Best Of
Side of the road find RT1000i
Picked up these on the side of the road. Hooked them up and figured out why. 1 amp dead and the other is buzzing. Decided to start with the buzzing one and the 4700uf filter caps seem to be bad. I don't have ESR meter yet but Fluke is not getting consistent reading on either. Measuring dc output I've got 25v on one side and 20v on the other with no loading. I've bought some cheap 35v 4700uf caps on Amazon for fast delivery and will install then report back. I'd not be surprised if this is the issue, installed ones are 25v and rail voltage is 25v so no margin. Internet searches seem to show some people had similar issue with filter caps so who knows. Not got much to lose right now, only invested $7 so far. Vinyl on face of speakers has shrunk and pulled away from wood. I'll have to source replacement for that if I successfully repair the amps. Also it looks like the RCA inputs might have fried, but possibly thats just discoloration (see pic).
Chuck_S
1 ·
Re: Building a vacuum tube tape preamp
Well, the next step is to get some new tubes. The ones I've been using are pretty sketchy, just ones lying Around from old projects. There's some noise on one channel and I'm pretty certain it's tube related. I've ordered some Mullards from Tube Depot that seemed reasonable, all things considered.
Knobs is a continuing issue. I didn't think it through when I drilled the faceplate, but any knob with a counter requires a small hole below the dial to keep the outside part of the dial from turning when the knob is turned. The second problem is that there needs to be more of the potentiometer outside of the faceplate so the dial has something to lock on. I may have to visit my machinist friend again.
The calibration process involves mostly learning how the various adjustments effect the playback response. If the playback head has a high frequency resonance then the input loading can be used. The gain adjustment can be used to carefully match the two channels, but can also lead to oscillation. The sections of the feedback that influence the bass and treble are going to be dependent on the characteristics of the transport and how a test tape looks when connected.
At this point the LED lights up and that's a beginning, right?
Knobs is a continuing issue. I didn't think it through when I drilled the faceplate, but any knob with a counter requires a small hole below the dial to keep the outside part of the dial from turning when the knob is turned. The second problem is that there needs to be more of the potentiometer outside of the faceplate so the dial has something to lock on. I may have to visit my machinist friend again.
The calibration process involves mostly learning how the various adjustments effect the playback response. If the playback head has a high frequency resonance then the input loading can be used. The gain adjustment can be used to carefully match the two channels, but can also lead to oscillation. The sections of the feedback that influence the bass and treble are going to be dependent on the characteristics of the transport and how a test tape looks when connected.
At this point the LED lights up and that's a beginning, right?
SeleniumFalcon
1 ·
Re: Vintage Monitor and SDA Speaker Deals
Thanks for the info, learned something new today.
HzTweaker
1 ·
Re: You’re doing it wrong…
I liked the first generation of the Comet. When it came back as an "upscale" Maverick, not so much.
pitdogg2
4 ·
Re: Post a picture.....any picture...part deux...
SeleniumFalcon wrote: »That would discourage me...that dog doesn't look like he has a sense of humor.
That's a Rotty, they have that menacing look!
Six thousand years ago when I was the A-hole behind the USPS counter, one of my regs came in with a Rottweiler as a blind persons seeing eye dog. But this dog was like no other, her name was Faith, you could google her exploits, very smart dog.
Anyway, I was privileged to be able to have contact with Faith, the owner gave me her dog biscuits so every time they came in, I could give her one....ohhh she loved that.
As they would move through the line, Faith would be staring at me with drool dripping from her mouth, my other regs would say, Geoff, that dog looks like she wants to eat you! I'd laugh and say wait till you see when she gets here.
As I did with my husky back then, I'd put the biscuit in my mouth and let the animal take it from me. I had a low counter next to me so I could lean over and down, it took two visits to smooth out the transition, faith gave me a smashing headbutt the first couple of times.
But that isn't the cool part. Faith was a working service animal for an epileptic blind woman, she could open closed doors, and she could call 911 (google dog calls 911, opens door for police).
This customer had become a POBox customer and came back to my counter and said, Geoff, I have something here and I don't know what it is, can you please help me? Of course I answered professionally and politely as I had a customer in front of me.
So I come out into the lobby and said, hold the letter out and I'll take it. The letter drops to the floor. I bend down to pick it up with finger and thumb on the edge, Faith also puts her paw on it and going down pick it up in her mouth and I freeze.
And there we are, face to face looking right at each other. Then she bites my head off and I die instantly, oh wait, different story
Seriously, Faith lifts her paw and licks me on the cheek, allowing me to do her job. I was in awe. I told my customer what just happened, and she said, Faith loves you Geoff, she wouldn't let anyone else do that.
I have a few special moments working with the public. That one rates high on the list.
Geoff4rfc
8 ·
Re: You’re doing it wrong…
I remember pulling into dmv years ago for a vehicle inspection on my 74 Ford Comet. I stepped on the floor dimmer switch while waiting and it went through the rusty floorboard. My instant fix was to crush an empty soda can and slip it under the dimmer. It got me though inspection. Gotta do what you gotta do sometimes to keep the wheels turning.
motorstereo
5 ·
