WTD: valve integrated

[Lawrence001]

Want to try something with my new Celestions. Have owned a couple in the last few years, a Yarland FB34B, and an Opera Consonance Cyber I got for £400, and I'm looking for something in a similar price range of similar quality. Wish I had kept one of them now!

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[Lawrence001]

Now sorted at last, just need to get the bias sorted out as my digital multimeter is not really available and I can see the glow brightly through the plates of two of the EL34s and they are chucking off a lot of heat!

[Edward]

Now sorted at last, just need to get the bias sorted out as my digital multimeter is not really available and I can see the glow brightly through the plates of two of the EL34s and they are chucking off a lot of heat!


Oh what did you get Lawrence?

[agk]

I wouldn't worry about the heat as tubes do get pretty hot.

[Lawrence001]

Yarland FV34B same as I stupidly sold last year. One of the best budget valve amps out there and rarely available as I guess people keep them.

The bias is definitely set wrong on one side as both valves light up like I've never seen before, I imagine if you can see the glow through the metal of the plates they are definitely running too hot. Also the glass shelf above was too hot to touch above those 2 valves after just a few minutes.

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[agk]

Oh definitely bias the thing chap, I just mean expect it to get hot especially with a shelf above. As you've already owned it you'll know it better than me so I shall get my coat...

[struth]

must be drawing a lot lol. yes get em checked. valves could be goosed too

[Edward]

Yarland FV34B same as I stupidly sold last year. One of the best budget valve amps out there and rarely available as I guess people keep them.

The bias is definitely set wrong on one side as both valves light up like I've never seen before, I imagine if you can see the glow through the metal of the plates they are definitely running too hot. Also the glass shelf above was too hot to touch above those 2 valves after just a few minutes.

Sent from my NEM-L51 using TapatalkVery nice Lawrence.

Pity about heat. As you say probably the bias. But maybe a valve has gone south as well.

I have an old analog volt meter you can borrow if you like. I just tested it against a digital multimeter, it is spot on.

You know how to contact me if you are interested.

Ehttps://uploads.tapatalk-cdn.com/20170828/8db54d27dd6bd429a62a59637b05f7e8.jpg

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[Arkless Electronics]

Now sorted at last, just need to get the bias sorted out as my digital multimeter is not really available and I can see the glow brightly through the plates of two of the EL34s and they are chucking off a lot of heat!

If we get beyond the Americanisms... I presume the anodes are glowing red? This is indicative of a major problem. Do not use it like that if you value your output transformers and mains transformer. Either blown valves (not tubes FFS! :steam:), faulty/well out of adjustment bias supply (if it is a fixed bias unit... counter intuitively, you can adjust the bias on fixed bias amps... but not on cathode bias amps... It shouldn't really be possible to set the bias so low that they glow if properly designed) or duff capacitors.

[Lawrence001]

Thanks Edward appreciate the offer. I've got an analogue one somewhere but I'm not sure its that accurate even after calibration. Also it has crocodile clips when I need probes. I think I'll temporarily under bias the valves until I can get hold of my digital meter.

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[Edward]

Equally you can borrow my multi meter - but I would want it back within a few days.

But I wonder if the amp has been left on for some time without a speaker (or dummy) load. Not a "good" thing.

But I'm sure Jez can give precise details from an EE point of view.

E

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[Lawrence001]

I don't think so the previous owner knew what he was doing and gave it to his nephew with some Klipsch speakers but he just wanted to sell them and only took them out of the box to take pics.

I calibrated my meter to 0 ohms resistance then tried it. The correct bias is 0.32v and the meter shot off the 0.5v scale. Have biased to 0.25v for now and will listen later.

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[Lawrence001]

There are a few flecks of whitish material on the inside of the bottles not sure if this shows they have been pushed too far. Will try some new tung sols I have if needed.

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[Lawrence001]

Just saw all the other advice, thanks for that, it's strange tapatalk was only showing Edward's posts previously. In the light of the above I might move straight on to the tung sols.

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[Arkless Electronics]

I don't think so the previous owner knew what he was doing and gave it to his nephew with some Klipsch speakers but he just wanted to sell them and only took them out of the box to take pics.

I calibrated my meter to 0 ohms resistance then tried it. The correct bias is 0.32v and the meter shot off the 0.5v scale. Have biased to 0.25v for now and will listen later.

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:scratch: You only need to do that to measure resistance. I presume from this you are using an analogue meter...

[Lawrence001]

:scratch: You only need to do that to measure resistance. I presume from this you are using an analogue meter...The only calibration available is a knob that says 0 ohms calibration on it so I assumed this was the way you set the initial position of the needle and the rest all fell into place from factory settings. Otherwise the voltage cannot be calibrated without a known reference voltage(which I don't have)?

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[Arkless Electronics]

The only calibration available is a knob that says 0 ohms calibration on it so I assumed this was the way you set the initial position of the needle and the rest all fell into place from factory settings. Otherwise the voltage cannot be calibrated without a known reference voltage(which I don't have)?

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:scratch: again.... With the meter set to Ohms you short the probes together and the needle should go up to 0 Ohm which will be nearly full scale deflection. You set it to the zero using that control. It applies only to resistance readings. If there's no or dead battery/ies in it then the Ohms scales won't work but everything else is unaffected.

Voltage and current readings obviously start at zero and you set this zero point (if it needs setting. It's usually set and forget) with the screw through the little hole just below the needle pivot point, usually in the perspex or Bakelite. You don't need to calibrate anything beyond this.

When setting the bias what we really mean is the - (minus) volts applied to the first grid of the output valves, about -30-40 ish volts for the EL34 IIRC. A resistor of, in your case I'll hazard an educated guess of 10R (R is short for Ohms up to 999), is between the cathodes and ground and so this measures the actual current by the voltage drop across the resistor (Ohms Law). 0.32V/10R = 0.032A or 32mA.

[itskeith]

Hi Lawrence,

Got a Puresound A30 for sale. Info here:
http://theartofsound.net/forum/showthread.php?52743-For-Sale-Puresound-A30-Integrated-Valve-Amplifier

Bit over your budget, but very highly regarded. Selling for the same price I paid for it and have seen them go for a lot more than this!
Keith

[Edward]

I don't think so the previous owner knew what he was doing and gave it to his nephew with some Klipsch speakers but he just wanted to sell them and only took them out of the box to take pics.

I calibrated my meter to 0 ohms resistance then tried it. The correct bias is 0.32v and the meter shot off the 0.5v scale. Have biased to 0.25v for now and will listen later.

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Showing my ignorance here, but how come on my Radford I set the bias to 2.00v but yet on your amp it is set to only 0.32v?




There are a few flecks of whitish material on the inside of the bottles not sure if this shows they have been pushed too far. Will try some new tung sols I have if needed.

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I had that on one of my EL34s recently. Turned out that the valve (tube :) ) had given up the ghost.


Just saw all the other advice, thanks for that, it's strange tapatalk was only showing Edward's posts previously. In the light of the above I might move straight on to the tung sols.

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I was using Tapatalk earlier and you received an instant notification via Tapatalk - on non Tapatalk posts there will be a delay as Tapatalk I assume does not see non Tapatalk posts in real time.

Anyway, good luck with things.

Did you see this (https://www.head-fi.org/threads/how-to-bias-the-yarland-fv-34a-tube-amp.590131/)? Scroll towards the end.

[Arkless Electronics]

Showing my ignorance here, but how come on my Radford I set the bias to 2.00v but yet on your amp it is set to only 0.32v?





I had that on one of my EL34s recently. Turned out that the valve (tube :) ) had given up the ghost.



I was using Tapatalk earlier and you received an instant notification via Tapatalk - on non Tapatalk posts there will be a delay as Tapatalk I assume does not see non Tapatalk posts in real time.

Anyway, good luck with things.

Did you see this (https://www.head-fi.org/threads/how-to-bias-the-yarland-fv-34a-tube-amp.590131/)? Scroll towards the end.

Those resistors I mentioned are 39R on an STA25. 2V/39R = 51mA. This is a more typical figure. Either the bias on the OP's amp is set to maximise valve life or my guess that the resistors in his are 10R is wrong.... If they are 6.8 then the current is about the same as on yours. I'll make another guess that I'm probably right and they are set low to prevent problems with original equipment el cheapo Chinese EL34's self immolating!

[Lawrence001]

Hi Lawrence,

Got a Puresound A30 for sale. Info here:
http://theartofsound.net/forum/showthread.php?52743-For-Sale-Puresound-A30-Integrated-Valve-Amplifier

Bit over your budget, but very highly regarded. Selling for the same price I paid for it and have seen them go for a lot more than this!
KeithThanks I did enquire about the cage a few days ago but in the end decided I wanted to collect and I'm not going to Nottingham at any point in the near future, whereas I managed to get a day trip planned to Oxford to collect the Yarland.

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[Lawrence001]

:scratch: again.... With the meter set to Ohms you short the probes together and the needle should go up to 0 Ohm which will be nearly full scale deflection. You set it to the zero using that control. It applies only to resistance readings. If there's no or dead battery/ies in it then the Ohms scales won't work but everything else is unaffected.

Voltage and current readings obviously start at zero and you set this zero point (if it needs setting. It's usually set and forget) with the screw through the little hole just below the needle pivot point, usually in the perspex or Bakelite. You don't need to calibrate anything beyond this.

When setting the bias what we really mean is the - (minus) volts applied to the first grid of the output valves, about -30-40 ish volts for the EL34 IIRC. A resistor of, in your case I'll hazard an educated guess of 10R (R is short for Ohms up to 999), is between the cathodes and ground and so this measures the actual current by the voltage drop across the resistor (Ohms Law). 0.32V/10R = 0.032A or 32mA.Thanks for that, I forgot about the little screw setting, all done now!

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[Lawrence001]

Showing my ignorance here, but how come on my Radford I set the bias to 2.00v but yet on your amp it is set to only 0.32v?





I had that on one of my EL34s recently. Turned out that the valve (tube :) ) had given up the ghost.



I was using Tapatalk earlier and you received an instant notification via Tapatalk - on non Tapatalk posts there will be a delay as Tapatalk I assume does not see non Tapatalk posts in real time.

Anyway, good luck with things.

Did you see this (https://www.head-fi.org/threads/how-to-bias-the-yarland-fv-34a-tube-amp.590131/)? Scroll towards the end.Looks like these might also be at the end of their natural life then. Thanks for the link I saw that when I had to bias the first one I bought but it was the wrong model. Anyway this one came with the manual which had the information in. (Including how to connect the "louder speakers", I wonder if you can use quieter speakers too??).

So I rebiased it with the Tung Sols and after a warm up period of an hour or so it suddenly came to life and glorious music was forthcoming. At last I've got my Virgos sounding just right. Somehow even the bass is tighter with this amp than my 1000wpc class d power amp. If you are still looking for some nice wife and valve friendly speakers Edward, you are welcome to come and hear these, I would recommend them to anyone.

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[Lawrence001]

Ps if anyone has a couple of 6N3P valves(preferably EV) or maybe 5670s, then I'd be very interested, will start a wanted thread shortly.

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[itskeith]

Thanks Lawrence, Hope you have fun with the Yarland.

[Edward]

Looks like these might also be at the end of their natural life then. Thanks for the link I saw that when I had to bias the first one I bought but it was the wrong model. Anyway this one came with the manual which had the information in. (Including how to connect the "louder speakers", I wonder if you can use quieter speakers too??).

So I rebiased it with the Tung Sols and after a warm up period of an hour or so it suddenly came to life and glorious music was forthcoming. At last I've got my Virgos sounding just right. Somehow even the bass is tighter with this amp than my 1000wpc class d power amp. If you are still looking for some nice wife and valve friendly speakers Edward, you are welcome to come and hear these, I would recommend them to anyone.

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Good to hear that things worked out ok and yes your Virgo 'louder' speakers look awesome. Yes it would be great to hear your new setup sometime - North London bakeoff! :)

[Lawrence001]

I'll try and organise something when I've got the house to myself. Which is rare these days :(

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[Lawrence001]

Just an update to this which might be of interest to some. I had started to tire of the sound a little and, after a bias check showed they had not drifted, I thought I'd try some new Shuguang EL34s. This is what the amp first came with but I hadn't tried them as I thought the Tung Sols would be an upgrade. Anyway, the amp is now sounding as sweet as I remember my last one sounding. So the moral here is either that Russian valves are not necessarily better than Chinese ones, or it is often better to replace valves with the ones the amp was voiced with than to upgrade them.

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