Jolida - Fusion 3502 tube integrated amp ...

I just took possession of a used 3502rc, aluminum chassis with factory upgraded parts. I'm using it in bypass mode, with a separate preamp. It came with EL34s. although the EL34s have great mids and highs, when I cranked it up to half volume, the bass sounded flabby, less controlled than I'd like, and the low mids sounded hard. I took a chance that it was the tubes and not the amps fault, and ordered KT150s.
Right out of the box, the 150s were way better. Way tighter bass, but still rich and deep, and I think the mids and highs are just as good as the EL34s, but I'm not 100% on that.
Now I'm wondering if changing the driver tubes, maybe sylvania or siemens would tighten it up even more?
 
Pretty much any AX7 or AT7 from the 50's or 60's would be an improvement over the Chinese tubes and might have been worth changing before the EL-34's. I would look more for RCA, Tung Sol and Raytheon over Siemens and Sylvania, but that's just me.
 
I thought I'd go for the jugular and replace the EL34s first. I have no experience with AX7 or AT7, but I do with 6SN7 and 12AU7.
Generally I like the RCAs warmth, but find syls, tele, and siemens to be leaner in the bass. I'm only guessing these attributes are the same in the AX7 & AT7. I think I'l talk to Andy about that.
 
Interesting discovery: I'm getting more hum/buzz from the speakers, hearable from the seat with the Jolida than the F6. I think its the preamp though,
as when I mute the preamp the noise is reduced considerably. I'd imagine it has something to do with the input/output impedance being different between the solid state amp vs the tube amp?
 
A little checking and I found the f6 and the 3502 both have 100k input impedance, so I still don't know why the preamp
seems noisier with the jolida...
 
So I changed to a modwright preamp and still the buzzing is hearable from the seat.
sounds like 60hz or a harmonic thereof.
Anybody else getting this?
I hooked it up with a cheater plug to check for ground loops, but the buzz didn't change.
 
If the Jolida is quiet when used as an integrated and only noisy when used as a power amp then you have a grounding issue somewhere. Try the cheater plug on all of the components in the chain one at a time.
 
the buzz is the same without anything hooked up to the jolida, except the speakers.
I guess its in the design?
it would be unbearable if my speakers were more sensitive.
 
Hi, my first post here about the Jolida Fusion 3502c, just to share my experiences with this great integrated/power amp.

I ordered a 3502p (power amp only) to pair with my fancy FA Euforia, (European preamp/hp amp) but the dealer sent an integrated instead. I didn’t complain, the int costs a bit more, and features a bypass switch to be used as a power. So far so good, what I did not expect was that even with its standard tubes, the pre section of the 3502C sounded great, maybe not as good as my reference preamp, but close enough to try some NOS tubes on it, and see what happens...

No absolute values here, it all depends on your gear (sources, speakers), and the power tubes involved. With MY setup, the standard EH EL34s are fantastic tubes, with proper “burn in” they will sound magical (some say they are a perfect clone of vintage Siemens) and while my old Sylvanias 12AX7WA, Mullards, and specially Amperex are really good, I got hooked with the sound of the GE and Sylvanias 5751 black plates, triple micas from the fifties. Better synergy with the EL34s, not too warm, tight bass, 3D... And your choice of 12AT7s is also critical. While my vintage Sylvanias triple mica from the fifties are excellent, the Brimar ECC81s are in another league, some kind of deep synergy ?

I swapped the EL34s for some highly regarded Genalex KT77s Gold Lions, and after a good 30 hours really like that tubes, way more neutral and detailed than the EL34s, but not the same midrange magic, and just received a set of KT150s, heard them for about two hours, very nice, but so different from the other two that I need more time for an opinion..

Anyway, my pre combo sound great in this amp with any power tubes....
 
Just pulled the trigger on a 3502P with 6550 tubes...in part, because of this thread.

Bought a pair of 1984 Klipsch Cornwalls this year, re-capped the crossovers, and have been told I'm missing out by not feeding them with tubes. So here I go.
 
JohnW said:
Just pulled the trigger on a 3502P with 6550 tubes...in part, because of this thread.

Bought a pair of 1984 Klipsch Cornwalls this year, re-capped the crossovers, and have been told I'm missing out by not feeding them with tubes. So here I go.
Click to expand...

Congratulations and welcome to the forum. My brother bought mine and is still using it. We love it. And, for the money, stellar. Give it time to break in and enjoy! I use an external meter and biased it that way, seems more accurate.
 
joeinid said:
Congratulations and welcome to the forum. My brother bought mine and is still using it. We love it. And, for the money, stellar. Give it time to break in and enjoy! I use an external meter and biased it that way, seems more accurate.
Click to expand...

How do you adjust bias with an external meter?
 
JohnW said:
How do you adjust bias with an external meter?
Click to expand...

Unless they changed the bias system, you can use the LED lights called EZ-Bias and adjust that way or use a volt meter with pointed probes. There's a negative or common point then 4 additional points for each output tube. You place the probes in the appropriate points and adjust the values depending on tube used.



Bias Settings: 400 millivolts + 40 mV For EL 34s or 500 millivolts + 50 mV for 6550s


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