Dummy load guitar amp May 27, 2025 · New to this forum. Feb 14, 2007 · Bought 6 of these total. I'm creating a 200w, 8ohm dummy load to run the speaker out of my guitar amp into. New to some aspects of guitar amps,or perhaps many!. Unused cabinet jacks are automatically excluded and locked Sep 9, 2016 · Dummy loads: Who’s the dummy? A dummy load is a resistive load and in some cases a more advanced simulated speaker load that is used to load an amplifier when a speaker load is not wanted. com> Below is a copy of a post I made a year or two ago on a reactive speaker load design. Common Use-Cases – ways to integrate guitar, pedals, amps with an interface; 3. Nov 2, 2011 · About to do some mods, service and recap on my Fender amps. The PDI 03 JB Speaker Simulator is a professional passive DI box for guitar amps. May 6, 2023 · A dummy load is basically a load you can plug into the speaker out socket of a guitar amp so you can perform tests on it without risking damage to your hearing if you need to crank the amp Build an 8. You must use a non-reactive load, however, when testing an amplifier for power output, because the power measurement is only accurate into a purely resistive load. The Bad Cat Unleash and Fryette Power Station are good examples. 2 Ohm/110W Dummy Load for testing, or servicing guitar amps. 2 reviews for Tru-Load Dummy Load. Definitely mount it to a heat sink if you're going to max ot the wattage. The circuit is shown in Figure 1, and each 4 ohm load section uses 9 x 3. This protects the amps from a 'no load' scenario. Zog-zog – lightbulb attenuator with line out tap and dummy load; Software. The amplifier needs to see a “load” — normally from a speaker — that gives the power it puts out somewhere to go. If you are going to do Power Testing, yes, you should get near the rated resistance so your numbers are "proper". So I just have two dummy loads for each load resistance. Nov 12, 2019 · Re: Guitar amp dummy load box « Reply #7 on: November 16, 2019, 04:05:32 pm » Yes but as a speaker has wildly different impedance vx frequency, so adding a simple resistor in front of it will also alter the attenuation of different frequencies. 9 ohm resistors. The purpose of this load box is to Aug 15, 2014 · Guitar Combo Amps Guitar Amp Heads Guitar Amp Cabinets Acoustic Guitar Amps Bass Combo Amps Bass Guitar Amp Heads Bass Guitar Amp Cabinets Guitar Effects Multi-effects Pedals Distortion, Overdrive, Boost & Fuzz Reverb & Delay Compressor & EQ Chorus Wah Looper Amp & Cabinet Simulators Acoustic Guitar Effects Pedalboards & Power Supplies If the amp does oscillate, it may need less negative feedback, or phase compensation of the loop. While a speaker can be used, a 1 Khz sine wave fed into an amp and ramped up to the amp's maximum output will be deafening. Links to power attenuator schematics and dummy load schematics. But the (very) good news is that the change is merely a change in EQ. Apr 25, 2016 · These attenuators require external power because they incorporate an amplifier stage. Great for working on tube amplifiers. Made a switchable dummy load . Do you think it's safe to use two in parallel as a dummy load, just for checking that everything is ok? I'm not gonna blast the input with a sine wave. All unused amps are muted at the inputs, so no signals can reach the amp. Another dummy load is 2x 50W and is 8 ohms. This load box is useful in Dummy load boxes are decent choice for several applications: Use a small tube amp into a dummy load, tap the signal out and re-amp it with a higher power amp. Sponsored. The right setup and I can run 150 watts into each one without problems. It's my DIY tube guitar amp project. 15 delivery. When using a tube amp, a speaker is usually connected. Songworks - 3350LT (ext) - 1/4 watt 12AX7 power amp, dummy load, and solid-state 33-50 Watt amp in compact combo package. Load Detection - The cabinet outputs of the KHE are supervised for a speaker cabinet or load box. guitar. I built a Weber Dummy load lets you run an amp without an actual speaker. You can expect the resistors for the basic load (one section as shown) to cost well under $40 Input (guitar amp or stereo) can be routed to a 4/8/16 ohm dummy load or to each of 2 guitar outputs or a stereo speaker terminals output on the backside. Dec 28, 2023 · Diy guitar amp dummy load box with line out. Most dummy loads offer a speaker-level input and a line-level output for connecting to a live or studio console, or for feeding an effects device for creating a wet/dry rig for amps without an effects loop or preamp output. Rated 5 out of 5. There is no need to get a 8. Hence the use of dummy loads. Designing A Reactive Speaker Load Emulator . In a typical guitar amp, the loudspeaker is the load. A speaker presents a varying impedance load to the amp. I've been doing some research over the past few days to either buy a guitar amp load box (dummy load) or build one, and it seems that it's much cheaper to build one (~$50). May 1, 2013 · The first set is built using resistors R1 through R25 for making a load of about 8 Ω. Hardware – choosing and configuring hardware for modeling; 2. This is a selection on the impedance Nov 24, 2016 · A pure resitive load may be good for starters, but a realistic dummy load should be designed with an impedance close to the one that the speakers will have that you intend to use with your amps. 00 ohm resistor to load an amp. We'll discuss how to build your own switchable resistive dummy load box for use on your electronics testing bench. The Carvin Audio Vintage 16 tube amplifier has a dummy load built in and this can be found in other small tube amps. If possible, run at a lower power, as the load could get uncomfortably warm after a time, though the power reduction resulting from using a 16 ohm load will help in this respect. A great Tech Tip from D-lab electronics. Speaker Out jack for attenuated guitar signal. This is more true on transistor amps than on tube amps. When I first started doing this a friend and mentor gave me a pair of 50 watt 8Ω resistors May 25, 2023 · An audio load is an essential piece of test equipment for any audio electronics workshop. Click here to read a paper on designing reactive loads. My first guess is that I need a second dummy load. The Dummybox Home version provides a solution for virtually every live and/or recording situation, or for playing with your amp at full blast in your bedroom. I run my amps speaker output into a Weber attenuator (which also provides a dummy load). The third set is built using resistors R36 through R60 for making a dummy load of about 8 Ω. If your amp has gNFB, it's probably ok without a load, because gNFB has to clamp down the output when unload, but if zero feedback must have a load. Nov 11, 2019 · Hello, We would like to build a dummy load box for our guitar amps. Providing a frequency compensated, transformer balanced direct feed to mixing consoles or soundcards it connects between the amplifier output and loudspeaker or equivalent dummy load. This one is a 25 watt model util Oct 31, 2019 · I built a dummy load using similar (golden) devices for 400 watts. Dummy loads are also used for guitar amplifier power attenuation. Oct 26, 2011 · A dummy load would be selected to withstand the full output power of the amp. The second set is built with resistors R26 through R35 for making a dummy load of about 24 Ω. Aug 5, 2024 · Hi guys, today in this video you will find all the steps for creating proper Audio Dummy Load for your amplifier tests. Plenty of musicians swear by the warm sound of a… Let’s start with some basics: a load is simply the part of an electrical circuit that consumes power. We tried all the attenuators on the market, but they muffled the sound and made even THD amps sound dull. Series and parallel combinations can be used to Dummy load boxes are decent choice for several applications: Use a small tube amp into a dummy load, tap the signal out and re-amp it with a higher power amp. Load boxes. Connect the oscilloscope to the amplifier’s output: Use a BNC to BNC cable to connect the oscilloscope’s probe to the amplifier’s output. The ID-5252 contains four 8Ω, 60W power resistors. Load guitar box amp dummy diy lineLoad dummy fever Dummy 50w load rat ohm english box made reverbLoad dummy speaker proposition. We needed a good attenuator for our in-house testing of THD amplifiers. A basic power resistor is enough to work on the amp. The dummy load is a resistor that mimics the impedance of a speaker, preventing damage to the amplifier. However, they make it very clear that the Z Matcher is not an attenuator and it's not meant to handle a dummy load. The goal of this post is to explain what is going on from an elecrical engineer's perspective and at the same time, describe what is as going on in the head of every player that ever grabbed a guitar and cranked the amp to 11. Toggle allows user to switch between 4 or 8 ohm applications. I then used L-shaped aluminium profile to bolt them together. The power amp is made as Single Ended triode stage using the 2nd half of the ECC82 tube. Buy It Now +$6. But if you have a 200W guitar amp, building a suitable 300 W rated dummy load is a project in itself, and will require a heatsink and the use of many power resistors wired so as to share the power. But it's for only one channel and 4 ohms. I have 6 mounted to and old stripped down automotive amp heat sink with a dc cooling fan. If you want to use your amp silently, you […] Sep 29, 2020 · Hi all: I'm a guitar player, and I built a resistive load box in order to operate my 100W tube amp head through my computer (a DI box - store bought) without speakers attached (without frying my output transformer) My goal was to avoid paying for an expensive load box, since I happened to have May 18, 2011 · An external box that connects to a guitar amplifier and that provides a dummy load. If you are planning to troubleshoot noise hiss buzz etc in your amplifier, make sure to utilize a dummy load resisto This is my first experience with soldering and electronics, so please be gentle lol. Luckily for guitarists, there's a bevy of devices designed to control, capture, and sculpt the tone of any amp. After constructing an AMP6 T-Amp kit, and while testing the maximum power output using 4. 4BEA@mindspring. What I think I need: 50 Watt Audio Dummy Load Switchable 4 or 8 Ohms Finally! A reasonably priced tool for safely working on tube amps without a speaker. This combination has a free air power rating of 90W, or 180W when connected as an 8 ohm load. Resistor load is fine for the amp. Never used it, though. Having created the very popular Heathkit ID-5252, more than 35 years ago, Gary Galo decided to design a new option for everyone to build now. The dummy load took away a bit of bass and treble, so all you have to do is put that back with EQ. Speaker Through jack, which is parallel with speaker in jack. July 22, 2000. A speaker appears inductive below resonance and at high frequencies where the voicecoil's inductance has an effect, and is capacitive above resonance, but before the point where the impedance flattens Aug 26, 2006 · Newsgroups: alt. This works also with 4 ohm speaker output from amplifier. A real speaker dummy load will typically have an inductor in series with the resistor to mimic the voice coil inductance, and you also need a big A standard dummy load fails to test an amplifier's response to reactive loads, and this has led to some seriously flawed designs over the years. Apr 29, 2015 · It's an old problem: Guitar amps can be unruly beasts, hard to tame and difficult to mic live and in the studio. Connect switch S1 and the loads as shown in Fig. I used two fat heat sinks and mounted four on each. The speaker dissipates energy from the amp as sound. Bought a Marshall MG250 and wanted to hook it up to my Weber Dummy Load Box, but I soon realized that there are two speaker outputs on back of amp, left and right, min 8ohms, 2 X 50w rms into 8 ohms. in this video. Rated at 50 watts Jan 16, 2009 · This refers to a simulated electrical load, frequently used in the testing of audio equipment or radio transmitters. Could post piccies if Aug 24, 2022 · The sound produced by any given electric guitar is shaped not just by the instrument itself but by the amplifiers chosen to make that sound audible. This is useful to compare how two amps with similar specs will compare in a "real world" scenario. Crank the heck out of the amp and re-amp it with either a headphone amp or a small amp to get it to sub ear-bleeding level. $34. Despite the wattage on the resistors (or rather due to lack of heatsinks) it takes ca 40W in mono or 60W stereo for extended times. Paul Willett – Owner at True Fret Guitar and Amp Repair, Milton WI (verified owner) Feb 18, 2016 · It’s not safe to operate a tube guitar amplifier with no speaker connected. The biggest limitation of the Heathkit load is power handling. This circuit will apply a resistive based load to safely discharge a tube amp Sep 4, 2018 · You can easily find an off-the-shelf 25W, 8 ohm power resistor to protect the output of a typical 15W guitar amp. Four 20W 8-ohm resistors wired in series-parallel a basic dummy load. Aug 24, 2022 · Stereophile tests amplifiers using either resistive dummy loads, or a "simulated speaker load", which is a more complex circuit of resistors, capacitors, and inductors, designed to replicate the sort of load an actual speaker presents. Dummy 5e3 modification spk 8ω specimenproductsSwitchcraft guitar amp dummy load Compact stereo dummy load for amplifier testing – toli's diyDummy switchcraft reverb. 2. It will also have speaker output and volume control to play through the speaker cabs. We have a 25W, 35W, and a 85W guitar amp. 7 ohm 50W ceramic power resistors the hot resistors had begun to scortch a cutting mat they were resting on and also melting the wire insulation of test leads which had fallen on one of the hot Jul 29, 2005 · A long while ago, I made a very simple load box to be used with a guitar amp (8-ohm load). I could record straight from the attenuator line out but instead I tap off the signal via a Behringer Ultra-G DI box because it has a nice speaker emulator built in. I'd like to reamp files through an EL84 version of this, A/B'ing the power tube distortion quality versus the 12AX7 design. One of them is a Bassman 135. Brand New. Digital Modeling – series of articles on software digital modeling 1. Apr 20, 2019 · When testing amplifiers a dummy load is used. Scalable 100 W reactive dummy load with -12 dB, -15 dB and -20 dB and Off steps to reduce amp output power even to total silence. Audio manufacturers commonly use dummy loads to test how an amplifier handles large power levels, so they don’t have to actually produce the loud sounds. I mount a pair back to back and the speaker plug is connected directly to wire lead, for very quick manual switching between the speaker and dummy. Guitar amps that use vacuum tubes in the power section require a load for safe operation, so don’t run your tube amp without the speaker or a load attached. A dummy load is simply a large wattage resistor that is a known resistance. 4/8/16 ohms - 300/600 W🤔 If you want In guitar amps we often have a cabinet fall-off which is compensated by allowing the bass resonance to run strong, so the result is sorta-flat and bumped-dipped according to our taste in the bottom octave and the speaker's bass-handling ability. The stated impedance is usually measured at 400Hz, and can vary widely over the frequency range. serial effect loop, dummy load for the power amp, channels can be changed using external footswitch, Line Jun 28, 2016 · Tolerance +-5%, 40W without heat sink. org Reactive speaker load circuit, by Randall Aiken - duncan's amp pages. 11 watchers. 99. My understanding is that if the head is plugged into the alternate cabinet it will not need a load box, or something that can act as the dummy load, because the new speakers are acting as the load. amps Subject: Re: proper dummy load on output of tube amp? Date: Sun, 13 Dec 1998 00:49:05 -0500 Organization: MindSpring Enterprises Lines: 159 Message-ID: <36735551. Reaper – DAW – how to pick good a DAW software Dec 10, 2007 · DIY Speaker / Amplifier Dummy Load. I think I have the tools to build one, but I don't really have much of the know-how to make sure I'm not going to blow up my amp in the process. I edited it a bit, since the original post was Apr 19, 2019 · So what we're going to do is to input a clean sine wave into the amp, and connect the output to a dummy load. You can expect the resistors for the basic load (one section as shown) to cost well under $40 For start-up testing of guitar amps: 10 ohms and plenty of watts. This small durable tool simply plugs into the output jack instead of a speaker. The Koch Dummybox Home is an innovative ‘multi-tool’ should be found in every guitar player’s toolbox. Speakers generally have a large resonant peak that can be as much as 5 times the rated impedance, or even higher. Without a load, a tube amplifier will likely be damaged. Only for setting bias and check other voltages. See full list on mozartproject. General . The original signal from the tube amp is reduced to line-level through the load box, then directed to the power amp’s tubes, where it is brought to the desired volume – providing the perfect signal at the required volume!” TAD Silencer™ can be used in LOAD mode as a pure loadbox. I live in a dorm room, and can't run it through speakers period, so I'm planning on using a dummy load to tank the signal while I use the amp's balanced output to go into my Useful tool for rehearsal room, live and recording applications | Tube amplifiers as they sound best - high output level with reduced and controlled volume | Can also be used as a dummy load | Input power up to 100W | LED with overload indicator | Quiet fan | Controls: Speaker Level and Line Level | Inputs: 4/8/16 Ohm | Balanced speaker output | XLR DI output with speaker simulation . 50 Watt Audio Dummy Load Switchable 4 or 8 Ohms Guitar Amp Tool. The amps have to be tested at all volumes, clean and pure to wild distortion, and we were tired of our ears hurting. Sep 12, 2016 · I put together a pretty simple load box with a line out for silent recording. If you want the load to also contribute frequency characteristics like a speaker - for example when sampling off the load for recording - then we can add reactive components to it, more or less like building a Jun 19, 2012 · So the bad news is that yes, using a proper resistive dummy load on a tube guitar amp usually will change the sound, and usually not in a good way. Jun 19, 2012 · All, WARNING! Extremely Long Post Here is my experience in building and using dummy loads, both 100% resistive and 100% reactive. 8Ω is the most common value used for this, for obvious reasons. Load Resistors - All amps are connected to a dummy load resistor. The two 4 ohm sections can be paralleled to give 2 ohms (at 180W). The resistors specified are rated at 25 Watts each so the maximum continuous power this load will handle is 4 x 25 Watts, or 100 Watts. The signal from the guitar amp ‘sees’ a passive dummy load and a small part of the amp signal is then fed to an onboard amplifier that feeds the speakers. Input (guitar amp or stereo) can be routed to a 4/8/16 ohm dummy load or to each of 2 guitar outputs or a stereo speaker terminals output on the backside. The Hot Plate® also makes a perfect dummy load. After many requests, here it is, the simple 4 or 8 ohm switchable resistor dummy load. This is a simple DIY Speaker dummy load that was put together very quickly. The dummy load would have a switch to select 4R, 8R and 16R. Opens in a new window or tab. 4 8 and 16 ohm configuration. I strongly prefer to end the chain with a tube power amp pushing a guitar speaker to at least one watt, therefore I do not promote cabinet simulation filters much. I've found 10 ohm 50W resistors in a local shop. guitar amp master volume mod schematic. qivz kxov fadhvdn vxmwm ulyqgmu nvlv lzrcb uknb roffr gzwfgtvy