at high frequency because of the slow negative feedback and due to the low slew rate of many non-ideal op-amps.
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From Wikipedia, the free encyclopedia. Main article: Operational amplifier. Main article: Differential amplifier. Main article: Instrumentation amplifier. Main article: Wien bridge downooad. Main article: Active filter. Main article: Comparator. Main article: Comparator applications.
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Main article: Op amp integrator. Main article: Gyrator. Main article: Negative impedance converter. Main article: Precision rectifier. See also: Log amplifier. Current-feedback operational amplifier Free compensation Operational amplifier Operational transconductance amplifier Transimpedance amplifier. Horn, 4th ed. McGraw-Hill Professional,p. Retrieved Introductory electronics for scientists and engineers 2nd ed.
Add a. I now recommend a. The ticking caused by the Vibrato is caused by improper lead dress. It can almost be "cured" by connecting a. This resistor is located on the parts panel. If present, remove the capacitor in parallel with the 10 meg ohm resistor old download. In other words, run the cap from the junction of the 10 meg downooad and the opto-isolator to ground [as in photo above]. If this does not produce the desired results, then the leads should be dressed as follows and excessive lengths shortened.
Dress the leads to the vibrato speed and intensity controls away from the tone controls and filter leads. Silverface amps have a female RCA jack for the tremolo foot switch. Tremolo download turned on when the footswitch is closed. This little shorted male RCA plug will turn on the tremolo without having to plug in the tremolo footswitch. I like to keep mine in all the ibas. To short the plug insert a amp wire all the way through the connector--there's a hole in the end of the prong so run the wire all the way through then solder both ends of the wire to the plug.
Be generous with the solder. Trim the wire free at both ends and you're done. The Reverb driver 1M grid leak works with the pF Reverb Filter cap to form a CR capacitance-resistance high pass filter with a corner freq of Hz everything below Hz is cut. By replacing the 1M grid leak with a 1MA pot you will not only cut the bias of guitar signal entering the reverb driver as you turn down the Dwell pot but you will lower the CR corner freq as well which will allow more low freqs into the reverb circuit.
Place your dwell pot or trimmer wherever you want. Remove the 1M downlpad. Wire bias pot's left terminal to any ground. Wire the right terminal to the now empty right resistor eyelet or turret. Wire the pot's center terminal wiper to V3 12AT7 pin 7. Putting pF bright caps around the k Channel Mixing resistors will slightly brighten the tone of the modified channel.
You can do one or both channels. You can alligator clip the cap in amp temporarily to see if you like the am. The Vibrato Channel Mixing resistor is R The Deluxe, Deluxe Reverb, Vibrolux and Tremolux amps run with low voltage preamps compared to the other silverface amps. The schematic for the Deluxe shows only idle volts on the preamp tube plates while the Twin Reverb shows v.
You can add preamp clean headroom by changing the two power voltage dropping resistors to the Twin Reverb values which will bump up the phase inverter and downoad plate voltage. When doing this mod be sure and sample the max dosnload distortion tone to ensure the power tubes aren't pushed too far. This is an excellent mod for people that want to run 6L6 power tubes in their 6V6 amps.
The high preamp voltage silverface amps like the Twin Reverb use a 1k 1 watt "C" power node power resistor and 4.
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The D resistor is a 4. I recommend you start by modifying just the C power node power resistor first and sample the modified tone. Reducing the value of the C power resistor will raise the voltage on all the tube plates cree the power tubes. Replace the C power resistor with a 1k 3 watt. I recommend a 3 watt rating for these resistors for longevity's sake. The C and D power resistors are located in the "doghouse" which is located outside the chassis next to the output transformer.
You can temporarily alligator clip a resistor in parallel with the existing power resistor to try a lower value. For example, the Deluxe Reverb has dowbload 10k C resistor so paralleling a 1.
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You don't have to use a 1k resistor here, you can chose any resistor value between the original value and 1k to tweak the tone change to your liking. If you like the change and want more then replace the D power resistor with a 4. Again, you don't have to use a 4. The C and D power resistors are downloda at upper left in the filter cap "doghouse.
The C and D power voltage dropping resistors are located at upper-center left in the filter cap "doghouse.
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If your particular speakers are giving you too many 'ice pick' highs simply adding a pF Mica capacitor across the feedback resistor will filter out some very high freqs that can cause ice free highs. The cap allows high freqs to go around the feedback resistor so they are used for feedback which will reduce them from the amp's output. This is a nice, subtle mod that won't screw up your silverface's perfect tone. It's easy to use alligator clips to clip the cap in place temporarily to see if you like the mod.
If you would like to cut even more highs than the pF cap, you can go all the way up to a. There's a small chance the Ice Pick Cap can induce oscillation at high volume. If that happens you can put a 4. Just put the cap around the ohm Negative Feedback resistor. This simple mod allows you to balance the voltage of the 6. Use a or ohm, 1 watt or greater linear pot. The Humdinger pot replaces the power transformer's 6. Remove your current 6. You simply turn the amplifier up and adjust the pot for minimum hum.
If you don't hear a difference just center the pot. The or ohm linear pot wiper is connected to chassis ground and the two outside pot terminals are connected to the heater wires at any spot along the heater circuit. The pot needs to be rated at 1 watt download higher. This ohm, 5 watt pot is perfect as a humdinger. Weber 12F Vintage American Voice, 12", ferrite magnet, 1. Bias and my recommendation for the silverface amps that use 12" speakers.
Both require a long, 50 hour break in amp you have Weber do their free break in service. Weber Ceramic Signature 10" and 12" for the budget minded. Some actually prefer the Sigs to the more expensive 10F and 12F Four Sig 10's in a Super Reverb sound absolutely glorious. The traditional build materials offer warmth, dynamics, low note articulation and proper distorted harmonic content layering.
Clean and full, with lots of body and sparkle. Smokey smooth with high-end definition. Country, Jazz or Classical guitarists take notice. Best defense against ham fisted drummers. You can always find a blown one and have it reconed. Celestion 12M Greenback Warm and Woody with relatively early breakup. Cleaner British voiced tone with a full low end, warm, throaty mids and a very open top end.
Turn up the volume and turn back the clock. This speaker is for classic rock, country, and blues. The Bandmaster Reverb head has an extra large cabinet to keep the power transformer away from the reverb pan. This extra cab size allows two 8" speakers to fit nicely. I recommend you leave your original "baffle board" alone and create a copy to cut the speaker holes in. You can buy silverface grill cloth and Fender logos to cover the new board. You should also paint the new board black.
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The two 25 watt speakers sound great with a Vibrolux kind of vibe and can handle 50 watts together so they can handle the amp fully cranked. With a low efficiency of 93dB they're not too loud and are great for getting a little dirt at practice volume. Of course this assumes you don't use the Normal Channel because tube V1 is the Normal Channel first and second preamp stages.
Pulling V1 changes the amp circuit because the V1B and V2B triodes share an ohm cathode resistor. Two triodes sharing an ohm cathode resistor is the equivalent of each triode having its own downllad. If you remove V1 then the V2B Vibrato Dwonload second gain stage preamp goes from normal center bias to a warm bias with an ohm cathode resistor.
In other words pulling V1 is exactly like changing the Vibrato Channel second preamp gain stage from a 1.Sep 06, · I absolutely love BIAS Amp 2; the clean tones are extremely realistic, which is something that no other amp sim can really do. If you can spend about $50, then I’d highly recommend the BIAS amp sims, they are just too realistic. Related: List of the 18 best Free Synth VST Plugins. Amplifikation Lite by Kuassa. Spark Amp: Smart Jam, Chords is an Android Music & Audio app developed by Positive Grid Inc and published on the Google play store. It has gained around installs so far, with an average rating of out of 5 in the play store. $70 Off Spark Pearl + Free Bag. The smart guitar amp and app that jam along with you. Auto Chords, access to 10,+ tones and so much more. learn more. BIAS FX 2 The All-In-One Guitar Effects Software. The ultimate amp & guitar effects powerhouse that turns your computer into a virtual guitar rig.
This warm bias increases gain and makes creamy amp asymmetric clipping more likely. Removing V1 will also raise the plate voltage on all the preamp gain stages which adds a some gain also. Removing V1 works really well with hot boost pedals or even hot humbucker guitars. Replace V1 or V2 with a 12AY7. The 12AY7 was used as the first gain bizs for many of the tweed amps and will offer fre more clean headroom because its lower gain will reduce preamp distortion.
This swap can really shift the distortion balance between preamp and power amp to downloaad power dkwnload distortion when you combine it with the V6 phase inverter tube change as discussed in the next biaz. The 12AX7's extra gain will hit download power tubes with a hotter signal. You can balance the extra gain from the 12AX7 in one of the channels by swapping out V1 Normal channel or V2 Vibrato channel with a lower gain 12AY7 to make your clean channel cleaner. The Reverb pot can downolad a little touchy with a usable range from 0 to 3 or 4.
A 12AU7 won't push the reverb circuit as hard so the usable range can extend up to 5 or 6 on the dial and make dialing in just the right amount amp reverb easier. The lower gain 12AU7 can also reduce reverb circuit noise. Another option to tame the diwnload level is to install a or 12DW7 tube in V4. Decreasing the reverb recovery's gain makes the Reverb Control less touchy, somewhat enhances the reverb tone and can decrease reverb noise.
Running 6V6 power tubes in a big bottle silverface amp will give you small bottle tone but with lots more power tube overdrive because the preamp is tuned to hit the phase inverter and power tubes harder than in the small bottle amps. To compensate for the different power tube impedance we need to adjust the speaker impedance. Since the little 6V6s put out much less current they need a higher impedance load.
For a big bottle amp with a 4 ohm output transformer secondary we need to connect an 8 ohm speaker. With a 2 ohm secondary we need a 4 ohm speaker or with an 8 ohm secondary we need a 16 ohm speaker. JJ 6V6S power tubes are good for plate volts so they can handle 6L6 voltage but for normal 6V6 bjas you must do something to lower the plate voltage to keep from frying them. For amps with tube rectifiers you can plug in a lower rated rectifier like dodnload 5R4 less sag or 5Y3 more sag bias bring down the voltage.
For amps with solid state rectifiers like the Twin Reverb and Single and Dual Showman you can plug the amp into a variac and turn down the amp's input voltage. A bucking transformer at its lowest setting may also do the job. You may also need to adjust the bias after installing the 6V6 tubes. See this to measure and adjust the bias. You can get a different tone from the small bottle Deluxe Reverb by installing 6L6 power tubes but the power and output transformers can't supply all the extra current needed to actually get much more volume at the speaker.
Running 6L6 tubes will stress the transformers so I don't recommend it but if you want to give it a try then you should make a change to the aml load to free for the different power tube impedance. Just use a 4 ohm speaker with the Deluxe Reverb's 8 ohm secondary. The amp may sound more sterile because the low voltage preamp and phase inverter are tuned to drive the 6V6 so you'll get less power tube distortion.
If you plan to permanently swap to the 6L6 then I recommend you raise the preamp and phase inverter voltage to better drive the 6L6 power tubes. Everyone that moves up from small bottle power tubes to large should measure their 6. The extra current draw of the big tubes can over tax some power transformers. Keep an eye on your power transformer's temperature when running the big power tubes but be careful because bias transformer can get hot enough to burn your fingers.
I use an bias red no-touch thermometer to monitor amp component temperatures. Take a measurement with the normal 6V6 tubes so download have a baseline temp to compare to how hot it gets with the big tubes. Replacing the GZ34 tube rectifier with a solid state rectifier like the plug-n-play Weber WS1 Copper Cap will supply the amp with a little more voltage and current to better drive the big 6L6 tubes. You will probably need to turn up the bias to get the most from your 6L6 tubes.
Many push-pull amps designed to run 4 power tubes can be run with 2 power tubes to cut the output power in half. But since the output transformer was designed to load the current download out by 4 power tubes we need to make an adjustment on the speaker end to load 2 tubes properly. Since 2 power tubes put out half the current of 4 tubes we need to double the speaker impedance so 2 tubes feel the same load as when 4 tubes are used. For example your amp is designed to run an 8 ohm speaker with 4 tubes it will need free 16 ohm speaker when run with 2 power tubes.
To run two power tubes you pull the two outside power tubes, which in the Twin Reverb are V7 and V10 tube numbering starts with the first preamp tube on the far right. The plate voltage will be higher with only two tubes pulling current through the power supply so you may need to adjust the amp's bias. As stated above we need to up the speaker impedance when substituting 6V6 tubes in a 6L6 amp and we also need to up the impedance when running only 2 power tubes in a 4 tube amp so we need to take two steps up in speaker impedance to run 2 6V6 power tubes in an amp designed for 4 6L6 tubes.
For an amp with a 2 ohm free we would need an 8 ohm speaker, a 4 ohm secondary needs a 16 ohm speaker and an 8 ohm secondary would need 32 ohms of speaker load two 16 ohm speakers wired in series. For example, the Twin Reverb has a 4 ohm output transformer secondary. It has two 8 ohm speakers wired in parallel to give the transformer its needed 4 ohm load. Fdee two 6V6 tubes the amp will need a 16 ohm load which can be done by simply wiring the two speakers frfe series.
You must consider the power tube plate voltage when running 2 6V6 tubes. With only two small power tubes pulling current through the power supply all the voltages in the amp will be higher than normal. JJ 6V6S power tubes are good for plate volts so they can handle the Twin Reverb's voltage but for normal 6V6 tubes you must do something to lower the plate voltage to keep from frying them. For amps with solid state rectifiers like the Twin Reverb you can plug the amp into a variac and turn down the amp's input voltage.
You will probably need to rownload the bias when running two 6V6 tubes. Blackfaced it but chose to leave the power tube grid leak resistors at k to help reduce blocking distortion. Installed a slightly tweaked version of the Lead Channel Mod with 2. Reduced the V4 shared cathode resistor from ohms 1. Turned the Normal channel's second gain stage into a Marshall style Cold Clipper with an un-bypassed downlowd cathode resistor.
A previous owner had already replaced all the filter caps, installed two 8" Jensen Special Design C8R 8ohm 25W 93dB speakers, and added adjustable bias to the bias balance circuit. The Normal channel is now geared toward lead guitar and works great with boost pedals for a leaner, cleaner, more modern overdrive tone. I also had to change my AA's phase inverter coupling cap from. Here's the voltages I measured on my bone-stock AA Bandmaster Reverb schematic values in parenthesis :. Phase Inverter V7.
Power 1 Plate 2 Grid 0 0 0. V5 Tremolo voltages amp. Tremolo set to minimum speed and intensity. Heater voltage was 6. The 68 CDR is not a silverface amp, it is an almost exact copy of the 65 Deluxe Reverb Reissue with just a few valuable tweaks.
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Click the image for the full size schematic. This is a early silverface Deluxe Reverb. Almost everything is original. Large screen resistor lower center biaw not original. The chassis interior is very blackface. Standby Switch at far left, Power Switch, Fuse, Ground Switch with "death cap" hiding underneath and power receptacle at donload right. Thanks again to Psionic Audio for the use of these excellent photographs of a very original silverface Deluxe Reverb.
I highly recommend Psionic for tube amp maintenance and repair. They are located in Memphis, TN. Morgan Jones, Valve Amplifiers4th Edition. Robert C. It includes many graphs to help make the material easier to understand. Slow the Tremolo Slow is good. The blackface mods are shown in red.