[baronbeehive]

I did the work on David's amp(headphone), and it is a nicely designed unit. If you want it for Modding experience, I might suggest something else, since the Modding you can do on it is really limited to the coupling and cathode capacitors. The rest of the amp circuit is Surface Mount, and the Power supply is Switched mode which I wouldn't touch. Also, there isn't a lot of space for adding boutique caps, unless you are willing to modify the case as well (as several posters have done)..

I misunderstood your earlier post about desolder vacs, I thought you were referring to the electric continuous vacuum desoldering gear which heats up and desolders all in one continuous operation. I found it difficult to get the hang of heating up the joint with the iron and using the manual vac at one and the same time! Have you used the electric one, it looks so easy this way, and I would get one of these if I had to do a whole lot of desoldering again.

 

[Makiah S]

5751 type is prob the best 9pin i ever tried...
Edit or at least the most resolving.
There is always a stand out tube in every type like the 180cc and e80cc types which had a bit more Soundstage at trade off of liveiness..

For a driver stage, better to have the most resolving tube, like the resolving 5751.
Best for me yet was the 12SL7 8pin with adapter.

You can gain back any Soundstage lost with power tubes choice anyways.
The 6L6 on this amp does it with largest Soundstage while sounding refined,
But at a trade off of sounding more laid back.

The 6v6 are most balanced ,
but for me the 6f6 was most resolving.

I couldn't resist... I went ahead and grabbed the Slyvania 6w6GTs an bid on two of the 6F6's I'm curious to see how they compare to the JJs I got from Amazon. Pairing with a TungSol 12sn7

 

[MrSlim]

I misunderstood your earlier post about desolder vacs, I thought you were referring to the electric continuous vacuum desoldering gear which heats up and desolders all in one continuous operation. I found it difficult to get the hang of heating up the joint with the iron and using the manual vac at one and the same time! Have you used the electric one, it looks so easy this way, and I would get one of these if I had to do a whole lot of desoldering again.

No, I haven't used one of the electric ones. I learned how to use the manual "solder sucker" years ago, and have just stuck with it. I don't do a lot of "rework" so the manual one has been good enough for me. I've been debating buying a hot air SMD station to make it easier to do SMD work, but I'm not sure if I can justify it yet.

 

[Maxx134]

I did the work on David's amp(headphone), and it is a nicely designed unit. If you want it for Modding experience, I might suggest something else, since the Modding you can do on it is really limited to the coupling and cathode capacitors

This is precisely why I would recommend this amp for beginners,
Because of so little to do, and so little needs to he done.

I specifically DO NOT recomended ANYONE wasting their hard earned money on any kit like a crack amp.
You get alot of headaches and waste alot of money that way..


Reverse engineering and upgrading on already well designed units is optimal, IMHO.

ALL commercial tube amps, no matter how expensive,
In order to be competitive, they will ALWAYS have non-optimal coupling of stages.
Simply because most will not use interstage Transformers,
And high quality caps for coupling are expensive.

The cheap alternative for most, is to get away with high voltage wima caps or other cheap caps as long as they high voltage rated they will sound better.
It's just smart business for them.

So no matter how expensive the "tube" amp is, it will be compromised in same key areas of coupling,
and also tube supply demands, with newer Solid state solutions like implementation of CCS . (Speedball lingo for crack amp)

The only time you are forced to learn is either when something breaks, or something you want to change.

I found it difficult to get the hang of heating up the joint with the iron and using the manual vac at one and the same time

Yeah I have a real cheap one from ebay does the trick, but not really need it most time.

Pairing with a TungSol 12sn7

You will need a 9pin to 6pin adapter for that, and it has to be a 12v, not a 6v one.

 

[Makiah S]

This is precisely why I would recommend this amp for beginners,
Because of so little to do, and so little needs to he done.

I specifically DO NOT recomended ANYONE wasting their hard earned money on any kit like a crack amp.
You get alot of headaches and waste alot of money that way..


Reverse engineering and upgrading on already well designed units is optimal, IMHO

Yeah I have a real cheap one from ebay does the trick, but not really need it most time.


You will need a 9pin to 6pin adapter for that, and it has to be a 12v, not a 6v one.

Yea modding this little guy with some basic upgrades seemed like a smart idea to me too! I'll eventually waste my money building some other kits, just not now

Hmm well I got this
http://www.ebay.com/itm/1pc-Gold-12...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

and this

http://www.ebay.com/itm/Tung-Sol-12...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

The adapter is an Octal 12SL7/SN7 to 9 Pin 12AX7 and it's rated for 12.6V

the Tube is a 12SL7 and it's an octal... for Drivers I'm just hoping the 6F6, 6W6GT and 6V6 plug into the power sockets without the need for an adapter. I should have everything I need or am I missing an adapter?

 

[Maxx134]

the Tube is a 12SL7 and it's an octal... for Drivers I'm just hoping the 6F6, 6W6GT and 6V6 plug into the power sockets without the need for an adapter. I should have everything I need or am I missing an adapter?

That is perfect.
Also the unit takes many tube variants ,

but just need to be gentle with sockets.

 

[Maxx134]

Really was alot of fun trying different power tubes.

Its quite amazing looking at such a tiny amp with big tubes!

 

[Makiah S]

OOOH Yea I forget I wanted to get some Socket Savers!!! Thank you!

I heard they've cracked on some people so I might as well anticipate and prevent that early on, any recommendations? Also what are some better sockets to upgrade to

These seem to be 8pin to 8pin, and the 6V6 seem to be 4pin sockets, would it work

http://www.ebay.com/itm/1-Octal-Gol...d=282369339088&_trksid=p2047675.c100011.m1850

 

[Maxx134]

I tried socket savers but the one i got on ebay was just too cheap and too tight.

You don't want to have to place so much pressure on socket yet the socket savers didn't work for me.

Once I settle on the big power tubes I only roll the center driver tube.

I would not worry about socket savers for the power tubes as also it looks too tall.

 

[baronbeehive]

I tried socket savers but the one i got on ebay was just too cheap and too tight.

You don't want to have to place so much pressure on socket yet the socket savers didn't work for me.

Once I settle on the big power tubes I only roll the center driver tube.

I would not worry about socket savers for the power tubes as also it looks too tall.

I also don't think socket savers are a good idea, if you keep changing tubes in the socket saver it is so tight that you have to keep a firm grip to stop it moving about in the socket as you remove the tube so I think it is best to gently remove the tubes in the original socket.

 

[Makiah S]

Good to know! Input from you both has been duly noted

 

[CZ4A]

Does the pa1502a, needed moddeing due to bad build quality???

All the modding I've seen of this amp have been to improve the sound signature, not for repair or reliability reasons.

For PA1502A users who've experienced failures, do you happen to know what failed and/or have any pictures of obviously failed components, like bad caps?

 

[Hippocamp]

A "Solder Vac" is your friend. I would never attempt any component replacements without it. https://www.amazon.com/High-Vacuum-...?srs=4905462011&ie=UTF8&qid=1503758304&sr=8-3 is my favorite as far as manual options are concerned (and I've used a few).
Here are a few more tips:
Heat the joint until the solder is fluid and then while the iron is still on the joint, suck up the solder with the solder vac. If the hole doesn't look completely clean, add solder and repeat the process.
Once the hole is clear, the lead may still be connected to the through-hole metal (unless it is a single sided board) due to the capillary effect. At this point, apply heat to the joint again and use the tip of the iron to push the lead away. You should feel the lead pull away from the side of the hole. Repeat this step until the lead is loose in the hole and you can wiggle the component you are removing.
I have used this technique many times and have not had a damaged pad in a very long time.

Great tip, thanks. Still waiting on my caps -- backordered.

Have been practicing on some old, dead equipment. I found that "chipquick" helps a lot. Keeps the solder molten long enough to get the solder sucker tip in place.

 

[Makiah S]

Great tip, thanks. Still waiting on my caps -- backordered.

Have been practicing on some old, dead equipment. I found that "chipquick" helps a lot. Keeps the solder molten long enough to get the solder sucker tip in place.

that's an excellent idea, thank you for that tip

 

[Makiah S]

@Maxx134 and others

I got two 6w6GT Sylvania's but the pin out's are different? Which should I keep and which do I need to exchange or should I not use either one