Aiqin/Oldchen Tube Amps

[Miletus]

I've just picked up one of these amps as a first DIY nodding project. What a great thread here!

This is the one I've bought:



In terms of collating all the various mods in this thread and writing them up in a list of priorities, what would be the best starting point?

Can anyone share their thoughts as to what mods made the biggest changes to the sound?

Thanks in advance!

 

[contoursvt]

I recently got the oldchen one in black - and running some efficient speakers and I'm kind of at a loss at how good it sounds compared to my solid state. It sounds neutral to me - no obvious tube sound but I can hear more detail and faint sounds are more clear and bass is surprisingly tight. This is my first adventure into tubes. I feel like I'm losing my mind.

I am running mine off an APC LineR-1200 regulator set to 110V just in case.

 

[hurdy_gurdyman]

I recently got the oldchen one in black - and running some efficient speakers and I'm kind of at a loss at how good it sounds compared to my solid state. It sounds neutral to me - no obvious tube sound but I can hear more detail and faint sounds are more clear and bass is surprisingly tight. This is my first adventure into tubes. I feel like I'm losing my mind.

I am running mine off an APC LineR-1200 regulator set to 110V just in case.

Makes you wonder why the world ever went solid state in the first place, doesn't it?

 

[Saponetto]

For a serious advantage... mosquitoes don't fry on SS amps.
Just kidding... currently have two NS-02 that are equal to the above BL-02, tried several times to make 'em a good retirement but at the very end these ugly things still fry mosquitoes and make my heart lose beats.
Enjoy 'em!

 

[joshbru3]

Hello everyone, long time reader, first time poster. I've been a guitar player most of my life and have been using tube amps for years. Just recently I've gotten into Hi-Fi tube audio amplifiers and decided to dive in slowly and check out an Oldchen tube amp. I've read some really great things about them.

For my first amp, I really wanted something that was low powered and reminiscent of circuits used in 1940s/1950s radio and stereo consoles. I didn't want Bluetooth, a remote, or any modern comfort. Just a very basic, vintage inspired amp. Obviously I was looking into something stereo verses mono and have always loved the vintage sound and feel of 6V6 power tubes. It's fairly uncommon today to find Hi-Fi amps utilizing 6V6 tubes, so when I found out that Oldchen produced a 9W (per channel) 6V6 amp, I jumped on it.

I just received it today, so I haven't even attached speakers to it yet. I will be retrofitting a vintage stereo console with this amp and new Klipsch speakers with high sensitivity driven by a modern turntable.

The factory tube compliment for this amp is a 5AR4 rectifier, (4) 6V6 power tubes, and (2) 6SN7 pre-amp tubes. Both the rectifier and pre-amp tubes were produced by PSVANE, and the power tubes were basically unbranded Ruby's. Since I've been an avid tube roller for years, I had quite the stockpile of vintage American tubes.

I swapped the factory Chinese tubes for a 1960's GE 5AR4 brown base, (4) 1950's Bendix 5992's, and (2) Sylvania 6SN7WGTA's. The photo still shows the PSVANE 5AR4 in place however. I'm really excited to hear this thing in action.

Will keep you guys updated.

 

[Saponetto]

Wow, gorgeous!
Eagerly waiting for your user's thoughts!

 

[laper]

I recently got the oldchen one in black - and running some efficient speakers and I'm kind of at a loss at how good it sounds compared to my solid state. It sounds neutral to me - no obvious tube sound but I can hear more detail and faint sounds are more clear and bass is surprisingly tight. This is my first adventure into tubes. I feel like I'm losing my mind.

I am running mine off an APC LineR-1200 regulator set to 110V just in case.

The same happened with me. I'm running my Klipshes RP-500M. It sounds ridiculously good!

 

[Paco LM]

I read the entire thread days ago so i ordered one and finally got it yesterday; this is my first tube amp.

I'm using a Pioneer Sa-8500 as a preamp and this thing sounds great. Some people remarked the lack of bass but i don't know if the Pioneer mitigates that, in fact i had to tone it down using the knobs because there was too much rumble. I'm running it with some PSB Alpha T1 speakers.

Already thinking on upgrading the tubes; any recommendation??

 

[Saponetto]

Congrats for your new "tubey thing"!

Let some time for make all parts under the hood regimate, then let the tube roll start!
Back on topic, Psvane stock tubes are fine imho, tested some EH EL34 that sounds fine also but the stock ones better works trebles and cymbals.
Bass extension is not that bad at all, even considering the dimension of the output transformers.
Very, very good with jazz and prog-rock, it seems made for play this music.

Happy listening!

 

[Mr Boochie]

Congrats for your new "tubey thing"!

Let some time for make all parts under the hood regimate, then let the tube roll start!
Back on topic, Psvane stock tubes are fine imho, tested some EH EL34 that sounds fine also but the stock ones better works trebles and cymbals.
Bass extension is not that bad at all, even considering the dimension of the output transformers.
Very, very good with jazz and prog-rock, it seems made for play this music.

Happy listening!

One suggestion. Apply Deoxit D100 onto the pins and sockets before starting the tube rolling party.

This will help preserve those sockets.

D100L.

 

[vinylkid58]

Some people remarked the lack of bass but i don't know if the Pioneer mitigates that, in fact i had to tone it down using the knobs because there was too much rumble. I'm running it with some PSB Alpha T1 speakers.

The low damping factor and high output impedance of these budget single ended amps really aren't a great match for modern vented speakers. Bass will quite often sound bloated and will lack definition. And the low power means there's very little headroom.

jeff

 

[Paco LM]

Congrats for your new "tubey thing"!

Let some time for make all parts under the hood regimate, then let the tube roll start!
Back on topic, Psvane stock tubes are fine imho, tested some EH EL34 that sounds fine also but the stock ones better works trebles and cymbals.
Bass extension is not that bad at all, even considering the dimension of the output transformers.
Very, very good with jazz and prog-rock, it seems made for play this music.

Happy listening!

Thanks. I think i'll leave it like that for some months and then think about upgrading. I listen rock and jazz mostly.

One suggestion. Apply Deoxit D100 onto the pins and sockets before starting the tube rolling party.

This will help preserve those sockets.

D100L.

Thanks for the tip!

The low damping factor and high output impedance of these budget single ended amps really aren't a great match for modern vented speakers. Bass will quite often sound bloated and will lack definition. And the low power means there's very little headroom.

jeff

Didn't know about that, thanks for the knowledge. I lowered the bass level a bit and it improved a lot.

 

[rlaudio]

I’ve noticed I started to get an intermittent, but more frequent, high pitched noise coming out of my left channel. Any thoughts on what I can do to eliminate that? Is that a sign the tube might be going? I’ve had mine for a few years, but only use it as my winter amp. I’m still using the original PS Vane tubes that came with it. Maybe it’s time to try some other tubes? Which ones would everyone recommend and which ones would I most likely need to replace to solve the buzz in the left channel? The right channel seems fine.

Thanks for any advice. I love this amp. I’ve got it hooked up to a pair of Kef Q150’s for a nice bedroom system. I have those hooked up to the 4 ohm outlets as I read the Q150’s can dip below 4 Ohms even though they are rated at 8 Ohms.

 

[Nirky]

I’ve noticed I started to get an intermittent, but more frequent, high pitched noise coming out of my left channel. Any thoughts on what I can do to eliminate that? Is that a sign the tube might be going? I’ve had mine for a few years, but only use it as my winter amp. I’m still using the original PS Vane tubes that came with it. Maybe it’s time to try some other tubes? Which ones would everyone recommend and which ones would I most likely need to replace to solve the buzz in the left channel? The right channel seems fine.

Thanks for any advice. I love this amp. I’ve got it hooked up to a pair of Kef Q150’s for a nice bedroom system. I have those hooked up to the 4 ohm outlets as I read the Q150’s can dip below 4 Ohms even though they are rated at 8 Ohms.

Sounds like oscillation. Easy first, switch the output tubes. If no change, try different preamp tube.

 

[rlaudio]

Thanks for the quick reply. I’m clueless when it comes to tube amps and learning. Which are the output tubes? And when you say switch, do you mean swap right to left and see if the problem occurs in the right channel? If so, then replace those output tubes? Are the output tubes the furthest to the edge of the amp? I have the el-34b amp. Thanks so much.

 

[Nirky]

Thanks for the quick reply. I’m clueless when it comes to tube amps and learning. Which are the output tubes? And when you say switch, do you mean swap right to left and see if the problem occurs in the right channel? If so, then replace those output tubes? Are the output tubes the furthest to the edge of the amp? I have the el-34b amp. Thanks so much.

Exactly, switch the EL34's and see if the oscillation follows the tube or stays in the left channel. When I say preamp tube, I mean the driver tubes which gives its signal to the EL34 outputs. I see now from a pic that the amp uses two drivers, one for each channel. Switch those just as you did with the outputs and see if the oscillation is still in left channel.
If neither attempt works, I'd look at the capacitors, cathode caps & coupling caps.

Warning: changing any capacitor could be dangerous if you are not used to working with tube amps as there could still be high voltage present even when unplugged due to the power supply capacitors, which can hold a charge if there is no bleeder resistor in the ps circuit. Be safe and have somebody help you if unsure.

 

[Nirky]

Thanks for the quick reply. I’m clueless when it comes to tube amps and learning. Which are the output tubes? And when you say switch, do you mean swap right to left and see if the problem occurs in the right channel? If so, then replace those output tubes? Are the output tubes the furthest to the edge of the amp? I have the el-34b amp. Thanks so much.

The EL34's are taller than the driver tubes. Scroll up this post to see a pic of an Oldchen amp; the rectifier is center tube, next to it are the left & right EL34 outputs, with the preamp tubes on either side of EL34's.

 

[rlaudio]

Thank you very much for the explanation. Yes, I have that exact amp at the top of this page. The noise seems to have gone away for now (seems intermittent). Maybe it just needed to warm up? So sounds like it could be either the EL34 tubes or those shorter preamp tubes? I think I’ll look into getting some spare tubes for if/when these go. Thank you again for the explanation!

 

[Nirky]

So sounds like it could be either the EL34 tubes or those shorter preamp tubes?

I don't know, you didn't say which switch - the EL34's or preamp tubes - caused the left channel to work correctly again. Having a second set of tubes on hand is always a good idea. I remember when I got my Oldchen, two of the tubes didn't light up! The mfg didn't even bother to test the tubes or amp. They did however send me two replacement tubes, I guess they figured customer service was cheaper/faster than quality control.

 

[rlaudio]

What would you or anyone recommend as replacement tubes? I’d love to try something different than the PS Vane’s if I can get a better/different sound (though I’m not unhappy with the PS Vanes).