Quote:
It would certainly be the easiest option to get, however, what do you think the projected cost would be, and if i get one that is old, should i re-cap it?
Do some carefull shopping and you might be able to snag one reasonable. I would consider a $275-325 range as a good price. The days of the $100 Dynaco Stereo 70 are long gone.
Always recap ANY older piece of tube gear. In other words change the caps on the driver board. This is good practice and will
in most cases save a set of output tubes if the coupling caps are bad. You don't have to go hog wild and purchase high dollar caps
because you probably will NOT hear that much difference between the expensive caps and the more general type. Replace with the same voltage rating and value. The upgrade to a more expensive cap can come later when your budget will allow for such.
Good hunting..
It would certainly be the easiest option to get, however, what do you think the projected cost would be, and if i get one that is old, should i re-cap it?
Do some carefull shopping and you might be able to snag one reasonable. I would consider a $275-325 range as a good price. The days of the $100 Dynaco Stereo 70 are long gone.
Always recap ANY older piece of tube gear. In other words change the caps on the driver board. This is good practice and will
in most cases save a set of output tubes if the coupling caps are bad. You don't have to go hog wild and purchase high dollar caps
because you probably will NOT hear that much difference between the expensive caps and the more general type. Replace with the same voltage rating and value. The upgrade to a more expensive cap can come later when your budget will allow for such.
Good hunting..
Hi Alex,
I would agree with you. Build something even if it's a kit.
The ST-70 puts out about 35 WPC. Try first something like a 6BQ5 P-P. There are reasons I suggest this that may be more clear later. That will give you 12 ~ 14 WPC. You will understand better about power later.
This should be a fun project for you. The higher voltages increase costs and difficulty. Let the first project be successful. Remember, you are already playing with 250~320 VDC now. I suspect that you will want to play with the design after it's done. By doing this you will be able to better define how a bigger amp goes together.
Relax and do.
-Chris
I would agree with you. Build something even if it's a kit.
The ST-70 puts out about 35 WPC. Try first something like a 6BQ5 P-P. There are reasons I suggest this that may be more clear later. That will give you 12 ~ 14 WPC. You will understand better about power later.
This should be a fun project for you. The higher voltages increase costs and difficulty. Let the first project be successful. Remember, you are already playing with 250~320 VDC now. I suspect that you will want to play with the design after it's done. By doing this you will be able to better define how a bigger amp goes together.
Relax and do.
-Chris
anatech said:Hi Alex,
I would agree with you. Build something even if it's a kit.
The ST-70 puts out about 35 WPC. Try first something like a 6BQ5 P-P. There are reasons I suggest this that may be more clear later. That will give you 12 ~ 14 WPC. You will understand better about power later.
This should be a fun project for you. The higher voltages increase costs and difficulty. Let the first project be successful. Remember, you are already playing with 250~320 VDC now. I suspect that you will want to play with the design after it's done. By doing this you will be able to better define how a bigger amp goes together.
Relax and do.
-Chris
I agree, and I love buiding stuff, and if a build it, I can claim it as my senior project (at my school, all seniors are required to complete a large-scale project) I am looking for a p-p 6bq5 shcematic right now
Hi Alex,
No shortage of schematics available. Look up any of the Heathkit / Eico / Dynaco web sites. I'd vote for an ultralinear type. There are many other brands that were not kits as well. Just grab a pair of output transformers new (Hammond is one brand) rated a little higher than your target output power. Say 20 W for an example.
http://www.triodeelectronics.com/
http://www.one-electron.com/
http://users.rcn.com/fiddler.interport/eico.htm
http://www.one-electron.com/FC_Consumer.html
My Heathkit link is dead. But there is a ton of information out there.
-Chris
No shortage of schematics available. Look up any of the Heathkit / Eico / Dynaco web sites. I'd vote for an ultralinear type. There are many other brands that were not kits as well. Just grab a pair of output transformers new (Hammond is one brand) rated a little higher than your target output power. Say 20 W for an example.
http://www.triodeelectronics.com/
http://www.one-electron.com/
http://users.rcn.com/fiddler.interport/eico.htm
http://www.one-electron.com/FC_Consumer.html
My Heathkit link is dead. But there is a ton of information out there.
-Chris
I found one that looks like fun
http://www.electra-print.com/images/PSA_EL84_reva.pdf
What do you all think? here is the link to the full info about it
http://www.electra-print.com/EL84PSA_2.html
http://www.electra-print.com/images/PSA_EL84_reva.pdf
What do you all think? here is the link to the full info about it
http://www.electra-print.com/EL84PSA_2.html
Not totally gone, but you have to look in out of the way places. I got one for $25 an a church rummage sale 2 blocks from my house. I also got one for $50 at a flea market that was down a dirt road in rural Ohio.
My wife and a few of her friends were out yard sale shopping here in Fort Lauderdale. She called me to tell me she found something that looked like it had tubes in it, but the tubes were missing, at a church bazzar sale. When I asked her to describe it, she said that it was shiny and it said McIntosh on it. It was $5. I informed her to buy it now and go hide it in the trunk of her car. It turned out to be a MX-110 tuner - preamp, still a deal at $5.
If you have any friends who go yard sale shopping, show them what tubes look like. Show them pictures of old ST-70's, old Fisher, Marantz, McIntosh, etc. Ask them to call you if they see anything like it. They are getting rarer, but they turn up. I have got McIntosh, Eico and Fisher gear from the neighborhood trash pickup. If your area has an Electronics Recycling program, make friends with the person who runs it.
tubelab.com said:
I found my first tube appliance (an all american 5 radio) in my grandparent's basement. i'll never forget my Admiral 5e33 the first time i got it to power up....
what got me into hi-fi tubing was when i found a SE counsole el84 hi-fi for 15 bucks at Bibles for Mexico (thrift store, i don't know if they are national) That made me a tube nut! but the problem with that was that i got it working, however i could never get anything to work right at any desent volume with the ceramic phono input, so now I want something with tubes, and in Stereo so bad it hurts. Does anyone here ever buy organs and rip out the amplifiers? because at this thrift store they have an endless supply of old organs, most of them tube
Many people use organ amplifiers for stereo amps. These are often cheap and have good bass response. It would be cool if you could find two that were the same. Many old organs come with a lifetime supply of 6SN7's or 12AU7's too. They were used in the frequency dividers of many organs from the 50's and 60's. Many newer ones used neon bulbs for frequency dividers.
If nothing else they are a good source of transformers.
I got the chassis from an old Magnavox console stereo from the trash. It used 6BQ5's in SE for about 5 watts per channel. It turns out that the line out from a CD player, or a computer sound card plays pretty good through that ceramic cartridge input. I had that thing on my desk at work for a while until the plant safety people declared it unsafe.
If nothing else they are a good source of transformers.
I got the chassis from an old Magnavox console stereo from the trash. It used 6BQ5's in SE for about 5 watts per channel. It turns out that the line out from a CD player, or a computer sound card plays pretty good through that ceramic cartridge input. I had that thing on my desk at work for a while until the plant safety people declared it unsafe.
I have seen organ amps from 5 watts to 50 watts. If you can get a look inside, find out what tubes are in the power amp. This may give you a clue to the power output.
1 6V6 5 watts
2 6V6's or 2 6BQ5's 10 to 15 watts
2 6L6's 25 to 50 watts
4 output tubes is usually 2 amps, one for bass, and one for mid and treble (seperate speaker connections), but could be one big amp.
1 6V6 5 watts
2 6V6's or 2 6BQ5's 10 to 15 watts
2 6L6's 25 to 50 watts
4 output tubes is usually 2 amps, one for bass, and one for mid and treble (seperate speaker connections), but could be one big amp.
wait! hey, I found the schematic I want! its 11w el84 pp the only problem is It has no power supply with the schematic, so I need some help figuring out how to make one
http://www.bonavolta.ch/hobby/en/audio/el84_5.htm
http://www.bonavolta.ch/hobby/en/audio/el84_5.htm
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