Bottlehead Forum
Bottlehead Kits => Legacy Kit Products => Stereomour => Topic started by: srhombeus on June 10, 2014, 11:37:25 PM
-
Hi All,
I'm a new member from Turkey.My stereomour kit is shipped yesterday.And I have a few questions to ask you.. How will be voltage measurements for 240V transformator? I think it will be different from the manual results.. And also I am planning to build the kit as 4 ohm,I will use it with my visaton B200s. They are at 6 ohms.
I think ı would have more questions when ı'll receive the kit. :)
Ä°t's great to be a member of bottlehead community.
-
The voltage measurements are not taken on the incoming line side of the transformer. So the output voltages and the rectified voltages will all be the same as in the US. There was one Bottlehead who had a 220V incoming rather 240 and the output voltages ran a little low.
As always, with an odd impedance, try each secondary tap and see which sounds the best to you.
-
Thanks for your answer sir.Our country has also 220V. It looks there will be some change in the measurements..
-
The problems people are having with 220V is on the Paramount. The Stereomour uses a different power transformer and is a completely different design. There was one person on the forum who was concerned about having issues with their Stereomour before it even arrived (sound familiar...?). He never posted a followup about whether or not he had any issues with the built amplifier.
As for impedance selection, 6Ω is a nominal figure- all speakers have varying impedance over different frequencies. It's fine to have a higher impedance speaker on a low tap, but lower impedance being driven by high is something you always want to avoid. Looking at the graph, your speakers are below 8Ω from 70Hz to 4KHz. 4Ω is the much better choice in this instance; set it and forget it.
-
Thanks for your informations,I just wanted to get some information about measurements before i start to assembly.I don't think there will be any problem with the kit,because there are also a few guys who are using stereomour in my country with 220V..
The problems people are having with 220V is on the Paramount. The Stereomour uses a different power transformer and is a completely different design. There was one person on the forum who was concerned about having issues with their Stereomour before it even arrived (sound familiar...?). He never posted a followup about whether or not he had any issues with the built amplifier.
As for impedance selection, 6Ω is a nominal figure- all speakers have varying impedance over different frequencies. It's fine to have a higher impedance speaker on a low tap, but lower impedance being driven by high is something you always want to avoid. Looking at the graph, your speakers are below 8Ω from 70Hz to 4KHz. 4Ω is the much better choice in this instance; set it and forget it.
-
Hi again.I finally received the kit today.Thanks for great packing.I started to assembly very fast.But unfortunately,while soldering the pcb,i made a mistake with the 300k ohm 3 watt resistor.While desoldering I brake one lead of the resistor and It's impossible to solder it now.. Is it possible if i can substitute it with an other resistor in my country? I am waiting for your advices.Thank you very much.
-
Sounds like you are not near any store that might have a replacement part.
Would it be possible to solder a piece of wire to the resistor where the lead broke off? Is there any part of the lead left there?
-
No unfortunately,there's no lead left on the resistor..
I will look at the stores but i don't think that i will find the same part with same specs. I completed 2 boards today but unfortunately just this part is missing.
Sounds like you are not near any store that might have a replacement part.
Would it be possible to solder a piece of wire to the resistor where the lead broke off? Is there any part of the lead left there?
-
Luckily, the 300K/3W part isn't an incredibly sensitive value.
You can probably find a 270K resistor easily enough, and a 2W or 3W part will work well. (We don't recommend a 1W resistor here, it will get hot enough to char your driver PC board)
You could also go a little over 300K, a 330K 2W resistor would also be OK.
Let us know if we can be of any additional assistance.
-PB
-
Thanks for your help.Tomorrow i will look at the stores for these specs.I would also like to ask you if the side of the resistor is important while assembling ? Does it have negative,positive side ?
-
Nope, resistors can go in any way you like.
-PB
-
Hi,I just found 301k 2 watt metal film and 330k 2 watt carbon resistor from the stores. Which one do you suggest that i use ? 301k 2 watt is really smaller than the one you send with the kit..
-
Since both are 2W I would use the 301k since it is essentially the design value.
-
Thanks for your answer.I checked the ohms with the voltmeter.No problem with the ohm,but how can I check the wattage of the resistor ? I am not sure if the seller had mistake,because this resistor is nearly the half of the old one..I don't want the blow the pcb because of this cheap part.
-
Sometimes the power rating is written on the resistor sometimes it is not. I don't know another way to verify its power rating.
-
No problem with the ohm,but how can I check the wattage of the resistor ?
You can't really do that, other than finding the part number and reading the datasheet.
The part that we include with the kit is a 3 Watt part that seems to be a bit conservatively rated. There are 2W parts that are indeed much smaller.
-
Thanks again for your replies.But unfortunatly there are also 2 screws missing for the terminal strips screws.I will place an order for replacement of these two screws and also for these two resistors if possible. Because i couldnt find inch screws in my country.I think I am a little bit unlucky..
-
Hi,while soldering Ac filaments of the 9 pin socket,I've noticed that one lead is different.I think it's in the reverse position.Do I need to fix this lead or there won't be any problem for connection?
-
Hi,while soldering Ac filaments of the 9 pin socket,I've noticed that one lead is different.I think it's in the reverse position.Do I need to fix this lead or there won't be any problem for connection?
Can you be a bit more specific about page number and instruction?
Also, if you're missing a #4 screw, a similar M3 screw will likely work in its place.
-PB
-
One lead (solder part) of the 9 pin socket is in reverse position,it looks like it's in opposite direction.
And for the screw I tried too many metric sizes but i didn't find suitable one.But yesterday Mrs. Eileen send me the screws and resistors.
-
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fs30.postimg.org%2F45pw3b1gx%2FIMAG0007.jpg&hash=6ada2f87ce27c0139ac45c95b3d6463c12524e9a)
-
Well that's odd, that pin of the 9 pin socket has a PC board pin instead of a solder lug.
That pin will still work if you'd like to use it, you will have to carefully wrap your wire around it.
That is very unusual, I don't believe that I've ever seen that production error from our socket supplier.
-PB
-
It was hard to explain without a picture :). My only concern was,there are two cables wrapped around this pin.But I dont think that will be a problem with the connection..
-
I've finished the assembly today.But unfortunately there's no sound in left channel and there are cracks,pops in both channels.I've changed the inputs and tubes but it's allways left channel.I don't know where to start.Resistance check looks okay,tubes glows properly.But I think there are some problem with AC/DC checks.. 2a3 tubes looks 2 volt instead of 2,5 for example.
-
The place to start would be with posting your DC voltages.
-PB
-
Volume pot has burned when I last turn on the amp.. Can i still make voltage/Dc check ? Should it be plugged to the electricity ?
-
Can you take a photo of what your volume pot looks like? And maybe some general photos of the build.
It would be very unusual for the pot to dissipate any heat whatsoever.
-
I will post the pictures.Can i still make the voltage checks? From manual,I understand that the amp should be turned off and uplugged from electricity while doing voltage measurement?
-
From manual,I understand that the amp should be turned off and uplugged from electricity while doing voltage measurement?
The amp has to be plugged in and turned on to measure voltages.
-
I checked again the solder points.But now,when I turn on the amp,there's no smoke but there's some sound like small explosion.. when i hear it,i turn off the amplifier.I don't know where this sound come from.And now,the two leds near to the volume pot doesn't glow. I checked the fuse,there's no problem with it.It's working..
-
Do not turn the amp on again. Go back and do the resistance measurements and report to us any terminals that are not the same as the manual.
-
Do not turn the amp on again. Go back and do the resistance measurements and report to us any terminals that are not the same as the manual.
There's no movement on terminal 2. All of them are in range..
-
Maybe you can just start with the pictures?
-
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi.hizliresim.com%2FjzPaXr.jpg&hash=8a886805ce59b5dd9bcbde153cea76513387bd5e)
-
I think that the problem is with the red led,because when i check with voltmeter,there are electricity until OA.I resoldered all parts in this board.
-
I've noticed that i made a big mistake.. After changing the broken 330 kohm resistor,I forgot the connect the cable going through bA pad - bB pad . I hope I didn't damaged any 2a3 tube etc. Now i will reorder active load pc board. Because it's really dirty with remaining solders and i don't know which parts are damaged. And also i need a potentiometer,i plan to buy alps blue velvet 100k if it's suitable for stereomour. I think that will be the longest assembly process in the forum,i am a real amateur. Sorry for asking too much question,but i am waiting for your advices.
-
A 100k Ohm volume pot is the universal replacement for all Bottlehead products.
-
A 100k Ohm volume pot is the universal replacement for all Bottlehead products.
Thanks for your reply. I think the problem is in active load pc board,probably leds. How can i check the power supply board correctively? Because I heard little explosion sound 2 times when i turn on the amp,i think it was from 2 leds blown.. I have to understand which parts are defeated before ordering.
-
Sorry for asking too much questions.But today I plan to order new active load pc board with all parts.How can I be sure that other parts are all okay? Fuse is okay,there was no smoke from transformators.Tubes looks okay. Just two leds are not glowing,and there was a smoke from potentiometer,today i placed an order for alps blue velvet 100k. And I will replace an order for the remaining parts after your informations. For the resistance measurements,only terminal 2 looks not in range.All of them looks ok. I can't find all parts in my country,so i am thinking to order all needed parts in one time. Thanks again.
-
Does your 100K pot look OK?
You may have had the solder joint on pin 1 of the 9 pin socket touch pin 2 of the 9 pin socket, which would warm up your pot pretty quickly.
-PB
-
Does your 100K pot look OK?
You may have had the solder joint on pin 1 of the 9 pin socket touch pin 2 of the 9 pin socket, which would warm up your pot pretty quickly.
-PB
There was a smoke on the 100k pot,I've ordered alps blue velvet for replacement. And also 2 red leds dont glow.I've ordered new cs4 board from mrs. Eileen tonight. My question is how can I test power supply board? Because i dont want to burn another parts when i turn on the amp again.
-
You can run the amplifier with the 2A3's installed to test the power supply board.
A DC voltage of 55-65V on pins 1 and 4 of each 4 pin socket would indicate a working power supply PC board.
-PB
-
How can i disconnect c4s board while doing that? Do i have to take off all the cables coming from power supply board to c4s board ?
You can run the amplifier with the 2A3's installed to test the power supply board.
A DC voltage of 55-65V on pins 1 and 4 of each 4 pin socket would indicate a working power supply PC board.
-PB
-
How can i disconnect c4s board while doing that? Do i have to take off all the cables coming from power supply board to c4s board ?
If the C4S board is out of the amp, you're OK. The two black wires that go to bA and bB should be temporarily soldered together. The red wire leaving the high voltage supply on the PC board can poke up in the air, just don't touch it while you're testing.
-
You mean the two black wires coming from -reg of each side? And there are also two red wires of high voltage of power supply board. Do i have to take two of these wires and also black ground wire?
If the C4S board is out of the amp, you're OK. The two black wires that go to bA and bB should be temporarily soldered together. The red wire leaving the high voltage supply on the PC board can poke up in the air, just don't touch it while you're testing.
-
Yes, sorry, the -reg wires need to connect to each other.
The red high voltage wires can be left floating in the air.
-
Ok,and the ground cable leaving the power supply board,do i have the take it out also? Because I am planing to take completly out the c4s board before connecting to new one ..
Yes, sorry, the -reg wires need to connect to each other.
The red high voltage wires can be left floating in the air.
-
The GND cable leaving the power supply board is one of the two black wires that you need to connect together.
If you disconnect it at the power supply end, then you will open the circuit that would allow current to flow through the power supply, and you will be unable to test the board.
-PB
-
Sorry but I totally dont understand it.. Because there are three black cables leaving the power supply board.Two of them are K cables going through terminals and the third one is GND cable..
The GND cable leaving the power supply board is one of the two black wires that you need to connect together.
If you disconnect it at the power supply end, then you will open the circuit that would allow current to flow through the power supply, and you will be unable to test the board.
-PB
-
The K wires are not ground wires, they allow the cathode bypass capacitors to attach to the hum pot on the 2A3's. Those wires need to be left in place.
The black cable leaving the power supply PC board GND pad needs to connect to the black wire that connects from -reg to the terminal strip at the front of the chassis.
-
Ok,thank you.I got it know.The ground cable coming from terminal 8.
The K wires are not ground wires, they allow the cathode bypass capacitors to attach to the hum pot on the 2A3's. Those wires need to be left in place.
The black cable leaving the power supply PC board GND pad needs to connect to the black wire that connects from -reg to the terminal strip at the front of the chassis.
-
I've made the measurements.All the values for the power supply board and 4 pin sockets are in range.There is no problem with them.But while checking the 220 ohm resistors,I saw that the value for the terminal 7U to B2 is around 240 ohm and 9U to B7 is around 170 ohm. The amp was turned off and unplugged. Is this a problem,this resistor could be damaged also?
The K wires are not ground wires, they allow the cathode bypass capacitors to attach to the hum pot on the 2A3's. Those wires need to be left in place.
The black cable leaving the power supply PC board GND pad needs to connect to the black wire that connects from -reg to the terminal strip at the front of the chassis.
-
The 220 Ohm resistors are an arbitrary value. The could be 0-5,000 Ohms without noticeable operating changes.
-
Hi,Can i use 240 ohm 1/4 watt resistor instead of 237 ohm in the c4s board?
-
Yes.
-
Hi,I've newly assembled c4s board.4 leds are ok,all tubes are ok.Voltage checks are ok except terminal 2 and 14.they are a little lower than range.The right channel sound ok.There is also sound in left channel but there are some cracks,pops in left channel.I dont use potentiometer now,i am waiting for alps potentiometer to arrive.Where should I check for this left channel problem? Thanks again.
-
I would first clean the left channel tube socket and tube pins. Just remove the 2A3 and insert it 10 times. Do the same thing with the 12AT7, it serves both channels.
Although Bottlehead buys new tubes and sockets either one could have been sitting on a shelf for a decade and have some oxidation on the metal.
-
I've tried this but my problem still continues.I think side C is left channel and side A is right channel.Where do you suggest to look at it for this weird sounds?
-
Please post the actual voltages that you have.
-PB
-
Here are the voltage checks :
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi.hizliresim.com%2FlBkolX.jpg&hash=cc03b37d59b6463a0619a71f91e9b787dbb79f47)
-
Can you triple check that you have a 12AT7 in the 9 pin socket?
It's also possible that you don't have a ground reference for the grids of the 12AT7. Try soldering a jumper between 7 and 8, as well as 8 and 9, the see if that makes your OA/OB voltages fall into line.
-PB
-
Yes it's written U.S.A. 12at7 in the tube. You mean terminal 7-8-9 or pin 7-8-9 ?
-
Terminals.
-PB
-
I've assemled these jumpers.Now terminal 2 is 206-207 but terminal 14 is 77-78. I think this is the problem with this left channel.Where should I look?
Edit : Now there is only a little popps when turning on the amp.But there is no sound on both channels..
-
This suggests that there is an issue with the volume pot, either the pot itself or the way it is wired.
Are the Kreg voltages the same on both sides of the board?
-
I don't use potentiometer now,i am waiting for alps potentiometer to arrive.I just connected the left channel cables from the switch,red to 7 black to 8 and for the right channel's red to 9,black to 8.Ground cables are not connected to 8L. Is there a mistake?
Kregs are same value..
-
Yes, the 100K pot provides resistance to ground for the grids of the 12AT7. Without that path to ground, the operating point of the 12AT7 will move around.
-
I have a cheap B100k potentiometer,i will try with it.Do i have to remove the jumper between 7-8 and 8-9 ?
-
I've connected the potentiometer.I've dettached the jumpers.Now I can hear the sound from right channel,there are no cracks pops but I can hear the sound from left channel when I turn on the volume pot at maximum. I dont understand but the kreg at near power supply is 0,6 now. The terminal 14 , Ob and kreg at B side values are lower than needed range..
-
I think the best course of action here is to take the amp all the way back to stock.
This means obtaining the stock volume pot, and potentially replacing the TL431 regulator that's giving you low voltage.
-PB
-
Now I have connected alps potentiometer,changed the tl431,changed every part right side to left side.Now kreg is 2,5 finally at b side.But voltage at terminal 14 is low,around 80. I can hear the left channel volume when i turn the potantiometer at maximum.Could the problem with the 12at7 tube ?
I've noticed that at maximum volume kreg is 2,5 at b side.And also terminal 9 value is not 0 , it's around 2-3.
-
I've noticed that at maximum volume kreg is 2,5 at b side.And also terminal 9 value is not 0 , it's around 2-3.
This is either a problem with your volume pot, or you have the connections to pins 7 and 8 reversed at the socket. (220 Ohm resistor goes to pin 7, black wire to the PC board goes to pin 8)
If these pins are touching each other, this would also explain the symptoms.
-
I've ordered gold lion 12at7 tube,I will try it tomorrow.My suspect is from the tube's left channel.Because,before when I first assemble the amp,I've burned the potentiometer,and Dac's left output.And I saw some flashing in the 12at7 tube.I think tube's left channel is also burned. Because I've changed every part except this tube. Is it possible?
-
Finally I have great news,I've tried the amp with the new 12at7 tube.This was the last part which is not replaced.It works perfectly.Real music,incredible details..
Thank you very much again Mr.Paul and Mrs. Eileen and all for your great support.