aristocrat said:
You can take the same voltages. This is to simplifie it. Normaly you must measure the anodevoltage( B+), Aquire the max. power rating of the tube and then calculate the biascurrent. There is a excel sheet to do that but to keep it simple use the value above.
Excel calculation
http://www.ict-net.net/load.xls
keithgreenhalgh said:I'm confussed!Are you saying that I should set the bias to .4 to .45volts giving me a current of 40 to 45 ma. on my yaqin 100B amp.Why would the people building the amp recromend a higher current and how will this affect the power output? Are we sure about this?
The higher the current the longer the amp works in class A but the shorter the live of the tubes. A current of 40/45mA is gives no sound disadvantage but give longer tubelive. No less poweroutput.
keithgreenhalgh said:Also on the schematic,where are the test points for adj the voltage?
boboo said:
The points are there where they always are in de Cathode thrue the ground.
Koifarm said:
You said that you have a lot's of experience with this amp and thats very good because than you can tell me why I got that no bass at all.
It's there but nothing to comapere with my hudred years old harman Kardon 730 twin receiver.
This junk just realy don't satisfy me at all!
It is possible that your loudspeakers need a lot of power for the bass because of low impedance and spl. It is also possible that the input impedance of the amp is lower as the other amp. If your source has a to little output Capacitor the low frequenties will cut off.
To Koifarm
You wrote
"It is possible that your loudspeakers need a lot of power for the bass because of low impedance and spl. It is also possible that the input impedance of the amp is lower as the other amp. If your source has a to little output Capacitor the low frequenties will cut off."
Okay that’s very understandable even for me but how can I improve the quality? Here is the list what I have on each channel
Okay the speakers it’s mostly all JBL .
In one channel for example I got 2x15” bass split in to two, very low so called air suspension cabinet and high bass closed cabinet.
Than, you got two drivers in a wooden horn low and high come in different size with 2 x 4” which overlap the two drivers and just for coloring the sound.
On the top there is one JBL 075 and four Piezzo discount.
Now the other side is almost the same but there is one 15” sitting in one big cube very low frequented faced to the flour to balance and color the other sides air suspension cabinets sound. I got a very rich sound! That’s why it’s so difficult to find other amps because I’m loosing it.
So what do you think?
You wrote
"It is possible that your loudspeakers need a lot of power for the bass because of low impedance and spl. It is also possible that the input impedance of the amp is lower as the other amp. If your source has a to little output Capacitor the low frequenties will cut off."
Okay that’s very understandable even for me
but how can I improve the quality? Here is the list what I have on each channelOkay the speakers it’s mostly all JBL .
In one channel for example I got 2x15” bass split in to two, very low so called air suspension cabinet and high bass closed cabinet.
Than, you got two drivers in a wooden horn low and high come in different size with 2 x 4” which overlap the two drivers and just for coloring the sound.
On the top there is one JBL 075 and four Piezzo discount.
Now the other side is almost the same but there is one 15” sitting in one big cube very low frequented faced to the flour to balance and color the other sides air suspension cabinets sound. I got a very rich sound! That’s why it’s so difficult to find other amps because I’m loosing it.
So what do you think?
You heard of Google... 
First you switch on your amplifier, then use rubber sole shoes and rubber gloves to avoid beeing electrocuted, as another Portugues guy said, you might have letal voltage on the capacitors between the transformers...
Then you switch on your voltmeter to measure DC, low voltage setting, and stick the two ends on the little holes that say BIAS TEST POINT...
Like by magic, the needle of the meter, or numbers if it is digital will move and you will get a value...
Now get the screwdriver, stick it in the appropriate hole, the one for the same tube saying BIAS ADJ, and rotate until is shows the value that the experts told you to use, or what says in the manual...
See, very easy, but be carefull or something painfull to say the least, can happen...
First you switch on your amplifier, then use rubber sole shoes and rubber gloves to avoid beeing electrocuted, as another Portugues guy said, you might have letal voltage on the capacitors between the transformers...
Then you switch on your voltmeter to measure DC, low voltage setting, and stick the two ends on the little holes that say BIAS TEST POINT...
Like by magic, the needle of the meter, or numbers if it is digital will move and you will get a value...
Now get the screwdriver, stick it in the appropriate hole, the one for the same tube saying BIAS ADJ, and rotate until is shows the value that the experts told you to use, or what says in the manual...
See, very easy, but be carefull or something painfull to say the least, can happen...
Lowrider said:You heard of Google...
First you switch on your amplifier, then use rubber sole shoes and rubber gloves to avoid beeing electrocuted, as another Portugues guy said, you might have letal voltage on the capacitors between the transformers...
Then you switch on your voltmeter to measure DC, low voltage setting, and stick the two ends on the little holes that say BIAS TEST POINT...
Like by magic, the needle of the meter, or numbers if it is digital will move and you will get a value...
Now get the screwdriver, stick it in the appropriate hole, the one for the same tube saying BIAS ADJ, and rotate until is shows the value that the experts told you to use, or what says in the manual...
See, very easy, but be carefull or something painfull to say the least, can happen...
Yes sir! Of course I google but on the different sites lIke on those photography and x-ray sites which of course not much to do with my Amp.
And i'm working hard right now as I have a big exhibitoin (one man show) comig up in the autumn in Budapest in the museum there and in May I got to deliver all the images! So I'm not on a 100% google now.
Duch customs canibals
Hallo aristocrat, I recived yesterday my brandnew Yaqin MC-100B ,the trip is followd on internet DHL till he is on Schiphol netherlands. and wil stay there for 3 day,s by the customs for investigation When I open the box I see that the customs canabilised my Yaqin MC-100B with a hammer.The power transformer is totall los. So my request on you is can you send me a better readable scematic pls rgrds from the netherlands
aristocrat said:
Hallo aristocrat, I recived yesterday my brandnew Yaqin MC-100B ,the trip is followd on internet DHL till he is on Schiphol netherlands. and wil stay there for 3 day,s by the customs for investigation When I open the box I see that the customs canabilised my Yaqin MC-100B with a hammer.The power transformer is totall los. So my request on you is can you send me a better readable scematic pls rgrds from the netherlands
Re: To Koifarm
This is a very difficult setup for amps. Usally i use 2 or more amps for this type of setup. My favourits are then Hypex UCD 400 for bass and sub. KT88 amp for mid and high or better a seperate amp also for high ( 300B type ).
If you want to drive this with one amp then you can use Hypex UCD 400 with Tube preamp.
What sources do you use? And do you use the 4 or 8 Ohm LS output connection? When you use both this is not right with a output transformer.When possible draw schematic of the loudspeakers connections and filters.
Dear Boboo, i can say more when you tell my the types of JBL 15" woofers. So i can look up specs.boboo said:You wrote
"It is possible that your loudspeakers need a lot of power for the bass because of low impedance and spl. It is also possible that the input impedance of the amp is lower as the other amp. If your source has a to little output Capacitor the low frequenties will cut off."
Okay that’s very understandable even for me
Okay the speakers it’s mostly all JBL .
In one channel for example I got 2x15” bass split in to two, very low so called air suspension cabinet and high bass closed cabinet.
Than, you got two drivers in a wooden horn low and high come in different size with 2 x 4” which overlap the two drivers and just for coloring the sound.
On the top there is one JBL 075 and four Piezzo discount.
Now the other side is almost the same but there is one 15” sitting in one big cube very low frequented faced to the flour to balance and color the other sides air suspension cabinets sound. I got a very rich sound! That’s why it’s so difficult to find other amps because I’m loosing it.
So what do you think?
This is a very difficult setup for amps. Usally i use 2 or more amps for this type of setup. My favourits are then Hypex UCD 400 for bass and sub. KT88 amp for mid and high or better a seperate amp also for high ( 300B type ).
If you want to drive this with one amp then you can use Hypex UCD 400 with Tube preamp.
What sources do you use? And do you use the 4 or 8 Ohm LS output connection? When you use both this is not right with a output transformer.When possible draw schematic of the loudspeakers connections and filters.
Boboo i just read your other thread. And i must say that you have bought the wrong amp for your speakers.
You can do two things:
1- Sell the yaqin on ebay or so and buy a stable amp like Hypex UCD with tube preamp for the nice sound.
or
2- Modifie the yaqin to you wishes like more bass. I can recommend you the following mods.
- Change tubes, for more and firmer bass i use always this tube setup. 4x EH KT90, 4 EH 6SN7 and 2 x EH 5751 Goldpin. if this is not enough,
- I change Capacitors C6 and C7 for Clarity Caps SA 0,47uF.
The input impedance of this amp is quit low, about 20K. So your sources must have at least 1 uF or higher Capacitors at the output.
You can do two things:
1- Sell the yaqin on ebay or so and buy a stable amp like Hypex UCD with tube preamp for the nice sound.
or
2- Modifie the yaqin to you wishes like more bass. I can recommend you the following mods.
- Change tubes, for more and firmer bass i use always this tube setup. 4x EH KT90, 4 EH 6SN7 and 2 x EH 5751 Goldpin. if this is not enough,
- I change Capacitors C6 and C7 for Clarity Caps SA 0,47uF.
The input impedance of this amp is quit low, about 20K. So your sources must have at least 1 uF or higher Capacitors at the output.
Koifarm said:
you were faster than me no wonder I work with my exhibition to at the same time but you can read it anyway even if you been on the otherside, Here it goes!
Gosh' than I got to open all the boxes to give you more specks on each elements because I don't remember any longer. what I know for sure that the system is 8 ohm and aruond a 110 db.
big sound very powerful but what is more intresting that it works fine with this old harman kardon 730 twin powered receiver.
I had tryed to replace the harman many times because it's sick and had been for a long time now and barrowed a lots of powerful things well known amps recivers they all cross my living room but it were the same as with the yaqin. Only the Harman works and do a job sound big on all frequences deep powerful bass and marcant discant. For ecxample a cube sound actualy only with four or five songs and when it does everybody jumps and my glasses shakin in the kitchen.
When I find the yaqin I thoght finaly I find the right one but couldn't listen to it because it were in Hong Kong. But I thought this is a twin to so maybe it would do the job.