[baronbeehive]

I bought some new coupling caps for this amp (clarity CMR), to see if I can help increase the soundstage.

Hey Maxx!

See if you can put those caps in without trashing the PCB this time LOL!

Here is a funny pic for you.
Expensive driving cheap!
Nice.

Wow I never realised that was so expensive, well... the APPJ is expensive... in performance anyway.

For the 1502 model, Most of the good tubes on my amp are a bit forward with the exception of the Gold Lion KT66, which runs hotter than the rest..

I haven't found any Gold Lions for my amp, not sure they do 12Ax7's. I doubt if yours would run hotter than the Little Dot with 6 big bulb tubes anyway.

 

[baronbeehive]

The story with this amp, is that in stock form, the bottom lid closes all the way, and effectively shields the power supply section, which is a "switching" PSU .
So you can try to help with shielding if you like, by moving caps away and/or covering the PSU section, but be careful not to short anything out with any added metal.

Yes he could move the caps out of the way of all that EMF coming from the transformer coil, and out of the PSU section altogether.

If the caps don't fit so well he could extend the bottom like we did with a box of aluminium heat sink sheets screwed together.

 

[baronbeehive]

This morning the tube amp repair guy call me up and asked to repair the amp myself..
I am a bit puzzled by his request thus i went over his place and he showed me one of the jupiter caps was picking up the buzz from the transformer. He asked me to repair it myself
Lol

Yes, repair guys can be a bit sniffy about working on modded amps.

When you move the caps be careful to check that the solder connections haven't become loose or broken. Also when you bend the cap legs be careful they don't break, it is best to bend them away from near the cap body.

 

[baronbeehive]

Don't bend the legs like this near to the cap body. Now that you've done it I wouldn't bend it again from there, I broke a leg like this, which was expensive!

 

[baronbeehive]

Also check this solder joint when you move the caps, it looks a bit dodgy from here, but maybe OK.
.

 

[jekjek]

After a few trial and error on Jupiter caps and Mundorf
I gave up and fix the Wima back on the amp
To my surprise the hum was gone. So now I am a happy APPJ owner again

 

[baronbeehive]

After a few trial and error on Jupiter caps and Mundorf
I gave up and fix the Wima back on the amp
To my surprise the hum was gone. So now I am a happy APPJ owner again

OK .

The original is still very good as I remember, maybe keep the project for the future?

Glad everything is still working fine.

Don't know what could have caused that other than where you put the caps, in the PSU area was not a good idea, the switch mode power supply does voltage conversion constantly which causes a lot of noise which is usually out of range of hearing.

I would suggest if you do that I future to get the DMM though. If you have that it is easy to check if the connections are still good after you have done anything to the amp, in which case everything should still be OK.

So enjoy your amp…!

 

[jekjek]

thanks Baron
the amp is still very good with Wima

 

[Maxx134]

thanks Baron
the amp is still very good with Wima

There are even better wima higher pulse rating and, also, the blue ones.
Same size.

 

[1800yolk]

Hi guys!
I remember coming to this thread about 3 or 4 years ago and reading it a lot before purchasing this amp. I saw that it would be a great companion for my HE-400i headphones & Bimby DAC, and they definitely have been! Another thing that caught my eye was the fact that I could make changes to the sound by buying new tubes and possibly swapping out the capacitors. Well, as much as I've wanted to all this time I've never had any money to buy anything for it! I still don't have much money to throw at it, but

if you could spend around $50 on replacement tubes, which ones might you go for? Main goal is to find something clear but also warmer in the high 10khz+ frequencies would be nice.

Thank you!! I'll be reading older posts to try to find a good option but it is a lot to sort through

 

[Makiah S]

It's not a triple Mica but I picked up both a 6072A 5 Star [1875/1875] and a non 5 Star for comparison (From Doug's Tubes with the Balanced Triodes option picked)

So that'll be fun, I'll be comparing them again'st my 100%/100% Sylvania 12SL7GT

 

[baronbeehive]

Hi guys!
I remember coming to this thread about 3 or 4 years ago and reading it a lot before purchasing this amp. I saw that it would be a great companion for my HE-400i headphones & Bimby DAC, and they definitely have been! Another thing that caught my eye was the fact that I could make changes to the sound by buying new tubes and possibly swapping out the capacitors. Well, as much as I've wanted to all this time I've never had any money to buy anything for it! I still don't have much money to throw at it, but

if you could spend around $50 on replacement tubes, which ones might you go for? Main goal is to find something clear but also warmer in the high 10khz+ frequencies would be nice.

Thank you!! I'll be reading older posts to try to find a good option but it is a lot to sort through

Ha, nice to see this thread still trundling along periodically!

Sorry for the late replay, most of the information can be found a few pages back, but I will try to answer. Difficult because there are several types of "warm". For driver tubes, Sylvania, 12AX7, or better triple mica 5751, are warm and bright, especially in the high frequencies. They are a tad light sounding, Mullard, ECC83 are warm in the soft cosy blanket sense if you see what I mean. I really like the Mazda,12AX7A silver anode for warmth, with a delicate sound with clearly defined edges to the sounds, they might be a bit expensive though. I managed to get more warmth with the power tubes, but I won't recommend these as they are different to the types you have on yours.

So check out the last pages and see if there are any power tubes back then that would suit.

Glad to see you are enjoying the amp!

 

[baronbeehive]

It's not a triple Mica but I picked up both a 6072A 5 Star [1875/1875] and a non 5 Star for comparison (From Doug's Tubes with the Balanced Triodes option picked)

So that'll be fun, I'll be comparing them again'st my 100%/100% Sylvania 12SL7GT

Hey Mshenay!

So you've still got your APPJ, it must have made a bit of a impression, I thought you had replaced it!

I haven't come across the 6072A's but I imagine they would be totally different to the 12SL7 Sylvanias. The different gain and other factors could make this tube quite interesting.

 

[Makiah S]

Hey Mshenay!

So you've still got your APPJ, it must have made a bit of a impression, I thought you had replaced it!

I haven't come across the 6072A's but I imagine they would be totally different to the 12SL7 Sylvanias. The different gain and other factors could make this tube quite interesting.

Well I've been wanting to get rid of it but my guy has been fine-tuning his amp for a year now

I'm experimenting with an Auris Euterpe as a potential replacement go with the stock JJ tubes it's unimpressive, or it's a bit too full for my taste though I don't think it's going to take much to push it over the edge

And I actually did purchase a triple Mica an 80s double Mica and five star, I found that I tend to like the 12A U7 and these are apparently an ay7 which has a slightly higher gain than the AU series but not as much as the AT definitely not as much is the AX

And I will again be comparing them against my Psvanne 12au7 and 12SLGT7

 

[Maxx134]

And I will again be comparing them against my Psvanne 12au7 and 12SLGT7

I have plenty of the 12 pin types then I will be putting up soon in the for sale threads, and I have to say the older the tube, the better sound...

so late production tubes are not as good as the oldest ones.
C
Don't ask me why it is, but that is what it is...

That's a general statement, but it can almost be considered a fact(!), because of how prevalent it is.
Oldest tubes are usually the best.