Shocking bit of information about old Silverfaces
- Thread starter Securb
- Start date
Securb
One of Jerry's Kids
Re: Shocking bit of information about old Silverfaces
I can pull an old Ace tone out of the Silverface in a pinch. The Silverface is the Rich Little of amps, the amp of a *thousand voices.
*with the right pedals.
I can pull an old Ace tone out of the Silverface in a pinch. The Silverface is the Rich Little of amps, the amp of a *thousand voices.
*with the right pedals.
PFDarkside
of the Forum
Re: Shocking bit of information about old Silverfaces
Great news that the amp is back to perfect condition, but even better that you are still here to play it.
What, may I ask, is the weight of that beast?
Great news that the amp is back to perfect condition, but even better that you are still here to play it.
What, may I ask, is the weight of that beast?
Securb
One of Jerry's Kids
Re: Shocking bit of information about old Silverfaces
Stock it is about 90 lbs but I think the Celestion speakers I put in added a couple of lbs. I don't see it leaving the house ever again. It is retired, it's gigging days are over.
Great news that the amp is back to perfect condition, but even better that you are still here to play it.
What, may I ask, is the weight of that beast?
Stock it is about 90 lbs but I think the Celestion speakers I put in added a couple of lbs. I don't see it leaving the house ever again. It is retired, it's gigging days are over.
Stratman
Guitaris Maximus
Re: Shocking bit of information about old Silverfaces
I used to own a Silverstone (Sear) amp.
I believe the model number was 1664 - the one with the 6-10inch speakers and a cabinet that you placed the head into the back.
I also got a serious shock from it.
It did not fly very well out the window, shortly after that!
I used to own a Silverstone (Sear) amp.
I believe the model number was 1664 - the one with the 6-10inch speakers and a cabinet that you placed the head into the back.
I also got a serious shock from it.
It did not fly very well out the window, shortly after that!
Re: Shocking bit of information about old Silverfaces
I generally have three ground points. I ground the power cord ground by itself near where it comes in. Right onto the chassis. I then split the preamp grounds and star them as far away fro the power tubes as possible. And the power section grounds go onto a small lug attached to one of the mounting bolts on the PT.
Amps are quiet as a mouse fart (which is the imperial unit of negligible sound I use. Rat farts are messier ).
I generally have three ground points. I ground the power cord ground by itself near where it comes in. Right onto the chassis. I then split the preamp grounds and star them as far away fro the power tubes as possible. And the power section grounds go onto a small lug attached to one of the mounting bolts on the PT.
Amps are quiet as a mouse fart (which is the imperial unit of negligible sound I use. Rat farts are messier ).
Myaccount876
Amira-Maker
Re: Shocking bit of information about old Silverfaces
I guess this is as good a thread of any for Silverface Fender mods, so I'll describe what I did to my '77 Bassman 70.
Here's the schematic for my amp, so you can see what I'm talking about: http://elektrotanya.com/PREVIEWS/63463243/23432455/fender/fender_bassman-70_sch.pdf_1.png
Generally, there's quite a bit of things in common with the basic idea of the Silverface Fender designs I've looked at, so this is probably applicable to quite a few Silverface amps. (thanks to Edgecrusher for helping me along the way).
Coming out of the output transformer (the transformer that goes to the speaker jacks in the schematic), there are the green, green-yellow wires, and black wires. On most other amps, there is just the green and black wires (secondary and primary wires) coming out of the output transformer, but my amp has a recording line out jack so it has the extra wire. Attached to the secondary (green) wire is the 820 ohm resistor in parallel with a .01 uF capacitor. This is your negative feedback loop. What negative feedback does, is it takes certain frequencies, inverts them (negative), and reintroduces or "feeds" them back into the circuit against the same positive frequencies. These frequencies cancel out, and it colors the EQ and cleans up the amp. This is common with Fender and Marshall designs, but not Vox designs which usually have something called no-negative feedback. This makes the amp louder, overdrives easier, and has a percieved midrange boost against the lows and highs. If you simply cut the wire between the secondary wire and the resistor, you take the negative feedback out of the circuit, making the amp a no-negative feedback amp.
Now, what I did is utilize the ground switch, which I disabled, to switch between the stock negative feedback, no negative feedback, and a presence control.
The presence control is part of the negative feedback circuit, where a potentiometer acts as a variable resistor, and as you turn the pot up (increasing resistance), less highs are fed back as a part of the negative feedback circuit. This allows more highs to leave the amp unaffected, resulting in a brighter sound. I used a 20K resistor in series with a 50K pot (the 20K resistor is to prevent too much negative feedback, which makes the amp quieter and darker), and I have a very effective presence control that sounds like a nice in-between of the stock wiring and the no-negative feedback wiring. You can also put a .0047uF capacitor in series (after the presence control) to boost the lows (this acts like a "fixed" resonance control). As a place to add the presence control, I used the empty Hum Balance hole, as I removed the hum balance for the fixed 100 ohm resistors between both ends of the pilot light and ground.
In addition to the modification Securb mentioned about the 120pF cap and the bright switch, you can further tailor the tone stack to your liking. On the Normal channel, there is a 6.8K resistor in series with the bass pot and a .047uF cap that goes to ground. This 6.8K resistor is your midrange "control". It is a fixed value, and increasing the resistance to 10K or 20K will really boost the midrange. You can add a simple variable resistor, or just remove the bright switch circuit for the capacitor to either be fixed or removed, and use the switch to switch between different resistor values to control the midrange. The same applies to the bass channel which has a 8.2K resistor. If there's too much midrange on the bass channel, you can lower this resistor value.
Hopefully this helps some of you that are interested in mods.
I guess this is as good a thread of any for Silverface Fender mods, so I'll describe what I did to my '77 Bassman 70.
Here's the schematic for my amp, so you can see what I'm talking about: http://elektrotanya.com/PREVIEWS/63463243/23432455/fender/fender_bassman-70_sch.pdf_1.png
Generally, there's quite a bit of things in common with the basic idea of the Silverface Fender designs I've looked at, so this is probably applicable to quite a few Silverface amps. (thanks to Edgecrusher for helping me along the way).
Coming out of the output transformer (the transformer that goes to the speaker jacks in the schematic), there are the green, green-yellow wires, and black wires. On most other amps, there is just the green and black wires (secondary and primary wires) coming out of the output transformer, but my amp has a recording line out jack so it has the extra wire. Attached to the secondary (green) wire is the 820 ohm resistor in parallel with a .01 uF capacitor. This is your negative feedback loop. What negative feedback does, is it takes certain frequencies, inverts them (negative), and reintroduces or "feeds" them back into the circuit against the same positive frequencies. These frequencies cancel out, and it colors the EQ and cleans up the amp. This is common with Fender and Marshall designs, but not Vox designs which usually have something called no-negative feedback. This makes the amp louder, overdrives easier, and has a percieved midrange boost against the lows and highs. If you simply cut the wire between the secondary wire and the resistor, you take the negative feedback out of the circuit, making the amp a no-negative feedback amp.
Now, what I did is utilize the ground switch, which I disabled, to switch between the stock negative feedback, no negative feedback, and a presence control.
The presence control is part of the negative feedback circuit, where a potentiometer acts as a variable resistor, and as you turn the pot up (increasing resistance), less highs are fed back as a part of the negative feedback circuit. This allows more highs to leave the amp unaffected, resulting in a brighter sound. I used a 20K resistor in series with a 50K pot (the 20K resistor is to prevent too much negative feedback, which makes the amp quieter and darker), and I have a very effective presence control that sounds like a nice in-between of the stock wiring and the no-negative feedback wiring. You can also put a .0047uF capacitor in series (after the presence control) to boost the lows (this acts like a "fixed" resonance control). As a place to add the presence control, I used the empty Hum Balance hole, as I removed the hum balance for the fixed 100 ohm resistors between both ends of the pilot light and ground.
In addition to the modification Securb mentioned about the 120pF cap and the bright switch, you can further tailor the tone stack to your liking. On the Normal channel, there is a 6.8K resistor in series with the bass pot and a .047uF cap that goes to ground. This 6.8K resistor is your midrange "control". It is a fixed value, and increasing the resistance to 10K or 20K will really boost the midrange. You can add a simple variable resistor, or just remove the bright switch circuit for the capacitor to either be fixed or removed, and use the switch to switch between different resistor values to control the midrange. The same applies to the bass channel which has a 8.2K resistor. If there's too much midrange on the bass channel, you can lower this resistor value.
Hopefully this helps some of you that are interested in mods.
