Ciao Rod
I am recycling old V2 regs for a new projects and they have TO220 devices spaced 50mm each other (actually 49.5mm). What's that distance on the latest version? I'll leave extra holes in the chassis
Ciao Gianluca! Latest RC-V9 now has one power transistor. Assembly document shows the mounting hole positions, and details of the new version; web search: "Coleman Regulator V9" (Select DOCS) ... or send me some email or PM.
I trust that the «Water Babies» are giving good service!
thanks Rod! good memory indeed. That amp was dismantled and parts recycled. Some, including the old V2 regs, will go into a 300B amp, let's see how it turns out.
I read 71-73mm distance between the (2?) holes on lyrima
Yes, drill n.2 Ø3,5mm holes ca. 72mm apart. The new V9 board is 64 x 40mm. Please leave a 30mm gap around it for th power transistor, and for air flow. Fix Q5 to one hole (loose) then add the board. Solder Q5 when the board and Q5 are already fixed.
Coming from V2 regs, you'll enjoy the better sound, and the DC voltage stability is now notably better.
Coming from V2 regs, you'll enjoy the better sound, and the DC voltage stability is now notably better.
What ever happened to the idea of placing a ratio of cathode bias resistors on each end so as to even out emission across the filament. It's been done by a few different designers. There was a schematic at the beginning of this thread that showed that. It has been removed. Just wondering . . . . . . . . .
Yes, I did post a drawing with that feature .... but that was nearly nineteen years ago, in year 2004, on this long-life thread!
Cathode Resistors on both sides of the filament, even different values, only serve to drain off some extra current from the heater supply. The cathode current cannot be trained to divide between them. With the RC-V9 regulator, cathode-current should only be returned to anode supply 0V (Ground) via the FIL- terminal. Good sounds for a New Year, Ian!
First I have to say what a true gentleman Mr Coleman is! Thank you for your help and Stay tuned...
2nd, I just found this thread, and have not read all 50 pages yet...
Can anyone recommend a recent jump in point ?
In April of 2021 I ordered Rods Raw DC and Regulator kit for the 300B....
I believe when I received everything it was V8... Is there a significant difference for V9 ?
I didn't want to pester Rod, a few questions you fine folks may be able to help with....
Are there any reasons why someone who might be in the process of ordering a custom power transformer would NOT want to plan for the raw DC kit and Coleman regulator to run off of it aside from cost to wind ?
To be sure, what I have understood the Raw DC board requires 4-5V AC above the 5 required for the 300B, so that would be 10v rms (raw ac) comfortably at 5A (ac) for each filament ?
Thanks in advance!
2nd, I just found this thread, and have not read all 50 pages yet...
Can anyone recommend a recent jump in point ?
In April of 2021 I ordered Rods Raw DC and Regulator kit for the 300B....
I believe when I received everything it was V8... Is there a significant difference for V9 ?
I didn't want to pester Rod, a few questions you fine folks may be able to help with....
Are there any reasons why someone who might be in the process of ordering a custom power transformer would NOT want to plan for the raw DC kit and Coleman regulator to run off of it aside from cost to wind ?
To be sure, what I have understood the Raw DC board requires 4-5V AC above the 5 required for the 300B, so that would be 10v rms (raw ac) comfortably at 5A (ac) for each filament ?
Thanks in advance!
Thanks!
> Are there any reasons why someone who might be in the process of ordering a custom power transformer would NOT want to plan for the raw DC kit and Coleman regulator to run off of it aside from cost to wind?
For the best performance, a separate transformer keeps rectifier pulses out of the anode supply; coupling between secondary windings is possible.
> the Raw DC board requires 4-5V AC above the 5 required for the 300B, so that would be 10v rms (raw ac) comfortably at 5A (ac) for each filament ?
The input voltage is a little lower for the new V9 regulator. For 300B, 7 - 7.5V RMS AC and a 50VA transformer is best.
8V RMS for the V8. Full examples and transformer suggestions are in the documentation for V8 or V9 versions.
Yes, the V9 is fairly new. It improves DC stability, and gives better sound; there are some reports from those who have tried it on the forum.
> Are there any reasons why someone who might be in the process of ordering a custom power transformer would NOT want to plan for the raw DC kit and Coleman regulator to run off of it aside from cost to wind?
For the best performance, a separate transformer keeps rectifier pulses out of the anode supply; coupling between secondary windings is possible.
> the Raw DC board requires 4-5V AC above the 5 required for the 300B, so that would be 10v rms (raw ac) comfortably at 5A (ac) for each filament ?
The input voltage is a little lower for the new V9 regulator. For 300B, 7 - 7.5V RMS AC and a 50VA transformer is best.
8V RMS for the V8. Full examples and transformer suggestions are in the documentation for V8 or V9 versions.
Yes, the V9 is fairly new. It improves DC stability, and gives better sound; there are some reports from those who have tried it on the forum.
Perhaps this question has already been answered, but here it comes:
Would it be OK to "steal" some juice from the raw DC before the regulators to heat IDH input/driver tubes? As long as the power supplies can handle the extra load and the heaters are not connected to anything else, of course.
Would it be OK to "steal" some juice from the raw DC before the regulators to heat IDH input/driver tubes? As long as the power supplies can handle the extra load and the heaters are not connected to anything else, of course.
You might be able to get away with a 300mA heater, on the Raw DC.
But as Bela says, the IDHT heater must have no other connexions.
Beware: any leakage current or noise (h→k) of the IDHT is common mode, and will run to 0V(anode)/Ground via the DHT cathode resistor. It's not usually a big effect, but be aware of it.
If there are very large swings on the IDHT cathode, these might couple a small common-mode current through Chk.
Also, note the the IDHT heater will be above ground by whatever voltage is on the DHT's cathode resistor; be sure that the max V(hk) is respected.
But as Bela says, the IDHT heater must have no other connexions.
Beware: any leakage current or noise (h→k) of the IDHT is common mode, and will run to 0V(anode)/Ground via the DHT cathode resistor. It's not usually a big effect, but be aware of it.
If there are very large swings on the IDHT cathode, these might couple a small common-mode current through Chk.
Also, note the the IDHT heater will be above ground by whatever voltage is on the DHT's cathode resistor; be sure that the max V(hk) is respected.
Thanks! The tubes in question are 6B4G and either 6J5 or 2C22 so 300mA is exactly the current I had in mind. Allowing the input tubes to "hitchhike" on the raw dc for the output tubes would make things easier since the amp and the power supply will be in separerat chassis, connected through an 8 pin circular connector.
Fixed bias, so almost no DC potential between filament and ground. Possibly a few volts of signal swing if I decide to try CFB from the OPT secondary winding.
Fixed bias, so almost no DC potential between filament and ground. Possibly a few volts of signal swing if I decide to try CFB from the OPT secondary winding.
...and one more question, if you gentlemen don't mind: Since the filaments are essentially fed by a CCS, they will take a bit longer to get warm. Will they (in my case 6B4G/6S4S) reach full emission before the HT from a damper diode (6AU4GTA) rectified PSU hits the DHTs. I guess the HT can be delayed a bit further by adding resistors or even NTCs in series with the damped diodes to make them heat up even slower.
I'm not overly worried about this but it would be nice to build an amp with a perfectly undramatic startup procedure without having to use time relays etc.
Best regards,
Daniel
I'm not overly worried about this but it would be nice to build an amp with a perfectly undramatic startup procedure without having to use time relays etc.
Best regards,
Daniel
Yes, some modern production power DHTs have very slow warming filaments, and may take longer than a damper to fully warm up. But the slow warming means more uniform warming; and formation of hotspots is much less likely. Hotspots can be troublesome, as there can be local overloading of the emissive surface. If the filament is within 10% of nominal Uf by the time that the anode current demand has reached ca. 10mA, I would not expect much trouble.
But if you judge the warm up time still be too slow compared to the damper, a separate mains power switch is a simple way to address it, without a Timer.
Then, power filament, select beverage and recordings, power the anodes.
But I get 30s delay and 30s ramp up with 6CJ3 dampers; and a similar result with FET capacitor multipliers.
But if you judge the warm up time still be too slow compared to the damper, a separate mains power switch is a simple way to address it, without a Timer.
Then, power filament, select beverage and recordings, power the anodes.
But I get 30s delay and 30s ramp up with 6CJ3 dampers; and a similar result with FET capacitor multipliers.
I guess that would work too, as long as the circuit timer circuit is floating and doesn't draw too much current.
Speaking of raw supplies: I'm doing some experiments right now with LCLC-filtering. With 15VAC input and some rather high-ish DCR chokes in the second position (one in the positive rail and one in the negative) the resulting DC output is pretty much where I want it at about 9,5Vdc.
Since I would prefer slightly larger margins, could I replace the generic silicon diode bridge with Schottky diodes? The choke input filter worries me a bit here, since I've read some reports about choke input filters killing solid state rectifiers.
Speaking of raw supplies: I'm doing some experiments right now with LCLC-filtering. With 15VAC input and some rather high-ish DCR chokes in the second position (one in the positive rail and one in the negative) the resulting DC output is pretty much where I want it at about 9,5Vdc.
Since I would prefer slightly larger margins, could I replace the generic silicon diode bridge with Schottky diodes? The choke input filter worries me a bit here, since I've read some reports about choke input filters killing solid state rectifiers.