This amplifier is my take on the Ampeg V4, but with a ton of very important improvements. Overall, the tone circuit and topology of the original design is maintained; but more options have been added, obsolete or unobtainable parts have been swapped for parts that are identical in circuit and sound but easily sourced, and tour worthiness or dependability of the overall design and power circuit have been vastly overhauled.
The essential design elements are:
- Enhanced Tone Options
- Power supply stability
- Turret board construction
- Hand Welded Stainless Steel Chassis
- All Preamp tubes are 12AX7 or 12AU7
- All Poweramp tubes are 6L6GC
There are still some changes that will be put into the amp from the photos of the design / build, but overall the prototype is really hitting all the essential marks that need to be hit. It is really well enunciated, the ever powerful active mid controls are as responsive as ever, and the lows are absolutely absurd. I'm overall much happier with this build than I was with the V4; for the overall stability of the parts within and the additional controls.
CONTROLS:
- Input I, Input II, Both (I+II): This is a continuation of later ampeg heads, where people would jumper the leads and use both channels. Here, you don't have to use a jumper to get access to both. The individual inputs are still available if you want you use something like an A/B/Y pedal to be able to swap between the different inputs as a semi-channel select.
- Sensitivity: Each channel has a sensitivity control. These activate a cathode bypass circuit and create a uniquely tighter sound. Not the best at describing these, but they are cool.
- Ultra Low: Each channel has an ultra lo switch, that brings in an entire network of caps and resistors into the chain, that give a much woolier sound to the channel. Great blended with one channel on and one channel off for this switch, or for use in a strictly low end bass sound
- Ultra High: Each channel has an ultra hi switch as well, this can either add or subtract highs from the channel, and is a nice simple control that I generally use after everything else is tuned in.
- Gain: The last control for each channel before they join at the tone stack. Self explanitory, it is the overall volume for each channel, and lets you get decently hot
- Bass / Treble: A simple tone stack for the lows and highs, a reductive circuit that is based on baxandall.
- Midrange: An active mid control that is surprisingly deep and powerful
- Midrange frequency: The mids themselves can be shifted and totally alter the entire feeling of the amp. This switch basically shifts the entire amp's feel into 3 seperate amps.
- Volume: Available on some amps and not on others, seems like an easy addition to tame in the 100 Watts into something usable in smaller venues without obliterating your mind.
If you have questions about this amplifier, please send a message. There is a lot of crazy details here, and it is a wild ride to get into. I'm extreamely happy with the overall performance of this death machine.
TIMELINE:
These are going to be made as a first come / first serve basis. I have capped the total ammount available to 5 of each transformer type, and won't be adjusting that until those orders are completed. I expect to take about 6 months to line them up and get them done, but could take upwards of 9 months depending on tube supplies. If all of them get picked up super fast, I will probably get them done first thing; but my expectation is an order or two trickling in, so work will be sporatic on them. That said, I have delivered every order that has ever been placed with me; sometimes a couple months late, but have always exceeded customer's expectations and will continue to do so for this amplifier.
DEEPER READING:
So, for those of us that want to dig into every absolute detail of this amplifier, I will go over every engineering detail here. Starting from the outside in, lets dig it apart
MECHANICAL / HOUSING:
This may seem like a small detail, but the mechanical properties of the amp are often the first look and feel of how people overall feel about an amp. I don't want to miss any details here, to make sure that you know the parts of the design I find important, and the parts that can be changed to fit your own aesthetic.
- Amp Shell
- Shell casing for this was done using the standard ~3/4" Baltic Birch cabinet grade plywood. Unfortunately, due to the ongoing Ukrainian war; getting A/AA grade plywood is almost impossible. That means that most of the sheets have eye fills, which are a bit unsightly and not optimal. They do have a B/BB supply which I will include as an option, since I think one side is a good veneer.
You will see a variety of options for solid woods, and tolexed ply as well. The tolexed ply will be the double thick style as shown in the images, much like an Orange head. The solid wood finishes will be 3/4" thickness, more like a Fender or Verellen styled design; with box joint edge detailing (think 3/4" wide fingers). Solid wood double thickness can be sourced and made, but it will cost considerably more; so this will only be offered on request with a conversation
- Shell casing for this was done using the standard ~3/4" Baltic Birch cabinet grade plywood. Unfortunately, due to the ongoing Ukrainian war; getting A/AA grade plywood is almost impossible. That means that most of the sheets have eye fills, which are a bit unsightly and not optimal. They do have a B/BB supply which I will include as an option, since I think one side is a good veneer.
- Chassis
- The chassis is something that I wasn't willing to go light on; I've seen too many thin chassis that eventually sag and it isn't worth saving the extra 5 pounds of weight and 50$ of materials. These are using 14 gauge marine grade stainless steel. The sides are then welded into place with full length welds. Now, I will say my welding isn't absolutely stunning, but my penetration is great and they will be ground flush. You will note a darkening / blackening on the interior, which is to be expected with stainless steel welds
- The chassis is something that I wasn't willing to go light on; I've seen too many thin chassis that eventually sag and it isn't worth saving the extra 5 pounds of weight and 50$ of materials. These are using 14 gauge marine grade stainless steel. The sides are then welded into place with full length welds. Now, I will say my welding isn't absolutely stunning, but my penetration is great and they will be ground flush. You will note a darkening / blackening on the interior, which is to be expected with stainless steel welds
- Mounting
- The mounting inside the chassis is going to use snap in retainer nuts. I've tried press fit, riviting, and the snap in nuts; and these have been the most impressive in terms of overall maitenance. Both the press fit and riviting have a possibility of rotating in the housing, which can create a massive issue when removing the amplifier. The snap ins, even in a similar scenario, can be easily removed and replaced in about 5 seconds. They also allow for some flexibility in hole placement, making installing the amplifier after repairs much simpler; and then tighten down nicely for a locked in mechanical joint. Their only downside is a slight price increase but the benifits of overall road security are worth it. They can be seen here
- The mounting inside the chassis is going to use snap in retainer nuts. I've tried press fit, riviting, and the snap in nuts; and these have been the most impressive in terms of overall maitenance. Both the press fit and riviting have a possibility of rotating in the housing, which can create a massive issue when removing the amplifier. The snap ins, even in a similar scenario, can be easily removed and replaced in about 5 seconds. They also allow for some flexibility in hole placement, making installing the amplifier after repairs much simpler; and then tighten down nicely for a locked in mechanical joint. Their only downside is a slight price increase but the benifits of overall road security are worth it. They can be seen here
- Corners
- Corners are not shown in the example casing, we will be using these two screw small corners. Other corners can be specified and used per request.
- Corners are not shown in the example casing, we will be using these two screw small corners. Other corners can be specified and used per request.
- Handles
- Side Handles will be as shown (large metal recessed spring loaded with rubber grip handles), which make for easy lifting, not awkward when handling the entire load up onto a cab, and won't rattle. Top handles will be added as well, these seem to be the best fit. A middle single handle can be added on request, but single hand carrying an amp this big is possibly harmful so by default it will not be on the amplifier
- Side Handles will be as shown (large metal recessed spring loaded with rubber grip handles), which make for easy lifting, not awkward when handling the entire load up onto a cab, and won't rattle. Top handles will be added as well, these seem to be the best fit. A middle single handle can be added on request, but single hand carrying an amp this big is possibly harmful so by default it will not be on the amplifier
- Feet
- Bottom feet are simple rubber feet. On request they can be swapped over to wooden slats if you want that old Matamp vibe.
- Bottom feet are simple rubber feet. On request they can be swapped over to wooden slats if you want that old Matamp vibe.
- Faceplates
- These are Aluminum sheet metal stock that are in house engraved with the needed details. Of things that need to be updated, the knob labels should be above the knobs, not below. Also I will be using black enamel paint to fill the details, sharpie was not effective and rubs off easily.
ELECTRICAL COMPONENTS:
Again, I know it's nuanced but part selection is a big detail for making sure the amplifier is road worthy.
- Switches
- For the tonal options, the switches will maintain the rocker style that is iconic for the V4 specifically. This will not change in further designs, and is part of the specifications
- For the tonal options, the switches will maintain the rocker style that is iconic for the V4 specifically. This will not change in further designs, and is part of the specifications
- Power Capacitors
- Although fitting radial caps is easier for the power supply, their specifications for max temperature swings aren't as robust as the axial caps from F&T or other trustworthy suppliers. This will stay as part of the overall part choices, to continue to maintain a long lifespan and road worthiness
- Although fitting radial caps is easier for the power supply, their specifications for max temperature swings aren't as robust as the axial caps from F&T or other trustworthy suppliers. This will stay as part of the overall part choices, to continue to maintain a long lifespan and road worthiness
- Potentiometers
- PEC seems to be making the best ones on the market. Stainless steel sealed pots are the way to go for that same enduring usage without issue.
- PEC seems to be making the best ones on the market. Stainless steel sealed pots are the way to go for that same enduring usage without issue.
- Resistors
- For the majority of the resistors (not power related), 1% 600mW metal film Vishay resistors should do the trick. There are some alternatives that I've found that I may use if supply runs out, but those values and composition will be uncompromised. They are low noise, tight tolerance, and well made.
- For the majority of the resistors (not power related), 1% 600mW metal film Vishay resistors should do the trick. There are some alternatives that I've found that I may use if supply runs out, but those values and composition will be uncompromised. They are low noise, tight tolerance, and well made.
- Capacitors
- Yellow Mallory capacitors should do the trick for most of the tone circuit and pathing. There will be some that are impossible to supply as such, but those mostly are for cathode bypassing or other applications. This is more typical of amplifiers of this style, and should be both high quality and look ..... "cool"
- Yellow Mallory capacitors should do the trick for most of the tone circuit and pathing. There will be some that are impossible to supply as such, but those mostly are for cathode bypassing or other applications. This is more typical of amplifiers of this style, and should be both high quality and look ..... "cool"
- Turrets
- This will be a turret board construction as shown. The boards are CNC made in house and hand pressed, and the turrets should allow for easy maitenance if and when a part blows out. There will be an update to the overall layout of all the parts such that a number can be removed from the switchs where they are point to point, and instead onto the board to make maitenance easier. This will mean that some parts will be sharing turrets or stacks, so it won't be dead simple (like a Hiwatt for example), but the circuit is orders of magnitude bigger and more complex; so that simplicity can't be expected without increasing the chassis size
- This will be a turret board construction as shown. The boards are CNC made in house and hand pressed, and the turrets should allow for easy maitenance if and when a part blows out. There will be an update to the overall layout of all the parts such that a number can be removed from the switchs where they are point to point, and instead onto the board to make maitenance easier. This will mean that some parts will be sharing turrets or stacks, so it won't be dead simple (like a Hiwatt for example), but the circuit is orders of magnitude bigger and more complex; so that simplicity can't be expected without increasing the chassis size
- Wire
- This is one of the big changes that will be made in future models. A large majority of the wiring will be stepping away from the fibre wound solid core over to an PTFE stranded wire. This should save significant space, create a cleaner layout, and allow for bundling of wires.
- This is one of the big changes that will be made in future models. A large majority of the wiring will be stepping away from the fibre wound solid core over to an PTFE stranded wire. This should save significant space, create a cleaner layout, and allow for bundling of wires.
- Transformers
- I have 5 sets of left over Heyboer transformers from a previous job, so those will be on a first come first serve basis. Otherwise the best supplier out there seems to be Mercury. They respond fast, have things in stock, and are well built. You do pay a price for them, but it seems worth it.
CIRCUIT MODIFICATIONS:
There are several modifications to the overall design of the circuit. Essential here was keeping it able to be run standard, while cleaning up several things that aren't bad but overall make the design unreliable. While we are adjusting things inside the circuit, it made sense to increase the overall options.
If a part of the circuit was not mentioned, assume that it is stock like a V4
- Inputs
- Slight modification here, a third jack was added that bridges the two inputs. Simple and clean
- Slight modification here, a third jack was added that bridges the two inputs. Simple and clean
- Ultra Lo
- This is an option that was only on the V4B, but seems like a cool addition. It does not sound the same as the cathode bypass on the input sensitivity; despite having read that somewhere. This switch basically is the "blanket over the amp" addition. I find it works great for even more lows if you use both inputs and turn one to ultra lo and use the volume to basically add "woof" to the lows
The important thing about this is that, when off, the amp is returned to stock V4 without the ultra lo switch
- This is an option that was only on the V4B, but seems like a cool addition. It does not sound the same as the cathode bypass on the input sensitivity; despite having read that somewhere. This switch basically is the "blanket over the amp" addition. I find it works great for even more lows if you use both inputs and turn one to ultra lo and use the volume to basically add "woof" to the lows
- Lo and Hi Switches
- These have been doubled. Basically, instead of having one switch for both channels; each channel now can be controlled independently without affecting the other. They combine after where these switches were designed, so it made sense to be able to control more. So now, each channel can independently change its sensitivity, its ultra lo, and ultra hi.
- These have been doubled. Basically, instead of having one switch for both channels; each channel now can be controlled independently without affecting the other. They combine after where these switches were designed, so it made sense to be able to control more. So now, each channel can independently change its sensitivity, its ultra lo, and ultra hi.
- 6K11 and 12DW7
- These NOS only tubes have been replaced entirely. The 6k11 was just one 12ax7 and 1/2 12au7 in one tube as a sort of gimmic, so that has been replaced with those tubes respectively; and the 12DW7 is 1/2 12ax7 and 1/2 12au7, so the remaining half of the previous 12au7 is used, and another 12ax7 was added.
Although this overall adds an additional preamp tube to the amp, the ease at which these can be purchased makes the choice obvious.
- These NOS only tubes have been replaced entirely. The 6k11 was just one 12ax7 and 1/2 12au7 in one tube as a sort of gimmic, so that has been replaced with those tubes respectively; and the 12DW7 is 1/2 12ax7 and 1/2 12au7, so the remaining half of the previous 12au7 is used, and another 12ax7 was added.
- FX loop
- A front panel FX loop has been added. It has been labeled a bit more descriptively with preamp out and poweramp in. When not in use, the circuit is the same as stock. When using the Poweramp input, the preamp is bypassed entirely and left in a slave state. Note that the preamp output has no volume control, only the poweramp input has volume control. This can be moved per request.
A last note about this: using the preamp output will still have you connected to the amp's poweramp; it is basically a slave output. Neither of these turn off the power section, so the amp will still always require a speaker cabinet to always be connected to the output.
- A front panel FX loop has been added. It has been labeled a bit more descriptively with preamp out and poweramp in. When not in use, the circuit is the same as stock. When using the Poweramp input, the preamp is bypassed entirely and left in a slave state. Note that the preamp output has no volume control, only the poweramp input has volume control. This can be moved per request.
- Half Power
- This is a common mod in push-pull 100 watt amplifiers to use without blowing the room out. It basically disconnects the outer two tubes from the circuit, thus cutting the power output in half. Importantly, it does also double the required load on each setting in the output; so it isn't super simple but is an easy thing to remember. In full power, the mod has no effect on the circuit.
- This is a common mod in push-pull 100 watt amplifiers to use without blowing the room out. It basically disconnects the outer two tubes from the circuit, thus cutting the power output in half. Importantly, it does also double the required load on each setting in the output; so it isn't super simple but is an easy thing to remember. In full power, the mod has no effect on the circuit.
- Flyback Diodes
- In the scenario of a catastrophic failure, flyback diodes have been added to the output transformer taps, that will pop the fuse and shut the amp down for overall safety.
- In the scenario of a catastrophic failure, flyback diodes have been added to the output transformer taps, that will pop the fuse and shut the amp down for overall safety.
- 7027A
- These tubes have been replaced with 6L6GC. A more easily purchased option for on the road stability, and are the same overall design as the 7027As.
- These tubes have been replaced with 6L6GC. A more easily purchased option for on the road stability, and are the same overall design as the 7027As.
- Bias
- Using the Hiwatt transformers instead of the normal ampeg transformers means that the overall output is dropped to 100 watts instead of 120 watts; but also has a dedicated bias tap. The circuit is otherwise not changed, just no longer pulled off the rectified mains
- Using the Hiwatt transformers instead of the normal ampeg transformers means that the overall output is dropped to 100 watts instead of 120 watts; but also has a dedicated bias tap. The circuit is otherwise not changed, just no longer pulled off the rectified mains
- Fuses
- There will be a mains 5A slow blow fuse for overall safety, and then each side of the rectifier will be switched and fuse; to overall have less wear on the switches and be more safe with the power supply.
- There will be a mains 5A slow blow fuse for overall safety, and then each side of the rectifier will be switched and fuse; to overall have less wear on the switches and be more safe with the power supply.
- Power Smoothing
- The Power Totem stacks have been changed from 2X (110 uf / 100k) up to 2x (200 uf / 220k). Additionally, this stack has been duplicated for the B power tap instead of either none or 40 uf. This should make the power supply to the power section more reliable and less saggy, and overall uniform.
- The Power Totem stacks have been changed from 2X (110 uf / 100k) up to 2x (200 uf / 220k). Additionally, this stack has been duplicated for the B power tap instead of either none or 40 uf. This should make the power supply to the power section more reliable and less saggy, and overall uniform.
- Heaters
- The heaters are elevated to a 50vDC to keep them overall quiet.
