Hi , I am planning to builld a custom high power tube amp.I am looking at using 520b or 1605 tubes, 2 per channel operation inclass AB1 push pull. If I chose the 520b, they will run a bout 120ma each, with anode voltage at lleast 580V. To supply the DC current, i figure on using 3 parallel rectifiers . If I chose 2x274b I can B expect to have 3x 160 ma @550 to 600 v ( total 580 available ma current; or I could try 3 x5Z3 , which would produce 3x 260= 780 ma, but only a maximum of 500 to 550 volts. 3 /‘274b heaters would need 6 amps. While : 5Z3 would ned 9 Amps Im leaning towards the 274b , withlower heater draw, and the reqquired 600 V on the anodes. I also see advantages as 3 parallel tube rectifiers would lower te voltage sag a cross the rectifiers substantially and see 6 amps at the heaters much less problematic that 9 amps if I chose 5Z3( or 5U4). My questions are : 1. Does using 3 parallel rectifiers make power supply
Filter easier or more difficult? And the data sheetd for 274b ?(and 5Z3) dont say whether 3 paralleled rectifiers need enable more ir less filter and/or reservoir capacitance? The rectifiers are all Emission Lab mesh plates. I ran 2 paralell 274b on my last amp, and it worked great. All EML woud say was I could double C1 from 4 if to 8uf. That was with capacitors loaded powersupply. But now tohit 600v, I must use choke loaded power supply. Wirh a Llundahl 1673 dual choke. Can anyone offer advice? I know that I will need a helluva power transfrer. The EML tubes Can be ordered a 6. 5 V 1.5 amp heater, a 5V 2 amp Heater or a balanced 5v ( 2x2.5v 2 amp center tapped B heater. EMLrecomnends the6.5 v 2amp heater for push pull amps .this means 8 amps juzt to heat 4 ppower tubes. Or i could use the more muscular 1605 . It can delivrre almozt 30 watts per tube. It had two heaters options 5v 2.1 amp or 5 v ( 2 x 2.5v) center tapped 2.1 amps. K Ty s wuite s challenge with either power tube, im leaning towards the. 520 b
I welcome all comments. Cautions or advice I am most interested in power supply, filter and power transformer .
Filter easier or more difficult? And the data sheetd for 274b ?(and 5Z3) dont say whether 3 paralleled rectifiers need enable more ir less filter and/or reservoir capacitance? The rectifiers are all Emission Lab mesh plates. I ran 2 paralell 274b on my last amp, and it worked great. All EML woud say was I could double C1 from 4 if to 8uf. That was with capacitors loaded powersupply. But now tohit 600v, I must use choke loaded power supply. Wirh a Llundahl 1673 dual choke. Can anyone offer advice? I know that I will need a helluva power transfrer. The EML tubes Can be ordered a 6. 5 V 1.5 amp heater, a 5V 2 amp Heater or a balanced 5v ( 2x2.5v 2 amp center tapped B heater. EMLrecomnends the6.5 v 2amp heater for push pull amps .this means 8 amps juzt to heat 4 ppower tubes. Or i could use the more muscular 1605 . It can delivrre almozt 30 watts per tube. It had two heaters options 5v 2.1 amp or 5 v ( 2 x 2.5v) center tapped 2.1 amps. K Ty s wuite s challenge with either power tube, im leaning towards the. 520 b
I welcome all comments. Cautions or advice I am most interested in power supply, filter and power transformer .
There are two typos/errors in your post:
1) 3 x 160 mA = 480 mA (so not 580 mA).
2) The 520B-V2 is rated for 6.5 V / 1.5 A, so four of them would need 6 A (so not 8 A).
When using a choke-input filter, the uF value of the capacitor after the choke is not so critical. If you study datasheets for tube rectifiers you will notice that for choke-input filters there is no (maximum) value for the capacitor given.
If you still have to order the Lundhal chokes, than be sure to order the LL1673/10H variant. Only that variant can handle the current (580 mA if wired in parallel, giving 2.5 H inductance).
1) 3 x 160 mA = 480 mA (so not 580 mA).
2) The 520B-V2 is rated for 6.5 V / 1.5 A, so four of them would need 6 A (so not 8 A).
When using a choke-input filter, the uF value of the capacitor after the choke is not so critical. If you study datasheets for tube rectifiers you will notice that for choke-input filters there is no (maximum) value for the capacitor given.
If you still have to order the Lundhal chokes, than be sure to order the LL1673/10H variant. Only that variant can handle the current (580 mA if wired in parallel, giving 2.5 H inductance).
Thanks for your help. Note the followig: max performanr of274b iis550 dc and140 ms dc I tfollowing.thr max im I n B digging deep into the data and footnotesin the EML lab website it notes the following about thd 274b rectifier( mesh plate) c1 max connected to anode is 4uf. They emphasise never to exceed 4uf. It notes you can get C1+C2> 24 uf if you run a Bleeder resisters and c-l-c ( cap loaded max550 v 160 ma; but cannot achievre Both limits,0ne must bererated, but 520b must have 600V and160ma. Rectified dc current of 160 ma must be supplied be simultaneously putti 600v pn anode. acievrd. The trick is
In post #1 you wrote: "But now tohit 600v, I must use choke loaded power supply.". So I thought that you meant that you are planning to use a choke-input filter. In a choke-input filter there is no capacitor before the choke. The value of the capacitor after the choke is not so critical.
In addition you have to take into account that with a choke input filter you'll need a CT'ed secondary winding of about 1.5 kV to get 600 Vdc@ ~300 mA, using a pair of 274A's.
Best regards!
Best regards!
I would have 3 parallel 274b rectifiers. That cut tvs rectifier lag by )0% sbd connectting 3 274 b inparallel using C-RL/-c. I g go et fully /)0 ma per rectifier total 480 m 600 vomrz on anodes and i just need 4 hearer taps at 1.5 amp 6 volts from piwer transformer
I adl theforum can2 tein triode 5751 work as lone input/ driver? Snd can pair o6189w tein triodfe hamdle phase onvdftrt fuctio ? S d suggestion for ljtpuh transformetd?
Noe to fet 600 volts i meed center tap piwerf transforer : 45450 ought to wor4 520beed 4 heatsrxtaps at 1.5 amps. Esch 520 b tubrz runon 110 ma x4 440 ma toral recticidrd shoolt 480 mz
If: 274b C are matginal b i can alway strp up to 3 c (z3
I adl theforum can2 tein triode 5751 work as lone input/ driver? Snd can pair o6189w tein triodfe hamdle phase onvdftrt fuctio ? S d suggestion for ljtpuh transformetd?
Noe to fet 600 volts i meed center tap piwerf transforer : 45450 ought to wor4 520beed 4 heatsrxtaps at 1.5 amps. Esch 520 b tubrz runon 110 ma x4 440 ma toral recticidrd shoolt 480 mz
If: 274b C are matginal b i can alway strp up to 3 c (z3
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This thread is more a linguistic challenge than a technical one...
Ill retype it. I would have 3 parallel274b rectifiers. That would cut voltage sag across the rectifiers by 60%. To get max performance( 480 ma 600V) I need A
design of C-RL-c design ( from EML website)
circuit 5 shows the best design. It has dual coil Llundahl choke c1 4uf, bleeder resistor parallel to c2.
my question is this: with 3 rectifiers providing 480 ma DC. And powet transformer having 2 6v, 3amp taps for power tube heaters, and 1 tap at 5v, 6 amps for rectifiers, I stil need to account for driver and phase inverters.
Can a single ztwin triode 5751 drive 4 520b poet tubes? A d would a pair of 6189w B work ad phase inverters ?
can i find a power transformer with 12 amps heater taps, and extra g mmmm to power 1 5751 and 2 6189w?
Is 480 ma from rectifiers sufficient for 4 x 520b ( using110 ma each) ? Would the 3 274b have enough to handle 5751 And pair of 6189?
design of C-RL-c design ( from EML website)
circuit 5 shows the best design. It has dual coil Llundahl choke c1 4uf, bleeder resistor parallel to c2.
my question is this: with 3 rectifiers providing 480 ma DC. And powet transformer having 2 6v, 3amp taps for power tube heaters, and 1 tap at 5v, 6 amps for rectifiers, I stil need to account for driver and phase inverters.
Can a single ztwin triode 5751 drive 4 520b poet tubes? A d would a pair of 6189w B work ad phase inverters ?
can i find a power transformer with 12 amps heater taps, and extra g mmmm to power 1 5751 and 2 6189w?
Is 480 ma from rectifiers sufficient for 4 x 520b ( using110 ma each) ? Would the 3 274b have enough to handle 5751 And pair of 6189?
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As far as I know, you can use 12 uF (3 x 4 uF) as the value for C1 when you use three paralleled 274B's. But I would probably like it a bit safer so I would use 8 uF for C1.
But you can't run a Lundahl LL1673 connected like in circuit 5 at 480 mA since the two coils are than in series. The recommended current for that with the 10 H variant is only 200 mA (with saturation at 290 mA). And running the Lundahl LL1673 10 H variant connected like in circuits 1 to 4, with the two coils connected in parallel, would mean running them at a higher current than the recommended dc current of 400 mA. I don't think that is a wise thing to do.
A section of a 5751 has an amplification factor of 70 so you could squeeze a voltage gain of about 45 out of them. Thats not enough to drive the 520B's so per channel one section of the 6189's also has to be wired for a bit more voltage gain, leaving the other section of the 6189's for a concertina phase splitter (I don't think the 6189 is a good candidate for a long-tail pair phase splitter).
But you can't run a Lundahl LL1673 connected like in circuit 5 at 480 mA since the two coils are than in series. The recommended current for that with the 10 H variant is only 200 mA (with saturation at 290 mA). And running the Lundahl LL1673 10 H variant connected like in circuits 1 to 4, with the two coils connected in parallel, would mean running them at a higher current than the recommended dc current of 400 mA. I don't think that is a wise thing to do.
A section of a 5751 has an amplification factor of 70 so you could squeeze a voltage gain of about 45 out of them. Thats not enough to drive the 520B's so per channel one section of the 6189's also has to be wired for a bit more voltage gain, leaving the other section of the 6189's for a concertina phase splitter (I don't think the 6189 is a good candidate for a long-tail pair phase splitter).
I don't think that one 12AX7 per channel is possible. You can squeeze a voltage gain of 75 out of a section of a 12AX7, but I think that would still not be enough to drive a pair of 520B to full power with some quality. And using the other section of a 12AX7 as a concertina phase splitter is also not a good idea with these kind of power triodes.
I advise you to look on this site or on the internet for some proven designs of push-pull amplifiers with 2 x 300B and start from there. It's not very usefull (atleast in my view) to just mention certain tube types. There's way more to a good amplifier design than particular tube types, especially when it comes to the preamplification and phase splitting for a pair of power triodes like the 520B.
I advise you to look on this site or on the internet for some proven designs of push-pull amplifiers with 2 x 300B and start from there. It's not very usefull (atleast in my view) to just mention certain tube types. There's way more to a good amplifier design than particular tube types, especially when it comes to the preamplification and phase splitting for a pair of power triodes like the 520B.
If i run 3 x 274b in parallel., that yields 480 ma Dc current. Allowing 110 ma for 4 x (520b) power tubes, that leaves 40ma to run the input/driver and 2 twin triodes phase inverters. If the power transformer supplies all the heaters, will thst 40ma be enoigh for 1 2Ax7 driver and 2 (5963) as phase inverters?
I dont underdtand tube curve sheets, canyou give me anexample of a. Driver tube that woould work?
If i parallel 3 274b , what efffect does thst have onnnumber and value of filter caps? Can the power supply use more or less filter caps?