#61
|
|||
|
|||
Swap the reverb send and return cables and repeat the bump test to see if you get a crash. It's not unheard of for a tank to get damaged in shipping. Make sure the foam shipping blocks aren't still packed in the tank as well.
__________________
"You don't have to be great to start, but you have to start to be great." -Zig Ziglar Acoustics 2013 Guild F30 Standard 2012 Yamaha LL16 2007 Seagull S12 1991 Yairi DY 50 Electrics Epiphone Les Paul Standard Fender Am. Standard Telecaster Gibson ES-335 Gibson Firebird |
#62
|
|||
|
|||
Quote:
I guess having only one output tube was enough to get sound yesterday, but two is way better :~).
__________________
jf45ir Free DIY Acoustic Guitar IR Generator .wav file, 30 seconds, pickup left, mic right, open position strumming best...send to direct email below I'll send you 100/0, 75/25, 50/50 & 0/100 IR/Bypass IRs IR Demo, read the description too: https://youtu.be/SELEE4yugjE My duo's website and my email... [email protected] Jon Fields Last edited by jonfields45; 02-18-2024 at 08:51 AM. |
#63
|
|||
|
|||
The problem was loose RCA plugs on the reverb tank cables.
My only gripe is if I turn the reverb up beyond where I would like to use it (higher than 3) there is an increasing hum as I go further. No problem at reasonable reverb settings. Grounding the return triode's grid does not eliminate the noise (so it's not the spring picking up the noise). Grounding that triode's cathode does silence it (saturates the tube and probably zeroes the AC gain…). I'm going to think about this a while before putting the amp fully together. It would seem there is leakage from the AC filament to the cathode, but the tube tests good, and a replacement did the same thing. Checking around the cathode bias network everything looks fine with my meter (resistance to ground is correct and the ground is solid).
__________________
jf45ir Free DIY Acoustic Guitar IR Generator .wav file, 30 seconds, pickup left, mic right, open position strumming best...send to direct email below I'll send you 100/0, 75/25, 50/50 & 0/100 IR/Bypass IRs IR Demo, read the description too: https://youtu.be/SELEE4yugjE My duo's website and my email... [email protected] Jon Fields Last edited by jonfields45; 03-05-2024 at 08:49 AM. |
#64
|
|||
|
|||
Lay a cookie sheet or similar across the open chassis and see if it helps. Fender closed the shielding around the circuit with aluminum window screen type material in the top of the cabinet. With it open like that you're subject to any environmental noise.
__________________
"You don't have to be great to start, but you have to start to be great." -Zig Ziglar Acoustics 2013 Guild F30 Standard 2012 Yamaha LL16 2007 Seagull S12 1991 Yairi DY 50 Electrics Epiphone Les Paul Standard Fender Am. Standard Telecaster Gibson ES-335 Gibson Firebird |
#65
|
|||
|
|||
The cookie sheet did not help. I verified that the ground is quiet where the reverb recovery triode's cathode bias is connected (screwdriver from that eyelet to the chassis). Since the reverb is crazy over the top compared to a 65 Princeton a friend owns as I turn it up, and the tube tested as on the very edge of high in-spec gain, I might reduce the gain of that stage after verifying that the current resistors are in-spec. It could be as simple as a bad solder joint on the plate resistor (driving up the resistance and gain).
__________________
jf45ir Free DIY Acoustic Guitar IR Generator .wav file, 30 seconds, pickup left, mic right, open position strumming best...send to direct email below I'll send you 100/0, 75/25, 50/50 & 0/100 IR/Bypass IRs IR Demo, read the description too: https://youtu.be/SELEE4yugjE My duo's website and my email... [email protected] Jon Fields Last edited by jonfields45; 02-19-2024 at 07:53 AM. |
#66
|
|||
|
|||
__________________
jf45ir Free DIY Acoustic Guitar IR Generator .wav file, 30 seconds, pickup left, mic right, open position strumming best...send to direct email below I'll send you 100/0, 75/25, 50/50 & 0/100 IR/Bypass IRs IR Demo, read the description too: https://youtu.be/SELEE4yugjE My duo's website and my email... [email protected] Jon Fields |
#67
|
|||
|
|||
Well done.
|
#68
|
|||
|
|||
Congratulations. Well done!
|
#69
|
|||
|
|||
I went to Guitar Center and tried out the PCB based Princeton Reverb on the floor. Fender changed the reverb return circuit quite a bit in the PCB versions (the foot switch grounds the reverb after the triode instead of before, and the peak amount of reverb is dramatically less). It was not quite worst case Guitar Center noisy, but for similar amounts of reverb I heard similar amounts of 60 Hz hum.
Case closed.
__________________
jf45ir Free DIY Acoustic Guitar IR Generator .wav file, 30 seconds, pickup left, mic right, open position strumming best...send to direct email below I'll send you 100/0, 75/25, 50/50 & 0/100 IR/Bypass IRs IR Demo, read the description too: https://youtu.be/SELEE4yugjE My duo's website and my email... [email protected] Jon Fields |
#70
|
|||
|
|||
Quote:
|
#71
|
|||
|
|||
The hum too? Thanks!
__________________
jf45ir Free DIY Acoustic Guitar IR Generator .wav file, 30 seconds, pickup left, mic right, open position strumming best...send to direct email below I'll send you 100/0, 75/25, 50/50 & 0/100 IR/Bypass IRs IR Demo, read the description too: https://youtu.be/SELEE4yugjE My duo's website and my email... [email protected] Jon Fields |
#72
|
|||
|
|||
I'm not sure about the hum, but definitely had way more reverb than he needed past about 3 on the knob. I just talked to him on the phone and he told me that although he got a majority of the parts for his Princeton from Mojotone he wound up building his PR from the layout on Rob Robinette's page...
https://robrobinette.com/AA1164_Princeton_Reverb.htm He also said he didn't get hum as much as white noise at higher reverb levels (more of a hiss than a hum) Last edited by rockabilly69; 02-19-2024 at 02:39 PM. |
#73
|
|||
|
|||
I built the champ kit in January and it sounds great. I did have to get an amp tech to go through it for me because it was failing the first tests - even though the light came on. He found a bad solder joint. Then after I brought it home I found an issue with the 12ax7 and thought it was a bad tube socket. So I replaced that socket - and sure enough that solved my issues. The thing sounds great. I have thought about trying to one day do the Princeton kit but worry it might be too complex.
|
#74
|
|||
|
|||
Quote:
I've stumped a fellow EE with tube experience. He agrees if V3a hums, V1a should similarly and it doesn't. This is more about OCD than circuits :~). If I ever get an excuse to open it up, I'll knock down the max reverb and max hum by 6 dB. If you build another kit, I could talk you through the debug. I had a intermittent cable killing the reverb and miss wired the filament supply to the V5 6L6. This gave me a poor sounding class A amp with no reverb for a very short while.
__________________
jf45ir Free DIY Acoustic Guitar IR Generator .wav file, 30 seconds, pickup left, mic right, open position strumming best...send to direct email below I'll send you 100/0, 75/25, 50/50 & 0/100 IR/Bypass IRs IR Demo, read the description too: https://youtu.be/SELEE4yugjE My duo's website and my email... [email protected] Jon Fields Last edited by jonfields45; 03-06-2024 at 06:09 PM. |
#75
|
||||
|
||||
Congrats on your build, on completion, and on a great amp!
Bob
__________________
"It is said, 'Go not to the elves for counsel for they will say both no and yes.' " Frodo Baggins to Gildor Inglorion, The Fellowship of the Ring THE MUSICIAN'S ROOM (my website) |