There is a 10k resistor that discharges the RC. Making the cap smaller will engage the relay at turn on sooner too. Its OK as it is, so I would experiment with a smaller one than 10k to drain the system faster, so to disengage faster. Haven't actually tried that though, because the disengage time is OK. That ''bleeder'' resistor will ask more current from the 7812 during normal operation, so you better use a little sink for it.
I have placed a 470uF cap in parallel with the 100uF. As planned, start time rises up to 1 minute. But shuting down time remains the same, 1 second. I will try changing the resistor...
The next thing I tried is to change the 10k res. (still having 100uF). Measuring it at the board gives you 2.3 kOhm because is paralleled with other things. By placing a 1k res. in parallel with the 10k (thus making an equivalent of 0.9kOhm), it gives a resultant resistance of 0.7kOhm.
but the strange thing is that it does nothing to the delay times. It continues turning on and off at the same times. What is wrong, Salas?
but the strange thing is that it does nothing to the delay times. It continues turning on and off at the same times. What is wrong, Salas?
Don't know, haven't tried to shorten disengage time as I told, seems the main filter charge isn't draining enough any faster no matter the heavier bleeder.Try less than 47k R to C this time, parallel one resistor and see what happens. Why you want super fast release? What is it in danger?
I am going to integrate an LDR volume control. It is supplied by +5v, so I am going to tap +17v from the main filter capacitors to a +5v regulator. The problem is that LDR volume control start to misbehave when they have less voltage than 5v. As it goes down, there is a point where it sounds at max volume, something REALLY disgusting.
So I have two approaches:
-To put a BIG capacitor after the 5v regulator, so the LDR will keep being supplied a bit longer.
-To enshort the relay shut down time, so it doesnt have time to get a lower voltage than 5v, thus closing the relay before it reach that maximum volume fault.
-Wait to have the LDRs delivered at home and check if maybe I am too paranoid, and the 1 second it actually takes to shut down is more than enough. By looking at how the voltage supplied by the main filter caps decreases when I shut it down, my bet goes for this option. The DMM display is not fast enought, but I think that it still says 7v in the main filter caps when I hear the relay closing. Then it goes down to 2v.
Is has the same problem when starting up, but I already have a 10 seconds start delay on my DCB1, so half of the problem is solved. I will try to change the resistor you say. I may solve that just by adding a big cap after the 5v regulator, but it has became a curiosity matter. I NEED to be able to tweak things
So I have two approaches:
-To put a BIG capacitor after the 5v regulator, so the LDR will keep being supplied a bit longer.
-To enshort the relay shut down time, so it doesnt have time to get a lower voltage than 5v, thus closing the relay before it reach that maximum volume fault.
-Wait to have the LDRs delivered at home and check if maybe I am too paranoid, and the 1 second it actually takes to shut down is more than enough. By looking at how the voltage supplied by the main filter caps decreases when I shut it down, my bet goes for this option. The DMM display is not fast enought, but I think that it still says 7v in the main filter caps when I hear the relay closing. Then it goes down to 2v.
Is has the same problem when starting up, but I already have a 10 seconds start delay on my DCB1, so half of the problem is solved. I will try to change the resistor you say. I may solve that just by adding a big cap after the 5v regulator, but it has became a curiosity matter. I NEED to be able to tweak things
If someone are interested in larger time delay, here is my experience.
Yesterday I make delay relay for tube preamp, part of amb's Epsilon 12 schematic. This is very similar to DCB1 time delay, except it use 1N4148 darlington, instead of two npn's.
I use 1M resistor and 470 uf cap and get about half minute delay, adding second 470 uf in parallel give about 1 minute delay. Adding or removing 10K not make big change (amb's shematic are without it).
It powered from 12V regulated, relay used - TYCO ELECTRONICS MT2-C93402
TYCO ELECTRONICS|MT2-C93402|RELAY, PCB, DPCO, 12VDC | Farnell Latvijas Republika
Thanks, I'll run earth ground to the chassis.
I've got 750ma slow-blow fuse installed, if I remember correctly, that is what was spec'd out.
Thanks,
JG
JG, have you had a chance to listen to it yet? I always enjoy reading subjective opinions.
I've got some parts on the way from Parts Connexion, Vishay MKP-1837's to replace the LED 'lyctics (.2 uF each position), and new PRP resistors (33,33,27) to run the heavy shunt current. Found some thick aluminum bars to replace the puny heatsinks currently in there, hopefully it will be enough. I'm going to yank the Takman carbon films out of the Hypnotize and replace with the PRP metal films, leaving Takman's in the Mesmerize. I can compare one DCB1 with the other just by swapping harnesses inside.
I've got some parts on the way from Parts Connexion, Vishay MKP-1837's to replace the LED 'lyctics (.2 uF each position), and new PRP resistors (33,33,27) to run the heavy shunt current. Found some thick aluminum bars to replace the puny heatsinks currently in there, hopefully it will be enough. I'm going to yank the Takman carbon films out of the Hypnotize and replace with the PRP metal films, leaving Takman's in the Mesmerize. I can compare one DCB1 with the other just by swapping harnesses inside.
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I'm finally done wiring them up. Is it ok to leave AC ground floating or should I tie it down to something.
Thanks,
JG
have you tried F5 without B1
My F5 is still under construction; I may abandon it if I can't figure out what to do with the heatsinks / case.
I've got the 2 channels and ps board ready. I could use some help with it.
I'm working on a couple of other things I'd like to get out of the way before I tackle the rest of the F5.
No, I haven't listened to the dcb1 yet. I really need to get a good pair of speakers for 2 channel audio. ( I have speakers for my 5.1 surround sound system).
I have been looking at some cases from Antek on eBay...
eBay Stores - Transformers, Enclosures items on eBay.com
One of which looks really interesting...
Power Amp / Amplifier DIY HiFi Case Heatsink Kit - eBay (item 250515881584 end time May-15-10 15:32:11 PDT)
It might be too small for an F5 but I like the integrated heatsinks. The price is not too bad but I would want to be sure it could hold the necessary items.
Carbon is generally a better practice for gate stoppers and grid stoppers because they present no resonance dangers with parasitics. In this particular shunt the theoretical phase margin is vast (over 130deg) and normal 1/4W metal film will work too. Still, carbon stoppers are good not only to avoid real oscillations if a design is on the verge, but transiently a preferable measure. Minimum impact in this case though. I don't find subjective influence in the shunt from resistors. Dale and PRP are very good in the audio part, in the shunts part only capacitors matter, and I would save money by using generic resistors in the shunts.
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Did I get lucky? I feel lucky...
My local electric service is over the top, literally. The transformer sits at the corner of my yard. I have ~122 VAC. Along with this I am using a "25.2 VCT" transformer. It is pretty generous as well.
I have +/- 14.7 VAC rails going to this. I hoped to be able to "hot rod".
V across R1's are 1.462 & 1.502
The output relay clicks.
DC offset is .001/.003 V
Vout is 9.48 & -9.19
The mosfets are P140 & P9140. I do plan to heatsink them.
My local electric service is over the top, literally. The transformer sits at the corner of my yard. I have ~122 VAC. Along with this I am using a "25.2 VCT" transformer. It is pretty generous as well.
I have +/- 14.7 VAC rails going to this. I hoped to be able to "hot rod".
V across R1's are 1.462 & 1.502
The output relay clicks.
DC offset is .001/.003 V
Vout is 9.48 & -9.19
The mosfets are P140 & P9140. I do plan to heatsink them.
Samoloko: Yes, there is 10mm pitch in the Blue. We are going for Big Blue (The IBM of buffers?) Tea-Bag is near to order a proto for a check build. The Gerbers print out correctly. Maybe with a bit of a turn we can have the 7.5mm pitch too, if aligned, the pads will almost overlay.
Ed: Nice.
) Tea-Bag is near to order a proto for a check build. The Gerbers print out correctly. Maybe with a bit of a turn we can have the 7.5mm pitch too, if aligned, the pads will almost overlay.Ed: Nice.