[Makiah S]

is there any better choice for similar amp , for planar headphone.

Honestly I'm enjoyed my project Ember II from garage1217 for quite a while there are power supply upgrade you can purchase like the noise nuke that floats around you can also put all of the bypasses in and fully simplify the circuit which makes it very heavily colored by the choice of two and have yourself a really nice hybrid amp for planar magnetic headphones the schiit lyr three is also good as is the Cavalli hybrid from massdrop,

As far as DIY or existing products to modify I believe there are some little dot Hybrids that people like the mod

 

[qingcai]

Honestly I'm enjoyed my project Ember II from garage1217 for quite a while there are power supply upgrade you can purchase like the noise nuke that floats around you can also put all of the bypasses in and fully simplify the circuit which makes it very heavily colored by the choice of two and have yourself a really nice hybrid amp for planar magnetic headphones the schiit lyr three is also good as is the Cavalli hybrid from massdrop,

As far as DIY or existing products to modify I believe there are some little dot Hybrids that people like the mod

thanks, I will check it out.
I own a darvoice, it does sound good to my ears. so that bring my interest of tube amp.

 

[qingcai]

this is 2nd time I saw people mentioned about ember ii.
thanks.

 

[qingcai]

hello

I am searching any opinion about this: Gemtune APPJ PA1502A tube amp ,probably it is based on Miniwatt N3 APPJ PA0901A speaker amp
and if so miniwatt has good review ,has anybody hear of it ? is it worth any attention ?


Description


Class-A single-ended triode and 100% tube amplification. Designed for resolution of fine musical details, expansive soundstage presentation, and lush tonal quality.
6P6P Replaceable Tube: 6V6
6N4 Replaceable Tubes: 12AX7, ECC83, ECC803
Specifications:
• Tube: 6N4+6P6PX2
• Input: RCA Jacks
• Input Impedance: 10K ohms
• Input Sensitivity: 800mV
• Output: 6.3mm Jacks
• Output Impedance: 8 to 600 (Japan Z11-EI48*24 Output Transformers)
• Output voltage: 18Vp-p
• Frequency Response: 30-30Khz (+-1db)
• Input AC Voltage: 100-250V AC
• Power Consumption: 27W
• AC: Standard IEC Jack with Fuse protection (2A Fuse)
• Weight: 2.5kg
• Dimensions: 160mm (w) x 134mm (d) x 125mm (h)
• 0.13W/600 ohms 0.26W/300 ohms 0.5W/100 ohms 1W/32ohms

very curious about the output transformer. some people mod the "capacitors" , are these capacitors output capacitors ?

 

[Maxx134]

very curious about the output transformer. some people mod the "capacitors" , are these capacitors output capacitors ?

Transformers I can't say.
Capacitors changed are not output. The ones mentioned in thread to be changed are the "coupling caps". They "couple" the driver stage (that middle tube) to the output stage (two bigger tubes which are connected to the transformers for output).

 

[qingcai]

Transformers I can't say.
Capacitors changed are not output. The ones mentioned in thread to be changed are the "coupling caps". They "couple" the driver stage (that middle tube) to the output stage (two bigger tubes which are connected to the transformers for output).

thanks for the reply, I just read from the begining, and I got my appj today.

 

[qingcai]

my changes. 0.1uf + 1500uf for bypass. 0.47+0.1 for coupling.

 

[CJG888]

This is my PCB, very similar to yours, very neat and tidy inside:



And these are the finished mods:
1 - Coupling caps: Jupiter copper foil paper and wax caps, 0.47uF, 600V
2 - Cathode caps: Audio Note Kaisei , 1000uF, 25V




I'm also going to put in a new AMR Audio 90% Silver Alloy Fuse Tube 5x20mm (Slow Blow).
Unfortunately I can't say anything about the sound due to an ear infection but if it's even slightly better then it will be pretty amazing.
Also doing some cosmetic mods. Pics to follow....

Had one scary moment, I plugged in the power cord without realising it had switched itself on, and there were no tubes in, I quickly switched off and no harm done

.

Edit: Looking forward to your tubes post Maxx134!

Sorry to dredge up a really old thread, but I am in the process of recommissioning my old PA0901A. So far, it sounds good on the end of a WBA tube preamp, driving my home-designed and built Tangband full-range desktop monitors. I’m using NOS Philips “foreign” EL84s and an EI ECC83 (made on an old Philips production line). A JJ ECC83S is incoming for comparison purposes.

Now to the issue of capacitors: are the polar AN Kaiseis the correct ones for the cathode? I presume they should be… As for the coupling caps, I have a bunch of NOS RCL 0.22uF PIOs and also a selection of 0.22uF Mullard “mustard” foil caps in my “box of bits”. All are rated at 400V. Would you recommend using either of them? I don’t really want to go all out for the Jupiters yet.

Presumably I can just connect a pair in parallel to get to 0.44uF.

 

[CJG888]

OK, I have a plan. The nasty steel feet have come off, to be replaced with three RDC cones, attached to the bottom plate. The Audio Note Kaiseis are on their way over from the UK, and will be bypassed with 0.10uF ICW polypropylene caps which I still have from the 1990s (NOS). Coupling caps will be a pair of NOS vintage RCL 0.22uF PIOs.

 

[Maxx134]

Nice. PIO caps have good natural sound.

 

[baronbeehive]

Sorry to dredge up a really old thread, but I am in the process of recommissioning my old PA0901A. So far, it sounds good on the end of a WBA tube preamp, driving my home-designed and built Tangband full-range desktop monitors. I’m using NOS Philips “foreign” EL84s and an EI ECC83 (made on an old Philips production line). A JJ ECC83S is incoming for comparison purposes.

Now to the issue of capacitors: are the polar AN Kaiseis the correct ones for the cathode? I presume they should be… As for the coupling caps, I have a bunch of NOS RCL 0.22uF PIOs and also a selection of 0.22uF Mullard “mustard” foil caps in my “box of bits”. All are rated at 400V. Would you recommend using either of them? I don’t really want to go all out for the Jupiters yet.

Presumably I can just connect a pair in parallel to get to 0.44uF.

Hi there, it is a very old thread by now! Yes all good. What rated Kaiseis are you using? I think the amp needs 1000uF or at least quite a high rating to complement the sound and power output otherwise it will probably be a bit too treble centric. That's what I have in mine together with the .1uF bypasses.

You might need to extend the bottom of the chassis, if so go back to around page 19 and 28 or so to see.

What sensitivity are your monitors?

Be careful soldering to the PCB pads they come off quite easily.

 

[CJG888]

 

[CJG888]

OK, the AN caps haven’t arrived yet (Brexit!).

I’ve fitted the vintage PIOs, and the sound is already much more transparent and open.

Those woolly pads are IKEA cabinet feet, to keep the capacitor leads away from the casework! The central standoff has been insulated with heatshrink.

Will the cathode caps not fit inside the case?

 

[baronbeehive]

OK, the AN caps haven’t arrived yet (Brexit!).

Haha, I know the problem, it's the same here!

OK, the AN caps haven’t arrived yet (Brexit!).

I’ve fitted the vintage PIOs, and the sound is already much more transparent and open.

Those woolly pads are IKEA cabinet feet, to keep the capacitor leads away from the casework! The central standoff has been insulated with heatshrink.

Will the cathode caps not fit inside the case?

Great to hear!

I don't know, if they are 1000uF, 16v ones then they are 26mm, as mine were 25v I can't say definitely they seem to have changed the range of caps at Audio Note. So you will have to measure. If they don't fit upright then you will have to put them in sideways like your coupling caps.

 

[CJG888]

In went the Kaiseis today. They are a tight fit, but can be installed in the positions of the stock caps.

Unfortunately, none of the coupling caps which I have to hand could be made to fit (those NOS PIOs are huge), so I have left them out for now. If required, maybe a pair of Solens can be made to fit on top of the board…

As it is, treble doesn’t seem to be missing, though. I’ll wait and see how the caps burn in.

After several hours of running-in, I can say that bass extension and dynamics have improved dramatically.