Nope, have not decided on a speaker kit yet. Madison offerings are mighty tempting but.
I am defintely able to make my own chassis as i have woodworking tools.
I'm trying to find an equivalent to the pa0521 on digikey but have not had much luck. Reason i'm after digikey is that there is a free shipping bonus after spending more then $200, of which i will be purchasing 2x hammond 1650r for opt's.
Just wondering, can anyone suggest which 2-way speakers on Madison would suit vocal/ trance/ instrumental music best?
I'm leaning towards the SR71 or Eaton S7.
Regarding the amplifier, i think i will most likely go for an ST70 kit from Triode Electronics based on rmyauck advice, and change some parts to suit KT88 tubes.
Just from other people experiences, i believe i need to get an upgraded choke, change to solid state rectifiers and get some inrush current limiters. Did i miss anything?
I'll also change the OPT's to Hammond 1650R as its easier to source them and cost around the same as buying and shipping two A470's. I'm a little unsure what resistor values i might have to change though.
Still unsure what PT i can change to, as digikey does not seem to stock any hammond ones that are suitable or cost below 200.
If anyone has any more suggestions, please throw them at me.
Btw regarding the chassis, can i build it out of wood/ glass? Or would i get a lot of EMI.
I'm leaning towards the SR71 or Eaton S7.
Regarding the amplifier, i think i will most likely go for an ST70 kit from Triode Electronics based on rmyauck advice, and change some parts to suit KT88 tubes.
Just from other people experiences, i believe i need to get an upgraded choke, change to solid state rectifiers and get some inrush current limiters. Did i miss anything?
I'll also change the OPT's to Hammond 1650R as its easier to source them and cost around the same as buying and shipping two A470's. I'm a little unsure what resistor values i might have to change though.
Still unsure what PT i can change to, as digikey does not seem to stock any hammond ones that are suitable or cost below 200.
If anyone has any more suggestions, please throw them at me.
Btw regarding the chassis, can i build it out of wood/ glass? Or would i get a lot of EMI.
Regarding the amp I only pointed you to Triode Electronics for PS transformer specs, and that they were one of 2 chassis suppliers. Sorry to confuse you with all the advice on SS and tube rect.
I did point out on post #36 page 4 that you could build your own point to point board to save money or pick the boards I pointed to on diytube.com if you wanted a PCB board with everything on it for ease in building. I think it would be the easiest for someone new to get a great sounding amp (Based on Eico HF-89 Mullard 5-20 circuit) if your going to build your own chassis for not too much $.
By using a different board than the stock original , you end up with other than the Dynaco ST-70 any way which usually will be sonically better according to most people.
The original Dynaco ST-70 board was simple granted, but 7199 tubes are hard to come by and so are pricy. Dynakitparts.com sells original board copies with or without parts and adapters for an easier to find NOS ( not in production, but many out there now anyway) replacement tube. The triode board does copy the stock circuit the closest with available presently produced tubes.
For chassis, most builders use metal ( aluminum for ease of cutting holes and drilling or steel) for the top and wood can be used for the base. You might find aluminum chassis over there from Hammond also. Aluminum, good SS or anything not metallic would be preferable for less EMI. Putting the transformers in the right places & orientation helps too.
The lowest cost PS trans may be the Antek toriod then, but you would also have to order a small one for the bias supply voltage.
Randy
I did point out on post #36 page 4 that you could build your own point to point board to save money or pick the boards I pointed to on diytube.com if you wanted a PCB board with everything on it for ease in building. I think it would be the easiest for someone new to get a great sounding amp (Based on Eico HF-89 Mullard 5-20 circuit) if your going to build your own chassis for not too much $.
By using a different board than the stock original , you end up with other than the Dynaco ST-70 any way which usually will be sonically better according to most people.
The original Dynaco ST-70 board was simple granted, but 7199 tubes are hard to come by and so are pricy. Dynakitparts.com sells original board copies with or without parts and adapters for an easier to find NOS ( not in production, but many out there now anyway) replacement tube. The triode board does copy the stock circuit the closest with available presently produced tubes.
For chassis, most builders use metal ( aluminum for ease of cutting holes and drilling or steel) for the top and wood can be used for the base. You might find aluminum chassis over there from Hammond also. Aluminum, good SS or anything not metallic would be preferable for less EMI. Putting the transformers in the right places & orientation helps too.
The lowest cost PS trans may be the Antek toriod then, but you would also have to order a small one for the bias supply voltage.
Randy
The Eiclones, sort of died in popularity a few years ago as probably as a result of the Dynaco Mark III & ST-70 boards becoming more popular. They probably became more popular because there are a lot of used and new chassis out there in NA so people didn't have to make there own.
I noticed Shannon who makes the boards recently announced another run of them as people were asking for them. The circuits are similar between the boards , but the Dynaco ones use SS CCS (transistors) on the phase inverter tail. Some don't want that and in fact a poster on diytube commented that he preferred the sonics of the Eiclone.. SS circuits add more reliability issues to some also, as they can die and may be harder to troubleshoot.
The poster used the 6SL7 instead of the 12AX7 which may have helped the sonics too for all Octal tubes in the driver section. It seems to be popular now to build Octal tube driver boards for the ST-70 chassis too as many prefer them. Many other after market boards out there now have CCS on them.
Since your going to make your own chassis I thought it might be a nice option using a well regarded amp design . You could always add CCS later to even the PCB board version if you want to try it on a small perf board. I don't know if you want to try point to point wiring like the example I pointed out to you. The PS could be done that way also. You just have to learn the schematics and copy proven layouts. PCB construction is certainly faster though, but a bit more $.
I should explain there are basically 3 types of amp circuits out there and modifications out there. The Mullard , also called LTP or differential phase splitter. Some times it's combined with the Williamson or Split Phase on hi power amps. The Mullard circuit came out last and is popular today as it's stable with many tubes and OPT's so is used in many commercial amps and by diyer's.
The simplified Williamson or split phase was started in the 50's and is still popular today for low power PP 6V6 and EL84 tube amps as those lower power tubes are easy to drive.
Another tube that was just as easy to drive was the 7868/7591 and so used that circuit due to it's simple design with nice sonics.
The Paraphase was the first well used phase splitter in the 30's for affordable equipment of the day. Costlier Transformers were used as the splitter before that and by some today . The Floating Paraphase was an improved version still used today by some. The Williamson came out in the late 40's and can be used for high power amps and a simplified version is what Dynaco used in there amp designs.
A more complicated circuit is usually required to drive the big tubes on a high power amp successfully which is the reason there are so many out there with boards out there for the Dynaco's, and good driver tubes are hard to find.
If your going to build with P2P (point to point) , one thought is that you could build the driver circuit like the one I linked to on a separate metal plate like that one I linked to with your own chassis to save $ and shipping. It would also allow you to try different circuits later. Also for your first P2P it would be easier to troubleshoot as it is separate from the rest of the circuit.
Hope that helps!
Randy
I noticed Shannon who makes the boards recently announced another run of them as people were asking for them. The circuits are similar between the boards , but the Dynaco ones use SS CCS (transistors) on the phase inverter tail. Some don't want that and in fact a poster on diytube commented that he preferred the sonics of the Eiclone.. SS circuits add more reliability issues to some also, as they can die and may be harder to troubleshoot.
The poster used the 6SL7 instead of the 12AX7 which may have helped the sonics too for all Octal tubes in the driver section. It seems to be popular now to build Octal tube driver boards for the ST-70 chassis too as many prefer them. Many other after market boards out there now have CCS on them.
Since your going to make your own chassis I thought it might be a nice option using a well regarded amp design . You could always add CCS later to even the PCB board version if you want to try it on a small perf board. I don't know if you want to try point to point wiring like the example I pointed out to you. The PS could be done that way also. You just have to learn the schematics and copy proven layouts. PCB construction is certainly faster though, but a bit more $.
I should explain there are basically 3 types of amp circuits out there and modifications out there. The Mullard , also called LTP or differential phase splitter. Some times it's combined with the Williamson or Split Phase on hi power amps. The Mullard circuit came out last and is popular today as it's stable with many tubes and OPT's so is used in many commercial amps and by diyer's.
The simplified Williamson or split phase was started in the 50's and is still popular today for low power PP 6V6 and EL84 tube amps as those lower power tubes are easy to drive.
Another tube that was just as easy to drive was the 7868/7591 and so used that circuit due to it's simple design with nice sonics.
The Paraphase was the first well used phase splitter in the 30's for affordable equipment of the day. Costlier Transformers were used as the splitter before that and by some today . The Floating Paraphase was an improved version still used today by some. The Williamson came out in the late 40's and can be used for high power amps and a simplified version is what Dynaco used in there amp designs.
A more complicated circuit is usually required to drive the big tubes on a high power amp successfully which is the reason there are so many out there with boards out there for the Dynaco's, and good driver tubes are hard to find.
If your going to build with P2P (point to point) , one thought is that you could build the driver circuit like the one I linked to on a separate metal plate like that one I linked to with your own chassis to save $ and shipping. It would also allow you to try different circuits later. Also for your first P2P it would be easier to troubleshoot as it is separate from the rest of the circuit.
Hope that helps!
Randy
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If you are after a higher powered amp and have not built a tube amp before, I would recommend something like Pete Millett's universal driver board. Takes away a lot of the guess work getting the layout right. Poor layout will lead to hum,oscillation and other nasties that may discourage a new builder with little experience. Pete Millett's DIY Audio pages
This looks like a very good regulated power supply from one of the DIYAudio members tomchr 21st Century Maida Regulator : Neurochrome.com : : Audio
This looks like a very good regulated power supply from one of the DIYAudio members tomchr 21st Century Maida Regulator : Neurochrome.com : : Audio
Ok, So i priced the 2 amplifiers together. The ST70 from Triode and the Eiclone.
See link,
https://docs.google.com/spreadsheet/ccc?key=0Aj2cMd31GhpMdENyX2QxZU9CaWd0WHY2WTBNNHBON0E&pli=1#gid=0
Both are around the same pricing. Which one should i really really go for? The Eiclone bom does not really use any premium audio parts i believe.
That said i'm leaning towards the eiclone even though the forums seem dead.
See link,
https://docs.google.com/spreadsheet/ccc?key=0Aj2cMd31GhpMdENyX2QxZU9CaWd0WHY2WTBNNHBON0E&pli=1#gid=0
Both are around the same pricing. Which one should i really really go for? The Eiclone bom does not really use any premium audio parts i believe.
That said i'm leaning towards the eiclone even though the forums seem dead.
They are two totally different circuits as I mentioned. The ST-70 kit from Triode has a lower B+ so can support the lower power less costly tubes, because of the lower B+. You could save money by going to the Antec PS transformers I would think even with shipping, but, covers would have to be made and then more would be probably be saved by probably just by buying their board kits and other parts separately.
The Eiclone could be run with similar lower power PS trans to run similar tubes, by juggling resistors in PS for driver stage etc.
In all the Eiclone might be better with KT-88's for longer tube life and there are good affordable ones out there. You can run 6550's at a lower bias setting , but sonics may suffer. In all it depends on what your wall voltage is as this will affect the B+ too. In NA it can hit 125-127V. Maybe better regulated over there and hopefully close to 220-230V.
The Elicone would also be the simplest to put together and wire as all is on one board. Mono blocks would be nice for stereo separation and easier moving of amps. I would try 6SL7 instead of the 12AX7 for sonic reasons.
Hope that helps!
Randy
The Eiclone could be run with similar lower power PS trans to run similar tubes, by juggling resistors in PS for driver stage etc.
In all the Eiclone might be better with KT-88's for longer tube life and there are good affordable ones out there. You can run 6550's at a lower bias setting , but sonics may suffer. In all it depends on what your wall voltage is as this will affect the B+ too. In NA it can hit 125-127V. Maybe better regulated over there and hopefully close to 220-230V.
The Elicone would also be the simplest to put together and wire as all is on one board. Mono blocks would be nice for stereo separation and easier moving of amps. I would try 6SL7 instead of the 12AX7 for sonic reasons.
Hope that helps!
Randy
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Those coupling caps should be a nice upgrade, where you should hear the difference in that place. I haven't had the funds to try more expensive caps so I don't know how different ones sound., but I did read they are well liked. You could also try .22 uF of the same voltage too for maybe extended frequency response.
It's also good too add (4) 100 ohm screen grid resistors to the parts list for installation of one each at pin #4 of the output tubes to the OPT transformer leads. This will help the output tubes last with the added capacitance in the PS.
Randy
It's also good too add (4) 100 ohm screen grid resistors to the parts list for installation of one each at pin #4 of the output tubes to the OPT transformer leads. This will help the output tubes last with the added capacitance in the PS.
Randy
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