[sufjennheiser]

General Question:
Tube rolling experts, I made a mistake today by assuming 7 pin had just one size. I was wrong! Bought some 7-pin off of amazon, and it does not fit the P20 (significantly too small). Here is the link for reference: https://www.amazon.ca/gp/product/B086HJ6L2T/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

Now the obvious question is, what tubes can you recommend, especially those available in Canada? If you are not in Canada, general recommendations are welcome. I will also browse this thread to see what you guys already recommend.

But yes, please help me with the fact that tube sizes vary, even with 7 pins. In the future, how can I tell its exact size?

Cheers!

I placed an order for 6N3P-DR on ebay. Shipped from Romania; cost 28$ for 4 tubes incl. shipping to India. So I believe the seller would ship to canada ar a reasonable rate too!

 

[jenkinsontherun]

I placed an order for 6N3P-DR on ebay. Shipped from Romania; cost 28$ for 4 tubes incl. shipping to India. So I believe the seller would ship to canada ar a reasonable rate too!

I ordered those too, haha. Just didn't want to wait 1-2 months potentially for them to get here. Seller hasn't shipped them yet

 

[sufjennheiser]

I ordered those too, haha. Just didn't want to wait 1-2 months potentially for them to get here. Seller hasn't shipped them yet

ah. mine too took a week or so to ship. plus they've been in Bucharest ever since

 

[CADCAM]

Loxjie SMSL Oppo system

 

[jenkinsontherun]

My oh my, how good the P20 matches the Sennheiser HD250 (Mk1). Before, the HD250 is arguable unlistenable, as I am quite sensitive to treble. But what the P20 did was melt away the treble - it's still there, but well extended, and softer, to put it plainly. The treble is the reason why I am keeping these, and even contemplating selling my HD800.

It's extremely good, buttery, engaging, warm - with the HD250. Admittedly, with something darker, it feels a bit too hazy. Note that I have stock tubes, and 1.67 amp.

I don't know if this is a testament of moving from a $100 amp/dac (E17K) pushing 300 ohm headphones (lol), or to the P20, or to tube amps in general.

The question then becomes, is there a direct upgrade to the P20... without sacrificing its warm characteristic and overall signature.

I'm gonna take the next few days to order a 3A PS, upgrade my $20 cable for a Cardas, get new tubes. It's gonna be a fun ride.

 

[CADCAM]

My oh my, how good the P20 matches the Sennheiser HD250 (Mk1). Before, the HD250 is arguable unlistenable, as I am quite sensitive to treble. But what the P20 did was melt away the treble - it's still there, but well extended, and softer, to put it plainly. The treble is the reason why I am keeping these, and even contemplating selling my HD800.

It's extremely good, buttery, engaging, warm - with the HD250. Admittedly, with something darker, it feels a bit too hazy. Note that I have stock tubes, and 1.67 amp.

I don't know if this is a testament of moving from a $100 amp/dac (E17K) pushing 300 ohm headphones (lol), or to the P20, or to tube amps in general.

The question then becomes, is there a direct upgrade to the P20... without sacrificing its warm characteristic and overall signature.

I'm gonna take the next few days to order a 3A PS, upgrade my $20 cable for a Cardas, get new tubes. It's gonna be a fun ride.

I put these in my P20 https://www.ebay.com/itm/6N3P-2C51-...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649
and the improvement was fantastic! Stock tube was ok I tried another Russian 6n3 which was OK then I tried these and finally!

 

[jenkinsontherun]

How long was shipping to NA? I actually ordered those yesterday.

 

[CADCAM]

I'm in Massachusetts and it took a while to get here...maybe 7 to 10 days if I remember.

 

[Hubert481]

Where do i get
6N3P-DR matched 1%.
in europe?

 

[CADCAM]

Where do i get
6N3P-DR matched 1%.
in europe?

Try this ebay seller
https://www.ebay.com/usr/tubes_old70?_trksid=p2057872.m2749.l2754

 

[zevind]

Got a question I'm hoping @DBaldock9 or someone might be able to help me out with.

TL;DR: Could a bad opamp make the left channel silent, but only in balanced output mode?

I've had my p20 for about a week now, and I am truly in love with it. I had read most of this thread before I bought it, so by the time it showed up, I had a 5A power supply and 6N3P-E tubes waiting for it.

But last night I finally got around to trying the balanced output, and, I have no left channel in balanced. I got out the DMM and double checked all my wiring and compared it to Hart Audio Cable's pinouts. Even tried a different set of balanced headphones, still no left channel. I opened it up and reflowed almost every thru-hole component with a little silver bearing solder, and still no dice.

I really don't want to return it, as this unit sounds amazing on SE, has no hiss or anything all the way at max volume, works great except for the balanced output. I was wondering if someone who knows the circuit layout better, or can easily remove their opamps, could tell me if maybe just a bad NE5532 would be making tthe left channel fail, but only in BAL? I have plenty of spare opamps sitting around, but don't wanna put all the soldering work in, trying to shotgun the problem, if I'm not even in the ballpark.

Thanks so much in advance!

 

[DBaldock9]

Got a question I'm hoping @DBaldock9 or someone might be able to help me out with.

TL;DR: Could a bad opamp make the left channel silent, but only in balanced output mode?

I've had my p20 for about a week now, and I am truly in love with it. I had read most of this thread before I bought it, so by the time it showed up, I had a 5A power supply and 6N3P-E tubes waiting for it.

But last night I finally got around to trying the balanced output, and, I have no left channel in balanced. I got out the DMM and double checked all my wiring and compared it to Hart Audio Cable's pinouts. Even tried a different set of balanced headphones, still no left channel. I opened it up and reflowed almost every thru-hole component with a little silver bearing solder, and still no dice.

I really don't want to return it, as this unit sounds amazing on SE, has no hiss or anything all the way at max volume, works great except for the balanced output. I was wondering if someone who knows the circuit layout better, or can easily remove their opamps, could tell me if maybe just a bad NE5532 would be making the left channel fail, but only in BAL? I have plenty of spare opamps sitting around, but don't wanna put all the soldering work in, trying to shotgun the problem, if I'm not even in the ballpark.

Thanks so much in advance!

That's certainly possible.
If the op-amp that drives the (L-) signal is faulty, then the Balanced 4-Pin XLR Output won't work - but the (L+) op-amp will still drive the Single-Ended 1/4" Output.
.
One IMPORTANT Thing To Note: The Loxjie P20 supplies ±18VDC to the op-amp sockets - so you probably shouldn't use any devices that are rated for less than ±18VDC, if you're doing op-amp rolling. For instance, the NE5532 is only rated for ±15VDC.

 

[zevind]

That's certainly possible.
If the op-amp that drives the (L-) signal is faulty, then the Balanced 4-Pin XLR Output won't work - but the (L+) op-amp will still drive the Single-Ended 1/4" Output.
.
One IMPORTANT Thing To Note: The Loxjie P20 supplies ±18VDC to the op-amp sockets - so you probably shouldn't use any devices that are rated for less than ±18VDC, if you're doing op-amp rolling. For instance, the NE5532 is only rated for ±15VDC.

Interesting. The chips in mine say JRC5532, which I assumed was just a JRC clone of the NE5532. I have a tube of LM4562's sitting around, they're rated for +-17v, though the spec sheet does say "Absolute Maximum 36V", which I'm gonna assume is equivalent of +-18V. I Guess I'm gonna try and tone out which opamp is the (L-). Already F'd, can't F it up anymore I suppose.
Thanks man!

 

[DBaldock9]

Interesting. The chips in mine say JRC5532, which I assumed was just a JRC clone of the NE5532. I have a tube of LM4562's sitting around, they're rated for +-17v, though the spec sheet does say "Absolute Maximum 36V", which I'm gonna assume is equivalent of +-18V. I Guess I'm gonna try and tone out which opamp is the (L-). Already F'd, can't F it up anymore I suppose.
Thanks man!

The NJM or JRC5532 is a "higher" performance version of the NE5532.
From the Data Sheet -
Operating Voltage = ±3VDC ~ ±20VDC

 

[Sebasistan]

I have an ifi ZEN DAC. Would that work as a balanced source for this one? I mean, it has a balanced, 4.4mm out, so I'd have to get a 4.4mm - 2x female 3pin XLR cable...