Winner? for crying out loud!
I think I've read over a hundred pages now including August 14-18 , 2011
this is driving me nuts - Who Won !?
I think I've read over a hundred pages now including August 14-18 , 2011
this is driving me nuts - Who Won !?
No tube regulation?
In the several schematics posted in this thread, I haven't seen any with tube regulation.
I understand that this may be due to the $99 buck price point.
But, I was wondering if it would even be noticable, as at 3 - 5 watts, you wouldn't get any B+ sag type distortion.
Thanks,
Paul
In the several schematics posted in this thread, I haven't seen any with tube regulation.
I understand that this may be due to the $99 buck price point.
But, I was wondering if it would even be noticable, as at 3 - 5 watts, you wouldn't get any B+ sag type distortion.
Thanks,
Paul
Regulation, or rectification?
Voltage regulators designed to provide a stiff regulated supply voltage are seldom used in guitar amps. First, a regulator wastes voltage, and voltage is power, and power SELLS. Second, a guitar amp running on a regulated power supply has a hard "edge". This is useful in some genres, but not a big seller.
There are speciallized voltage regulators that originated in the DIY world and have now found their way into some mainstream amps. These alow dialing back the power supply to allow distortion at less than stadium filling volume.
I have been experimenting with something I call the Sagulator that is like a reverse voltage regulator. It samples the output tubes cathode current to reduce the B+ voltage.
Tube rectification got cut from most of the amps here because of cost. At least that was the case in my amps. I did experiment with a tube rectifier in AMP 2.X. It got cut early on. It cost too much power.
It is possible to get significant sag in a small watt amp. Many small watt amps are class A SE designs. It has been said that sag doesn't exist in a class A amp. In theory this is true, but many Fender Champ players will state otherwize. Why? It's because that amp left class A as soon as you plugged in the stomp box and dimed the volume control. Given a little wimpy power transformer, small power supply caps and OPT with 400 ohms of DCR, the plate voltage drops nearly 50 volts when you hit it hard.
I get some sag in a little amp with an SS supply by using a voltage doubler with smallish caps and a cheap Chinese power transformer.
I am working on a little guy that runs off of a battery and gets its B+ from an unregulated booster. I have too much sag in that one.
I assume you meant "tube rectifiers". Yes they add cost. You can get the same effect by placing resisters in series with each solid state diode. The word "sag" is simply a word that means "high impedance power supply". A series resister will create that.
Yes cost. An extra tube, socket, bigger transformer to supply the heater and the static power drop of the rectifier. Also a tube rectifier rules out a bridge rectifier and some inexpensive transformer options can not be used.
Not a hundred buck amp but the above schematic partly came out of the ideas developed here. I laid out the part arrangement for the tone controls (remember, I am using dual pots), basically it is a 5E3 Fender Deluxe board with the input cathodes split with the tone control components mounted point-to-point on the top panel. This reduces the amount of wires running back and forth if the parts were on a board. I also wanted to stay away from a design with a custom board (although I will make one for myself) so anyone could take a standard 5E3 and modify it to also do the Blackface tone control. I am mulling over a switched PI for a LTP but I have not decided on it yet. So anyway, here is the layout.
Re Tube Rectification:
My current project uses a psu similar to ones I previously posted on this thread.
But...two of the silicon diodes in the rectifier are replaced by 2 cheap 6AL5 double diode tubes with both internal diodes paralelled.. Filaments wired in series across the 12vac for a total draw of 300mA. Each diode in the 6AL5 has a max of 9mA. Should be safe for a design using up to 27mA continuous.
Cheers
JimG
My current project uses a psu similar to ones I previously posted on this thread.
But...two of the silicon diodes in the rectifier are replaced by 2 cheap 6AL5 double diode tubes with both internal diodes paralelled.. Filaments wired in series across the 12vac for a total draw of 300mA. Each diode in the 6AL5 has a max of 9mA. Should be safe for a design using up to 27mA continuous.
Cheers
JimG
Greedy, greedy Fender: they want to cover every market niche! So they did their 100 buck challenge too but with some profit of course. Anyway, funny specs: 2W RMS into 8 Ohms - 45% THD. I'm guessing it's a 1W push pull (12AT7).
Pawn Shop Amplifiers
Pawn Shop Amplifiers
Also, Champ introduced sag by control grid of an output tube that regulates B+ for the preamp. I made this effect more pronounced in the "World Champion" amp in this thread.
winner
thank you. I did eventually read the rest of the thread .
i was am looking for a amp I can afford with the tone I'm looking for ..
If there is such a thing .. that I can afford .
considering I dont know a thing about building a amp Im also going to have to have it built.
I really thot this might lead to a workable solution for me and I really had my hopes up .
still looking
thank you. I did eventually read the rest of the thread .
i was am looking for a amp I can afford with the tone I'm looking for ..
If there is such a thing .. that I can afford .
considering I dont know a thing about building a amp Im also going to have to have it built.
I really thot this might lead to a workable solution for me and I really had my hopes up .
still looking