Thanks andyjevans, you are really starting to push me to consider DHT's, namely 10's. Any thing special, choke loads, IT coupling, or just the usual? The only thing I am worried about with DHT's is hum because of the filaments, but that can be designed for and solved. Have you by any chance heard a 26 -> 10Y -> 300B? I have wanted to try a 26 choke-loaded line stage for a while now, from what I hear people have listened to them and not gone back to anything else.
I have read too some compelling writing in favor of the 300B driven by a 417 with a interstage transformer. I suppose the 417 could be changed to something else.
The plot thickens, it seems this simple summer project has grown into something very deep and all the more mind bending. Like I said earlier I am striving to make my first 300B SET a positive one.
andyjevans, I too would like to play with some higher power tubes. I would love to do a 845, a 813 SET, and or a GM70. The 813 seems like it would a fairly easy project to tackle, seems to have more relaxed drive requirements. Mr. Millett did his with a single 12HG7, two tubes, no fancy coupling or parts, and approx. 20watts of DH Triode strapped 813 power! The problem I have is my 21yo never-shocked fingers make me nervous around 1kv!
Cheers
James
I have read too some compelling writing in favor of the 300B driven by a 417 with a interstage transformer. I suppose the 417 could be changed to something else.
The plot thickens, it seems this simple summer project has grown into something very deep and all the more mind bending. Like I said earlier I am striving to make my first 300B SET a positive one.
andyjevans, I too would like to play with some higher power tubes. I would love to do a 845, a 813 SET, and or a GM70. The 813 seems like it would a fairly easy project to tackle, seems to have more relaxed drive requirements. Mr. Millett did his with a single 12HG7, two tubes, no fancy coupling or parts, and approx. 20watts of DH Triode strapped 813 power! The problem I have is my 21yo never-shocked fingers make me nervous around 1kv!
Cheers
James
I wouldn't change much of anything about my little amp except that I wish it had a little larger chassis which would allow more room for experimentation. I'd like to try some different styles of filter caps in the amp but there really isn't enough room.
I would like to experiment with a few different cathode bypass caps to see if they make any real difference in the sound.
My amp uses a Hammond mains transformer and it seems fine it's quiet and it does not hum but it does get a little warm. A slightly larger one would be good. The output transformers are the One Electron and they seem to sound good and they only get moderately warm and probably most of that is what's radiated from the tubes themselves.
I listen to the amp nearly every day and sometimes it's on for several days at a time over the weekend and stuff.
I don't have any idea how long some of the components will last but I think the life of the 300B is quite long.
I would like to experiment with a few different cathode bypass caps to see if they make any real difference in the sound.
My amp uses a Hammond mains transformer and it seems fine it's quiet and it does not hum but it does get a little warm. A slightly larger one would be good. The output transformers are the One Electron and they seem to sound good and they only get moderately warm and probably most of that is what's radiated from the tubes themselves.
I listen to the amp nearly every day and sometimes it's on for several days at a time over the weekend and stuff.
I don't have any idea how long some of the components will last but I think the life of the 300B is quite long.
If you are looking for more than 8w look at Bob Danielak's EL 509 single ended amp. It is a very nice design, direct coupled and screen driven. No coupling caps, no killer HV 400v B+ and only 2 tubes per channel. Output is about 15w. One 6BM8 and a EL 509. The EL 509 is very good sounding tube. The output transformer should be around 4.8k, so output transformer isn't difficult to get.
300B amps are nice but 8w is a bit low for most speakers unless you have something over 100dB efficient or you have a small room.
300B amps are nice but 8w is a bit low for most speakers unless you have something over 100dB efficient or you have a small room.
Have you by any chance heard a 26 -> 10Y -> 300B? I have wanted to try a 26 choke-loaded line stage for a while now, from what I hear people have listened to them and not gone back to anything else.>>
Yes - I've used several combinations, like:
201A>26>300b
26>12A>300b
201A>10Y>300b
26>10Y>300b
In every instance the 10y was slightly better than the 201A or 26, but frankly they are pretty close. You save a lot of money using a 26 or a 201A. And you'll be pretty close to ideal. You won't be disappointed with any of these.
As for joining up the dots - my preference would be transformers.
Yes - I've used several combinations, like:
201A>26>300b
26>12A>300b
201A>10Y>300b
26>10Y>300b
In every instance the 10y was slightly better than the 201A or 26, but frankly they are pretty close. You save a lot of money using a 26 or a 201A. And you'll be pretty close to ideal. You won't be disappointed with any of these.
As for joining up the dots - my preference would be transformers.
JPeitzman said:
Here's a driver based on a 6SN7 and a 10y (or 801): http://members.aol.com/sbench/testamp.html
I built the driver as an amp, and it is a very nice 400mW. I think you could sub a 26 for the N7 and have plenty of gain for a driver. Steve has a hum cancellation scheme for the 801. I tried it, and it did make a significant difference, but I didn't have a scope to tune it, so I punted and bought some filament supplies from Tentlabs (they work very well). Nice thing about his supplies is that they have very low voltage drop, so you can try AC first, then switch to DC with the same filament supply, if you need to. I use this amp with headphones and it is very quiet.
Do play with filament voltage if you can set up your amp for it. Read his section on this. I can confirm that distortion can be minimized with a little playing here.
Sheldon
JimW, you make a good point about how I shouldn't write off the SRPP just because it is not in vogue. This is especially true since it is a topology that I haven't heard before. Thanks for the input.
Can the 10Y be used in a DRD setup with a 26 or 10Y input tube? I was thinking 26 choke-loaded driving the 10Y. Or can the 10Y be connected to the 300B choke-loaded, or is this a better job for a interstage transformer?
I think it is kind of down between the 91A design with a C3g or 12HG7 and the all DHT with 26 and VT-25.
Just out of interest how would the JE Labs Deluxe with the 6SN7 driver setup as a cathode follower work? I think I am still a little drawn to this design just because it is my first 300B build it is easy. Plus I have all the tubes but the 300B's. Of course I know all the designs use low parts counts. I have heard good things from other sources too about the all DHT amps, my biggest concern is getting all the hum out, especially with the 26 input. I could try my own methods though and if that didn't work I could do like Sheldon and buy some Tentlabs units.
Hopefully very soon I can start gathering the parts that will not change, output and power section and what not. Also hopefully I can start on the case work. I am thinking white cherry with a aluminum or copper top plate. I do however have to get a dovetail jig, I have the bit but not the jig. My father is going to help me as well with the case and both he and I have been busy with work and updating rental properties. I think we are going to do a couple trial runs of both the case and the dovetails to make sure we have it down. I build the audio circuits and he spent a solid 20 years of his life working with tubes, the rest has been spent running his current business, in other words most of our combined wood working skill is building walls and framing doors, not small finish work. We do have all the tools and knowledge to do it, just not the experience, hope we are fast learners. Once the case is done, hopefully in a months time tops, I fully take over and start building. I am hoping that once we build the first case it will be easy to reproduce. I am planing on building up a few of the raw wood frames for other projects. I think I may use this same style case for a 26 or VT-25 line stage as well. For that I can spin down some aluminum volume and selector knobs...or maybe some copper ones. Anyways if all goes as planed they will be done by July, the only problems I foresee are financial ones involving the iron. This is my target though because I want July and August to listen to them before school starts again. I would also like to fire them up on the 4th of July for friends and family along side my JLH and soon-to-be Zen amps; I can have myself a small July 4th amplifier shoot out, the battle of the 8-10watt amps.
Thanks for all the input and keep coming with any feedback of opinions. I think a lot of it now is up to me deciding which path to take and ultimately what my overall budget is, both time wise and money wise. The 26 line stage may come first to the test bench so that I can play a little with it and the hum. Hopefully in the next few weeks I can switch this from a discussion to pictures and questions. No guarantees though as far as the time frame, this project is a long time coming but it still will take a little to get off the ground. A lot of love goes out to this community for all the time and help. I know this thread has only been here for a few days but I have had question on other ones as well. Everyone is so helpful and friendly, more than likely because we are all united by a love for audio. I started this hobby on a whim and out of boredom, stumbling across a schematic of the JLH Class-A I said "I can build that". I have meet some amazing people and artists along the way even though my journey is just beginning. I think I have found my new passion and my new home, thanks to all.
Cheers
James
BTW1: Has anyone custom ordered caps through ASC?
BTW2: Sorry to take my own thread off topic but how does a C3g -> 300B -> GM70 sound? More than likely the 300B would go through a interstage transformer. The other option I have considered is replacing the 300B with a KT88 or EL34...this project is a ways away though, just thinking.
Can the 10Y be used in a DRD setup with a 26 or 10Y input tube? I was thinking 26 choke-loaded driving the 10Y. Or can the 10Y be connected to the 300B choke-loaded, or is this a better job for a interstage transformer?
I think it is kind of down between the 91A design with a C3g or 12HG7 and the all DHT with 26 and VT-25.
Just out of interest how would the JE Labs Deluxe with the 6SN7 driver setup as a cathode follower work? I think I am still a little drawn to this design just because it is my first 300B build it is easy. Plus I have all the tubes but the 300B's. Of course I know all the designs use low parts counts. I have heard good things from other sources too about the all DHT amps, my biggest concern is getting all the hum out, especially with the 26 input. I could try my own methods though and if that didn't work I could do like Sheldon and buy some Tentlabs units.
Hopefully very soon I can start gathering the parts that will not change, output and power section and what not. Also hopefully I can start on the case work. I am thinking white cherry with a aluminum or copper top plate. I do however have to get a dovetail jig, I have the bit but not the jig. My father is going to help me as well with the case and both he and I have been busy with work and updating rental properties. I think we are going to do a couple trial runs of both the case and the dovetails to make sure we have it down. I build the audio circuits and he spent a solid 20 years of his life working with tubes, the rest has been spent running his current business, in other words most of our combined wood working skill is building walls and framing doors, not small finish work. We do have all the tools and knowledge to do it, just not the experience, hope we are fast learners. Once the case is done, hopefully in a months time tops, I fully take over and start building. I am hoping that once we build the first case it will be easy to reproduce. I am planing on building up a few of the raw wood frames for other projects. I think I may use this same style case for a 26 or VT-25 line stage as well. For that I can spin down some aluminum volume and selector knobs...or maybe some copper ones. Anyways if all goes as planed they will be done by July, the only problems I foresee are financial ones involving the iron. This is my target though because I want July and August to listen to them before school starts again. I would also like to fire them up on the 4th of July for friends and family along side my JLH and soon-to-be Zen amps; I can have myself a small July 4th amplifier shoot out, the battle of the 8-10watt amps.
Thanks for all the input and keep coming with any feedback of opinions. I think a lot of it now is up to me deciding which path to take and ultimately what my overall budget is, both time wise and money wise. The 26 line stage may come first to the test bench so that I can play a little with it and the hum. Hopefully in the next few weeks I can switch this from a discussion to pictures and questions. No guarantees though as far as the time frame, this project is a long time coming but it still will take a little to get off the ground. A lot of love goes out to this community for all the time and help. I know this thread has only been here for a few days but I have had question on other ones as well. Everyone is so helpful and friendly, more than likely because we are all united by a love for audio. I started this hobby on a whim and out of boredom, stumbling across a schematic of the JLH Class-A I said "I can build that". I have meet some amazing people and artists along the way even though my journey is just beginning. I think I have found my new passion and my new home, thanks to all.
Cheers
James
BTW1: Has anyone custom ordered caps through ASC?
BTW2: Sorry to take my own thread off topic but how does a C3g -> 300B -> GM70 sound? More than likely the 300B would go through a interstage transformer. The other option I have considered is replacing the 300B with a KT88 or EL34...this project is a ways away though, just thinking.
Dear James,
Hereby I send you two schemes of 300B ampifiers. One with 76, 46 and 300B I built for myself. A foto of this amp can you find in this forum. And one with 6SN7, 6C45 and 300B. This amp is my next project. When you built a SE 300B amp the most important parts are the transformers and the tubes. The other parts comes later. Use a Interstage between the driver tube and the output tube. The Tango NC20 is a very good IT. Use no condensator between the input tube and the driver. Use for the input and the driver tubes tubes with high mu, low ra and high Ia, such as 6C45, WE 317 etc.
best regards
Jos
Hereby I send you two schemes of 300B ampifiers. One with 76, 46 and 300B I built for myself. A foto of this amp can you find in this forum. And one with 6SN7, 6C45 and 300B. This amp is my next project. When you built a SE 300B amp the most important parts are the transformers and the tubes. The other parts comes later. Use a Interstage between the driver tube and the output tube. The Tango NC20 is a very good IT. Use no condensator between the input tube and the driver. Use for the input and the driver tubes tubes with high mu, low ra and high Ia, such as 6C45, WE 317 etc.
best regards
Jos
Not a problem, thank you very much JosM! I always appreciate input and schematics, especially of amps that people have actually built. I have always been a little worried about using interstage iron, but I suppose if you use quality iron it wouldn't be any different than RC or LC coupling. If I did a design like this I would more than likely use custom iron from Electra-Print. These and Hammonds seem to be the easiest for me to get and I feel for the money that the Electra-Prints are high quality units.
andyjevans - I am surprised you haven't mentioned the 71A, I thought you liked this tube, end up liking the 10Y better. How do you think the 71A would sound in a choke loaded line amp compared to the 26 or 10Y? You really have me reconsidering DHT's now, I have been reading a lot about them. Do you think though that between the driver and the 300B a interstage transformers is the best or would DRD or choke-loading work?
Cheers
James
andyjevans - I am surprised you haven't mentioned the 71A, I thought you liked this tube, end up liking the 10Y better. How do you think the 71A would sound in a choke loaded line amp compared to the 26 or 10Y? You really have me reconsidering DHT's now, I have been reading a lot about them. Do you think though that between the driver and the 300B a interstage transformers is the best or would DRD or choke-loading work?
Cheers
James
JPeitzman said:
Use the Electra-Print iron, in this end of the market it is generally considerably better than the Hammond particularly where SE applications are involved, and is still sanely priced.. Hammond 300 series power transformers, filament transformers, and psu chokes are fine.
Other players for opts at least would be James, and MQ.
Any of the topologies and tube choices you mention if properly executed are going to perform very well. After many years of eschewing transformers in the audio path I have headed enthusiastically down that path, both my all SS dac, and my line stage are transformer coupled and overall are a huge improvement over what they replaced. (Dac is recent, line stage is not.) Think about your budget and choose the topology that you can build using very high quality parts throughout with your budget, if it stretches to good interstages I would go that route, otherwise choke loaded driver stages or a drd style amp would be good choices. My commercial 300B SE amps incidentally all used SRPP driver stages based on 6SN7 running at 10mA, and at a time when that was not yet fashionable except in Japan. (My current one does as well, and sounds as good as about any I have heard, and better than most - so execution even more than topology might play a role here.)
Have fun!
andyjevans - I am surprised you haven't mentioned the 71A, I thought you liked this tube, end up liking the 10Y better. How do you think the 71A would sound in a choke loaded line amp compared to the 26 or 10Y? You really have me reconsidering DHT's now, I have been reading a lot about them. Do you think though that between the driver and the 300B a interstage transformers is the best or would DRD or choke-loading work?>>
Love the 71a as a driver. Just it's lower gain than the 46 or 10Y so depending on your speakers, gain gets marginal. I'm shooting for three stages total out of an average CD player. 201A>10Y>300b just about gets you there, or substitute 26.
I haven't used choke loading - I go for interstage from driver to output to keep the high voltage, then drop down the HT for the first stage. You can direct couple or cap couple the iput to the driver, choke load, as you like, or use another interstage. The topologies just posted look fine. I'd put in a 26 or something for the 6SN7 otherwise good stuff.
I never had a microphonics problem with 10Y, 201A or 26 as long as the tube is good - you do get bad ones that are microphonic like everything else but that's a malfunction.
Re hum, you do need to be careful about where you locate the transformers and chokes in the case of HT and filament supply, plus your transformers need to be PLENTY big enough - go for at least 150% and don't be stingy. Consider 15,000uF capacitance in the filamant supply then a current reg, or a voltage reg followed by a current reg. LM1084s are good and cheap. You can use bench supplies to get you started. Consider outboard filament supplies. For sockets, I'd use the bigger UX4 chinese ceramic type. If necessary these can be got in octal, but UX5 is hard to get in octal size so bigger holes are safer.
Love the 71a as a driver. Just it's lower gain than the 46 or 10Y so depending on your speakers, gain gets marginal. I'm shooting for three stages total out of an average CD player. 201A>10Y>300b just about gets you there, or substitute 26.
I haven't used choke loading - I go for interstage from driver to output to keep the high voltage, then drop down the HT for the first stage. You can direct couple or cap couple the iput to the driver, choke load, as you like, or use another interstage. The topologies just posted look fine. I'd put in a 26 or something for the 6SN7 otherwise good stuff.
I never had a microphonics problem with 10Y, 201A or 26 as long as the tube is good - you do get bad ones that are microphonic like everything else but that's a malfunction.
Re hum, you do need to be careful about where you locate the transformers and chokes in the case of HT and filament supply, plus your transformers need to be PLENTY big enough - go for at least 150% and don't be stingy. Consider 15,000uF capacitance in the filamant supply then a current reg, or a voltage reg followed by a current reg. LM1084s are good and cheap. You can use bench supplies to get you started. Consider outboard filament supplies. For sockets, I'd use the bigger UX4 chinese ceramic type. If necessary these can be got in octal, but UX5 is hard to get in octal size so bigger holes are safer.
Wanted to pop by, I have been working all day and hanging out at the Pass forums by night. I got a little bored and side tracked from tubes and built a JFET Aikido to play with.
Anyways thanks JosM for the input and schematics.
If you don't mind let me know how it sounds after you get to it. If you don't, not a bid deal, but as always I am interested. I have been basing a lot off of peoples listening impressions since I have not had the chance to listen to a 300B myself.
Any recommendations on interstage transformers if I go this route? Like I said Hammond is easy for me to get, as is Electra-Print. Electra-Pint I think is what I would shoot for in a interstage, though I can also get James, MagneQuest, One Electron; with a little or a lot of work/money I may be able to get Sowter, Plitron, or Lundahl.
BTW how do the James' compare to the Electra-Prints or Hammonds? If they are better than Hammond for the outputs I may get them and move up to Electra-Prints later. I am working hard to try to outline a basic budget but it is kind of looking like the way I am more heavily leaning is all DHT. That would be 26 -> VT-25 -> 300B to begin with. This raises my cost and means that I may have to consider the James's and use Electra-Prints for the interstage between the driver and 300B. Of course this changes more than just that, such as can I fit such a beast in the case I have laid out!
kevinkr - You make some good points, especially with using high quality parts. I have more than enough for quality parts for a project like the JE 300B SE Deluxe, I am just afraid that I have been talked out of it due to drive problems. Since like I said I have never heard a 300B design of any sort I have to put my faith in the DIY community and in people that I feel know more on the subject than I. I must admit, selecting a design for a 300B is much more challenging that actually executing it! I may have to throw SRPP back on the table though. BTW I like your site, I have been reading over it with interest.
Maybe I should build up that DHT pre though and see just how I like the sound of DHT's. It will also give me a chance to play with them and see the best ways of reducing hum. I have thought many a time of just scraping it for later, but there is this deep urge in me to build these amps. It sucks being a college student on a tight budget! I don't know why I am so split on this amp, the money, the time, I don't know. For some reason one half of my head is going "build all DHT and don't look back!" and one half is going "save a few hundred and build a JE 300B DX to start". I don't know why I am so drawn to that design. I think it is because I don't know anything about 300B's or how to drive them well. Oh well, personal demons I guess.
Off to bed for me, 3:00am here and I am very tired. Big week a head too, hopefully I can get a couple parts lists and budgets laid out and pick the one that makes the most sense for this point in time. Mostly big though because I want to pick out wood for the amp and line stage cases and try to find a nice thick sheet of copper locally. I am also rebuilding my JFET Aikido and JFET Bride of Zen this week and I think I may start a F5 build. Can you tell I like to burn the candle at both ends!
Cheers
James
Anyways thanks JosM for the input and schematics.
If you don't mind let me know how it sounds after you get to it. If you don't, not a bid deal, but as always I am interested. I have been basing a lot off of peoples listening impressions since I have not had the chance to listen to a 300B myself.
Any recommendations on interstage transformers if I go this route? Like I said Hammond is easy for me to get, as is Electra-Print. Electra-Pint I think is what I would shoot for in a interstage, though I can also get James, MagneQuest, One Electron; with a little or a lot of work/money I may be able to get Sowter, Plitron, or Lundahl.
BTW how do the James' compare to the Electra-Prints or Hammonds? If they are better than Hammond for the outputs I may get them and move up to Electra-Prints later. I am working hard to try to outline a basic budget but it is kind of looking like the way I am more heavily leaning is all DHT. That would be 26 -> VT-25 -> 300B to begin with. This raises my cost and means that I may have to consider the James's and use Electra-Prints for the interstage between the driver and 300B. Of course this changes more than just that, such as can I fit such a beast in the case I have laid out!
kevinkr - You make some good points, especially with using high quality parts. I have more than enough for quality parts for a project like the JE 300B SE Deluxe, I am just afraid that I have been talked out of it due to drive problems. Since like I said I have never heard a 300B design of any sort I have to put my faith in the DIY community and in people that I feel know more on the subject than I. I must admit, selecting a design for a 300B is much more challenging that actually executing it! I may have to throw SRPP back on the table though. BTW I like your site, I have been reading over it with interest.
Maybe I should build up that DHT pre though and see just how I like the sound of DHT's. It will also give me a chance to play with them and see the best ways of reducing hum. I have thought many a time of just scraping it for later, but there is this deep urge in me to build these amps. It sucks being a college student on a tight budget! I don't know why I am so split on this amp, the money, the time, I don't know. For some reason one half of my head is going "build all DHT and don't look back!" and one half is going "save a few hundred and build a JE 300B DX to start". I don't know why I am so drawn to that design. I think it is because I don't know anything about 300B's or how to drive them well. Oh well, personal demons I guess.
Off to bed for me, 3:00am here and I am very tired. Big week a head too, hopefully I can get a couple parts lists and budgets laid out and pick the one that makes the most sense for this point in time. Mostly big though because I want to pick out wood for the amp and line stage cases and try to find a nice thick sheet of copper locally. I am also rebuilding my JFET Aikido and JFET Bride of Zen this week and I think I may start a F5 build. Can you tell I like to burn the candle at both ends!
Cheers
James
Couple quick questions and note.
1. First off for those who have used or have more experience than me, when using a interstage how is it better to connect it? I know on one side (primary) one wire is B+ and the other plate. On the secondary side however one wire is the grid of the 300B, is it better to ground the other or put a negative voltage on the other? Examples worth more than my poor words:
http://www.simpletube.com/databank/SingleEnded/300B_SE_417A_inter_SJS_Kit.gif
http://www.simpletube.com/databank/SingleEnded/300B_SE_437_417_A_inter_SJS_KIT_MK2.gif
2. When doing a Ultra-Path design do I need the voltages that I see in the Electra-Print schematic, or are they just higher because it's a DRD design? In other words can I get by fine with the 400 something volts I was planing on?
Just some notes on transformers if anyone is interested. I have been looking around this morning and have gathered some prices on output iron that I would consider.
1. Hammond 1627SE (2k5) or 1630 SE (3k5) are both about $140 for a pair.
2. James 6123HS are $218 from Euphoria, I have not checked THL Audio yet, I also saw someone who requested a quote from James and they where $150 a pair direct.
3. Electra-Print 3k can go from $330 to $400 or more depending on options.
4. One Electron UBT-3 (3k) are $220 a pair from AES.
You can see that the Electra's are the most expensive option on the list, though I feel they are the best. I know nothing about the One Electrons and would be willing to give them a shot if they would be as good as the Electra's or James'. I personally have decided that if I am going to cut costs at the output transformer that the James' are the lowest quality I will go. Saying that it seems that for now the Electra's are at the top of the list, James' at the bottom, and One Electron's in the middle unless I hear negatives about them; this would remove the Hammond's from the list. To me I feel that even though Hammond makes good iron, for $20 more (IF I can go through James direct) the James wins over them and it is almost not worth it NOT to go with them. The One Electron's have kind of peaked my interest though since I thought I would pay a lot more for them.
Speaking of THL, has anyone in the states ordered through them recently? I haven't dealt with them before, though I am sure they are reliable. I hear they have good prices on the James' if I don't go direct, they also have Caddock 2watt MS series resistors and a good selection of the 10watt Mills resistors.
Thanks, Cheers
James
1. First off for those who have used or have more experience than me, when using a interstage how is it better to connect it? I know on one side (primary) one wire is B+ and the other plate. On the secondary side however one wire is the grid of the 300B, is it better to ground the other or put a negative voltage on the other? Examples worth more than my poor words:
http://www.simpletube.com/databank/SingleEnded/300B_SE_417A_inter_SJS_Kit.gif
http://www.simpletube.com/databank/SingleEnded/300B_SE_437_417_A_inter_SJS_KIT_MK2.gif
2. When doing a Ultra-Path design do I need the voltages that I see in the Electra-Print schematic, or are they just higher because it's a DRD design? In other words can I get by fine with the 400 something volts I was planing on?
Just some notes on transformers if anyone is interested. I have been looking around this morning and have gathered some prices on output iron that I would consider.
1. Hammond 1627SE (2k5) or 1630 SE (3k5) are both about $140 for a pair.
2. James 6123HS are $218 from Euphoria, I have not checked THL Audio yet, I also saw someone who requested a quote from James and they where $150 a pair direct.
3. Electra-Print 3k can go from $330 to $400 or more depending on options.
4. One Electron UBT-3 (3k) are $220 a pair from AES.
You can see that the Electra's are the most expensive option on the list, though I feel they are the best. I know nothing about the One Electrons and would be willing to give them a shot if they would be as good as the Electra's or James'. I personally have decided that if I am going to cut costs at the output transformer that the James' are the lowest quality I will go. Saying that it seems that for now the Electra's are at the top of the list, James' at the bottom, and One Electron's in the middle unless I hear negatives about them; this would remove the Hammond's from the list. To me I feel that even though Hammond makes good iron, for $20 more (IF I can go through James direct) the James wins over them and it is almost not worth it NOT to go with them. The One Electron's have kind of peaked my interest though since I thought I would pay a lot more for them.
Speaking of THL, has anyone in the states ordered through them recently? I haven't dealt with them before, though I am sure they are reliable. I hear they have good prices on the James' if I don't go direct, they also have Caddock 2watt MS series resistors and a good selection of the 10watt Mills resistors.
Thanks, Cheers
James
Sorry to dig this up with just a few questions and no pictures or anything. I do have a few final design questions though:
1. In the opinions of the experts is the 91A type design, mine using C3g or 12HG7, a better overall choice than the JE Labs Deluxe? I assume yes since when triode connected the 12HG7 outputs more voltage at a lower distortion than the 6SN7.
2. Any info on One Electron transformers? I have searched a little and found just that, a little. They seem quite reasonably priced compared to some of the others out there, yet still seem to be good quality.
3. I was looking at some of the One Electron iron and came across their PRC-2 Choke. I am wondering now, since it can be wired in parallel or series if I can wire it for 12H + 12H and make a CLCLC or LCLC PSU filter with it? This would really help to save me some space, two chokes for the price of one. The only disadvantage is that the PRC-1 is about the cost of two chokes.
4. I was looking at James chokes and was quite impressed with their specs. 10H at 200mA or 250mA, I am wondering though if it would be better to go with something like the 20H @ 150mA if I got chokes from them instead?
5. Sorry to keep dragging the subject of the JE Labs design up over and over again but I have a couple questions on it. I think I have ruled the design out after seeing Mr. Millett's driver shoot out and after hearing from some of the experts here. I am interested though, why is this such a popular design especially in commercial equipment when give such poor drive to the 300B? Is it because the 6SN7 is an iconic tube that the non DIYer's and other people that can afford this equipment like the snob appeal of having a 300B AND a 6SN7 under the same hood? Is it along the same lines but because companies are afraid that people won't shell out the big money for some thing with an "obscure tube" like the 12HG7 or the D3a? Or is it because the 6SN7 is so popular and there are so many out there it is easier for the non in the know (or the in the knows for that matter) people to tube roll? Or is it just because it is stupidly simple for the designers to design and implement? I am sure it is a OK design, after all there are a lot of them out there. I am glad I started this thread though, it has shed some light on the short comings of this design.
So I think that these are the designs I am considering in order.
1. 300B driven by a 12HG7 (or D3a or C3g....)
2. Something, 417A maybe, transformer coupled to a 300B
3. The beast, 26 to a 10Y to the 300B
4. The Electra-Print DRD
I do not have SRPP on the list but that doesn't mean I won't consider it. I just wish I could audition each of the designs before committing to parts and build time. #1 I feel is so because it seems like a very versatile design. The cost of the tubes and circuit means also that I can spend more on higher quality parts and iron. #2 because it would give me a taste of transformer coupling. This design is VERY easy to implement but costs are higher because of the interstage iron. I have however read good reviews about this design. #3 would make a lovely, lust inspiring amplifier, the down side is that it might break the bank. If I don't do it now though you can be assured that one day this amp will grace my house! #4 can be done with a quick re-wire and couple more parts added to #1 so that is why it is at the bottom.
Thanks again to all that have helped out this tube newbie, well kind of. I am new to building from the ground up, not new to tubes or fix old tube equipment. I at least have a small idea of what I am doing, just indecisive
Cheers
James
BTW, I recently went to my local, well out of town but not to far, surplus shop where I sometimes pop in and buy tubes when they have them. I dug through the dusty boxes and pulled out the usual 5U4G's, 6SN7's, 12AX/AU/AT, 6SL7, a whole box of NOS 6V6's, etc... As I was digging though one box I came to an industrial tube I didn't recognize right away, it was a brand new CBS tube, a 7729. Not knowing what it was of course I bought it, I paid $0.50 for it. Got it home and found out I may have bought, well "stolen" at that price, quite a little gem here. My question is has anyone heard a 7729, I can find very little on what they sound like. I am thinking of building a Dynaco Low Power 6V6 amp to use some of my 15 or 20 6V6's. (I don't know much about this design, a good one or betters out there?) I will build it with 12AX7 more than likely but would like to roll the 7729 in one of them to see how it sounds. Can anyone who knows this tube suggest if there is a better project for it, like a phono or something. I only have one but I called the guy and said if I pop in every once in a while I may be able to get more. I guess they come in and out of stock from colleges, test equipment? Thanks!
1. In the opinions of the experts is the 91A type design, mine using C3g or 12HG7, a better overall choice than the JE Labs Deluxe? I assume yes since when triode connected the 12HG7 outputs more voltage at a lower distortion than the 6SN7.
2. Any info on One Electron transformers? I have searched a little and found just that, a little. They seem quite reasonably priced compared to some of the others out there, yet still seem to be good quality.
3. I was looking at some of the One Electron iron and came across their PRC-2 Choke. I am wondering now, since it can be wired in parallel or series if I can wire it for 12H + 12H and make a CLCLC or LCLC PSU filter with it? This would really help to save me some space, two chokes for the price of one. The only disadvantage is that the PRC-1 is about the cost of two chokes.
4. I was looking at James chokes and was quite impressed with their specs. 10H at 200mA or 250mA, I am wondering though if it would be better to go with something like the 20H @ 150mA if I got chokes from them instead?
5. Sorry to keep dragging the subject of the JE Labs design up over and over again but I have a couple questions on it. I think I have ruled the design out after seeing Mr. Millett's driver shoot out and after hearing from some of the experts here. I am interested though, why is this such a popular design especially in commercial equipment when give such poor drive to the 300B? Is it because the 6SN7 is an iconic tube that the non DIYer's and other people that can afford this equipment like the snob appeal of having a 300B AND a 6SN7 under the same hood? Is it along the same lines but because companies are afraid that people won't shell out the big money for some thing with an "obscure tube" like the 12HG7 or the D3a? Or is it because the 6SN7 is so popular and there are so many out there it is easier for the non in the know (or the in the knows for that matter) people to tube roll? Or is it just because it is stupidly simple for the designers to design and implement? I am sure it is a OK design, after all there are a lot of them out there. I am glad I started this thread though, it has shed some light on the short comings of this design.
So I think that these are the designs I am considering in order.
1. 300B driven by a 12HG7 (or D3a or C3g....)
2. Something, 417A maybe, transformer coupled to a 300B
3. The beast, 26 to a 10Y to the 300B
4. The Electra-Print DRD
I do not have SRPP on the list but that doesn't mean I won't consider it. I just wish I could audition each of the designs before committing to parts and build time. #1 I feel is so because it seems like a very versatile design. The cost of the tubes and circuit means also that I can spend more on higher quality parts and iron. #2 because it would give me a taste of transformer coupling. This design is VERY easy to implement but costs are higher because of the interstage iron. I have however read good reviews about this design. #3 would make a lovely, lust inspiring amplifier, the down side is that it might break the bank. If I don't do it now though you can be assured that one day this amp will grace my house! #4 can be done with a quick re-wire and couple more parts added to #1 so that is why it is at the bottom.
Thanks again to all that have helped out this tube newbie, well kind of. I am new to building from the ground up, not new to tubes or fix old tube equipment. I at least have a small idea of what I am doing, just indecisive
Cheers
James
BTW, I recently went to my local, well out of town but not to far, surplus shop where I sometimes pop in and buy tubes when they have them. I dug through the dusty boxes and pulled out the usual 5U4G's, 6SN7's, 12AX/AU/AT, 6SL7, a whole box of NOS 6V6's, etc... As I was digging though one box I came to an industrial tube I didn't recognize right away, it was a brand new CBS tube, a 7729. Not knowing what it was of course I bought it, I paid $0.50 for it. Got it home and found out I may have bought, well "stolen" at that price, quite a little gem here. My question is has anyone heard a 7729, I can find very little on what they sound like. I am thinking of building a Dynaco Low Power 6V6 amp to use some of my 15 or 20 6V6's. (I don't know much about this design, a good one or betters out there?) I will build it with 12AX7 more than likely but would like to roll the 7729 in one of them to see how it sounds. Can anyone who knows this tube suggest if there is a better project for it, like a phono or something. I only have one but I called the guy and said if I pop in every once in a while I may be able to get more. I guess they come in and out of stock from colleges, test equipment? Thanks!
just a quick note on the One Electron output transformers - I used them in my 300B project and was quite happy with the results. Certainly bested the budget AN (experimenter series) and Hammond iron I used in the past. How does it compare to the more expensive stuff? I can't say! If I remember correctly, tubelab gave them the thumbs up for his SE experiments (do a search to confirm).
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