Tom,
Which chassis are you considering?
I prefer a chassis with ~400 mm depth as it makes it easier to place the components inside. However the 4U, 400mm chassis available from the diyAudio store does not have the holes drilled in the heatsinks as per UMS standard. For that you will need to get the 5U 400mm chassis.
The drilled and tapped holes make life easier during the build.
Which chassis are you considering?
I prefer a chassis with ~400 mm depth as it makes it easier to place the components inside. However the 4U, 400mm chassis available from the diyAudio store does not have the holes drilled in the heatsinks as per UMS standard. For that you will need to get the 5U 400mm chassis.
The drilled and tapped holes make life easier during the build.
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I'm considering one channel per chassis in a 3U form factor (1 device on 1/2 a board per heatsink). I have concerns in making unintended antennas, ground loops or voltage drops but my dad, who got me started in electronics, swears I should be fine as long as I observe good wiring/grounding practices. Otherwise, was looking at a Deluxe 4U which only comes in a 300mm deep chassis. More research/reading to do.
After hearing the spookiness of the ACAs as balanced monoblocks, I was considering 2 full versions running as balanced monoblocks but I keep thinking about 2 of these F6 beasts idling in Class A...
Tom,
The power draw of the F6 will depend on the voltage rails and bias that you finally settle on. Having mono-blocks or dual-mono in the same chassis will not necessarily result in higher power draw.
3U 400 mm might be just enough, but 4U 400 mm will be better. And again, if you planning a single chassis solution, 400 mm depth is highly recommended.
By "Dual-mono" I a mean having each channel powered by it's own independent power supply; each channel will have it's own PSU board and toroidal transformer. That means you will have 2 power supply PCBs and 2 toroidal transformers in your chassis. For dual-mono config you can go with two units of 200VA transformers instead of a single 300VA or 400VA that is required with one PSU powering both the channels.
Have you drilled and tapped heat-sinks for any project yet?
The power draw of the F6 will depend on the voltage rails and bias that you finally settle on. Having mono-blocks or dual-mono in the same chassis will not necessarily result in higher power draw.
3U 400 mm might be just enough, but 4U 400 mm will be better. And again, if you planning a single chassis solution, 400 mm depth is highly recommended.
By "Dual-mono" I a mean having each channel powered by it's own independent power supply; each channel will have it's own PSU board and toroidal transformer. That means you will have 2 power supply PCBs and 2 toroidal transformers in your chassis. For dual-mono config you can go with two units of 200VA transformers instead of a single 300VA or 400VA that is required with one PSU powering both the channels.
Have you drilled and tapped heat-sinks for any project yet?
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Planning on 2 separate chassis. True monoblock. Already have 2 PSU boards and eyeing two of the 3U mini-Dissipantes.
I'm still looking for information on having two separate boards half stuffed for each channel. I don't know if I'll be creating any antennas or causing voltage differences with the circuit not sharing the same physical board ground. I do like to make things difficult but I learn more in the process.
I'm still looking for information on having two separate boards half stuffed for each channel. I don't know if I'll be creating any antennas or causing voltage differences with the circuit not sharing the same physical board ground. I do like to make things difficult but I learn more in the process.
Finally got a chance to run the Halcyons with the Aleph J. Plenty of power. I believe the Aleph has around 25 watts per side. The amp was loafing while the Halcyons were playing louder than I wanted to listen. You can see the ACAs sitting on top of the right speaker. They weren’t quite powerful enough, while the Aleph J was more than adequate.
I’m not sure why, but it didn’t seem to be a very good match. The highs seemed a little harsher than with the ACA or the VTA ST-120 (Dynaco clone). And the bass was a little boomy. Should I stick some more stuffing in there? The room they are in now isn’t ideal, obviously, but I just can’t swing a “listening room” and alimony.
Since we are talking about amps recently, does anybody have a recommendation for a good SET amp, preferably a kit? I was thinking of 300B only by reputation. Previously Dave steered me away from Decware as it’s good, but not a great value. Does anybody have a better idea along those lines, preferably kit? A few names I’ve run across are Elekit and Transcendent. Both of those are pushing $2k without tubes. Is there something along the same lines but perhaps less powerful and cheaper?
I’m not sure why, but it didn’t seem to be a very good match. The highs seemed a little harsher than with the ACA or the VTA ST-120 (Dynaco clone). And the bass was a little boomy. Should I stick some more stuffing in there? The room they are in now isn’t ideal, obviously, but I just can’t swing a “listening room” and alimony.
Since we are talking about amps recently, does anybody have a recommendation for a good SET amp, preferably a kit? I was thinking of 300B only by reputation. Previously Dave steered me away from Decware as it’s good, but not a great value. Does anybody have a better idea along those lines, preferably kit? A few names I’ve run across are Elekit and Transcendent. Both of those are pushing $2k without tubes. Is there something along the same lines but perhaps less powerful and cheaper?
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I'd try some more stuffing. Cheap and easy experiment. I ended up with 3.5 lb per side and that's with the 4 ohm capability of the ACAs as parallel monoblocks. The main reason I ruled out the Aleph J is the published numbers for 4 Ohm output showing a lesser capability to support such a load.
For the harshness, I don't know. Is this at any level?
For the harshness, I don't know. Is this at any level?
That hould help.
Yes. The SE EL84, when it was cheap, and avaialable as a kit, was good value and showed many th epotential of a single EL84. Then it became not a kit and tripled(?) in cost. I have a client with a couple of the larger Decwares that had to be completely rebuilt.
The SE300B kit currently at the top of my list is the Elekit from Victor. You can tart it up as much as you’d like with various upgrade kits available on order.
dave
And what do i just run across… last half od the article:
Gramophone Dreams #48: The Venus Tube, Western Electric's 300B | Stereophile.com
dave
Gramophone Dreams #48: The Venus Tube, Western Electric's 300B | Stereophile.com
dave
I miss the Audio Electronic Supply side of Cary Audio. They had a beautiful 300B kit for ~$900 (the SE-1).
Doctorjohn Cheaptubeaudio: Audio Reviews and More: AES SE-1: Schematic and Info
Doctorjohn Cheaptubeaudio: Audio Reviews and More: AES SE-1: Schematic and Info
Great! Now the Elekit is going to be even harder to get with longer wait time.
Anybody know anything about Transcendent Audio? Sounds interesting, but I haven't seen any 3rd party reviews. The guy certainly doesn't lack for self confidence.
Pinnacle 300B OTL
Anybody know anything about Transcendent Audio? Sounds interesting, but I haven't seen any 3rd party reviews. The guy certainly doesn't lack for self confidence.
Pinnacle 300B OTL
Alan,
If I understand correctly, you are finding the ACAs underpowered for driving your Halcyons? If that is the case, why look for a SET which also be in the similar ball park of watts?
Have you considered a good Class AB amp?
If I understand correctly, you are finding the ACAs underpowered for driving your Halcyons? If that is the case, why look for a SET which also be in the similar ball park of watts?
Have you considered a good Class AB amp?
I built his Grounded Grid preamp awhile back. My 20 year old recollection is it sounded fast and transparent and one that would have been worth hanging on to. I do not have any experience with any of his power amp designs except at one point his commercial offering for an OTL made Stereophile's recommended list. He's also published a couple books on the basics of vacuum tube circuit design. I still have a hardcopy of his "Tubes and Circuits".
My plan is to sit down Sunday and put together the build list. Will let ya' know when I get it done. Already thinking thru the xformer question. 200VA transformers seem easier to source so I like that idea. It also leaves options open. Then need to look at available real estate. Also, thought about playing it safe and getting a couple of the 4U chassis and if I find the single channel config noisy, finish out full builds. Lots to consider, lots o' fun to be had!
Also, sometimes a Canadian named Young Ahn (Fluxeon) makes what look like great amps. Sometimes he does kits too, but apparently he doesn't have any now. Does anybody know about his stuff?
Here is a video he did for a 300B parallel SE dual mono DIY KIT. Looks interesting, and he seems to be a genuine perfectionist audio geek, based on the videos.
tube amplifier 300B parallel SE dual mono DIY KIT #2, wiring soldering GNDing 진공관앰프만들기 - YouTube
Here is a video he did for a 300B parallel SE dual mono DIY KIT. Looks interesting, and he seems to be a genuine perfectionist audio geek, based on the videos.
tube amplifier 300B parallel SE dual mono DIY KIT #2, wiring soldering GNDing 진공관앰프만들기 - YouTube
6sX7: Have you seen the 4U chassis in person? That is what my Aleph J is in (see picture above). Notice the comparison to the two ACAs. My point is that the thing is quite large. A couple of them is a lot of floor or shelf space.
I just noticed that the Transcendent Audio 300B kit is not SET. It is OTL. I get those confused. Both low output. I don't know much about the architecture, but SET is good because it you avoid the match-up of push-pull, at the expense of power. OTL loses the possibility of goosing current with an output transformer. Both are reputed to have next-level sound. Any thoughts as to which appendage you would rather lose in search of the perfect tone?