alexberger
Responses from alexberger
| 300b lovers @charles1dad 45 and 6v6 tubes that Lynn and Don use to drive 300b also designed and mostly used as output tubes and also give around 2 watts output power. | |
| 300b lovers Hi @charles1dad , I am not a tube amplifier design guru like Lynn, Ralph and Don. But here is some information about your amplifier. https://www.audioasylum.com/cgi/vt.mpl?f=set&m=75278 The 6EM7 is a very strong tube for the driver wit... | |
| 300b lovers 300B - the total input capacity is 82pF, voltage swing peak to peak 150 volt. 45 - the total input capacity is 35.5pF, voltage swing peak to peak 100 volt. There is a difference in number but it is not a huge. Why is so much harder to drive 300B? | |
| Speaker that are 'KEEPERS" for the long haul!!! I have been listening my Altecs 604E since 2005. | |
| 300b lovers Hi @atmasphere , McIntosh MC30 has the similar cathode follower driver 12ax7 to drive 6L6 directly. The output tube works in fixed bias in this schematics. Isn't it? Can you explain how the output tube bias is self adjusted? | |
| 300b lovers What is the minimal inductance is acceptable for 6sn7 interstage transformer ? 80H, 70H, 60H? The problem is transformers with high inductance have narrow high frequency bandwidth. But if interstage transformer doesn't have high enough inductance... | |
| 300b lovers Hi Lynn and Don, It is very interesting to hear more details about IT versus LC coupling between 6sn7 and 6v6. What is a difference in sound? | |
| 300b lovers Hi Lynn, I found online only one filament transformer for 5V - Hammond 546-166MS. This transformer has only one 5v 3A tap. So I need 2 such transformers. I use Hammond in my DIY phono stage. But IMHO Hammond transformers are built cheap compared ... | |
| 300b lovers Hi Lynn and Don, What do you think? Is it a good idea to use driver-input power transformer taps to feed 300B filament? This power transformer should be less pushed then the 300B power transformer. I don't use only electrolytics capacitors for B+.... | |
| 300b lovers Hi Lynn, Reading your previous post encouraged me to order a power transformer and a pair of 15H chokes for input and driver tube. It will give me not just PS separation but also reduces the load current to the 5u4g rectifier that I use for all t... | |
| 300b lovers I use 1/2 of 6sn7 in the input stage. The driver stage is the 6f6 tube drives the 300b though interstage transformer. The coupling between 6sn7 and 6f6 is RC with Vcup Cutf capacitors. | |
| 300b lovers I have a question about the first 6sn7 stage in my 300B SET. What is the best way to make load and coupling? 1. The drawback of the interstage transformers is a narrow bandwidth in combination with 6sn7 that has high internal impedance. But low di... | |
| 300b lovers Dear Don, I'm also going to make an independent power supply for the driver and input stages. Now I use one 5u4g rectifier for both channel tubes 2x 300B 2x 6f6 2x 6sn7. The total current is 180mA. Is to much for one 5u4g. Now I have very big B+ ... | |
| 300b lovers Dear Lynn, Thank you for convincing me to use an interstage transformer for driving 300B in my SET. I installed Hashimoto A305 into my amp. I put 82K Ohm Kiwame load resistors.. First I measured the 6f6 driver stage with an oscilloscope. There is ... | |
| 300b lovers I upgraded my DACT VC by using constant serial resistors and "half" of DACT itself like a shunt resistor. I used Shinkoh 0.5W resistors before and now I use AN Silver 2W resistors. |