The Blackface Amps
Are these the most popular amps of all time? Probably anyone having even a casual interest in amps would have heard of the Fender Blackface line. Starting in 1964 and in constant production through the 70's and up into the 80's when the hand wired amp was finally abandoned for the lure of the robotic assembly line versions.
While I tend to try to give a little background on all the amps I build, there is so much written about the Blackface amps and so many other amps are always compared back to them, that for once I will cut it short and just so you an example or two.
I have built many of the different models of the Blackface line. I have also used them as springboards for amps somebody wanted that was never actually built by Fender. I have owned several, still do. I have restored them, modded them or just tuned them up for folks.
Perhaps the Deluxe Reverb is the best place to start. The same basic circuit used in the Deluxe with changes for other tube types are found on many other Blackface models. Put 2 6L6 tubes in this and add four 10" speakers and you get a Super Reverb. Add two more 6l6 tubes and two 12" speakers and you have a Twin Reverb. Or put it in a cabinet with a 15" speaker and you get a Vibroverb. So much of the basic circuit is common across the line. Its almost like they were designed to make a similar sound and take advantage of component sharing to make money. What a concept.
There is no denying however that they sound fantastic. Sweet, sparkly clean tones. Huge deep reverb and nice tremolo(vibrato) as well. Push them hard and the power tubes breakup in a unique way to the Blackface line. By this time, Fender had pushed the voltages in the Deluxe Reverb to over 475 volts and gotten 22 watts out of them. Compare that to 350-380 volts for a Tweed Deluxe and about 15 watts. More voltage and fixed bias vs. cathode bias gives them more clean headroom- also more trips to the tube store for new power tubes.
Below is the 6 preamp tubes of the Deluxe Reverb amp. Also you can see the small reverb transformer between the tubes and the classic "doghouse" cover over the power circuit capacitors right behind the preamp tubes. There are 9 total tubes in a Deluxe reverb. Gets expensive to retube one of these.
You can see the normal channel inputs and the Vibrato channel inputs in the picture below. Since the normal channel on the Deluxe (and the other Blackface amps of the same ilk) have a similar circuit that mimics the vibrato but with no reverb or tremolo, it does not get used much. I altered the normal channel in this amp to be more like a Tweed Deluxe and I dug deep into my stash of vintage components and installed the same Astron capacitors the tweed line used. They are those big yellow guys on the left side. I also used a famous "Blue Mallory" capacitor in there as well. Is there an audible difference? I honestly could not tell but since I originally built this amp for my own personal use, I decided to try them and see.You can also see the input and output jacks for the foot pedal switches that control the reverb and vibrato effects along the back wall of the chassis.
One more picture of the insides below. Lots of wires but still beautiful in a geeky amp guy kind of way. Its important to keep lead dress correct to avoid noise issues. This particular amp was mated with a 1966 12" Fender CTS alnico speaker and it sounded wonderful. It was sold ($1300) after I built it - that is a screaming good deal on a Vintage correct hand wired amp. I will not make one again for that price, but pretty close.
Below is a unique twist on the Blackface Twin. Built with only one channel but the full 80 watts of power. No reverb either but a Master volume (PPIV style). This amp was LOUD!
Here is another custom circuit. Its a Blackface Bassman with one channel, a full tone stack, a boost circuit and made with dual 6V6 power tubes for 20 watts vs. the usual 40 watts. And built into a lunchbox style enclosure which saves a lot of money as well.
This is a Super Reverb but built as a head. All the normal Super Reverb features and tone plus a first channel boost circuit, reverb and tremolo on both channels, a PPIV style master volume.
These are just some of the many Blackface style amps I have built over the years.
Here is a picture of the typical Marshall style turret board. They use raised posts or turrets rather than eyelets to solder components to. I hand build these and they are a pain but make a very secure amp. I also drilled holes by each turret to pass the socket connection wires through. This makes any debugging of the connections after the board is mounted easier as you can see the wire and make sure its well soldered. Sometimes I pass the wire from under the board through the top of the turret. Either way works, I just like to mix things up when I build. You can also see the central grounding buss on the right side of the board for all the grounds. This makes a quiet amp with little hum. There is a small toggle switch in blue on the left side of the picture- this is an added gain switch I added for the customer. He wanted a switchable gain option for more overdrive. Its cathode biased .Notice the tightly wound tone and volume control wires leading to the pots. I like to minimize noise and this technique takes more work but sounds better.
Here is a variation of the 1974 Marshall Circuit. Take just the TMB channel with its full tone stack then tweak it for more gain and you get a Superlite amp. Its like the Lite IIb concept of dividing the Marshall 1974 amp into two separate amps both sharing the same power output section but having the preamp tweaked for certain characteristics.
Mate an 18 watt power section to a Cascaded preamp front end with a full tone stack and you get hi gain supreme. Well, OK that is a little hyperbole, but you do get a huge amount of gain when you hit the boost switch. The preamp section can be run in a classic plexi style Marshall front end or when the switch is engaged, it "cascades" the preamps sections together for a lot more gain. Similar to how Mesa and other makers add gain to their designs. True to its 18 watt roots, its cathode biased but when the boost switch kicks in, there is a separate gain control pot that lets you tailor the gain "cascading" into the rest of the preamp section. When that circuit is in normal mode, that pot does not get used. Its a great circuit but easy to get out of control and I had to tweak the values to get it sounding smooth. It does sound great.
While I tend to try to give a little background on all the amps I build, there is so much written about the Blackface amps and so many other amps are always compared back to them, that for once I will cut it short and just so you an example or two.
I have built many of the different models of the Blackface line. I have also used them as springboards for amps somebody wanted that was never actually built by Fender. I have owned several, still do. I have restored them, modded them or just tuned them up for folks.
Perhaps the Deluxe Reverb is the best place to start. The same basic circuit used in the Deluxe with changes for other tube types are found on many other Blackface models. Put 2 6L6 tubes in this and add four 10" speakers and you get a Super Reverb. Add two more 6l6 tubes and two 12" speakers and you have a Twin Reverb. Or put it in a cabinet with a 15" speaker and you get a Vibroverb. So much of the basic circuit is common across the line. Its almost like they were designed to make a similar sound and take advantage of component sharing to make money. What a concept.
There is no denying however that they sound fantastic. Sweet, sparkly clean tones. Huge deep reverb and nice tremolo(vibrato) as well. Push them hard and the power tubes breakup in a unique way to the Blackface line. By this time, Fender had pushed the voltages in the Deluxe Reverb to over 475 volts and gotten 22 watts out of them. Compare that to 350-380 volts for a Tweed Deluxe and about 15 watts. More voltage and fixed bias vs. cathode bias gives them more clean headroom- also more trips to the tube store for new power tubes.
Below is the 6 preamp tubes of the Deluxe Reverb amp. Also you can see the small reverb transformer between the tubes and the classic "doghouse" cover over the power circuit capacitors right behind the preamp tubes. There are 9 total tubes in a Deluxe reverb. Gets expensive to retube one of these.
You can see the normal channel inputs and the Vibrato channel inputs in the picture below. Since the normal channel on the Deluxe (and the other Blackface amps of the same ilk) have a similar circuit that mimics the vibrato but with no reverb or tremolo, it does not get used much. I altered the normal channel in this amp to be more like a Tweed Deluxe and I dug deep into my stash of vintage components and installed the same Astron capacitors the tweed line used. They are those big yellow guys on the left side. I also used a famous "Blue Mallory" capacitor in there as well. Is there an audible difference? I honestly could not tell but since I originally built this amp for my own personal use, I decided to try them and see.You can also see the input and output jacks for the foot pedal switches that control the reverb and vibrato effects along the back wall of the chassis.
One more picture of the insides below. Lots of wires but still beautiful in a geeky amp guy kind of way. Its important to keep lead dress correct to avoid noise issues. This particular amp was mated with a 1966 12" Fender CTS alnico speaker and it sounded wonderful. It was sold ($1300) after I built it - that is a screaming good deal on a Vintage correct hand wired amp. I will not make one again for that price, but pretty close.
Below is a unique twist on the Blackface Twin. Built with only one channel but the full 80 watts of power. No reverb either but a Master volume (PPIV style). This amp was LOUD!
Here is another custom circuit. Its a Blackface Bassman with one channel, a full tone stack, a boost circuit and made with dual 6V6 power tubes for 20 watts vs. the usual 40 watts. And built into a lunchbox style enclosure which saves a lot of money as well.
This is a Super Reverb but built as a head. All the normal Super Reverb features and tone plus a first channel boost circuit, reverb and tremolo on both channels, a PPIV style master volume.
These are just some of the many Blackface style amps I have built over the years.
Here is a picture of the typical Marshall style turret board. They use raised posts or turrets rather than eyelets to solder components to. I hand build these and they are a pain but make a very secure amp. I also drilled holes by each turret to pass the socket connection wires through. This makes any debugging of the connections after the board is mounted easier as you can see the wire and make sure its well soldered. Sometimes I pass the wire from under the board through the top of the turret. Either way works, I just like to mix things up when I build. You can also see the central grounding buss on the right side of the board for all the grounds. This makes a quiet amp with little hum. There is a small toggle switch in blue on the left side of the picture- this is an added gain switch I added for the customer. He wanted a switchable gain option for more overdrive. Its cathode biased .Notice the tightly wound tone and volume control wires leading to the pots. I like to minimize noise and this technique takes more work but sounds better.
Here is a variation of the 1974 Marshall Circuit. Take just the TMB channel with its full tone stack then tweak it for more gain and you get a Superlite amp. Its like the Lite IIb concept of dividing the Marshall 1974 amp into two separate amps both sharing the same power output section but having the preamp tweaked for certain characteristics.
Mate an 18 watt power section to a Cascaded preamp front end with a full tone stack and you get hi gain supreme. Well, OK that is a little hyperbole, but you do get a huge amount of gain when you hit the boost switch. The preamp section can be run in a classic plexi style Marshall front end or when the switch is engaged, it "cascades" the preamps sections together for a lot more gain. Similar to how Mesa and other makers add gain to their designs. True to its 18 watt roots, its cathode biased but when the boost switch kicks in, there is a separate gain control pot that lets you tailor the gain "cascading" into the rest of the preamp section. When that circuit is in normal mode, that pot does not get used. Its a great circuit but easy to get out of control and I had to tweak the values to get it sounding smooth. It does sound great.