Greetings!
One of my CS 800 amplifiers is in need of an electrolytic replacement. It is the oldest (1977) out of my inventory and, still uses all it’s original parts. The amplifier works fine with the exception of a weak (declining torque strength) fan that I will be replacing today. The capacitor upgrade is merely based upon being 32 years of age.
I was curious if I increased the capacitance in this amplifier would I notice an improvement on the bass response. This amplifier, with the eleven others are used in bridged mono for sub duty ranging from 100 – 25.5 Hz (+/- 3dB).
Has anyone taken it upon himself or herself to increase the capacitance on these old amplifiers? Observing the schematics, I’ve noticed the capacitors are wired in series, which results in a micro fad of 7,500.
What I was proposing to do is increase the micro fad from 7,500 to 15,000 or even 30,000
If the results are stellar, I will upgrade the other four as well. Please bear in mind that the amplifier in question is the Non-DDT version.
Also,
Would anyone know if the CS 800X follows the same topology in terms of ratings and, use the series scheme as well? I do not have the schematics on the CS 800X to verify.
Cheers!
One of my CS 800 amplifiers is in need of an electrolytic replacement. It is the oldest (1977) out of my inventory and, still uses all it’s original parts. The amplifier works fine with the exception of a weak (declining torque strength) fan that I will be replacing today. The capacitor upgrade is merely based upon being 32 years of age.
I was curious if I increased the capacitance in this amplifier would I notice an improvement on the bass response. This amplifier, with the eleven others are used in bridged mono for sub duty ranging from 100 – 25.5 Hz (+/- 3dB).
Has anyone taken it upon himself or herself to increase the capacitance on these old amplifiers? Observing the schematics, I’ve noticed the capacitors are wired in series, which results in a micro fad of 7,500.
What I was proposing to do is increase the micro fad from 7,500 to 15,000 or even 30,000
If the results are stellar, I will upgrade the other four as well. Please bear in mind that the amplifier in question is the Non-DDT version.
Also,
Would anyone know if the CS 800X follows the same topology in terms of ratings and, use the series scheme as well? I do not have the schematics on the CS 800X to verify.
Cheers!
If I could find a pair of 30kuF, 47kuF, or 68kuF caps that would fit, I'd drop them in without a second thought. Are you running them at 8 ohms bridged or 4? At 4 ohms bridged, the existing 15kuF caps are marginal - you really need 20kuf on each rail or better to properly filter a supply for 2 ohm operation. I know, the CS800's don't recommend this, but the truth is those amps will tolerate it a lot better than an equivalent modern one will (which is probably why you're still using them).
Thank up wg_ski!
They are used @ 4 ohms bridged mono. However, based on the impedance rise/dips of the subs at the given frequencies the amplifier sees no less than 3.9 ohms minimum.
I haven’t had much luck online with mouser, digi-key and, so forth. So, I have decided to venture to a few electrical shops in town on Saturday.
Cheers!
They are used @ 4 ohms bridged mono. However, based on the impedance rise/dips of the subs at the given frequencies the amplifier sees no less than 3.9 ohms minimum.
I haven’t had much luck online with mouser, digi-key and, so forth. So, I have decided to venture to a few electrical shops in town on Saturday.
Cheers!
Mouser or Digi-Key could get the for you - for a price - and a very large MOQ. I was thinking surplus outlets. 100V are bit more difficult to find - I have 16 28kuF/150V, a handful of 200v at similar capacitance, and four 44kuF/100V but they're too tall to fit in a CS-800. Plenty of 68kuF/75V in the right form factor but that's not quite enough voltage.
Omnifex,
I just pulled the 800X schematic up and it uses 10KUF@75V. One caution on increasing the power supply caps, years ago Peavey added triac to the input of the power transformer, took the load off of the power switch. You might want to check your amps to see if they've been modified or even possibly manufactured that way, not sure what year they started that. Its pop-riveted to the bottom of the chassis, inside of course.
Craig
I just pulled the 800X schematic up and it uses 10KUF@75V. One caution on increasing the power supply caps, years ago Peavey added triac to the input of the power transformer, took the load off of the power switch. You might want to check your amps to see if they've been modified or even possibly manufactured that way, not sure what year they started that. Its pop-riveted to the bottom of the chassis, inside of course.
Craig
Thank you Gentlemen.
I'm going to stop by the electrical shop where I purchased 6 Gauge SO cable 10 years ago. At the time, they stocked a lot of industrial supplies.
That is a very noble of you. Thank you. I currently have the CS 800 “A” Series schematic. I would imagine the B & C versions are the same in the power supply section with the only addition being DDT.
I haven’t thoroughly examined the CS 800X other than cleaning heat sinks once a year. I own all the excluding the switch mode version so, I will open one of each to find out.
You should see a pm with my email address arriving shortly.
Cheers!
wg_ski said:
I'm going to stop by the electrical shop where I purchased 6 Gauge SO cable 10 years ago. At the time, they stocked a lot of industrial supplies.
llwhtt said:
That is a very noble of you. Thank you. I currently have the CS 800 “A” Series schematic. I would imagine the B & C versions are the same in the power supply section with the only addition being DDT.
llwhtt said:
I haven’t thoroughly examined the CS 800X other than cleaning heat sinks once a year. I own all the excluding the switch mode version so, I will open one of each to find out.
You should see a pm with my email address arriving shortly.
Cheers!
I was filter cap shopping recently. I found some of the best prices and selection here: http://capacitor.tedss.com
Overall, somewhat cheaper than both Mouser and Digi-Key.
Cheers,
Paul
Overall, somewhat cheaper than both Mouser and Digi-Key.
Cheers,
Paul
"Observing the schematics, I’ve noticed the capacitors are wired in series, which results in a micro fad of 7,500."
No, they're not.
The power supply is about ±80V, one cap per rail.
The amp will not have 'more bass' with bigger caps.
The bridge rectifier will probably blow up if you go over 30,000µF.
You will probably also eat the power switch, and then after replacing it do the triac switch mod (if you have an older CS800).
No, they're not.
The power supply is about ±80V, one cap per rail.
The amp will not have 'more bass' with bigger caps.
The bridge rectifier will probably blow up if you go over 30,000µF.
You will probably also eat the power switch, and then after replacing it do the triac switch mod (if you have an older CS800).
Cheers djk!
I wasn't aiming for more bass ( I can achieve 14,400 watts continuous using quite a few of them) but increasing the recovery time which is why, I was aiming for larger capacitance.
The power switch is not a concern for they are always on and powered up using 20-amp breakers. One for each amplifier.
I wasn't aiming for more bass ( I can achieve 14,400 watts continuous using quite a few of them) but increasing the recovery time which is why, I was aiming for larger capacitance.
The power switch is not a concern for they are always on and powered up using 20-amp breakers. One for each amplifier.
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