Audioromy FU-29 - push pull!

[giltuzon]

I would like to just converse with one person here but I am still under moderation and I can't do that. This was the latest thread I could find related to my inquiry. I just joined with some questions specific to Audioromy FU-29. I've been rolling power tubes for this amp with 828B, GU29, 3E29 and 1 CVxxx something today. I am at least a little bit above entry level in terms of tube rolling (last done with smaller tubes about 8 years ago) and parts replacements. Not comfortable doing bias adjustment and no means for tube testing, I was ready to waste some tubes from red plate. So far got 2 pairs good (3 pairs now good including the original FU-29) by just detaching/inserting new tubes. Two pairs showed red plate. I was not able to watch fully the last tube with red plate and it burnt one of the 1.2K ohm resistor (R57 in version 4.0 of the PS board).

As I will be ordering resistor replacement, I might as well order some replacement capacitors for the possible recap of the input board. I just can't interpret fully (even with initial web searches) the cap labels on the attached pics.

pic 1: Is that 0.22F or 0.22uF 250V? What is the A after 250? Is fake WIMA cap visually detectable?
pic 2: 0.1F or 0.1 uF 250V?
pic 3: 47uF 400V? What is the M after 47 u?

Thanks much,
gil

 

[giltuzon]

Further researched confirmed the WIMA numbers were in uF cross checking with web samples and latest schematics available. Inquiry answered.

 

[maddmaxxdrummer]

I would like to just converse with one person here but I am still under moderation and I can't do that. This was the latest thread I could find related to my inquiry. I just joined with some questions specific to Audioromy FU-29. I've been rolling power tubes for this amp with 828B, GU29, 3E29 and 1 CVxxx something today. I am at least a little bit above entry level in terms of tube rolling (last done with smaller tubes about 8 years ago) and parts replacements. Not comfortable doing bias adjustment and no means for tube testing, I was ready to waste some tubes from red plate. So far got 2 pairs good (3 pairs now good including the original FU-29) by just detaching/inserting new tubes. Two pairs showed red plate. I was not able to watch fully the last tube with red plate and it burnt one of the 1.2K ohm resistor (R57 in version 4.0 of the PS board).

As I will be ordering resistor replacement, I might as well order some replacement capacitors for the possible recap of the input board. I just can't interpret fully (even with initial web searches) the cap labels on the attached pics.

pic 1: Is that 0.22F or 0.22uF 250V? What is the A after 250? Is fake WIMA cap visually detectable?
pic 2: 0.1F or 0.1 uF 250V?
pic 3: 47uF 400V? What is the M after 47 u?

Thanks much,
gil

View attachment 1258483View attachment 1258484

View attachment 1258488

Hi, I have this amp but needs repair. I got it from a bulk sale. The rear is stamped 220V. But the last owner was using it in Canada. Trying to figure out if he actually had a 220v version and using a stepdown transformer or if it just wasn’t labeled 120v. Some times China manufacturers use a sticker. It maybe has fallen off. Also the fuse installed is a 6.3A fast blow. I’ve always seen slow blue fuses in tube amps. Maybe some one messed with this. Can you tell me what the fuse rating is in yours. Since u are in the US. The power is the same. 120v. Thx

 

[6A3sUMMER]

Good question about fuses!

For maximum protection, I use 2 fuses in series . . .
One Fast Blow
One Slow Blow

Example:

One tube amplifier has:

A 1.25A Fast Blow to protect against turn-on inrush current, and also to protect against Hot-Start inrush current.

The other fuse is a 0.6A (yes, 600mA) Slow Blow. It protects against such things as an output tube going into thermal run-away.
The output tube might loose a lot of lifetime hours, but the power transformer will be OK when the Slow Blow opens.

 

[maddmaxxdrummer]

Hi, ok which one is in the main socket ?

 

[maddmaxxdrummer]

Further notes- Audioromy FU-29 amp

Another year of daily use. Another 6N1 input tube failed- filament not open but tube has no gain. Replaced it, these are cheap tubes, easily gotten.

The plate caps for the FU-29 (829) tube have turned brown and brittle, I replaced them with some ceramic ones.

Amp still working fine.

Note that mine is the original SILVER version. The Audioromy FU-29 being sold now has a gold color top plate on the chassis, and different driver tubes; is supposed to sound better.

Daily use for more than 4 years and it only needed 2 cheap 6N1 tubes, that is pretty good IMHO. Many people claim that all Chinese-made audio is cheap unreliable junk, but here we have an amp with very nice sound you can get for under $500 and that is quite reliable. Cheap junk would never run day in and day out for 4 years. I've had expensive tube amps die in 6 months. Higher price does not guaranty higher quality.

That said, this is not a perfect amp- not as transparent as many other good amps. But pair it with the right speaker and you get a little magic. This amp with the little Polk RT25i gave me very satisfying and musical sound for under $700. I liked this amp with the RT25i better than any other amp I tried with the little Polks. I am arranging to try the amp with some other little 2-way speakers, which are upmarket from the Polks. I'll report on that in a later post.

I tried the FU-29 on my Quad ESL-57's and the sound was OK, but the Quads want more power. I usually use a Citation II on the Quads, that sounds much better to me. The Audioromy with the ESL-57's had a kind of bloated bass. Likely too much interaction with the weird impedance of the ESL-57's.

Hi, was wondering if you can help me since u have the same amp.
Do u have the version with 2x 6N2 outer and 2x 6N1 inner tubes? 4 in straight line.

I got mine with a blown channel. I was able to assess that the issue was caused by a missing capacitor on the preamp tube socket board. When I removed the board with the sockets to look under, I found that one capacitor (22uF 100V) in the bias circuit was missing on the blown side. (See pics) this caused the bias resistor to burn and the 1K resistor on the power supply to burn also. I have since replaced all the PSU resistors and capacitors on the PSU board and on the preamp tube socket board.

One capacitor I am not sure of is on the Power supply board. This unit was already tampered with before me and that capacitor value seems off to me. In Pieros schematic it shows a 330uF 400v. I had a 33uF 400v installed. But I wonder if this is because Piero is in a 220v zone. Maybe the values change depending on the mains voltage ? Are you in the US.. ? 120v zone ? Can you confirm if that capacitor is 33uF or 330uF ?

Also can you please confirm what the value of the main power fuse is? And if slow blow or fast blow.

Please help me I’m stuck with this lol

Thx