Edcor XPWR code for 380-320-0-320-380 @ 200mA
I just received the code from Phyillis at Edcor. It is XPWR144.
Just for the record, it is not shielded, does not have the 55v bias tap, and does not have the extra 1.5A 5V secondary.
Jeff
I just received the code from Phyillis at Edcor. It is XPWR144.
Just for the record, it is not shielded, does not have the 55v bias tap, and does not have the extra 1.5A 5V secondary.
Jeff
So one transformer and rectifier would have enough to power both channels if you so chose, right?
Any thought of having one separate power supply with umbilicals, rather than two? Just to save parts? It would be easy to convert to a 4 box design later when the budget allows.
I was thinking of trying a 274b rectifier, any thoughts? a good one is more expensive, so maybe starting with one power supply at first.
Yes, one could power two channels.
Sure you are only limited by your imagination I guess as far as umbilicals and power supply configurations go.....
I am not familiar with the 274b
I have not yet built a power supply with umbilicals. I am wondering if anyone here could suggest what type of connectors could be used (plug/socket, etc...)?
The 274b just sounds interesting, being a non-conformist. Very expensive except for the Valve Art version. Might be fun to try and upgrade to the fancier tube later if i feel like it. It is similar to the 5U4 but lower max current. Might need one per channel?
If the power supply is built right, it probably could use either tube.
Sophia Electric TJ Meshplates and the 274B Rectifier Tube - A Critical Review on TNT-Audio [English]
If the power supply is built right, it probably could use either tube.
Sophia Electric TJ Meshplates and the 274B Rectifier Tube - A Critical Review on TNT-Audio [English]
Sorry all, I am a newbie here and responded to the thread from in the middle somewhere. there was a gentleman suggesting that the 300B JE circuit circuit was inferior in some way to other builds. I am just finishing a long term build of these monoblocks and am still playing around with different caps, speakers, Etc. I used all Hammond iron per Walton Mk1. I think I am pleased but it is so new to my ears. What do people use for the bypass capacitors? Do you think a 33uf@160vdc would make a suitable sub for the 47uf@160? It is all I can find in a black gate. I initially built with Solen fast caps for the bypass caps but have read nasty things about them being used in audio. I know much is subjective in the matter.
Thank you and pardon for the intrusion,
Ian
Thank you and pardon for the intrusion,
Ian
Specimin,
The use of Fast caps as coupling capacitors is probably what is being referred to. You could use them as bypass caps, a bit bulky though. As far as the 33uF instead of the 47uF, it would work but you may loose a little of the gain on the lower frequencies. You might try Soniccraft.com, they shoud have this cap in Black Gate. Or if you have the black gates already, go ahead an use them....maybe even parallel a Solen 15uF along side it to get you closer to spec. I personally have tried Elna Silmic/Cerafine, Nichicon Muse KZ, and Black Gate....I can't say I can really tell too mush of a difference in the other 2 amps that I have toyed with different types of bypass caps. Maybe it is my system in general but it hasn't really seemed to make a really big difference.
Coupling caps do seem to make a difference in my system. So far my favorite is a fairly inexpensive Russian PIO, they are all over the place at eBay. The K40 variants have proven the best to my ears. I have put them side by side with Mudorf Silver/Gold, Jupiter, and Multicaps....I think for the money you can't beat them. There is alot of personal taste in this matter though. I bought 20 0.22uF and 20 0.33 not too long ago on eBay straight from a guy in one of the former USSR states for about $1 a cap + s/h.
As far as whether or not this is a good amp or not, well again, their are alot of opinions out there. I think it must be pretty descent as it has a pretty large following and has been built quite a few times as far as I can tell. On any given day you can go to Audiogon.com and find 1-2 of these custom built JEL variants for sale. I am sure there are better amps out there but for the few of us who have started this thread (I don't want to speak for everyone, but there are a couple here) it sems to have been chosen b/c it is a well recognized design that is supposed to preform well and is fairly easy to build. I myself have not built a DHT before this one and I wanted to start with a design that had lots of information and was well documented. I might try the T-rex down the road but for now this has satisfied my curiosity and desire to build a DHT SET.
Jeff
The use of Fast caps as coupling capacitors is probably what is being referred to. You could use them as bypass caps, a bit bulky though. As far as the 33uF instead of the 47uF, it would work but you may loose a little of the gain on the lower frequencies. You might try Soniccraft.com, they shoud have this cap in Black Gate. Or if you have the black gates already, go ahead an use them....maybe even parallel a Solen 15uF along side it to get you closer to spec. I personally have tried Elna Silmic/Cerafine, Nichicon Muse KZ, and Black Gate....I can't say I can really tell too mush of a difference in the other 2 amps that I have toyed with different types of bypass caps. Maybe it is my system in general but it hasn't really seemed to make a really big difference.
Coupling caps do seem to make a difference in my system. So far my favorite is a fairly inexpensive Russian PIO, they are all over the place at eBay. The K40 variants have proven the best to my ears. I have put them side by side with Mudorf Silver/Gold, Jupiter, and Multicaps....I think for the money you can't beat them. There is alot of personal taste in this matter though. I bought 20 0.22uF and 20 0.33 not too long ago on eBay straight from a guy in one of the former USSR states for about $1 a cap + s/h.
As far as whether or not this is a good amp or not, well again, their are alot of opinions out there. I think it must be pretty descent as it has a pretty large following and has been built quite a few times as far as I can tell. On any given day you can go to Audiogon.com and find 1-2 of these custom built JEL variants for sale. I am sure there are better amps out there but for the few of us who have started this thread (I don't want to speak for everyone, but there are a couple here) it sems to have been chosen b/c it is a well recognized design that is supposed to preform well and is fairly easy to build. I myself have not built a DHT before this one and I wanted to start with a design that had lots of information and was well documented. I might try the T-rex down the road but for now this has satisfied my curiosity and desire to build a DHT SET.
Jeff
Well, "good" is subjective - we have different concepts regarding what it means. Some people very much enjoy the presentation of the amp (and this type of circuit), others are likely more sensitive to its ‘deficiencies’ and relatively immune to its ‘charms’. Many people have settled with this amp, but most who have compared it to more 'modern' offerings have moved on. That said, I know of one person who has gone back to a 6sn7 driving a 300B after experimenting with other amps; he is an exception though, and he still listens to his other amps.
I have not heard the JEL, but from a quick look at the schematic and various comments regarding its sonics, it seems to have far too much gain for most systems and what many would consider the 'traditional 300B' sound – vivid/enhanced/hyper-real tonality and trippy sound-staging but somewhat veiled, soft and stumbling. I believe there are likely more modern designs that would have most of the strengths, fewer of the weaknesses, and offer considerable strengths of their own at a reduced cost and build difficulty so as to relegate the cascade 6sn7 and similar designs to legacy status.
As for why it is popular - it was one of the earlier well-documented designs when the SET 300B thing was (re)ascending. It remains one of the most widely and most comprehensively documented designs. Many people like the sonics.
If you wish to go down the JEL path, there are a few things that could likely make it more enjoyable (to me). Without refreshing my memory by looking at the schema: a lower DCR power supply, preferably with choke input and film oil caps; the use of grid choke on the 300B; decent filament supply to the 300B; and try a 60mA plate current, 350 plate voltage with a 3k5 to 5k load on the 300B (depending on the bass alignment of your speakers and sonic preferences). You could also flavour with film or film/oil caps on the cathodes; try a partial WE connection; CCS load the driver plate (mu out?) etc... but would it be worth the effort and expense?
Cheers
Raymond
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What would be the best 300B tube for the money to use for this project. I am still a newbie so I won't by the EAT or WE yet. I can't find new Svetlana 300B tubes. Are these good instead?
BLACK SABLE SED KT88
Jeff, are the Edcor codes still valid for the PS transformer? Even though I haven't finished the KT88 amp yet, I figured I'll get a head start on the JEL300B DX.
BLACK SABLE SED KT88
Jeff, are the Edcor codes still valid for the PS transformer? Even though I haven't finished the KT88 amp yet, I figured I'll get a head start on the JEL300B DX.
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Well, they are KT88 tiubes, not 300B to begin with. Other than that I am sure they are fine.
A good priced descent 300B is the EH Gold Grid variant from what I have read. Check Audiogon every now and then, there tends to be some great buys on good used tubes there. I think there is a pair of NOS Svetlana 300B's there now for around $200, a good buy. I bought the EH's, probably will never own a WE. Too darn expensive.
The Edcor code for the Angela semi-clone is XPRW144. Just ask Phyllis to hook you up. Tell her what it is for and that she just designed some for Jeff Miller (Me), I told her to be expecting some inquiries. 2 orders have been place for these since I had them designed so she will have no problems fixing you up. I expected mine to arrive today sometime but then I realized it was Sat. Should have mine by Mon.
Also, she designed a 5VCT 3amp filament transformer too. It has endbells and runs $24 each. You will need a pair of these too, or similar. When I had them design these I told them that it was very important that the center tap be exactly in the center b/c I use a balanced cathode drive for my heaters. They should be on the money. This way you can use the center tap as the lead to the cathode resistor and avoid using a hum pot. It will be $170 for everything plus about $20 for s/h. I think Angela sells the 5vct 3amp filament transformer for about $14 if you want to go more budget.
It takes them about 3-4 weeks (usually 4) to wind your order so if you are planning to get started soon......
For anybody interested I have all the resistors for this amp in IRC 3watts. I changed my mind and decided to go with Takman Carbon films. I also have the bypass caps in Nichicon Muse KZ. I will sell them for under what I paid just to unload them as I don't need them anymore. IRC is a very good metal precision resistor that is supposedly very low on noise. They were not expensive either, I think they were around 75c each, maybe a little less. Anyway, I have every value needed to complete the DX version of the amp (minus the 880R cathode resistor) so if you don't want to hunt around for parts drop me a message.
Jeff
Ah, I realize I have the wrong link for the 300B. I heard the newest of the Svetlana 300B tubes are very good and just shy of the WE in comparison article. Yes, I saw the Svetlana 300B on ebay this morning.
Here are the correct links:
300B Comparison Review
300B Shootout! by Thorsten Loesch
Great, so I'll get the XPRW144 and the 5VCT/3A filament transformer. 4wks?... Don't worry, I am in no rush since I am still completing the SE KT88 amp.
If one didn't go with a balanced cathode drive, would you just connect each of the 5VAC leads to the heaters, and leave the CT not connected?...
With the exception of the 300B and transformers, I have everything. I went with Kiwame carbon resistors, and Blackgates for the electrolytics.
Here are the correct links:
300B Comparison Review
300B Shootout! by Thorsten Loesch
Great, so I'll get the XPRW144 and the 5VCT/3A filament transformer. 4wks?... Don't worry, I am in no rush since I am still completing the SE KT88 amp.
If one didn't go with a balanced cathode drive, would you just connect each of the 5VAC leads to the heaters, and leave the CT not connected?...
With the exception of the 300B and transformers, I have everything. I went with Kiwame carbon resistors, and Blackgates for the electrolytics.
Yes, but why would you want to? I should have mine built before you get that far so I will give you a report on how well the balanced cathode drive works with the new Edcor 5VCT transformers. I used this design on my 2A3 and it is virtually silent. It would be very simple to connect your amp with the balanced cathode drive first and if you didn't like the results you could very easily disconnect the CT and place a pot across the two filament terminals in a hum pot configuration.
Jeff
Great! I am trying to better understand how to implement filament transformers. So there are generally 2 ways of supplying the heater voltage. I just don't want to burn out another rectifier tube on power up, like how I did with the SE KT88 amp.
1) Using each lead of 5VAC and not connecting the CT.
2) Using the CT and one of the 5VAC leads.
I would have never known to use a CT and a 5VAC just by looking at a schematic.
Thanks, Jeff!
1) Using each lead of 5VAC and not connecting the CT.
2) Using the CT and one of the 5VAC leads.
I would have never known to use a CT and a 5VAC just by looking at a schematic.
Thanks, Jeff!
Just to be sure we are on the same page....I am referring to the filaments on the 2A3/300B power tube, not the rectifier.
Here is a schematic with the balanced cathode drive implemented: http://www.hagtech.com/pdf/clarionarticle.pdf
I just finished this amplifier and this method works very well.
Jeff
Jeff,
Can you tell me about the "Cathode" connection for C9-10uF/630V?
Thanks, Scott
This is a type of parafeed to the cathode from the power supply. I am not too familiar with it, I just built it as is and it seems to work well. I have been meaning to lear more about it myself.
Jeff
Edcor transformers arrived!
Well I got the new Edcor transformers in the mail today. They are the usual high quality I have come to expect from them. I have posted a couple of low res pics from my webcam with a pair of pliers for perspective. The XPWR144 is the semi-clone of the Angela Universal. Again, the only difference is it doesn't have the bias tap and the extra 5V (only has one, not 2) secondaries. I had this developed this way because I use a second 5VCT (shown next to it) in a balanced cathode drive to eliminate the use of a hum pot. Also, if you plan to use either the Edcor or Angela in the stereo version you would need the extra 5vct trafos anyway.
The XPWR144 lists for $61 and the 5vct lists for $24.
The 5vct order code is EFT5-2-1.
For those of you wondering what the balanced cathode drive is that replaces the use of a hum pot look at this article. The schematic shows how it was implemented on this 2A3 build. http://www.hagtech.com/pdf/clarionarticle.pdf
You could go with the lower cost Hammond 5vct, I think it lists for about $15-16 most retailers. I asked for endbells which drives the cost up a little. I like the looks, kinda cute!
If you want more info on this semi-clone, lower cost alternative from Edcor you can PM me or contact Edcor directly and ask for Phyllis.
Jeff
Well I got the new Edcor transformers in the mail today. They are the usual high quality I have come to expect from them. I have posted a couple of low res pics from my webcam with a pair of pliers for perspective. The XPWR144 is the semi-clone of the Angela Universal. Again, the only difference is it doesn't have the bias tap and the extra 5V (only has one, not 2) secondaries. I had this developed this way because I use a second 5VCT (shown next to it) in a balanced cathode drive to eliminate the use of a hum pot. Also, if you plan to use either the Edcor or Angela in the stereo version you would need the extra 5vct trafos anyway.
The XPWR144 lists for $61 and the 5vct lists for $24.
The 5vct order code is EFT5-2-1.
For those of you wondering what the balanced cathode drive is that replaces the use of a hum pot look at this article. The schematic shows how it was implemented on this 2A3 build. http://www.hagtech.com/pdf/clarionarticle.pdf
You could go with the lower cost Hammond 5vct, I think it lists for about $15-16 most retailers. I asked for endbells which drives the cost up a little. I like the looks, kinda cute!
If you want more info on this semi-clone, lower cost alternative from Edcor you can PM me or contact Edcor directly and ask for Phyllis.
Jeff
Attachments
Chassis work finally done...almost
I just recently found some time to start working on this project again. I decided to keep with the same types of wood used on the 2A3 I completed in Feb. It is Spanish Modena and White Tiger Maple. I kept with the same general theme too except the power supply and signal circuits are in two separate compartments that are divided by the filter caps. As you can see I mounted them horizontal, 3 of them. The 4th will go inside the power supply compartment. I clap them in a 7mil thick sheet of copper. The 2 smaller copper tubes are for the wires to pass between the compartments. I will mount the power transformer and rectifier tube, as well as the 2.5vct transformer on one end. The 3 signal tubes and output transformer will be mounted on the other end. Each monoblock is rather large. They measure about 10.5 x 19 x 3 each. Each one is actually larger than the entire stero 2A3 I built. I wanted more room to work and I had the wood. Who says bigger is not better?
I will start cutting the tops for the components tomorrow and then starts the soldering. I can't wait to hear these babies.
Jeff
Lawton, OK, USA
I just recently found some time to start working on this project again. I decided to keep with the same types of wood used on the 2A3 I completed in Feb. It is Spanish Modena and White Tiger Maple. I kept with the same general theme too except the power supply and signal circuits are in two separate compartments that are divided by the filter caps. As you can see I mounted them horizontal, 3 of them. The 4th will go inside the power supply compartment. I clap them in a 7mil thick sheet of copper. The 2 smaller copper tubes are for the wires to pass between the compartments. I will mount the power transformer and rectifier tube, as well as the 2.5vct transformer on one end. The 3 signal tubes and output transformer will be mounted on the other end. Each monoblock is rather large. They measure about 10.5 x 19 x 3 each. Each one is actually larger than the entire stero 2A3 I built. I wanted more room to work and I had the wood. Who says bigger is not better?
I will start cutting the tops for the components tomorrow and then starts the soldering. I can't wait to hear these babies.
Jeff
Lawton, OK, USA
Attachments
You really do great work! If you're ever looking to unload any of your stuff, put me first on the list.
I haven't been following this thread but your chassis work has sparked my interest enough to go back and read the entire thing; I'm excited to see what I learn.
I haven't been following this thread but your chassis work has sparked my interest enough to go back and read the entire thing; I'm excited to see what I learn.
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