10-20-2024, 03:25 PM
Alright, now jumping back on the subject of building an amp. I am going to reorder some resistors to get something that might not smoke if I look at it wrong. I've been doing quite a bit of planning and researching on design, layouts, and common mistakes (yes, I'm guilty). One thing I have noted is that I often have hum and buzz problems, and on one of my previous posts I had someone mention ground loops. I've usually been able to get the problems resolved - for the most part. One mistake I am probably making is using the stainless chassis as my chassis ground. I am considering having my chassis float (to some degree), and use a heavy (#16) copper wire to tie my grounds directly to the B-. Then, ground the chassis through a safety cap and 100ohm resistor, tied from B- to chassis, then ground pin on the power plug. I've been reading in DIY Audio Projects.com and there's quite a few tips that I am taking notes of. So, with various grounding points on the SS chassis, that could be giving me hum problems. I also read something about bucking caps on the filaments. I'm sure I can get this together and running in a few hours, but I am spending quite a bit of time planning, drawing and researching. I'll also take notes while I am working so hopefully the 2nd and future projects will go smoother, and save some trouble shooting.
So, since this is an experiment, I will be trying some different OP trannys and tubes. I initially want to get it working then start playing. I found a set of New Sensor trannys that bolt up and match the holes already in the chassis exc. for 1. That's my 1st try. I have a new set from Musical Power Supplies, but am trying to decide if I should try or return. They don't match many holes and I originally thought they were UL (ultra linear), but they have 2 sets of primaries for different tubes. 8k and 6.6k. I saw a set of UL HiFi trannys but more money ... trying to make this budget friendly, yet still sound good. The trannys I have are "basic", not HiFi, good for up to 25w. Although I really doubt I could hear much difference.
One thing has me kinda scratching my head is the power trans. It is physically smaller than one I used previously on a PP kit. According to the label, it is .2 (200 ma?) on the 230v, same as the others, which should be adequate. The basic circuit schematic I'm following specs 160ma. It does only have 1 filament winding (3a) whereas the others had 2 or 3, so this could be part of the size difference. So I guess the current meter is the best way to know where I am.
So, since this is an experiment, I will be trying some different OP trannys and tubes. I initially want to get it working then start playing. I found a set of New Sensor trannys that bolt up and match the holes already in the chassis exc. for 1. That's my 1st try. I have a new set from Musical Power Supplies, but am trying to decide if I should try or return. They don't match many holes and I originally thought they were UL (ultra linear), but they have 2 sets of primaries for different tubes. 8k and 6.6k. I saw a set of UL HiFi trannys but more money ... trying to make this budget friendly, yet still sound good. The trannys I have are "basic", not HiFi, good for up to 25w. Although I really doubt I could hear much difference.
One thing has me kinda scratching my head is the power trans. It is physically smaller than one I used previously on a PP kit. According to the label, it is .2 (200 ma?) on the 230v, same as the others, which should be adequate. The basic circuit schematic I'm following specs 160ma. It does only have 1 filament winding (3a) whereas the others had 2 or 3, so this could be part of the size difference. So I guess the current meter is the best way to know where I am.
If I could find the place called "Somewhere", I could find "Anything"
Tim
Jesus cried out and said, "Whoever believes in me , believes not in me but in him who sent me" John 12:44