FU-19 (FM30, 829B) Single-Ended Tube Amp!

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nlitworld

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Re: FU-19 (FM30, 829B) Single-Ended Tube Amp!
« Reply #240 on: 12 Nov 2025, 01:33 am »
I'm glad someone finally jumped in with a cap mod. Kinda surprised the cap value change didn't alter the bass response more, but I could see those Jupiter caps really boosting the sound of this kit. Would be interesting a .33uf vs .22uf comparison.

shadowlight

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Re: FU-19 (FM30, 829B) Single-Ended Tube Amp!
« Reply #241 on: 14 Nov 2025, 12:07 am »
My speakers are around 94 db efficient and currently driving it with 2a3 amp.

Jon L

Re: FU-19 (FM30, 829B) Single-Ended Tube Amp!
« Reply #242 on: 14 Nov 2025, 05:46 pm »
My speakers are around 94 db efficient and currently driving it with 2a3 amp.

These things also depend on speakers' impedance curve, size of room/distance to listener, size of bass driver, etc.  But yeah, I've driven less efficient speakers with 2a3 SET just fine..

FullRangeMan

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Re: FU-19 (FM30, 829B) Single-Ended Tube Amp!
« Reply #243 on: 14 Nov 2025, 07:48 pm »
With a 2A3 tube and 94dB speaker just dont expect this tube last thousands hours.

Jon L

Re: FU-19 (FM30, 829B) Single-Ended Tube Amp!
« Reply #244 on: 17 Nov 2025, 11:59 pm »

Not having learned to leave well enough alone, I wanted to add a teflon bypass cap, but not having teflon caps in the 1/10th the value range, I ended up adding 1/5th the uF.  It still achieved the desired direction of change   :thumb:





nlitworld

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Re: FU-19 (FM30, 829B) Single-Ended Tube Amp!
« Reply #245 on: 18 Nov 2025, 02:59 am »
Lol, just some TFTF Vcaps laying around... no big deal. I bet that really took it up a notch with the cap upgrade!  :thumb:

Jon L

Re: FU-19 (FM30, 829B) Single-Ended Tube Amp!
« Reply #246 on: 18 Nov 2025, 03:59 am »
Lol, just some TFTF Vcaps laying around... no big deal. I bet that really took it up a notch with the cap upgrade!  :thumb:

Letting the teflon cap re-burn-in, but definitely more resolution. Some new cables just showed up, too, so those need burn-in as well.  :green:

FullRangeMan

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Re: FU-19 (FM30, 829B) Single-Ended Tube Amp!
« Reply #247 on: 18 Nov 2025, 05:21 am »
I really dont understand why you guys remove all these original parts in pérfect working condition and not change these cheap $1 ceramic socket for $30 Teflon sockets that will increase very much the sound quality.  :scratch: