Dating bassman 50

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Dating Your Fender Amp

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❤ : Dating bassman 50

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Solid-state rectifiers do not wear out as tubes do, nor can they be replaced by the user. From Marshall circuit modifications did not progress along a straight time line and some parts in later years actually reverted back to their original values. If your amp was meant for 6V6s, do NOT try 6L6s, as this will overload the power transformer.

Increased output power, post 1976. Recently turned it on after years of hibernation and remembered how much I liked it. He says he has a way of revoicing the bass channel on it in order to make it a useable, rockin' input, can do it while I wait.

Preferred Series 7025 and Tung-Sol 12AX7 are suitable, 5751 not recommended. Vibro Champ and Bronco AA764 - Tube Package Preamp tube is a 12AX7. If your'e a player, the one thing about the blonde bassman is it's responsiveness- it has that fuid feel and sustain of a compressy overdriven amp, but somehow it stays clean and punchy. I have had a sound guy ask me to turn up. DO NOT use other types. If you dating bassman 50 Eb or open D tuning, your Bassman will growl like a bear. Dating Fender Amps 1951-1967 — Tube chart on the inside of the amp is stamped with two letters A — Q : The first letter designates the year and the second letter designates the month. Good NOS 12AT7s may also be used here.

Cabinet for Vintage Bassman 135 - It's now an AB circuit.

It was introduced in 1951, primarily targeted for bass guitar players and promoted as a bass amp for the Fender Precision Bass guitar, the first mass-produced electric bass guitar ever. During the different eras the Bassman amp came in many different shapes and configurations. Few other models experienced so many changes in terms of looks and tone. The tube charts are not very useful for determining the circuit model. At the Fender factory they used old tube charts when new models came, probably because the tube layout was the same. Determining production date by serial number and transformer codes is better, and you should also inspect the circuit to be completly sure. The picture below shows a 1969 transition model amp. Unfortunately the Bassman was one of the first amps that CBS laid their hands on after buying the company from Leo Fender. A couple of things in the circuitry were immediately changed in 1965 when the AA165 and AB165 replaced the AA864. Amp collectors and idealists often prefer the pre-CBS models but if we study the AB165 circuit it does have something very interesting for guitar players who enjoy cranked Fender blackface tones. The AA165 is very rare and its circuit and tone is quite similar to the AA864. We will further focus mostly on the AB165 vs AA864. Some things have not changed since the beginning; The Bassman never had reverb or tremolo. All models have a push-pull class AB dual 6L6GC power amp configuration. Up to the blonde Bassman with blonde colored tolex circuit 6G6 they all had tube rectifier, but since then a diode rectifier was used. So what does the blackface Bassman sound like? The video below compares a Bassman AB165 to a Princeton Reverb and a Deluxe Reverb. Describing the blackface Bassman tone is best done with establishing a common and well-known reference point, for example the traditional blackface AB763 amps such as the Super Reverb and Twin Reverb. The Bassman is known for its simple, pure and raw tone. It is 50w loud with power supply and output transformers sized approx. The bass channel of the AB165 and AA864 is much mellower and deeper than the normal channel of any AB763 amps since it is voiced for bass guitars. The normal channel is more relevant for guitar players. The normal channel in the AA864 Bassman is cleaner than in the AB165 since it has no additional gain stage. The Bassman amps have more mids than the AB763-amps, and particularly without the reverb effect the reverbs thins the tone the Bassman experience is a fuller, direct and less camouflaged tone. The Bassman circuit is simpler and has less components and tubes than other AB763 amps. A less complicated circuit means fewer things that can go wrong, less component drift issues, easier to service and less potential for noise problems. The Bassman has significantly influenced the whole guitar amp industry since it was introduced. As for all amps you will be able to shape your tone significantly with selecting speakers and tubes. We usually start with explaining a mod from a functional perspective where we relate to components in the logical schematics diagram. Finally we point out location of components in the physical layout diagram. Its powerful response is appreciated by both bass players and guitarists who play loudly with significant amount of distortion. Bass and distortion compensate eachother nicely, and the Bassman will deliver lots of it. Replacing speakers is the easiest and most effective mod of them all. The speaker is the most important component in your amp which physically produces the air waves that your ears detect as a tone. See page for speaker recommendations. Jumping channels Jumping channels means that one splits the guitar signal in to both channels. Some Fender amps have the two channels out of phase due to different number of tube stages in each channel, like the AA864 and AA165 Bassman and most AB763 reverb amps. The AB165 Bassman channels are in phase and can be used together. Jumping channels in the AB165 Bassman will give you a wider spectrum of tones than by using just one channel. See picture below for example knob settings. We recommend a closed or semiclosed speaker cabinet for this setting. You may increase volume further for cranking the amp harder. If you use Eb or open D tuning, your Bassman will growl like a bear. These tubes have lower voltage gain and different frequency responses, particurlarly when distorting. One could describe these tubes to have less harsh and buzzy distortion. Pull V1 or V3 preamp tubes If you are a guitarist and use only the the normal channel, you can get a slight increase of preamp gain and volume on a given knob setting by pulling the V1 bass channel preamp tube. The effect is strongest in the bass channel and in the normal channel of the AB165 model since a stronger signal will push the second gain stage V2 tube harder with even more sustain, compression and harmomics added. The preamp tube circuit in the blackface Bassman is not similar to the AB763-amps. This results in a hotter bias for the remaining preamp tube. However, there is still a noticable effect in the Bassman since pulling a preamp tube reduces the current draw from the power transformer and the plate voltage B+ on remaining preamp tubes will increase. If one experiences more noise with pulling one tube, we suggest to put it back. Ideally one should ground some of the floating pins in the open tube socket. Replace the 12AT7 PI tube with a 12AX7 or 12AU7 — Less clean headroom. Very practical mod at practice and low volume environments. Tips: If you pulled the V1 or V3 12AX7 tube you may use it as V4 phase inverter. Not only was it simple and robust, it delivered pure, fat and sparkling Fender blackface tone. Some say the changes were unfortunate, but there are many players who find the AB165 tone to be equally good, if not better. CBS Fender made an interesting move with the AB165 wiring the normal channel so that is also uses second preamp tube V2 12ax7 , just like the Bass channel does in both AA864 and AB165. The previous AA864 only used one preamp tube V3 before the phase inverter. This means that the AB165, if turned up, will have more breakup, compression and sag than the AA864 Bassman and the AB763-amps. The power amp section of the AB165 got a couple of bad tweaks. One is the stupid, unbalanced bias circuit and a strange implementation of the strange negative feedback loop which was never seen in any Fender amp before or after. The bias setup will not affect the tone as long as you are lucky and able to find a sweet bias spot with a set of tubes. But the negative feedback will. However, the most noticable change in the AB165 was introducing a gain stage in the normal channel. What can we possibly draw from this knowledge with the AB165 and AA864? Is there any point in doing a blackface converting of silverface amps? The blackface AB165 and silverface AA270 have great tone as it is. If you are really interested in blackfacing or modding your Bassman, you should read the next chapter first. Additionally we apply a couple of mods to get more compression, sag and breakup at lower volumes. It can deliver pure, clean blackface tones as well as roaring, cross-Atlantic Marshall tones. An essential ingredient is disabling the negative feedback loop make it switchable and convert to cathode bias on the 6L6. We also add a 10K mid pot on the back of the amp described further down in this article. Simply explained, this amp is a Fender Marshall crossover amp. The steps are explained below. The youtube video below demos this amp: 1 Combining the AB165 and AA864 The schematics for this amp is explained below. The red circles in the schematic below illustrates these changes. From right to left: — Switch the polarity of the two wires coming from the output transformer going to the speaker terminals. You need to do this only if you change the negative feedback loop to AA864 specs. You will get more breakup and distortion and more volume at a given volume knob setting. Personally we have experienced good results with a 1. The negative feedback loop ends up at the left side of the 22 kOhm resistor which is a new soldering point. The NBF theory is that you take the signal from the speaker output, let it go through a resistor and mix it in at the entry point of the phase inverter. The speaker signal is out of phase 180 degrees with the signal at the entry point of the phase inverter and will cancel out equal frequencies. More white noise too. Most importantly the tone gets rougher and rawer with more mids and higher frequencies, aka presence. This mod is for those who want more bite and a tone that really cuts through in the mix. You may choose to implement the mod in several ways and in various combinations with the ground switch or a foot pedal. You will still have that beautiful Fender tone, just more and wilder. Simply disconnect the feedback loop a wire and tape insulate it. You get the most effect of this mod by disconnecting the NFB loop entirely. You may experience that the tone gets harsh, depending on guitar, speakers and EQ settings of course. If so, read more about the cap in the next bullet point. This cap will prevent the lower and mid frequencies to go through the NFB loop. Depending on the cap value treble frequencies will be fed back to the phase inverter which cancels out the treble in the main path. The tone gets less harsh and you still have a noticeable effect. You should experiment with different cap values. A good starting point is twice the original resistor value. This reduces the effect of the feedback loop, making the amp break up more when the NFB is engaged. If you make the NBF switchable there will be less volume difference if you use a high resistor value. Then wire the ground switch in series with the NBF resistor. When the ground switch has disconnected the NBF loop the higher frequencies are still fed back through the cap. In practice you solder each the two cap legs to at each side of the switch between speaker terminal and NFB resistor. Where to install footpedal or switch? The ground switch is easy available if you disable the power supply wires and death cap. For amps with reverb you could use the reverb footswitch phono plug if you are not using it. Many players are happy with the default 6. You may go from a scooped, clean blackface tone to burning British, Tweed or Brownface tone. You may install the mid pot at the left most side of back of the amp where the additional power supply is located. You can also use the reverb footswitch phono plug if you, like most players, never switch off the reverb with the footswitch. The cathode of the 6L6 power tubes is grounded. Hence, the voltage is fixed at zero. Having a fixed bias means, contradictionary perhaps, that you need adjust the bias current or voltage by using a bias pot. The bias is in fact adjusted continuously according to how much power the tubes are delivering and how much current is flowing from the cathode to ground. The more current that is flowing, the higher cathode voltage. In terms of tone this means that the clean headroom is reduced and most importantly, you get more compression and sag at both clean and cranked volume levels. There is less attack and a more sweet and forgiving tone. This can be desirable for those who have a hard pick attack. Converting to cathode bias in the blackface and silverface Bassman circuits, and other Fender amps with fixed bias, is very simple. It is in fact so simple that we recommend everyone to try it. Personally we prefer cathode bias in big, powerful amps with big transformers where you have more than enough power and attack. The schematics below show the AA864 Bassman and the narrow panel Tweed 5e3 Deluxe. We think that the cathode bias circuit design of the 5e3 works very well in the Bassman. You can simply let the bias pot circuitry stay where it is in case you want to roll back the changes or make it switchable between fixed and cathode bias.

Fender '59 Bassman and '65 Super Reverb Comparison (reissues)
Preferred Series 7025 and Tung-Sol 12AX7 are suitable, 5751 not recommended. Vibro Champ and Bronco AA764 - Tube Package Preamp tube is a 12AX7. If your'e a player, the one thing about the blonde bassman is it's responsiveness- it has that fuid feel and sustain of a compressy overdriven amp, but somehow it stays clean and punchy. I have had a sound guy ask me to turn up. DO NOT use other types. If you dating bassman 50 Eb or open D tuning, your Bassman will growl like a bear. Dating Fender Amps 1951-1967 — Tube chart on the inside of the amp is stamped with two letters A — Q : The first letter designates the year and the second letter designates the month. Good NOS 12AT7s may also be used here. Dating apps happn Chelsea kane and joe jonas dating Celebrity dating app los angeles