alexberger
Responses from alexberger
| 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. | |
| 300b lovers Hi @donsachs @lynn_olson , I have 300B SET with 6f6 driver in triode mode. I did 2nd harmonic distortion calculation using 3 point method and 6f6 plate characteristic graph. So with RC coupling that I have right now I get more than 2% dist... | |
| 300b lovers I have a question to @lynn_olson I have 300B SET 6sn7 input, 6f6g in triod driver with RC coupling. One friend of mine who reads DIY forums and tries all this thing by himself, recommended me to enlarge cathode capacitors up to 100,000uF in input... | |
| 300b lovers Hi @charles1dad , I don't have practical experience. But theoretically 300B is winn-winn vs 845. 1. Output transformer has wider bandwidth. 2. Easy to drive. Driver tube and driver transformer. 3. Easy to build a high quality PS for 400v vs 10... |