For testing, can I use a 360-0-360 (on the high voltage side, as it is rated 280 mA) to drive the 300B ?
From my experience with the KT88, with 50 ohm resistors on the secondaries, 22uF input cap, using the 5R4GB I should get around 400 V on the B+. But I am not sure of what will happen with the B-.
I can use 5000 ohm load.
Please advise,
Best Regards,
Davide
From my experience with the KT88, with 50 ohm resistors on the secondaries, 22uF input cap, using the 5R4GB I should get around 400 V on the B+. But I am not sure of what will happen with the B-.
I can use 5000 ohm load.
Please advise,
Best Regards,
Davide
Buzzing of the choke is the problem I had. I was using a very nice 10H electra_print. I am not sure what the difference is between a choke for a CLC or LC is, but there has to be some guidelines.
You could also use a couple of resistors just prior to the rectifier. If you look up your rectifier sheet it will give a list of recomended values for either CLC or LC configuration.
You could also use a couple of resistors just prior to the rectifier. If you look up your rectifier sheet it will give a list of recomended values for either CLC or LC configuration.
So, I still did not buy a power transformer for my tubelabSE. I am using the 360-0-360 with no problems now. I was ordering a 320-0-320, but I saw the specs of the 300B, and it looks like this tube likes to be driven at 400 V plate and 80 mA.
From the graph the distorsion is lower at this working point.
I understand that the power drive comes to work in the transients, but if I put a test tone, he does not add anything to the distortion of the tube.
I have the Golden Dragon 4-300BC (C stands for Carbon, I guess) and they should also have a higher voltage rate of the standard 300B.
This I cannot get with a 320-0-320.
What do you think ? Should I go for the 320 or keep it as it is ?
Please advice.
Best Regards,
Davide
From the graph the distorsion is lower at this working point.
I understand that the power drive comes to work in the transients, but if I put a test tone, he does not add anything to the distortion of the tube.
I have the Golden Dragon 4-300BC (C stands for Carbon, I guess) and they should also have a higher voltage rate of the standard 300B.
This I cannot get with a 320-0-320.
What do you think ? Should I go for the 320 or keep it as it is ?
Please advice.
Best Regards,
Davide
I am running the SimpleSE with an external psu, as I have one with very good components. If I decide to run the 300B around 400V, maybe I could just add the bias part at the PSU and use the same for both amplifiers.
I have all the parts for this.
I cannot decide, and I really would like to have a finished product, now it's Frankenstein style.
D.
I have all the parts for this.
I cannot decide, and I really would like to have a finished product, now it's Frankenstein style.
D.
Am I misunderstanding something about power supply design?
If you have a slightly over voltage transformer, couldn't you just adjust R5 and R6 to get the desired bias voltage and add an RC filter after C5 to get the desired plate voltage?
Or add resistors before the rectifier.
With simple modifications and PSD II it seems like anything in the range of 320-0-320 to 380-0-380 or even more would be manageable, although not necessary. So why not work with what you have?
If you have a slightly over voltage transformer, couldn't you just adjust R5 and R6 to get the desired bias voltage and add an RC filter after C5 to get the desired plate voltage?
Or add resistors before the rectifier.
With simple modifications and PSD II it seems like anything in the range of 320-0-320 to 380-0-380 or even more would be manageable, although not necessary. So why not work with what you have?
My limited understanding, having not yet built the amp, is that higher ( to a point) OPT impedance decreases distortion at the expense of power. The higher plate voltage and current may regain a little of that power, but not much and possibly at the expense of tube longevity.
But I agree, unless you need every decimal watt you can get, go for less distortion. If your system can play with 8 watts, it probably can with 6 or 7 too.
From reading the tubelab SE manual, it would seem the Greg prefers to run 5K OPT and 400V plates in his 300b version. But it may really end up being a matter of preferance. In which case, you won't know until you have heard both...Actually the tubelabe SE manual discusses this a little, so is worth a read.
But I agree, unless you need every decimal watt you can get, go for less distortion. If your system can play with 8 watts, it probably can with 6 or 7 too.
From reading the tubelab SE manual, it would seem the Greg prefers to run 5K OPT and 400V plates in his 300b version. But it may really end up being a matter of preferance. In which case, you won't know until you have heard both...Actually the tubelabe SE manual discusses this a little, so is worth a read.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.