Tube Amp Archive

I'll try both, thanks!

So it's ok to tie off the CT? I read somewhere a while back that the virtual tap can be more effective at reducing hum than a CT'd filament transformer. I've been building my amps with virtual taps and they're all quite. I didn't realize this transformer had a CT filament when I ordered it. If it's ...

I'm working on a new build and replacing the transformer in a donor chassis. The heaters are wired with a virtual tap, my new transformer has a CT 6.3v filament.

Does it make a difference if I have both? Meaning can I CT to ground and keep the virtual tap 100ohm resistors in place?

Sorry I took so long to respond. I wired LED's and typical cap/resistor on a toggle to the cathodes of the PI. I was plesantly surprised at the tonal change from the LED's. The LED's definitely added gain and some mids, maybe a slightly fuller sound. I took it a step further and and a toggle and LED...

Wow, great info! I appreciate the feedback.

I'm in the middle of another project right now, as soon as I finish I'll be giving this a try.

Will report back with my findings.

Interesting.. I've done quite a bit of research on this and like rp says it seems to be a hifi thing. It pops up a lot in the hifi forums when googling. I read somewhere that Supro used them as well; however, I was unsuccessful in finding schematics. I'm thinking I'll wire it to a switch to see if t...

After looking at the video closer the LED's seem to be connected to the cathode of the PI like Malcolm suggested. Looks like a 1.6k resistor from cathode to 2LED's in series, then to ground I would suppose. So I wonder what would the orientation of the LED's be +,-,etc? I still don't understand what...

Hello everyone, I recently finished building a Gibson BR6F circuit from an old piece of test equipment that just happened to have the same tube configuration. 6SJ7 in V1, and a 6SN7 PI going into a pair of 6k6's in PP. Just a volume pot, pretty simple and it sounds quite nice. I modified V1 by addin...

Turns out I was testing the relay poles incorrectly...

They're working as they should. Thanks again

Um, no. The relay that you linked only has a power consumption of 150 ma, on a dumble circuit you will never see anything near the switch rating of 0.5 amp. From experience, the 5 volt -H version of the same relay + LED only pulls 0.08 ma. Either, you have the flyback diode backwards, a wiring erro...

I may have solved my problem. Looks like the contact rating of this relay is .5a, somehow I missed this. My transformer doesn't have enough juice to activate these relays.


http://www.mouser.com/Search/m_ProductD ... o1Dw%3D%3D

I wonder if the relays you're using might be polarized. If that is not the case, have you checked the voltage at the output of the regulator when the relays are energized? Gil I read through as many relay threads as I could, I can't figure this out. My relays aren't completely engaging/making conta...

I read through as many relay threads as I could, I can't figure this out. My relays aren't completely engaging/making contact. I'm running radio shack transformer 273-1365A @ 12v 450ma, 7812 12v voltage regulator, G5V-2 12v relays, and a prefab relay board. I'm getting 17v dc coming out of the board...

Yup.. I killed one or both caps

I'm only getting about 130v dc on B+1, I have 450v going in.

My fluke doesn't have capacitence so I can't test them. I really need to upgrade this meter.

Thank you Fire Marshall Bob for pointing that out!

I do have the backing boards which I will be installing!