What Are You Building Today

[Skooby]

Thumbs-up on the Metcal!  Old tubes sometimes are humming too.

[jose]

Before leaving it, why do not you separate the trafo?

[spritzer]

Yup and swap out the tubes.  Is the shield on the transformer connected to ground?  Ideally it should be earthed... 

[n_maher]

I think you should carefully consider how disappointing it would be to tear it down, rebuild it, and then find the same problem still exists since you didn't bother to try to trace the source this time.  

[Peleus]

6 hours ago, Skooby said:

Thumbs-up on the Metcal!  Old tubes sometimes are humming too.

Thanks, it is old and used machine, but still very, very, useful and reliable one.

Old tubes humming...umh...I think that I may buy some tubes to try. Luckily, the tube is cheap and easily found in Taiwan.

2 hours ago, jose said:

Before leaving it, why do not you separate the trafo?

Well...It may help to confirm the source of humming, but I really need a One-Chassis headphone amp. 

2 hours ago, spritzer said:

Yup and swap out the tubes.  Is the shield on the transformer connected to ground?  Ideally it should be earthed... 

Yes, the shield is grounded. And, Thanks your earthed chassis advice. 

8 minutes ago, n_maher said:

I think you should carefully consider how disappointing it would be to tear it down, rebuild it, and then find the same problem still exists since you didn't bother to try to trace the source this time.  

Yup, You are right. I really be disappointed about the result.

You teach me a good advice that figuring out the problem first.

Thank you!

[Peleus]

Hi guys, 

Guess what? I've solved the humming problem! hu....Finally.

I asked the transformer supplier, and he said the transformer unlikely the source of problem. He suggested me try to ground the heater line. 

After doing some research on the google, I choose this solution, but mod little due to I don't have the pot now.

This is my solution as the below picture showed.

Great, No more hum in the low resistance on-ear headphone.

And More, NO rebuild and major modification again. Thanks God!

And, Thanks you all guys and your suggestions.

Sincerely, 
Peleus, Taipei, Taiwan
 

Edited February 5, 2019 by Peleus

[jose]

While I'm waiting for a custom toroid for my CFAE, I work on my 6SA7g amp. This thing really sounds good but I have a ground loop in someplace and I'm not able to find it.

 

 

Edited February 26, 2019 by jose

[Peleus]

Hi~ 

I just finished the GR regulator for my SONY PCM D50. 

This regulator is from my friend who is the original designer of GR regulator.

The schematic of  GR regulator is not new at all; however, the parts of the GR regulator is very very crucial.

So, check it out and find some awesome points of this new version of GR regulator.

 

[sbelyo]

finished my Twisted Pear BIII Pro SE (9028)

 

[mwl168]

Nice one Steve!

Is that the Mercury or IVY I/V stage you are using?

I also have the Cronus re-clocking and isolator with my dual-mono Buffalo II and , in my experience, a worthy investment!

[sbelyo]

That is an IVY III   I used PRP resistors, Nichicon Muse caps, Amtrans caps, and swapped out the opamp in the BAL/SE stage.  If you search the IVY thread on Diyaudio there's a record of what i did.  I'm going to build one more IVY with more tweaks just to see what it sounds like.

[randytsuch]

Thought I would share a pic of my current project as an introduction, since this is my 2nd post here.

The board is from Tubelab, its his Single Ended board, so this is a TSE amp.

For you purists, it uses sand for a current source, they are under the board so you can't see it in the pics.

Big tubes are 45's, driving Electraprint output iron which were wound for headphones, 5k@50ma  with 46 and 300 ohm secondaries

Edcor power tx, 5V4 rectifier into a CLC filter for B+ of 300V, and for now, a fairly simple DC reg for the DHT heater power.

Working on its chassis now, a wooden box made from curly maple.  The TSE pcb will be under a fiberglass plate that is all drilled out and ready.

I have a few other coupling caps I will try out, see what I like the best.

I also have a Coleman DHT filament heater that I am planning to use to drive the heaters in the 45's.

I'll also have a wiki page at some point soon, with more details on what's inside and how it was built.

Randy

 

 

[sbelyo]

I had acquired all the parts to build one except for the power transformer.  I too have a set of electraprint output with a 5K primary and 32, 80, 120, and 300 secondaries.  I sold the board and components but kept the OPT's and the 45 tubes.  Someone on DIYaudio had said that the secondary values I chose would be too noisy for headphones.  How does it sound on the 64 and 300 ohm taps?

[randytsuch]

51 minutes ago, sbelyo said:

I had acquired all the parts to build one except for the power transformer.  I too have a set of electraprint output with a 5K primary and 32, 80, 120, and 300 secondaries.  I sold the board and components but kept the OPT's and the 45 tubes.  Someone on DIYaudio had said that the secondary values I chose would be too noisy for headphones.  How does it sound on the 64 and 300 ohm taps?

So build is only a few weeks old, and still in flux.

I've mainly been using my he500's and the 64ohm taps, and it sounds great (IMHO).  Might be my new toy bias, but I'm happy with this combination.

Somewhere else I saw someone say 45's and orthos make a good combination, and based on my amp I'd have to agree.

With HD800's and 300 ohms, there is some background noise.  I think its coming from my B+, and I bought another inductor to make a CLCLC filter for B+ to knock down the noise.  To get B+ down to 300V, I'm using a pretty small cap for the first C, 1 or 2 uf.  This lowers B+, but makes more ripple than if I had a larger cap here.

I'll let you know how the 800's sound after I add the 2nd inductor.  I also have a different rectifier tube to try, got it last week, GZ30.  It would be underpowered for a 300b amp, but should be fine for a 45.

Did the diyaudio person tell you about the noise from experience, or from "knowledge"?  I'm not sure why those taps would be noisy?

What cans are you using?

BTW, I actually started this build maybe 5 years ago.  Researched, bought the TSE board, and most of the parts.  Even stuffed the board for the most part.  Oh, and did a not of work making custom heat sinks.  But I couldn't decide on the output tx, and wanted to be able to use either 300b or 45's and wanted to have a 2 chassis design.  Made it too complicated, so I just pushed it aside lol.  Resurrected beginning of the year, bought the electraprint iron and a few other bits and pieces, and got it running.  Really glad I did.

Randy

[jose]

Very interesting ... I have nothing with output trafos in my collection. Could you put the Tubelab link?

[sbelyo]

http://tubelab.com/

[randytsuch]

Tubelab SE

This is what I built. 

Since 45's run on a lower bias current, an output tranny for a 45 amp is cheaper than a 300b tranny, so while the iron wasn't cheap, it wasn't as much as I thought it would be.  I bought the low imd version, which adds a bit to the cost.  He wound quickly too, my iron was delivered to my house a week after I paid for it.

Its their DHT board.  Does take some research and figuring stuff out, because it supports different tubes you need to pick a tube, and then pick the iron and some other parts based on your tube.

EDIT:  He's revising the TSE to replace obsolete parts and make some other tweaks, I don't think the new board is available yet but it should be out pretty soon.

BTW, one other "problem" I had.  When I was swapping rectifier tubes soon after I got it running, I accidentally hit the switch to use the 300 ohm secondary.  When I listened to my he500's like this, amp would distort when playing louder passages in a song.  I thought somehow I had broken something, until I figured out the switch was in the wrong position.  All good when I switched it back.

I running it at a relatively low bias, around 25 ma.  If I upped the bias, should put out more power before it distorts, but I don't need the power as long as the switch is in the right position lol.

 

Randy

 

[sbelyo]

25 minutes ago, randytsuch said:

So build is only a few weeks old, and still in flux.

I've mainly been using my he500's and the 64ohm taps, and it sounds great (IMHO).  Might be my new toy bias, but I'm happy with this combination.

Somewhere else I saw someone say 45's and orthos make a good combination, and based on my amp I'd have to agree.

With HD800's and 300 ohms, there is some background noise.  I think its coming from my B+, and I bought another inductor to make a CLCLC filter for B+ to knock down the noise.  To get B+ down to 300V, I'm using a pretty small cap for the first C, 1 or 2 uf.  This lowers B+, but makes more ripple than if I had a larger cap here.

I'll let you know how the 800's sound after I add the 2nd inductor.  I also have a different rectifier tube to try, got it last week, GZ30.  It would be underpowered for a 300b amp, but should be fine for a 45.

Did the diyaudio person tell you about the noise from experience, or from "knowledge"?  I'm not sure why those taps would be noisy?

What cans are you using?

BTW, I actually started this build maybe 5 years ago.  Researched, bought the TSE board, and most of the parts.  Even stuffed the board for the most part.  Oh, and did a not of work making custom heat sinks.  But I couldn't decide on the output tx, and wanted to be able to use either 300b or 45's and wanted to have a 2 chassis design.  Made it too complicated, so I just pushed it aside lol.  Resurrected beginning of the year, bought the electraprint iron and a few other bits and pieces, and got it running.  Really glad I did.

Randy

If I remember it was from knowledge only.  I was going to build it around the same time frame you mention and at that time I don't think there was anyone using it with headphones.  I bought the custom iron, the board, and all components and then wound up selling the board and components to fund other projects at the time.  There's a TSE 2.0 board coming soon so I think I'll revisit this.

Definitely keep us posted on your efforts

[randytsuch]

46 minutes ago, sbelyo said:

If I remember it was from knowledge only.  I was going to build it around the same time frame you mention and at that time I don't think there was anyone using it with headphones.  I bought the custom iron, the board, and all components and then wound up selling the board and components to fund other projects at the time.  There's a TSE 2.0 board coming soon so I think I'll revisit this.

Definitely keep us posted on your efforts

I don't remember ever seeing anyone say that, but can't read all the posts lol.

Yeah, definitely not a lot of headphone TSEs out there that I know of.  Think there are more of the Tom Christiansen 300B Amps, but that's a more expensive build.

I'll see if I have time to play with the B+ filtering soon, but trying to finish the chassis and the NCAA tourney are taking up most of my free time right now lol.

A VERY preliminary version of my site for this build

Randy's TSE Site

Really need to add some pics to it.

 

Randy

 

 

 

[randytsuch]

For anyone following my project, I added another inductor and cap last night.

So now I have a CLCLC filter for B+.  Inductors are both Triad C-14X, 6H, 150 ohm, 200 mA.  Caps are 1uf, 47uf and 100uf right now.   B+ is now around 290V.

So I added the 47uf cap and 2nd inductor.  Didn't measure AC ripple before.  I tried with the meter I have on B+, but it gave me an ac number I didn't believe, hundred of volts.

But my subjective take is that noise level is down.  I tried with HE500 and HD800, and with both background hum is gone.  I heard a little noise, but I'm pretty sure its from the tubes I have installed, going to swap them out and see if that fixes the last bit of noise.

[jose]

You should try the most sensitive headphones you have ... or at least that's what I usually do.

[randytsuch]

55 minutes ago, jose said:

You should try the most sensitive headphones you have ... or at least that's what I usually do.

The only cans I plan to use with this amp are the hd800, he500 and alpha dogs.  Of these, the 800's are the most sensitive and I heard hum with them before adding the 2nd inductor.

Based on psud, adding a LC stage knocks the ripple way down, and based on what I hear I would have to agree.

[jose]

I always use an ATH or a Grado even if the amplifier is not intended for them. If you have any noise, those cans will tell you.

About the output. How do you select the secondary that you are going to use? It is not appreciated very well. Do you have a kind of selector?

[randytsuch]

16 minutes ago, jose said:

I always use an ATH or a Grado even if the amplifier is not intended for them. If you have any noise, those cans will tell you.

About the output. How do you select the secondary that you are going to use? It is not appreciated very well. Do you have a kind of selector?

I have a limited selection of cans, no grado's and no AT's.   I could connect IEM's to the amp I suppose.

In the picture I posted above, you can see red back of a double pole switch on the far right.   The output transformers are to the left of that, laying on their sides, and the headphone output jack is just below the switch.  So the switch is wired between the output transformers and the output jack.

[randytsuch]

My chassis is almost done now, finally.

Took a quick pic this morning, lighting not good, but will give you an idea.

The front accent pieces cover a drilling mistake lol.

 

I tried to add a pic of the top, but I think I reached my size limits for uploading pics maybe?