[DavidK35]

Is this the adapter?

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/201006223709

And the tube?

https://tubedepot.com/products/14n7

That is the right adaptor but it looks ugly without the outer sleeve IMO. The same supplier will do one for you with a gold outer sleeve for an extra $5. (xulingmrs,china, on ebay) just ask him.

 

[baronbeehive]

hello! got in on the massdrop deal for this amp. for $140, i think that's a good price. i'm excited and couldn't wait to get it and start modding. ETA is mid-august. Anyway, I have already bought the following:

ELNA CAP ALUM 1000UF 20% 25V RADIAL SILMIC II
Mundorf .47uf M cap supreme

I plan to listen to it for a couple of days with the stock caps then will replace them. For the tubes, i might get the tungsol KT66.

You guys still have this amp or have ya'll upgraded to something more high end?

Is your APPJ the same version as the one on this thread, there have been newer versions of some models.

You will need bypass caps for your Elna cathode caps, otherwise you will be disappointed as we have been without them. Look back in the thread.

It's already high end (with some mods/tube rolling), only those with upgraditus would want to move on to something else.

Correct. I've been cured of that for some time now!

 

[baronbeehive]

The gold-lion not only beats them out in stage, but does not suffer in presence or detailing,
But it does "add" a very slight touch of extra flavor to its sound, so it is not a neutral lean tube.

I've been interested in the Gold Lions but not tried them.

 

[Peekeesh]

Is your APPJ the same version as the one on this thread, there have been newer versions of some models.

You will need bypass caps for your Elna cathode caps, otherwise you will be disappointed as we have been without them. Look back in the thread.

I joined this drop. I haven't gotten it yet but massdrop says it will ship mid august.

https://www.massdrop.com/buy/appj-1502a-tube-headphone-amplifier/talk#discussions

How do i determine if I'm going to need bypass caps? what bypass caps would you recommend? Thanks!!

That is the right adaptor but it looks ugly without the outer sleeve IMO. The same supplier will do one for you with a gold outer sleeve for an extra $5. (xulingmrs,china, on ebay) just ask him.

Thanks. I sent the seller a message.

 

[baronbeehive]

I joined this drop. I haven't gotten it yet but massdrop says it will ship mid august.

https://www.massdrop.com/buy/appj-1502a-tube-headphone-amplifier/talk#discussions

How do i determine if I'm going to need bypass caps? what bypass caps would you recommend? Thanks!!

Maxx and I used Audyn True Copper MKP 0.1uF film cap to speed up response times and cover the frequencies lost with the electrolytic cap. The problem is that with the 1000uF electrolytic cathode caps they do provide efficient recovery time from power drains …. BUT … you lose top end sparkle which is why you need the lower capacitance bypass caps.

However they won't fit in the chassis unfortunately so we had to extend the bottom to accommodate them. You can see how we did it around page 19 on this thread. However for sound it was well worth it.

 

[Peekeesh]

Thanks @baronbeehive I saw the post. to be sure, the bypass caps are polarized and needs to be soldered to board the same way the cathode caps are?

 

[baronbeehive]

Thanks @baronbeehive I saw the post. to be sure, the bypass caps are polarized and needs to be soldered to board the same way the cathode caps are?

The Audyn film caps have a little arrow on one side and this needs to be connected to the negative terminal of your cathode cap, the other terminal from the Audyn cap to the other terminal of the cathode cap so that it is bypassing the cathode cap. The end of the cathode cap terminals are then soldered to the board as shown in the pics in the thread.

Edit: You could of course use other film bypass caps such as PME-080: 0.1uF 275Vdc Evox Rifa PME271M Metallized paper which may or may not fit without extending the bottom.

Good luck with your mods!

 

[Peekeesh]

I purchased 2 solen caps .1uf 630v, gonna use them as bypass caps, 14n7 NOS from tube depot and the adapter from ebay. I'll get the kt66 golden lion later once I determined it's safe to run them.

 

[baronbeehive]

I purchased 2 solen caps .1uf 630v, gonna use them as bypass caps, 14n7 NOS from tube depot and the adapter from ebay. I'll get the kt66 golden lion later once I determined it's safe to run them.

Sounds good, as long as the solen's are film caps for that extra fast response over the electrolytics.

 

[Maxx134]

How do i determine if I'm going to need bypass caps? what bypass caps would you recommend? Thanks!!

Since the cathode caps are cheap, it makes betybe sense to get electrolytics that are either known or meant to be "audio quality"...

So ditch those electrolytics you memtiment,
for either "Kaisie" caps, or other known Better ones,
like Jensen "audio grade" caps...

Cheaper than trying to fix with bypass.

Still with a size of 1000uf,
I would still add a bypass.

If it were 330uf or less, I wouldnt bother.

Yet, Since we trying to push this amp performance,
A bypass cap of small size is still recommended.

Even smaller than .1uf is good for bypassing with the better "audiofile" electrolytics, like even half value of that.
We just helping the top end transients..

Just ballpark figures are ok,
wich are usually same with many similar designs..

I have to redo my other main amp like this to try boost its performance more...

 

[baronbeehive]

I have to redo my other main amp like this to try boost its performance more...

Me too! I have 2 spare Kaisei caps which I could use on the other amp although they're only 25v, as compared to the 63v Ecap I have in now, I think they might be ok.

Even smaller than .1uf is good for bypassing with the better "audiofile" electrolytics, like even half value of that.
We just helping the top end transients..

The top end transients on this amp, just right, they have an edge that is palpable but I feel that anything sharper than this would be borderline sybillant on my speaker APPJ, (APPJ PA0901A), I don't know about yours, so I wouldn't go less than 0.1uF on mine. But those bypasses have to be there, without them the top end transients don't exist at all which you don't want because the sound is lifeless.

The transients are helped by my tube choice, with my previous favourite the TS 5751 the details were good but the transients were somewhat rounded off in that fabulous Tungsol liquid sounding way which made for great listening and they had a magical quality to the sound which no other tube had. But after hearing my latest fav tubes, the Philips 12ax7 and Mazda 12ax7, actually ECC83 since they are European made, the transients are that much sharper and more real anyway without any detriment overall SQ, and they have other qualities which raise them above others I tried IMO. I'm completely sold on these now although I've tried many good tubes on this amp.

I continue to be shocked by this little baby! Frankly I wouldn't change anything, it has reached top level for me.

 

[baronbeehive]

hello! got in on the massdrop deal for this amp. for $140, i think that's a good price. i'm excited and couldn't wait to get it and start modding.

Just a thought, but to anyone intent on modding the amp it is a good idea to check over the solder connections and wires after you've finished your mods, including the existing wires that can break off, before you start on the listening fun. If you can't do that then get someone who is experienced in electrononics to check it over.

If I hadn't done that mine would have gone up in smoke LOL. One or 2 on this thread lost their amp because of this, and the amp can be damaged on the PCB if you are not careful. But take care and you should be fine.

 

[baronbeehive]

Me too! I have 2 spare Kaisei caps which I could use on the other amp although they're only 25v, as compared to the 63v ECaps I have in now, I think they might be ok.



The top end transients on this amp, just right, they have an edge that is palpable but I feel that anything sharper than this would be borderline sybillant on my speaker APPJ, (APPJ PA0901A), I don't know about yours, so I wouldn't go less than 0.1uF on mine. But those bypasses have to be there, without them the top end transients don't exist at all which you don't want because the sound is lifeless.

The transients are helped by my tube choice, with my previous favourite the TS 5751 the details were good but the transients were somewhat rounded off in that fabulous Tungsol liquid sounding way which made for great listening and they had a magical quality to the sound which no other tube had. But after hearing my latest fav tubes, the Philips 12ax7 and Mazda 12ax7, actually ECC83 since they are European made, the transients are that much sharper and more real anyway without any detriment overall SQ, and they have other qualities which raise them above others I tried IMO. I'm completely sold on these now although I've tried many good tubes on this amp.

I continue to be shocked by this little baby! Frankly I wouldn't change anything, it has reached top level for me.

 

[baronbeehive]

Me too! I have 2 spare Kaisei caps which I could use on the other amp although they're only 25v, as compared to the 63v Ecaps I have in now, I think they might be ok.



The top end transients on this amp, just right, they have an edge that is palpable but I feel that anything sharper than this would be borderline sybillant on my speaker APPJ, (APPJ PA0901A), I don't know about yours, so I wouldn't go less than 0.1uF on mine. But those bypasses have to be there, without them the top end transients don't exist at all which you don't want because the sound is lifeless.

The transients are helped by my tube choice, with my previous favourite the TS 5751 the details were good but the transients were somewhat rounded off in that fabulous Tungsol liquid sounding way which made for great listening and they had a magical quality to the sound which no other tube had. But after hearing my latest fav tubes, the Philips 12ax7 and Mazda 12ax7, actually ECC83 since they are European made, the transients are that much sharper and more real anyway without any detriment overall SQ, and they have other qualities which raise them above others I tried IMO. I'm completely sold on these now although I've tried many good tubes on this amp.

I continue to be shocked by this little baby! Frankly I wouldn't change anything, it has reached top level for me.

Sorry for the double-triple post!

 

[Pratt99]

Me too! I have 2 spare Kaisei caps which I could use on the other amp although they're only 25v, as compared to the 63v Ecap I have in now, I think they might be ok.



The top end transients on this amp, just right, they have an edge that is palpable but I feel that anything sharper than this would be borderline sybillant on my speaker APPJ, (APPJ PA0901A), I don't know about yours, so I wouldn't go less than 0.1uF on mine. But those bypasses have to be there, without them the top end transients don't exist at all which you don't want because the sound is lifeless.

The transients are helped by my tube choice, with my previous favourite the TS 5751 the details were good but the transients were somewhat rounded off in that fabulous Tungsol liquid sounding way which made for great listening and they had a magical quality to the sound which no other tube had. But after hearing my latest fav tubes, the Philips 12ax7 and Mazda 12ax7, actually ECC83 since they are European made, the transients are that much sharper and more real anyway without any detriment overall SQ, and they have other qualities which raise them above others I tried IMO. I'm completely sold on these now although I've tried many good tubes on this amp.

I continue to be shocked by this little baby! Frankly I wouldn't change anything, it has reached top level for me.

@baronbeehive For the Philips 12ax7 and Mazda 12ax7, what would be a fair price to pay? I see they command a premium price, but I am interested in trying one. Thanks.