Hi all,
I am in the process of putting together the parts for my RH84 V.2 EL84SE valve amp.
RH Amplifiers: RH84 amplifier - revision 2
I will be using NOS Russian 6P14P-EV in place of the EL84s.
The suggested rectifier power supply by the designer is a 5R4
The datasheet is here
http://www.r-type.org/pdfs/5r4gy.pdf
I was wondering about using a Russian 5C3S which is being advertised as being equivalent to a 5U4G.
Russian tube 5C3S is a quality equivalent of the 5U4G. Military equipment, high reliability. Svetlana factory. OTK marking.
Name: 5C3S
Type: double-anode rectifier
Application: alternative current rectification
Cathode type: oxide, direct heating
Envelope: glass
Mass: 72g
Filament voltage: 5V
Filament current: 2,7-3,3A
Anode voltage: 75V
Anode current: 0,225A
Socket type: rsh5-1
Max.reverse anode voltage: 1,7kV
The data sheet is here
https://drtube.com/datasheets/5c3s.pdf
The reason is purely down to looks of the tube at this stage. I have tried using the PSD2 software but I am such a novice I am not sure if I have done it correctly.
I have bought Lundahl LL1663 SE OPTs
http://www.lundahl.se/wp-content/uploads/datasheets/1663.pdf
and a Toroidy 10H 250mA toroidal choke for the amp project and will be using 8ohm speakers.
TDS10/250 - Toroidal Choke 10H 250mA DC - Shop Toroidy.pl
I am thinking of using a Hammond 372DX Transformer with
600V CT@144ma, 50 VAC, 5vCT@3A, 6.3VCT@4A which is a bit overkill but would enable PSE in the future I think.
The B+ is 315V
Can anyone advise on the choice of Rectifier tube and any changes to the capacitor values that may be needed to make this work if possible run the PSUD2 software to check the values for me. If it is a no and not worth doing then please do say
If this is in the wrong section could admin move it to the right section?
Thanks for all your help.
Lee
I am in the process of putting together the parts for my RH84 V.2 EL84SE valve amp.
RH Amplifiers: RH84 amplifier - revision 2
I will be using NOS Russian 6P14P-EV in place of the EL84s.
The suggested rectifier power supply by the designer is a 5R4
The datasheet is here
http://www.r-type.org/pdfs/5r4gy.pdf
I was wondering about using a Russian 5C3S which is being advertised as being equivalent to a 5U4G.
Russian tube 5C3S is a quality equivalent of the 5U4G. Military equipment, high reliability. Svetlana factory. OTK marking.
Name: 5C3S
Type: double-anode rectifier
Application: alternative current rectification
Cathode type: oxide, direct heating
Envelope: glass
Mass: 72g
Filament voltage: 5V
Filament current: 2,7-3,3A
Anode voltage: 75V
Anode current: 0,225A
Socket type: rsh5-1
Max.reverse anode voltage: 1,7kV
The data sheet is here
https://drtube.com/datasheets/5c3s.pdf
The reason is purely down to looks of the tube at this stage. I have tried using the PSD2 software but I am such a novice I am not sure if I have done it correctly.
I have bought Lundahl LL1663 SE OPTs
http://www.lundahl.se/wp-content/uploads/datasheets/1663.pdf
and a Toroidy 10H 250mA toroidal choke for the amp project and will be using 8ohm speakers.
TDS10/250 - Toroidal Choke 10H 250mA DC - Shop Toroidy.pl
I am thinking of using a Hammond 372DX Transformer with
600V CT@144ma, 50 VAC, 5vCT@3A, 6.3VCT@4A which is a bit overkill but would enable PSE in the future I think.
The B+ is 315V
Can anyone advise on the choice of Rectifier tube and any changes to the capacitor values that may be needed to make this work if possible run the PSUD2 software to check the values for me. If it is a no and not worth doing then please do say
If this is in the wrong section could admin move it to the right section?
Thanks for all your help.
Lee
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Russian and Chinese ST bottle 5U4 "equivalents" are utter trash. 😡
As cosmetics are the driving force, acquire a 5R4GY. That variant has the ST bottle. I strongly suggest you make the 1st cap. in the Π section (CLC) filter a 15 μF. DC link film part. 47 μF. is OK for a 5AR4/GZ34, but trouble could be brewing using that value in combination with a 5R4. Increase C2 to 330 μF., for that "warm fuzzy feeling".
As cosmetics are the driving force, acquire a 5R4GY. That variant has the ST bottle. I strongly suggest you make the 1st cap. in the Π section (CLC) filter a 15 μF. DC link film part. 47 μF. is OK for a 5AR4/GZ34, but trouble could be brewing using that value in combination with a 5R4. Increase C2 to 330 μF., for that "warm fuzzy feeling".
The toroidal coke has much lower DCR than EI ones, so you have grater B+, than required.
Serial resistor will be required (maybe shared: one part before first capacitor, other after choke).
BTW what is the goal of B+ voltage and current?
Serial resistor will be required (maybe shared: one part before first capacitor, other after choke).
BTW what is the goal of B+ voltage and current?
Thanks Eli, Can you explain a bit more about the capacitor choice and values, and what is wrong with the circuit diagram, and also the problem with the Russian Reflectors?
Thanks, if I have understood you correctly the goal is B+315v to drive an AT127 and 2 x EL84 Single Ended amp.
Can you suggest the values of the series resistors I will need?
Thanks again
Many times I've assisted folks who had problems with turn on time arc over, when Chinese and Russian ST bottle 5U4 "equivalents" were in use. Invariably, the solution was switching to either U.S. made OS or current production (EH) 5U4GBs. Unfortunately, the 'GB has a straight sided bottle. BTW, the guano was failing into caps. that were within published limits. 😡
Examine the data sheets for various rectifier types. While the cap. I/P filter value limits provided are not "cast in stone", they do give you a darned good idea about what is safe. Of note is the fact that the 5AR4/GZ34 is, for a vacuum rectifier, unusually tolerant of comparatively substantial capacitance at the I/P of the PSU filter.
Examine the data sheets for various rectifier types. While the cap. I/P filter value limits provided are not "cast in stone", they do give you a darned good idea about what is safe. Of note is the fact that the 5AR4/GZ34 is, for a vacuum rectifier, unusually tolerant of comparatively substantial capacitance at the I/P of the PSU filter.
Most 5R4 types have a maximum first cap rating of 4uf so 47uf is asking for trouble IMO. The 5R4GB is rated for 20uf but even then, 47uf is pushing it.
The 5U4 has less voltage drop them the 5R4 (15-20v or so) so when using a choke with 150 ohms less DCR, your b+ will be (a lot) higher. At 100ma, your choke will drop another 15v less
The 5U4 has less voltage drop them the 5R4 (15-20v or so) so when using a choke with 150 ohms less DCR, your b+ will be (a lot) higher. At 100ma, your choke will drop another 15v less
The 5R4 in any version has more forward drop than other toob rectifiers. And needs to be preheated before HV is applied.The 5R4 was meant for operation at high altitude, other specs where affected. But OK for a Class A Amp where the current requirements do not fluctuate much.🙂
At the rated 250 mA., the forward drop in a 5R4 is a whopping 67 V. On a % basis, forward drop in 5Y3s is even worse.
That "potato masher" variant the OP provided a photo of was intended for use in B52 bomber avionics. High altitude? Darned tootin'!
As directly heated vacuum rectifiers turn on almost as quickly as SS diodes do, I like a CL-140 inrush current limiting thermistor in the line between rectifier and PSU filter.
I've been doing a lot of rectifier shootouts recently. I dismissed all the 5R4 types as warm and lacking bite. The GZ34 was pretty good in the Soviet version. But my interest was in the 5U4 types. The Sylvania long black plates were quite warm, which could sound nice on piano but wasn't so suited to voices. RCA was more neutral. GE 5U4GB straight bottle was a lighter sound. Some GZ33 types were in contention also.
But contrary to what's been posted previously, I'm finding I like the Chinese 5Z3PA and the same for the Soviet 5C3S which sounds similar. Neutral and detailed sound with good top end. Shorter grey plates with rounded sides. Used for ages as the stock rectifier tube for e.g. Cary SLI-80 Signature.
One reviewer stated "the Chinese 5Z3PA pretty much slaughters the RCA 5U4. Now here's something to think about: the RCA is acknowledged as a great tube, and it is in fact a great tube, but from a musical standpoint I like the 5Z3PA a lot better."
If these arc over, which I haven't experienced, maybe the first cap needs to be smaller? I've used from 12uF to 32uF, not more.
But contrary to what's been posted previously, I'm finding I like the Chinese 5Z3PA and the same for the Soviet 5C3S which sounds similar. Neutral and detailed sound with good top end. Shorter grey plates with rounded sides. Used for ages as the stock rectifier tube for e.g. Cary SLI-80 Signature.
One reviewer stated "the Chinese 5Z3PA pretty much slaughters the RCA 5U4. Now here's something to think about: the RCA is acknowledged as a great tube, and it is in fact a great tube, but from a musical standpoint I like the 5Z3PA a lot better."
If these arc over, which I haven't experienced, maybe the first cap needs to be smaller? I've used from 12uF to 32uF, not more.
I use HER308 -> 660uF -> 5R -> 990uF. The amp is silent, mechanically and the output.
I once built a choke input using full wave parallel 6D22S (4 of them) -> 10H -> 820uF -> 5R - 820uF which also worked but wasted tonnes of power for no apparent reason.
I have a box of tube rectifiers I don't need that I'd part with cheap, too.
I once built a choke input using full wave parallel 6D22S (4 of them) -> 10H -> 820uF -> 5R - 820uF which also worked but wasted tonnes of power for no apparent reason.
I have a box of tube rectifiers I don't need that I'd part with cheap, too.
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