Kuei
Well that's loud and clear, thanks for the quick response I'll just stick to wiring the earthing/grounding to minimise the already mega low hum levels.
Have you got any designs for an all singing all dancing power amp to drive my 4ohm 83db insensitive Maggies? My current amp is an Ella with the choke, kiwames and KT88's
Kev
Well that's loud and clear, thanks for the quick response I'll just stick to wiring the earthing/grounding to minimise the already mega low hum levels.
Have you got any designs for an all singing all dancing power amp to drive my 4ohm 83db insensitive Maggies? My current amp is an Ella with the choke, kiwames and KT88's
Kev
Konnichiwa,
Not really. my own speakers are between 12 - 16db more sensitive AND efficient. For me 7-10W "Ballpark" Amplifiers o fine, which means you need between at the very least 100W - 400W RMS Amplification to get really good sound quality.
Without pushing too hard a pair of EL34/KT88/6550 or indeed 300B's will give around 20 - 30W per pair in triode mode (all else is no really usefull for high SQ).
That means you need between 4 to 16 PAIRS of these to get the power you need.
More esotheric stuff like parallel push-pull 211's or 845's are possible wbut these cost even more to implement.
On the basis of some basic outline calculations building suitable amplifiers is a major project.
You could try to get away with monoblocked modified Ella's but even there you are running into limits too quickly.
The old Velleman K4000 Stereo Valve Amp (now K4040), while having a significant number of SUBSTANTIAL inbuild design errors could be a good platform to make a 100W+ triode connected monoblock from with not too many drastic changes, they are still available in the UK AFAIK (not sure, Maplin no longer lists them), cost was around 1K each kit last time I looked.
The K4000/4040 can be changed over to a more less close "clone" of the Seminal Quicksilver M135 (one of my favourite "normal" PP Valve Amp's) wither with less power (as stereo Amp) or with more power (as Monoblock) available.
Otherwise there are very few kits offring the neccesary hardware to cover that many Output valves and going for a "ground up" build may be a "project too far" (in honour to Remhagen).
If you wanted to, you could obviously go for Solid State or Hybrid Amplifiers, a "Bridge over the Gainclown" comes to mind, that is 4 - 6pcs LM3875 in bridge/parallel operation with a valve based input stage. I'm working on a commercial project that is based around this kind of approach, I cannot really divulge much except that the result is felt to be quite exceptional by harcore Valve Audio fans, so it cannot be that despite being a commercial design.
Finally, if you have space for Maggies, why not dump them and build a pair of JASD Dipoles with the Ciare CH250 Driver, they aint any larger but have a much more usefull sensitivity in the lower - mid 90's db range? Maggies distort and compress by far too much for my taste, nonwithstanding their more charming sonic attributes....
The JASD would give you a stylish solution that is very happy with a single 300B or a Triode Connected EL34 Pair in front.... Note that converting Ella to 300B outputs is possible and can make a very nice Amp. With an Octal and a Noval Socket per channel implementing an Amplifier circuit patterened for example on Allen Wrights 300B "Differential" design is a good possibility, that would give you maybe 15 - 20W really good watts, just right for a Pair of JASD.
Sayonara
KevinTams said:
Not really. my own speakers are between 12 - 16db more sensitive AND efficient. For me 7-10W "Ballpark" Amplifiers o fine, which means you need between at the very least 100W - 400W RMS Amplification to get really good sound quality.
Without pushing too hard a pair of EL34/KT88/6550 or indeed 300B's will give around 20 - 30W per pair in triode mode (all else is no really usefull for high SQ).
That means you need between 4 to 16 PAIRS of these to get the power you need.
More esotheric stuff like parallel push-pull 211's or 845's are possible wbut these cost even more to implement.
On the basis of some basic outline calculations building suitable amplifiers is a major project.
You could try to get away with monoblocked modified Ella's but even there you are running into limits too quickly.
The old Velleman K4000 Stereo Valve Amp (now K4040), while having a significant number of SUBSTANTIAL inbuild design errors could be a good platform to make a 100W+ triode connected monoblock from with not too many drastic changes, they are still available in the UK AFAIK (not sure, Maplin no longer lists them), cost was around 1K each kit last time I looked.
The K4000/4040 can be changed over to a more less close "clone" of the Seminal Quicksilver M135 (one of my favourite "normal" PP Valve Amp's) wither with less power (as stereo Amp) or with more power (as Monoblock) available.
Otherwise there are very few kits offring the neccesary hardware to cover that many Output valves and going for a "ground up" build may be a "project too far" (in honour to Remhagen).
If you wanted to, you could obviously go for Solid State or Hybrid Amplifiers, a "Bridge over the Gainclown" comes to mind, that is 4 - 6pcs LM3875 in bridge/parallel operation with a valve based input stage. I'm working on a commercial project that is based around this kind of approach, I cannot really divulge much except that the result is felt to be quite exceptional by harcore Valve Audio fans, so it cannot be that despite being a commercial design.
Finally, if you have space for Maggies, why not dump them and build a pair of JASD Dipoles with the Ciare CH250 Driver, they aint any larger but have a much more usefull sensitivity in the lower - mid 90's db range? Maggies distort and compress by far too much for my taste, nonwithstanding their more charming sonic attributes....
The JASD would give you a stylish solution that is very happy with a single 300B or a Triode Connected EL34 Pair in front.... Note that converting Ella to 300B outputs is possible and can make a very nice Amp. With an Octal and a Noval Socket per channel implementing an Amplifier circuit patterened for example on Allen Wrights 300B "Differential" design is a good possibility, that would give you maybe 15 - 20W really good watts, just right for a Pair of JASD.
Sayonara
JASD doesn't look too expensive to suck it and see, if I make it out of ply first.
I heard Maggies after years of living with box speakers and was blown away by the clarity of them, but I confess I've not listened to any other type of speaker for 18 months now. BTW the Ella at 4ohm is delivering about 20watts and will drive the MMG's to decent loudness.
Thanks for the info,
Kofi, apologies for hijacking your thread, I'll stop now!
Kev
I heard Maggies after years of living with box speakers and was blown away by the clarity of them, but I confess I've not listened to any other type of speaker for 18 months now. BTW the Ella at 4ohm is delivering about 20watts and will drive the MMG's to decent loudness.
Thanks for the info,
Kofi, apologies for hijacking your thread, I'll stop now!
Kev
Hijack away, Daddy-O! I've done it plenty.
Besides, it ain't hijackin' if its good and useful information! I love to hear about dipoles and hope to build a pair myself someday. Talk to Tim Foreman (Timn8er) and Dave (Planet 10) about dipoles and I think you'll find they like them quite a bit.
Kofi
Besides, it ain't hijackin' if its good and useful information! I love to hear about dipoles and hope to build a pair myself someday. Talk to Tim Foreman (Timn8er) and Dave (Planet 10) about dipoles and I think you'll find they like them quite a bit.
Kofi
Hey Kofi,
To bring this thread back to your psu...
I'm considering building the preamp. What caps did you use for the power supply and the 10nF caps? Where did you buy 'em?
Thanks.
Paul Ebert
To bring this thread back to your psu...
I'm considering building the preamp. What caps did you use for the power supply and the 10nF caps? Where did you buy 'em?
Thanks.
Paul Ebert
Kuei,
If one wanted to move up from the nichicon VX series caps what would you recommend? I can't seem to find those anywhere, btw, perhaps they are no longer available?
From the searching I have done, it seems like the USA is not the best place for buying good caps.
And, if one wanted to max out the power supply to the degree that makes sense for the preamp, what would that look like (parts-wise and/or topology-wise)?
Thanks.
Paul Ebert
If one wanted to move up from the nichicon VX series caps what would you recommend? I can't seem to find those anywhere, btw, perhaps they are no longer available?
From the searching I have done, it seems like the USA is not the best place for buying good caps.
And, if one wanted to max out the power supply to the degree that makes sense for the preamp, what would that look like (parts-wise and/or topology-wise)?
Thanks.
Paul Ebert
Paul Ebert said:
I used just some run-of-the-mill Nichicon electrolytics-- 47uF / 450V. I found that Mouser did not have any radial electrolytics that fit the bill. So, since I didn't want axials, I bought my PSU Nichicons from Digikey.
I used silver micas for the 10nF and 1nF caps, purchased from Mouser. Believe it or not, Mouser has a good selection of dipped silver micas. They're not cheap and I was going to get another type of cap, but Kuei advised that I would dishonor my ancestors unless I went with the micas, so I went with 'em.
I don't necessarily agree...
Your general all-purpose capacitors will generally be available from the likes of Mouser, Digikey and Newark-In-One. Higher-end stuff (the remaining stock of Black Gates, Hovlands, Wondercaps, Jupiter, etc.) can be purchased from Percy Audio.
Remember, you can't spell Cupasitor without U-S-A.
U S A!! U S A!! U S A!! (repeat)
Kofi
Kofi Annan said:
Pffbt... reminds me, I need to recap my amps with ceramic disks. Too bad 500V 0.1uF units are as expensive as mylar.
Tim
Re: Re: gilding the lily
Kuei,
Are you referring to voltage gain or current gain?
If you are referring to voltage gain then it is maybe easy to answer. If you are referring to current gain can you tell us how one would know when one has enough current gain and what parameters would be measured or used to determine that it is sufficient for the given design?
rgds, cb
Kuei Yang Wang said:
Kuei,
Are you referring to voltage gain or current gain?
If you are referring to voltage gain then it is maybe easy to answer. If you are referring to current gain can you tell us how one would know when one has enough current gain and what parameters would be measured or used to determine that it is sufficient for the given design?
rgds, cb
Re: Re: Re: gilding the lily
Konnichiwa,
Voltage gain, however, in the context there is enough "current gain" as well to cope with any load down to 10K.
Current gain is strictly not applicable to Valves anyhow, as under ideal conditions the grid draws no current at all, so current gain is always infinite. In bipolar transistors this measures has some value.
Otherwise people often talk wrongly about "current gain" in the context of buffers. The argument goes that the original source has not much output current, so the buffer provides "current-gain", which is untrue in the absolute sense, though it kinda makes sense in a popular science way.
Sayonara
Konnichiwa,
CraigBuckingham said:
Voltage gain, however, in the context there is enough "current gain" as well to cope with any load down to 10K.
Current gain is strictly not applicable to Valves anyhow, as under ideal conditions the grid draws no current at all, so current gain is always infinite. In bipolar transistors this measures has some value.
Otherwise people often talk wrongly about "current gain" in the context of buffers. The argument goes that the original source has not much output current, so the buffer provides "current-gain", which is untrue in the absolute sense, though it kinda makes sense in a popular science way.
Sayonara
OK-- so I have desoldered the entire phono pre and, of course, I broke some component leads from a few resistors. No biggie-- I bought Roederstein Resistas fom Percy Audio so I'll just order some new ones, right?
Well, of course Michael had to go an a damn vacation, so he'll be out for two weeks and I can't get my Resistas until then. So here's the question... do I:
(a) wait until he comes back and order them from him when he returns
(b) find another source for Resistas (help me with this one if this is the right answer-- I can't find any other source for these!!!)
or (c) choose another metal film resistor (recommendations welcome-- not too expensive, please).
I think its possible that since Resistas are now made by Draloric that the Vishay Dralorics at Parts Connexion are a reasonable facsimile, but I may be wrong. Sure would like it if they were, though.
Help a brother out.
Kofi
Well, of course Michael had to go an a damn vacation, so he'll be out for two weeks and I can't get my Resistas until then. So here's the question... do I:
(a) wait until he comes back and order them from him when he returns
(b) find another source for Resistas (help me with this one if this is the right answer-- I can't find any other source for these!!!)
or (c) choose another metal film resistor (recommendations welcome-- not too expensive, please).
I think its possible that since Resistas are now made by Draloric that the Vishay Dralorics at Parts Connexion are a reasonable facsimile, but I may be wrong. Sure would like it if they were, though.
Help a brother out.
Kofi
Depends on the position in the circuit. For plate resistors, I would go for wirewound. Quiet and tough. Grid stoppers seem to work best for me in carbon composition, but the metal films you referenced would undoubtedly work just fine. Many people like bulk foil, especially where some power might be dissipated (e.g., for output stage cathode bias resistors or screen supply). The Vishay bulk foil are probably another page or two later in the catalog- they look like TO220 packages.
Hi Kofi,
I've been following this thread recently... I too am very much interested in making Kuei's "EconoValvePhono" soon w/ help from a friend. Maybe I'd sell the phonostage I have now (it has too much gain for me anyway) when I get KYW's up and running... Anyways, I admire your tenacity. Thanks for posting your progress.
Some PSU questions though (for Kofi and anyone who may know):
1.) In the original PSU schema, the input C is a 10uF MKP. You have omitted that. What was the reason?
2.) In the RC stages you used 47uF instead of 100uF, is it because of the lower V power trannie you used (290V) plus the specific bridged diodes required less filter capacitance?
I have a spare 6X4 I guess if I sim mine in PSUDII I may get values quite close to the original schema if I use a pwr trannie w/ circa 300V secondary. I also have a spare 5V4G, I'll check later what I can come up with...
General Qestion:
1.) I read that the 6SL7 may be used in place of the 12AX7 in this crct. without changing parts values. Is the octal more prone to hum and microphonics than the 12AX7?
Thanksabunch guys,
fred
I've been following this thread recently... I too am very much interested in making Kuei's "EconoValvePhono" soon w/ help from a friend. Maybe I'd sell the phonostage I have now (it has too much gain for me anyway) when I get KYW's up and running... Anyways, I admire your tenacity. Thanks for posting your progress.
Some PSU questions though (for Kofi and anyone who may know):
1.) In the original PSU schema, the input C is a 10uF MKP. You have omitted that. What was the reason?
2.) In the RC stages you used 47uF instead of 100uF, is it because of the lower V power trannie you used (290V) plus the specific bridged diodes required less filter capacitance?
I have a spare 6X4 I guess if I sim mine in PSUDII I may get values quite close to the original schema if I use a pwr trannie w/ circa 300V secondary. I also have a spare 5V4G, I'll check later what I can come up with...
General Qestion:
1.) I read that the 6SL7 may be used in place of the 12AX7 in this crct. without changing parts values. Is the octal more prone to hum and microphonics than the 12AX7?
Thanksabunch guys,
fred
fred76 said:
Its called "stupidity" not "tenacity", but thanks anyway.
fred76 said:
Actually, I just used a PSU design that was posted by Yagoolar. See? Stupidity!
Anyway, according to PSUD, the design I have should yield little ripple. I also regulated the 6.3VDC filament supply, which should help with overall hum.
I just disassembled the assembly I had before so I can rewire and move the PSU off board to reduce hum. I must say that even with th hum, it sounded mighty nice.
fred76 said:
Can't help you with this one, I'm afraid. Anyone else have an answer?
Good luck with your project!
Kofi
OK-- I'm rewiring the amp today and I think I may have confused the filament wiring for the ECC83. If I'm using a 6.3V regulated filament do I:
(a) apply the fillament supply to pins 4 and 5 in parallel (shorted) and ALSO connect pin 9 to pins 4 and 5 and then ground 4, 5 and 9?
(b) apply the fillament supply to pins 4 and 5 in parallel (shorted) and ALSO connect pin 9 to pins 4 and 5 and NOT ground 4, 5 and 9?
(c) apply the filament supply to pins 4 and 5 in parallel (shorted) and NOT connect pin 9 to 4 and 5 and ground pin 9? OR...
(d) apply the filament supply to pins 4 and 5 in parallel (shorted) and NOT connect pin 9 to 4 and 5 and NOT ground pin 9?
Don't you just love choices?
Kofi
(a) apply the fillament supply to pins 4 and 5 in parallel (shorted) and ALSO connect pin 9 to pins 4 and 5 and then ground 4, 5 and 9?
(b) apply the fillament supply to pins 4 and 5 in parallel (shorted) and ALSO connect pin 9 to pins 4 and 5 and NOT ground 4, 5 and 9?
(c) apply the filament supply to pins 4 and 5 in parallel (shorted) and NOT connect pin 9 to 4 and 5 and ground pin 9? OR...
(d) apply the filament supply to pins 4 and 5 in parallel (shorted) and NOT connect pin 9 to 4 and 5 and NOT ground pin 9?
Don't you just love choices?
Kofi
Tie 4 and 5 together. That's one terminal. Pin 9 is the other. The heater supply is connected across these two pins.
As for grounding, let's get things stabilized in the Sudan first, OK?
As for grounding, let's get things stabilized in the Sudan first, OK?
Do you mean that the +6.3V is connected to 4/5 AND +6.3V is also connected to pin 9? Or is +6.3V connected to 4/5 and -6.3V connected to pin 9?
I know I have to prioritize. I just can't get my mind on the Sudan until I kill the hum in this amp. I guess I could ask Chirac for some help. Since he didn't get the Olympics he's got nothing to do right now.
Kofi
I know I have to prioritize. I just can't get my mind on the Sudan until I kill the hum in this amp. I guess I could ask Chirac for some help. Since he didn't get the Olympics he's got nothing to do right now.
Kofi
Let's be clear- if I read you correctly, you don't have + and - 6.3V, you just have a (at the moment) floating 6.3V supply. So the plus end is connected to the pin4-5 combination, the - end connected to pin 9. Or you can reverse that- polarity isn't important.
Chirac referred me to Schroeder. Schroeder said something like "SY, du bist haesslich und deine Muetter kleidet dich komisch." I think what he mean by that is that you should probably ground the - end of the heater supply (along with its associated tube pin). If there is any heater-induced hum, you can then start worrying about biasing the heaters up 20V or so above ground. All that was apparently a shorter sentence in German, but perhaps I missed some subtlety in Gerhardt's admonition.
Chirac referred me to Schroeder. Schroeder said something like "SY, du bist haesslich und deine Muetter kleidet dich komisch." I think what he mean by that is that you should probably ground the - end of the heater supply (along with its associated tube pin). If there is any heater-induced hum, you can then start worrying about biasing the heaters up 20V or so above ground. All that was apparently a shorter sentence in German, but perhaps I missed some subtlety in Gerhardt's admonition.
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