Hello,
I am in the process of sourcing parts for this build and noticed a descrepency between the parts list at the end of the article (here: http://www.hagtech.com/pdf/clarionarticle.pdf ) and the schematic.
The schematic shows a 10K 10 watt resistor at R7 where as the parts list shows 6.8K 10 watt.
I actually asked Jim Hagerman himself via email and his response.....well, it didn't help much. He basically said it was a good question and he had no idea....probably the 10K.
I was wondering if any out there have built this amp and what they used in the position at R7 or, if possible, might be able to deduce which one it should be. I imagine either one will work but I bet one will work better
Also, if there are any out there who have built this design, any tips, advice, or experience is always helpful.
For those unfamiliar with this amp it was an attempt to create a well designed DHT SET where all of the parts could be sourced from one supplier, namely AES (Antique Electronic Supply).
Personally, I have digressed quite a bit from the original intent as I have sourced higher end parts from many different vendors to include Sonic Craft High-End DIY Audio Parts (very good variety with excellent service, even a very knowledgeable tech who is easily available to talk with!)
Antique Electronic Supply (great source for basic stuff)
HiFi DIY Site - VT4C/211 Power Triode (great prices on great stuff but shipping is a bit high)
Parts ConneXion - The authority on hi-fi DIY parts and components (excellent source but slow service, esp with paypal)
I plan to post some pics and stuff here as this build progresses for those interested as I have not yet seen a builder's thread for this amp.
Thanks for everyones help in advance!
Jeff
I am in the process of sourcing parts for this build and noticed a descrepency between the parts list at the end of the article (here: http://www.hagtech.com/pdf/clarionarticle.pdf ) and the schematic.
The schematic shows a 10K 10 watt resistor at R7 where as the parts list shows 6.8K 10 watt.
I actually asked Jim Hagerman himself via email and his response.....well, it didn't help much. He basically said it was a good question and he had no idea....probably the 10K.
I was wondering if any out there have built this amp and what they used in the position at R7 or, if possible, might be able to deduce which one it should be. I imagine either one will work but I bet one will work better
Also, if there are any out there who have built this design, any tips, advice, or experience is always helpful.
For those unfamiliar with this amp it was an attempt to create a well designed DHT SET where all of the parts could be sourced from one supplier, namely AES (Antique Electronic Supply).
Personally, I have digressed quite a bit from the original intent as I have sourced higher end parts from many different vendors to include Sonic Craft High-End DIY Audio Parts (very good variety with excellent service, even a very knowledgeable tech who is easily available to talk with!)
Antique Electronic Supply (great source for basic stuff)
HiFi DIY Site - VT4C/211 Power Triode (great prices on great stuff but shipping is a bit high)
Parts ConneXion - The authority on hi-fi DIY parts and components (excellent source but slow service, esp with paypal)
I plan to post some pics and stuff here as this build progresses for those interested as I have not yet seen a builder's thread for this amp.
Thanks for everyones help in advance!
Jeff
OK then, it is done.
What do you think of this: K & K Audio - Lundahl Transformers, audio DIY kits and more ? I went ahead and bought 4 of these and received them in the mail today. I thought the price was a steal, I have not seen anything similar to this at this pricepoint.
So then 12mA is the sweet spot?
Any other recommendations?
Jeff
Progress
Just completed the chassis. It is all hand built from scratch. The sides are Spanish Modens and the top is laminated White Tiger Maple. I cut 1" x 1/2" slats about 20" long and laminated them together. On the bottom I used some Cherry veneer ply (3 layer) and glued it down to give it more strength across the laminations.
Seen here is all the connectors (Vampire and Connex) and x2 chokes and x2 2.5vct filament transformers. The vent plates for the tube sockets were purchased from VT4C.com. The James 6112HS output transformers are from TCTubes.com (best deal I have found with s/h included). The power transformer is Hammond as well, disassembled ans mounted sideways with a hand built cap out of the same wood as sides and top. Caps are ASC 45uF 370vac. I will parallel these with a 10uF Solen on each side for a total of 100uF as the last caps before the output stage. The 200uF between the 2 chokes will be a combination of Nichicon and Solen as well. I haven't decided on the 100uF called for at the driver stage, depends on how much real estate I have under the chassis as I get going. Either Elna Cerafine or a combination of Solen and ASC.
Hard part is done, the rest is a piece of cake. Should have it done by tomorrow afternoon if all goes well.
Remainder of parts are PRP resistors, Silver wire, Black Gate bypass, and Copper foil in oil coupling caps. I also will be using the K&K audio CCS on the drivers for plate load.
Jeff
Just completed the chassis. It is all hand built from scratch. The sides are Spanish Modens and the top is laminated White Tiger Maple. I cut 1" x 1/2" slats about 20" long and laminated them together. On the bottom I used some Cherry veneer ply (3 layer) and glued it down to give it more strength across the laminations.
Seen here is all the connectors (Vampire and Connex) and x2 chokes and x2 2.5vct filament transformers. The vent plates for the tube sockets were purchased from VT4C.com. The James 6112HS output transformers are from TCTubes.com (best deal I have found with s/h included). The power transformer is Hammond as well, disassembled ans mounted sideways with a hand built cap out of the same wood as sides and top. Caps are ASC 45uF 370vac. I will parallel these with a 10uF Solen on each side for a total of 100uF as the last caps before the output stage. The 200uF between the 2 chokes will be a combination of Nichicon and Solen as well. I haven't decided on the 100uF called for at the driver stage, depends on how much real estate I have under the chassis as I get going. Either Elna Cerafine or a combination of Solen and ASC.
Hard part is done, the rest is a piece of cake. Should have it done by tomorrow afternoon if all goes well.
Remainder of parts are PRP resistors, Silver wire, Black Gate bypass, and Copper foil in oil coupling caps. I also will be using the K&K audio CCS on the drivers for plate load.
Jeff
Attachments
In it's original form, you are correct. With a plate load CCS and a bypass cap it is estimated it will run at 2.5vrms which should be adaquate. If it is not I will add a gain stage with another 5687 or even possibly a 26 or 76 globe. I have left enough room on the top to add 2 more tubes, even the vintage globes if I decide to go that route.
Is this the same Alex who has the article on diyaudioprojects.com? I just finished that amp, albeit a bit changed from that circuit, basically the same amp. Wonderful performer!
Jeff
Actually, it is 4vrms according to Hagerman. Yes a cap will help but probably not enough in of itself. This is why I chose to go with a CCS. K&K Audio has an incredible little budget CCS that performs very well. I have tried the cascoded and the single and connot tell the difference with my ears (41 yrs old ears that can only hear to about 17khz!) but that might not say too much.
Nice thing about loosing my hearing is I can just snicker at what many people argue over.
Jeff
Am the same person.
Good job on that SE KT88, I have been reading your posts and I love what you did with the chassis.
Both the ECC99 and the 2a3 are wonderful tubes. I have done a similar amp, an EL84 driven 2a3 and it rocks! I will try the ECC99-2a3 amp.
Jeff, you have been a busy man, lots of wonderful project and excellent workmanship on those chassis! I wish I have enough free time to work on as much projects.
I am not sure what you are referring to @1.5V. Hagerman in his article reports a requirement of 4vrms input to drive the output to clip at 3 watts, 1.2% THD (mostly 2nd).
With the CCS and bypass cap (I will be using a 220uF) this should bring the sensitivity up to about 2 to 2.5vrms.
I am referring to the Clarion 2A3 project designed by Jim Hagerman. I quote him here via cut and paste from his article:
"The amplifier section is very straightforward with a single stage input/driver. This results in a relatively low sensitivity amplifier, requiring about 4Vrms input driving the output to clipping. Normally, designers add an extra gain stage, but I felt this was a reasonable compromise for the sake of simplicity. Most active linestages will be able to drive this without issue. You could also add a large capacitor to bypass R13, thereby increasing gain."
I had some help determining the sensitivity I quoted above. It is theoretical at this point, soon I will test it and see.
Thanks,
Jeff
I have a Simple SE with an ecc99 driver, 10M45 CCS loaded, with bypass cap. I also use 12BH7, which I prefer. I run them at 20 mA plate current. Power tubes are el34 or kt88 run in triode mode with no feedback, and there is not enough gain for some sources. I think you will need a preamp. I have a tube preamp with 28 or 12 dB gain, and use the 28 dB setting. On some of my 24/96 Vinyl rips played on foobar, you can still turn the volume up to 12 o'clock, but most listening is around 9. 12 dB would be enough gain but my preamp sounds better in the 28 dB setting...
Finished.....sorta
Here is a couple of pics of the underside all wired up. Delays due to the recent ice storm set this project back about 10 days. I still need to do a couple of things. The CCS from K&K Audio were defective so until I get the new ones in I wired it with the 10K plate load resistor and bypassed the cathode of the 5687 with a combination of 39uF film caps (yellow caps side by side in front on either side) and a Cerafine 470uF electrolytic. There are some electrolytics in the power supply mostly b/c this design calls for a ton of uF's in the PSU. The critical 100uF just before the power stage take off is ASC oil caps, the rest are high quality Nichicon coupled with Solen 10uF films. I haven't fired it up yet, just literally finish soldering the last few pieces together. I am about to check all the voltages and then will connect it to a pair of cheapo speakers. Next will be the scope.....soon will have some tracings if all goes well. I have decided to build another separate preamp using the 5687 tube, basically the modified clone of the Audionote M7 seen at DIYparadise.com, I hear it has superb sonics.
One last thing, I didn't realize the coupling cap was a 0.47uF, for some reason when I was buying the parts I thought I saw it was 0.22uF so I bought some Angela 0.22uF Copper films. I went ahead and installed these and coupled them with a pair of Mundorf 0.33uF films (black boxes above the Angela caps). This is a temporary fix until the new caps arrive, maybe....we'll just see how it sounds.
Jeff
Here is a couple of pics of the underside all wired up. Delays due to the recent ice storm set this project back about 10 days. I still need to do a couple of things. The CCS from K&K Audio were defective so until I get the new ones in I wired it with the 10K plate load resistor and bypassed the cathode of the 5687 with a combination of 39uF film caps (yellow caps side by side in front on either side) and a Cerafine 470uF electrolytic. There are some electrolytics in the power supply mostly b/c this design calls for a ton of uF's in the PSU. The critical 100uF just before the power stage take off is ASC oil caps, the rest are high quality Nichicon coupled with Solen 10uF films. I haven't fired it up yet, just literally finish soldering the last few pieces together. I am about to check all the voltages and then will connect it to a pair of cheapo speakers. Next will be the scope.....soon will have some tracings if all goes well. I have decided to build another separate preamp using the 5687 tube, basically the modified clone of the Audionote M7 seen at DIYparadise.com, I hear it has superb sonics.
One last thing, I didn't realize the coupling cap was a 0.47uF, for some reason when I was buying the parts I thought I saw it was 0.22uF so I bought some Angela 0.22uF Copper films. I went ahead and installed these and coupled them with a pair of Mundorf 0.33uF films (black boxes above the Angela caps). This is a temporary fix until the new caps arrive, maybe....we'll just see how it sounds.
Jeff
Attachments
Hi Jeff
Very nice work.
Also building this project at the moment. Was it finished and if so anything to watch out for and of course how does it sound? As you say any impressions really help others. This thread sorta died when it was sorta finished. Now a bit long in the tooth I know but would appreciate your advice.
tks Dave.
Well it’s been nearly a month and no replies. Now back on the Clarion Project and think understand maybe why the thread died at the ‘sorta finished’ stage. And it’s simple. Based on the pics posted the wiring error is confirmed. Connecting the driver filament as per schematic will result in very low cathode emission and a terrible sounding result.
The driver filament wiring schematic as published is wrong. At 6.3 volts the ECC99 needs pins 4 and 5 connected for one AC side and pin 9 CT for the other. Also be aware of the following.
1. Pin out for the alternative 5687 driver is different. Not mentioned in the article referenced. Connect pins 4/5 together and pin 8 for the other side. Pin 9 is a plate connection.
2. If you are building this in a country with more than the US 120 volts wall power supply BE VERY CAREFUL. Two of the 4 bulb holders are on the primary side of the main transformer. The bulb holder specified has exterior metal and is rated at 120 volts. Here in Australia. (240 volts). I took these 2 out and replaced them with more than needed 15W panel mount resistors RS part No. 159742. 2A3 filament voltage comes in at 2.55 volts.
And the result from this innovative design is I have to say superb. With a tube pre and FR AN5.6’s or Vulcan Horns. And that is before adding the K&K Audio CCS Plate loads scheduled for next week. Pic of the finished amp attached. Hope this helps.
Dave.
The driver filament wiring schematic as published is wrong. At 6.3 volts the ECC99 needs pins 4 and 5 connected for one AC side and pin 9 CT for the other. Also be aware of the following.
1. Pin out for the alternative 5687 driver is different. Not mentioned in the article referenced. Connect pins 4/5 together and pin 8 for the other side. Pin 9 is a plate connection.
2. If you are building this in a country with more than the US 120 volts wall power supply BE VERY CAREFUL. Two of the 4 bulb holders are on the primary side of the main transformer. The bulb holder specified has exterior metal and is rated at 120 volts. Here in Australia. (240 volts). I took these 2 out and replaced them with more than needed 15W panel mount resistors RS part No. 159742. 2A3 filament voltage comes in at 2.55 volts.
And the result from this innovative design is I have to say superb. With a tube pre and FR AN5.6’s or Vulcan Horns. And that is before adding the K&K Audio CCS Plate loads scheduled for next week. Pic of the finished amp attached. Hope this helps.
Dave.
Attachments
Tks. Will let you know the CCS result. Although it may take a while longer as I have decided to design a small PCB to allow use of either an ECC99 or 5687 by moving a jumper. This should also clean up some glitches on the scope due PtP wiring conflicts in this area.
Should have mentioned I only raised the beware bit as the project was said to be simple. Not so for a newbie if you don’t add the extra text.
Currently listening to the Clarion through a pair of open baffles. Not bad at all. In fact audio is such a subjective thing it now seems the best.
Sound familiar?
Dave
Should have mentioned I only raised the beware bit as the project was said to be simple. Not so for a newbie if you don’t add the extra text.
Currently listening to the Clarion through a pair of open baffles. Not bad at all. In fact audio is such a subjective thing it now seems the best.
Sound familiar?
Dave
Attachments
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