I just built the tubelab SE amp. and it runs 2A3 tubes. In the AC input I put the 3/4 A fuse. Is it suitable for the amp? The resaon I ask because I was running it for about 2 hr. and it blew fuse. I replaced another fuse and blew instantly. The power transformer hot but touchable. Please give me some advice.
Thanking you in advance!
Binh
Thanking you in advance!
Binh
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I suggest the following:
Insert a new fuse. Unplug the tubes in one channel. Insert an AC ammeter in series with the secondary and measure the current. Then calculate the power drawn by one channel as Pchannel = Isecondary*Vsecondary, where Pchannel is the power drawn by that channel, Isecondary is the current in the secondary, and Vsecondary is the voltage across the secondary. Then calculate the current drawn by the primary as Iprimary = (2*Pchannel)/Vline, where Vline is the AC line voltage (115 V in the US, Canada - 230 V most other places). I would probably go with a slow-blow fuse with a rating that's 2-3x Iprimary. Remember that the resistance of the heaters is about one tenth at cold than at hot, so the heaters draw 10x the current when you turn them on cold. See tubelab.com SimpleSE for information on how to deal with this (inrush limiters).
Whatever you do, do >>>NOT<<< insert the ammeter in place of the fuse to measure the current. If something is indeed wrong with the amp, you can cause some serious damage both to the ammeter and the amp (been there, done that!)
~Tom
Insert a new fuse. Unplug the tubes in one channel. Insert an AC ammeter in series with the secondary and measure the current. Then calculate the power drawn by one channel as Pchannel = Isecondary*Vsecondary, where Pchannel is the power drawn by that channel, Isecondary is the current in the secondary, and Vsecondary is the voltage across the secondary. Then calculate the current drawn by the primary as Iprimary = (2*Pchannel)/Vline, where Vline is the AC line voltage (115 V in the US, Canada - 230 V most other places). I would probably go with a slow-blow fuse with a rating that's 2-3x Iprimary. Remember that the resistance of the heaters is about one tenth at cold than at hot, so the heaters draw 10x the current when you turn them on cold. See tubelab.com SimpleSE for information on how to deal with this (inrush limiters).
Whatever you do, do >>>NOT<<< insert the ammeter in place of the fuse to measure the current. If something is indeed wrong with the amp, you can cause some serious damage both to the ammeter and the amp (been there, done that!)
~Tom
I can't quite read the label on your power transformer, what number is it? The Tubelab SE with 2A3's needs a 1 amp or 1.25 amp fuse depending on which power transformer is being used (on US 120 volt power). A Hammond power transformer will get pretty hot, but if you can keep your hand on it for 20 seconds or so without using bad language, it is probably OK.
I use Hammond 270HX power transformer for the amp. I will buy some new fuse tomorrow and re-check the amp. Thank you Tom and George.
Regards,
Binh
Regards,
Binh
I'd pickup some 1A and 1.5A slo-blo fuses. Start with the 1A. I suspect they will suffice if it was working for a while on a 3/4A.
At the electronic store this morning, there was no 1A fuse, I took the 1.5A slow-blow. I replace fuse and the amp. sings for almost 4 hrs until now. It sounds beautiful on Klipsch Heresy . Thank you all for your help.Best Regards,
Binh
Nice. If you don't mind, what type of 2A3s are you using? From experience, take note that you cannot run a JJ 2A3 on this amp. It will hum like crazy. I once had the same set up as yours and forced to replace my 370hx with an Angela universal power tranny and convert the amp into a 300B. Godspeed.
John Revilla
John Revilla
I am using RCA 2A3 black plate.
I just have the amp setup on board for testing even those it very quiet. I don't know about JJ 2A3 on this amp but I have read somewhere that if the amp using choke and put in wrong place it will hum a lot.
I just have the amp setup on board for testing even those it very quiet. I don't know about JJ 2A3 on this amp but I have read somewhere that if the amp using choke and put in wrong place it will hum a lot.
They are 98dB. The TSE with 45s has plenty of power for these speakers when I am sitting in front of them just listening to music. With 300Bs, they can play louder if I want but seem to lose some detail. I wish I had been able to find a set of KLF-20s or 30s because these speakers are 2-way and have a laid-back midrange. But, they are a huge step up from what I had and have the efficiency I needed to enjoy SE amps. They totally rock when hooked up to the Simple SE in my avatar.
Have you ever experience with Cornwall or La Scala? I wish to have either one to try out.The TSE with 2A3s sounds beautiful on Heresy but I also have another SE 6T9 compactron and it seem a little shy on the bass when hooked with Heresy.
Yes, in fact they guy I bought the KLFs from had both LaScala's and Cornwalls. I was a little shocked at just how huge the Cornwalls were. He was using the LaScala's as rear speakers! It was not a great example because he was just using some generic Sony receiver. You could hear the hiss from the amp with amazing clarity!
So I guess the answer is no. 🙂
As far as bass goes...power has a lot to do with it but so do the output traffos. The ones on my Simple SE are super overkill but man can they rock.
So I guess the answer is no. 🙂
As far as bass goes...power has a lot to do with it but so do the output traffos. The ones on my Simple SE are super overkill but man can they rock.
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