I am about to make an order on Mouser UK for an RH84v2 Project.
I want to order some capacitors described below
Can you say how the Rubycon LLE caps compare to the others mentioned in this thread?
They seem to be low ESR and long life with 105oC:
Load Life 105oC and a lifetime of 12000 -20000 hours
https://www.mouser.co.uk/datasheet/2/977/e_LLE-1600605.pdf
RH84 V2 (C1) 100UF Coupling Capacitor
I have bought some Elna Silmic II for the 100UF cathode bypass caps on the EL84.
I want to buy and try Nichicon FZ and FG as well.
FZ: https://www.mouser.co.uk/datasheet/2/293/e_ukz-3082249.pdf. These are available up to 100v
FG: https://www.mouser.co.uk/datasheet/2/293/e_ufg-3082295.pdf These are available up to 63v
Rubycon UKZ2A101MHM1TN https://www.mouser.co.uk/datasheet/2/977/e_LLE-1600605.pdf
I am looking at using them for the coupling cap on the EL84. Is it worth using 63v, 80v or 100v ratings or is that overkill for this position?
RH84v2 (C3) 10UF 400v Capacitor
I am also thinking of using the Nichicon LLE for the (C3) 10uf 450v capacitor on the RH84 V2, or I could use a 450v Kemet PEG124 Capacitor.
https://www.mouser.co.uk/datasheet/2/447/KEM_A4011_PEG124-3316431.pdf
I would really appreciate a steer on this as I am keen to order this week.
Thanks
I want to order some capacitors described below
Can you say how the Rubycon LLE caps compare to the others mentioned in this thread?
They seem to be low ESR and long life with 105oC:
Load Life 105oC and a lifetime of 12000 -20000 hours
https://www.mouser.co.uk/datasheet/2/977/e_LLE-1600605.pdf
RH84 V2 (C1) 100UF Coupling Capacitor
I have bought some Elna Silmic II for the 100UF cathode bypass caps on the EL84.
I want to buy and try Nichicon FZ and FG as well.
FZ: https://www.mouser.co.uk/datasheet/2/293/e_ukz-3082249.pdf. These are available up to 100v
FG: https://www.mouser.co.uk/datasheet/2/293/e_ufg-3082295.pdf These are available up to 63v
Rubycon UKZ2A101MHM1TN https://www.mouser.co.uk/datasheet/2/977/e_LLE-1600605.pdf
I am looking at using them for the coupling cap on the EL84. Is it worth using 63v, 80v or 100v ratings or is that overkill for this position?
RH84v2 (C3) 10UF 400v Capacitor
I am also thinking of using the Nichicon LLE for the (C3) 10uf 450v capacitor on the RH84 V2, or I could use a 450v Kemet PEG124 Capacitor.
https://www.mouser.co.uk/datasheet/2/447/KEM_A4011_PEG124-3316431.pdf
I would really appreciate a steer on this as I am keen to order this week.
Thanks
Right, so there's 3 types of caps in your amp: power supply, coupling, and cathode bypass.
PS caps tend to be EL caps, and Nichicon UCY and Panasonic EE seem to be the most used in our branch of the hobby. I can't speak to the suitability of those Rubycons, hard to decipher the datasheet. These caps tend to be rated at 450v. Higher b+ ranges will require higher ratings, possibly using film caps. 450v caps tend to be cheaper than 400v, 420v, etc, probably due to their popularity. Volume, baby.
Coupling caps are typically axial film caps and must be rated to withstand the full b+ voltage. There's a lot of hooey, bunkum, and snake oil associated with coupling caps. Orange Drops are good, so are Vishay MKP and WIMA MKP. Just don't spend too much to start.
Bypass caps, I like Nichicon UFG or MUSE, you want good Audio Grade caps. Sprague Atom and TE are popular in guitar amp world. They only need to be rated for the voltage seen at the cathode, maybe double that. I've read that an over-rated bypass cap can hurt bass response, so not too big.
There's nothing wrong with Rubycons, their factory has produced some of the most desirable products in the history of tube amps, it's just a question of suitability. And with so many choices it's easy to be overwhelmed and buy the wrong thing. I got some Rubycon caps for a heater supply (that were meant for LED) instead of the Elna Silmic II that were recommended and there was audible hum that went away when I put the right caps in there. If you're gonna go to all the trouble of building one of these things, don't re-invent the wheel too much. Use proven components.
Also, beware the Mouser Markup. I see much better prices on those orange drop caps and HV caps for the power supply from places like TubeDepot.com. I'll bet you can find better prices in the UK if you look around. But you can't beat the organization and selection of Mouser or Digikey.
Have fun, be safe, don't forget the bleeder resistor.
PS caps tend to be EL caps, and Nichicon UCY and Panasonic EE seem to be the most used in our branch of the hobby. I can't speak to the suitability of those Rubycons, hard to decipher the datasheet. These caps tend to be rated at 450v. Higher b+ ranges will require higher ratings, possibly using film caps. 450v caps tend to be cheaper than 400v, 420v, etc, probably due to their popularity. Volume, baby.
Coupling caps are typically axial film caps and must be rated to withstand the full b+ voltage. There's a lot of hooey, bunkum, and snake oil associated with coupling caps. Orange Drops are good, so are Vishay MKP and WIMA MKP. Just don't spend too much to start.
Bypass caps, I like Nichicon UFG or MUSE, you want good Audio Grade caps. Sprague Atom and TE are popular in guitar amp world. They only need to be rated for the voltage seen at the cathode, maybe double that. I've read that an over-rated bypass cap can hurt bass response, so not too big.
There's nothing wrong with Rubycons, their factory has produced some of the most desirable products in the history of tube amps, it's just a question of suitability. And with so many choices it's easy to be overwhelmed and buy the wrong thing. I got some Rubycon caps for a heater supply (that were meant for LED) instead of the Elna Silmic II that were recommended and there was audible hum that went away when I put the right caps in there. If you're gonna go to all the trouble of building one of these things, don't re-invent the wheel too much. Use proven components.
Also, beware the Mouser Markup. I see much better prices on those orange drop caps and HV caps for the power supply from places like TubeDepot.com. I'll bet you can find better prices in the UK if you look around. But you can't beat the organization and selection of Mouser or Digikey.
Have fun, be safe, don't forget the bleeder resistor.
Hi dubadub, thanks so much for taking the time to reply. It often seems a bit like audio voodoo with all the choice that there is to choose from.
What value would you use for the bleeder resistor and where does it go in the psu section?
Thanks again
What value would you use for the bleeder resistor and where does it go in the psu section?
Thanks again
Bleeder resistor is a simple resistor that goes from the + side of your power supply to the - side. It drains the caps. Normally the tubes do this, but if they aren't working correctly, you want a safety mechanism to bring down that HV. Ideally in under 10 seconds, which means the size of the resistor is determined by the amount of capacitance in your power supply.
Post #101 in This Thread covered bleeders in detail.
Post #101 in This Thread covered bleeders in detail.
Your schematic incorrectly shows the 5R4 as having a cathode (cathodes warm up slowly).
The 5R4 is a directly heated filament, it start up quickly.
The Loaded 315V B+ (might be more than 315V at power-on, because the input and output tubes are cold, no load to the B+).
That means that at power-on, 315V will be applied from R8 to R3, to C1, to R5, to ground.
315V will appear across C4 the coupling cap.
Rfb also applies 315V to C4 (across C4 at power-on).
Use at least a 400V rated coupling cap for C4.
If you build 2 mono-blocks, or one stereo amp, you have a great opportunity to do a double blindfold test to compare capacitors.
Read my Post # 6 here:
https://www.diyaudio.com/community/...an-ccs-heater-regulators.406549/#post-7534690
The 5R4 is a directly heated filament, it start up quickly.
The Loaded 315V B+ (might be more than 315V at power-on, because the input and output tubes are cold, no load to the B+).
That means that at power-on, 315V will be applied from R8 to R3, to C1, to R5, to ground.
315V will appear across C4 the coupling cap.
Rfb also applies 315V to C4 (across C4 at power-on).
Use at least a 400V rated coupling cap for C4.
If you build 2 mono-blocks, or one stereo amp, you have a great opportunity to do a double blindfold test to compare capacitors.
Read my Post # 6 here:
https://www.diyaudio.com/community/...an-ccs-heater-regulators.406549/#post-7534690
Caution!
Sorry, I forgot about the fact that the switch box does not have load resistors across the amplifier.
A 4 Pole 2 Throw switch is needed (4PDT), and 2 load resistors (load resistors do not need to be full power, we are only terminating the amplifier while it does not get any input signal.
Some amplifiers can be OK with just the DPDT and no load resistors.
All my amplifiers work OK that way; But some others can oscillate, arc, and destroy themselves.
Sorry, I forgot about the fact that the switch box does not have load resistors across the amplifier.
A 4 Pole 2 Throw switch is needed (4PDT), and 2 load resistors (load resistors do not need to be full power, we are only terminating the amplifier while it does not get any input signal.
Some amplifiers can be OK with just the DPDT and no load resistors.
All my amplifiers work OK that way; But some others can oscillate, arc, and destroy themselves.
Thanks 6A3sUMMER
I have some more questions.
'A 4 Pole 2 Throw switch is needed (4PDT)' We have 230v- 240v electricity in the UK, what rating does it need to be?
Do I put in two slow blow glass fuses on the + and - power
Can you advise what type and rating the two load resistors should be?
I was also going to install an Amphenol 2A Inrush Current Limiter.
Finally, is the bleed resistor connected between the first PSU capacitor C1: 47uf 450v and the choke on the CLC or is it connected after the second capacitor C2:200uf 450v C2?
I have some more questions.
'A 4 Pole 2 Throw switch is needed (4PDT)' We have 230v- 240v electricity in the UK, what rating does it need to be?
Do I put in two slow blow glass fuses on the + and - power
Can you advise what type and rating the two load resistors should be?
I was also going to install an Amphenol 2A Inrush Current Limiter.
Finally, is the bleed resistor connected between the first PSU capacitor C1: 47uf 450v and the choke on the CLC or is it connected after the second capacitor C2:200uf 450v C2?
The switch box only has to switch two things:
line level signal from the Left channel of your CD player,
And the power amplifier outputs to the speaker and to the load resistors.
A 250V switch is more than enough. Use one rated for 2Amps.
If you will listen to 10 Watts into an 8 Ohm speaker (when it is 8 Ohms impedance), the current is 1.1 Amp; or 2.2 Amp when the minimum impedance is 4 Ohms (and 2.2Amp that is 20 Watts into 4 Ohms).
Because only one amplifier is driven at a time, a 5 Watt load resistor does the job for the amplifier that needs a load during the time it has no signal from the CD player (the other amplifier is driving the speaker).
Use a load resistor that closely matches the amplifier output tap that you use to drive your speaker.
Example, amplifier output 8 Ohm tap, an 8 or 10 Ohm, 5 Watt resistor is fine.
The Only purpose of the switch box is just for double blindfold testing, and works for less formal testing of capacitors, tube rolling, etc.
(the link in my Post # 5 in this thread).
I think UK power does not have a Hot and Neutral like the US does.
I am not sure if the UK recommends a fuse in each Hot wire.
In the US, I double protect my amplifiers with a fast blow in series with a slow blow.
The idea is to use as small an amperage as possible; the fast blow has to survive power-on inrush current; the slow blow has to survive the long term warmed up amplifier operating current.
Example: one of my amplifier has a 1.25Amp fast blow, and a 0.6Amp slow blow (600mA).
If you fuse both Hot power leads, my technique would require 2 fast blow, and 2 slow blow fuses.
I do not use inrush current limiters, I use parts that can stand the inrush current.
My amplifiers use solid state rectifiers, so the inrush current is larger than it would be with a tube rectifier.
Most tube filaments are made to survive their own inrush currents.
Most power transformers are made to withstand inrush currents; if not, the wire is so small the transformer will heat up too much during normal operation
The bleeder resistor is supposed to discharge C1, C2, and C3.
The choke has to be good enough so it does Not open if there is a short.
So, you can put the bleeder across Either C1, Or across C2.
You have to make sure that R8 does not open, or C3 will not be discharged by the bleeder resistor.
Two 25k Ohm 5 Watt wirewound in Series makes a good bleeder. 315V and 50k Ohms is just over 6mA; the total bleeder dissipation is 2 Watts (10 Watts of bleeder resistors).
line level signal from the Left channel of your CD player,
And the power amplifier outputs to the speaker and to the load resistors.
A 250V switch is more than enough. Use one rated for 2Amps.
If you will listen to 10 Watts into an 8 Ohm speaker (when it is 8 Ohms impedance), the current is 1.1 Amp; or 2.2 Amp when the minimum impedance is 4 Ohms (and 2.2Amp that is 20 Watts into 4 Ohms).
Because only one amplifier is driven at a time, a 5 Watt load resistor does the job for the amplifier that needs a load during the time it has no signal from the CD player (the other amplifier is driving the speaker).
Use a load resistor that closely matches the amplifier output tap that you use to drive your speaker.
Example, amplifier output 8 Ohm tap, an 8 or 10 Ohm, 5 Watt resistor is fine.
The Only purpose of the switch box is just for double blindfold testing, and works for less formal testing of capacitors, tube rolling, etc.
(the link in my Post # 5 in this thread).
I think UK power does not have a Hot and Neutral like the US does.
I am not sure if the UK recommends a fuse in each Hot wire.
In the US, I double protect my amplifiers with a fast blow in series with a slow blow.
The idea is to use as small an amperage as possible; the fast blow has to survive power-on inrush current; the slow blow has to survive the long term warmed up amplifier operating current.
Example: one of my amplifier has a 1.25Amp fast blow, and a 0.6Amp slow blow (600mA).
If you fuse both Hot power leads, my technique would require 2 fast blow, and 2 slow blow fuses.
I do not use inrush current limiters, I use parts that can stand the inrush current.
My amplifiers use solid state rectifiers, so the inrush current is larger than it would be with a tube rectifier.
Most tube filaments are made to survive their own inrush currents.
Most power transformers are made to withstand inrush currents; if not, the wire is so small the transformer will heat up too much during normal operation
The bleeder resistor is supposed to discharge C1, C2, and C3.
The choke has to be good enough so it does Not open if there is a short.
So, you can put the bleeder across Either C1, Or across C2.
You have to make sure that R8 does not open, or C3 will not be discharged by the bleeder resistor.
Two 25k Ohm 5 Watt wirewound in Series makes a good bleeder. 315V and 50k Ohms is just over 6mA; the total bleeder dissipation is 2 Watts (10 Watts of bleeder resistors).
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