• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Building an amp from scratch - what features would i want

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
30 car batteries would give a 360V supply (or more when fully charged) so that might avoid the problem of putting in a three-phase supply, unless the charger needed a three-phase supply itself. This sounds just as realistic as the other items on the list.

Those of us poor souls who are content to listen via mere full-wave supplies perhaps need to get our ears checked.
 
30 car batteries would give a 360V supply (or more when fully charged) so that might avoid the problem of putting in a three-phase supply, unless the charger needed a three-phase supply itself. This sounds just as realistic as the other items on the list.

Those of us poor souls who are content to listen via mere full-wave supplies perhaps need to get our ears checked.

That might be a step backwards. I know that co-locating batteries close to loads like hi powered car amps is not enough of a solution unless you also co-locate large farad capacitors. Perhaps the rise time or response rate of plate batteries is just not fast enough not to limit dynamic's. Speaking from experience in my 1996 z28 which has a forward battery, a forward battery bus, a rear battery bus, a rear batter, and a large farad cap at the rear location all feeding my 5 channel power amp. So if you are going to go with batteries, you'll probally need a bank of caps as well.

running audio gear off batteries works well for DAC's, preamps, small T amps, etc.


thanks for you suggestion.
 
Impedances would be different. Putting 30 batteries in series means that you only need 1/30th of the current for a given power output. This is 900 times the impedance, but the total impedance of 30 batteries is only 30 times that for one - so you gain a factor of 30. I suppose you could put 30 big caps in series, and put that in parallel with the batteries. Such a supply would be dangerous, though: high voltage, low impedance.

I don't have all that stuff in my car, as I just use it as a mode of transport.
 
That might be a step backwards. I know that co-locating batteries close to loads like hi powered car amps is not enough of a solution unless you also co-locate large farad capacitors. Perhaps the rise time or response rate of plate batteries is just not fast enough not to limit dynamic's. Speaking from experience in my 1996 z28 which has a forward battery, a forward battery bus, a rear battery bus, a rear batter, and a large farad cap at the rear location all feeding my 5 channel power amp. So if you are going to go with batteries, you'll probably need a bank of caps as well.
Contrary to popular belief, the best way to power a car audio system is to replace (or have rewound) the alternator with a higher current version. If you continue to use the factory alternator in a high power multi-amp system you will not be able to keep the batteries charged (at high sustained output levels). Caps only make the situation worse because they represent an extra load on the (factory) alternator.

I have built many car audio systems (don't tell anyone) and worked in this industry for almost 30 years. I don't know everything, but the best way to get the most voltage and current to your amps is to replace the factory alternator with one that has a higher current rating and the biggest one that will physically fit into the OE location. Extra batteries will help after that, but the high capacitance caps, in my opinion are snake oil.
 
Speaking from experience in my 1996 z28 which has a forward battery, a forward battery bus, a rear battery bus, a rear batter, and a large farad cap at the rear location all feeding my 5 channel power amp.

And what kind of tube power amplifier is it that you have running on all these magnificent busses, batteries and capacitors ?


What kind of average and peak current draw and how does it compare to solid-state amplifiers most people put in their cars ?
 
hmmmn, interesting. I still don't see a single spec that can be designed to apart from output power, and even that is not defined.

You seem to have a lot of "stuff" and a lingering disatisfaction. What is/are your design goal(s) APART from output power?

If bottom end power is the underlying issue for you, have you considered bi-amping with SS lower frequencies and tubes in the mids and highs?

What speakers are you driving? What is their frequency vs impedance curve? Have you considered how this may be impacting on the performance of your amp(s)?

I get the feeling money isn't an issue for you!
 
Contrary to popular belief, the best way to power a car audio system is to replace (or have rewound) the alternator with a higher current version. If you continue to use the factory alternator in a high power multi-amp system you will not be able to keep the batteries charged (at high sustained output levels). Caps only make the situation worse because they represent an extra load on the (factory) alternator.

I have built many car audio systems (don't tell anyone) and worked in this industry for almost 30 years. I don't know everything, but the best way to get the most voltage and current to your amps is to replace the factory alternator with one that has a higher current rating and the biggest one that will physically fit into the OE location. Extra batteries will help after that, but the high capacitance caps, in my opinion are snake oil.


good points to check into. The batteries I am using require a min charge rate of 13.7 volts to charge. I get 14.5 at the front battery, and 14.1 at the rear battery. The diff is as a result of the battery isolator I am using, not the wire run. With the car off, using the standard charge rate table which considered static volltage and attemps to correlate the static voltage to charge state, I can get to 100% at the front, and 90& at the rear.

other than that, I bought, for 15 bucks, but never installed it, since it looked like I didn't need it, a reduction pully for my alternator. The pully is 33% smaller than the stock pulley, and as a result, spins up the alternater at a faster RPM. My car needs eng rpm of 1200 to even turn on the alternator (one wire system).

since the amp draw on the alternator is relatively low, looks like going bigger on the alternator is not needed right now. But, still not ruling out the install of the rudction pully.
 
I suppose you could put 30 big caps in series, and put that in parallel with the batteries. Such a supply would be dangerous, though: high voltage, low impedance.



If I use 450V/1500uf caps, would not need to put them in series. If I series 10 of them, my capacitance would drop to 150uf. My voltage handling would go up to 4500V's but the 30 car batteries would only provide 360 volts. A better use of 10 1500uf/450v caps would be to parallel them, since I already would have sufficient voltage handling. Paralleling 10 1500uf/450v caps would give me 15000uf 's of capacitance. much better than 150uf if you put them in series.
 
Contrary to popular belief, the best way to power a car audio system is to replace (or have rewound) the alternator with a higher current version. If you continue to use the factory alternator in a high power multi-amp system you will not be able to keep the batteries charged (at high sustained output levels). Caps only make the situation worse because they represent an extra load on the (factory) alternator.

I have built many car audio systems (don't tell anyone) and worked in this industry for almost 30 years. I don't know everything, but the best way to get the most voltage and current to your amps is to replace the factory alternator with one that has a higher current rating and the biggest one that will physically fit into the OE location. Extra batteries will help after that, but the high capacitance caps, in my opinion are snake oil.


good points to check into. The batteries I am using require a min charge rate of 13.7 volts to charge. I get 14.5 at the front battery, and 14.1 at the rear battery. The diff is as a result of the battery isolator I am using, not the wire run. With the car off, using the standard charge rate table which considered static volltage and attemps to correlate the static voltage to charge state, I can get to 100% at the front, and 90& at the rear.

other than that, I bought, for 15 bucks, but never installed it, since it looked like I didn't need it, a reduction pully for my alternator. The pully is 33% smaller than the stock pulley, and as a result, spins up the alternater at a faster RPM. My car needs eng rpm of 1200 to even turn on the alternator (one wire system).

since the amp draw on the alternator is relatively low, looks like going bigger on the alternator is not needed right now. But, still not ruling out the install of the rudction pully.
 
ground loop isolator. basically it's 4 diodes. two in series in each direction. the two sets are paralleled in opposite directions. connectted between the circut and the mains ground. this isolates the ground during non fault conditions. but when a fualt occurs that is greater than the forward voltage of two diodes in parallel, the diodes open and you have a normal saftey ground. a real ince way of having a virtual 2 prong plug that turns into a 3 prong plug during a fault condition.
 
here's more info
 

Attachments

  • Picture 3.jpg
    Picture 3.jpg
    452.8 KB · Views: 129
wiring color codes is something to think about. did a google search which brought me back here. with a potential rats nest of point to point wiring, using a color scheme would be useful for trouble shooting late down the road by me or a later owner.
 

Attachments

  • wiringcolours.pdf
    41.2 KB · Views: 31
Hello LinuksGuru,
Your amp seems to be very nice i would be delighted to build one can you share the details

Hi, viki_v2,

I will share details as soon as I will finish & test it. Right now I would like to re-design amplifier and output transformers in order to switch from 6L6GC to KT88/6550. May be I will make some changes on PCB. Need to say, there are no chassis yet either.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.