A Disease!?!
You are right about that, even my self, a very rational and sensible person(only I believe that!), who knows that we will never be able to reproduce a live concert through little squiggles on vinyl, rust flakes on cellophane or 0's and 1's on a silly plastic disc, has gotten infected by the disease of trying to prove that I can give the laws of the universe a slip.
Anyway again many thanks and I will soon be pestering you with more questions.
Surf, Sun & Sound
You are right about that, even my self, a very rational and sensible person(only I believe that!), who knows that we will never be able to reproduce a live concert through little squiggles on vinyl, rust flakes on cellophane or 0's and 1's on a silly plastic disc, has gotten infected by the disease of trying to prove that I can give the laws of the universe a slip.
Anyway again many thanks and I will soon be pestering you with more questions.
Surf, Sun & Sound
Hey SS & S,
Being in Oz too I would like to add a little to your knowledge and make a couple of suggestions as well...
First, I'm glad you found the Dyna 6v6/6bq5 circuit as this was the one I was going to suggest to you for two reasons: 1) as GR confirmed it is a good one designed by one of tube lore's giants, David Hafler; and 2) because in case you didnt know this has to be one of the cheapest amps to run if you noted the fine print at the bottom of the circuit... and instead of using the EL84/6BQ5 valve, you opted for the 6AQ5. The reason I am suggesting this is that in case you did not know the 6AQ5/EL90 is the same as the 6V6 in a miniature 7 pin tube. These are plentiful and cheap on ebay. Just compare what these three; 6V6, 6AQ5 and 6BQ5 go for on ebay and you will see what I mean...
Second, If I were you I would not discount bidding on the Mullard 10-10 for a number of reasons... the first is that if you can get it for a reasonable amount you will save yourself the trouble of hunting down suitable ouput/power trannies which are as rare as hens teeth down here and constitute the major expense in tube amps, tubes apart. The 6GW8/ECL86 tube the Mullard uses is basically a 6AQ5 pentode with half a 12AX7 triode in the same tube. What that means is that the o/p trannies in the Mullard are ideal for your project as they would be between the 7-10K primary that all three of these tubes need. Also bear in mind that the Mullard is also Ultralinear tapped which is what you will need in the o/p tranny if you use the Dyna circuit. Get my drift now? You can also re-use the chassis and quite possibly the pre-amp too, as the guy said he has the schematic. On a practical side It may be relatively easy to revive the Mullard in any case, The only proviso being finding some 6GW8/ECL86's. If you get stuck finding any let me know as I have some NOS east german ones if you get stuck.
Hope this helps,
tomcat
Being in Oz too I would like to add a little to your knowledge and make a couple of suggestions as well...
First, I'm glad you found the Dyna 6v6/6bq5 circuit as this was the one I was going to suggest to you for two reasons: 1) as GR confirmed it is a good one designed by one of tube lore's giants, David Hafler; and 2) because in case you didnt know this has to be one of the cheapest amps to run if you noted the fine print at the bottom of the circuit... and instead of using the EL84/6BQ5 valve, you opted for the 6AQ5. The reason I am suggesting this is that in case you did not know the 6AQ5/EL90 is the same as the 6V6 in a miniature 7 pin tube. These are plentiful and cheap on ebay. Just compare what these three; 6V6, 6AQ5 and 6BQ5 go for on ebay and you will see what I mean...
Second, If I were you I would not discount bidding on the Mullard 10-10 for a number of reasons... the first is that if you can get it for a reasonable amount you will save yourself the trouble of hunting down suitable ouput/power trannies which are as rare as hens teeth down here and constitute the major expense in tube amps, tubes apart. The 6GW8/ECL86 tube the Mullard uses is basically a 6AQ5 pentode with half a 12AX7 triode in the same tube. What that means is that the o/p trannies in the Mullard are ideal for your project as they would be between the 7-10K primary that all three of these tubes need. Also bear in mind that the Mullard is also Ultralinear tapped which is what you will need in the o/p tranny if you use the Dyna circuit. Get my drift now? You can also re-use the chassis and quite possibly the pre-amp too, as the guy said he has the schematic. On a practical side It may be relatively easy to revive the Mullard in any case, The only proviso being finding some 6GW8/ECL86's. If you get stuck finding any let me know as I have some NOS east german ones if you get stuck.
Hope this helps,
tomcat
Good day, Tomcat;
Thanks for the advice. It is good to hear that I have landed on a schematic that is meeting the approval of the "elders"! I can get new 6BQ5 tubes from Wes Components here in Ashfield, now I am sure that they are not as good as NOS from the past, but at $12.00 a piece, it will be a start. I am not an expert on tubes so I cannot make a judgenment about the pro and cons of the 6V6, 6AQ5, or the 6BQ5 and which one is better for what I want to do.
So I am all ears!
About the Mullard 10-10, I was thinking that I will go ahead and buy it inspite of Grey's advice to leave it go. Yes, I will most likely have to completely rebuild it, but that will not cost me any more than building a new amp. Plus if the price is right, it will save me the cost of buying new power and output transformers for a new amp. Since as near as I can tell, it will cost me a minimum of $300.00AU just for the transformers, which has completely shot my budget to pieces for this project. I have been in contact with Lancroft Transformers in Rockdale - www.users.bigpond.com/triode - and Harbuch Electronics in Hornsby - http://ourworld.compuserve.com/homepages/harbuch - about new transformers for this schematic. I would really like to keep the cost of this amp well under $200.00AU since it is a first time tube amp and I do not know what my thoughts will be on the end result. I am sure that if I see the potential or catch the valve virus that my budget for the next amp will be significantly more. As for the 6GW8/ECL86 tubes, I can get them from Valve Electronics Pty Ltd in Batemans Bay - http://www.electronvalve.com/ - about $22.00 a piece. Also the seller has sent me the following source for valves, ADELAIDE VALVE SALES - http://www.chariot.net.au/~lucas/v/Valves.html - I have not checked out this source as of yet, so I am not sure what they offer. Plus there is a pre-amp included, a little bonus I guess.
I am curious to hear what Grey has to say about this latest development. Thanks, Tomcat for the advice, I definitely have felt the pain of getting audio components at a reasonable price since moving here from the US.
Surf, Sun & Sound
Thanks for the advice. It is good to hear that I have landed on a schematic that is meeting the approval of the "elders"! I can get new 6BQ5 tubes from Wes Components here in Ashfield, now I am sure that they are not as good as NOS from the past, but at $12.00 a piece, it will be a start. I am not an expert on tubes so I cannot make a judgenment about the pro and cons of the 6V6, 6AQ5, or the 6BQ5 and which one is better for what I want to do.
So I am all ears!
About the Mullard 10-10, I was thinking that I will go ahead and buy it inspite of Grey's advice to leave it go. Yes, I will most likely have to completely rebuild it, but that will not cost me any more than building a new amp. Plus if the price is right, it will save me the cost of buying new power and output transformers for a new amp. Since as near as I can tell, it will cost me a minimum of $300.00AU just for the transformers, which has completely shot my budget to pieces for this project. I have been in contact with Lancroft Transformers in Rockdale - www.users.bigpond.com/triode - and Harbuch Electronics in Hornsby - http://ourworld.compuserve.com/homepages/harbuch - about new transformers for this schematic. I would really like to keep the cost of this amp well under $200.00AU since it is a first time tube amp and I do not know what my thoughts will be on the end result. I am sure that if I see the potential or catch the valve virus that my budget for the next amp will be significantly more. As for the 6GW8/ECL86 tubes, I can get them from Valve Electronics Pty Ltd in Batemans Bay - http://www.electronvalve.com/ - about $22.00 a piece. Also the seller has sent me the following source for valves, ADELAIDE VALVE SALES - http://www.chariot.net.au/~lucas/v/Valves.html - I have not checked out this source as of yet, so I am not sure what they offer. Plus there is a pre-amp included, a little bonus I guess.
I am curious to hear what Grey has to say about this latest development. Thanks, Tomcat for the advice, I definitely have felt the pain of getting audio components at a reasonable price since moving here from the US.
Surf, Sun & Sound
tomcat
SSS,
Glad you found WES Comps. I was going to recommend them to you as well. They have a web site now: http://www.wescomponents.com/ The Sovteks they sell are quite good so you can't go wrong there. A peice of advice... I don't know if it's your bid on the Mullard, but leave it till the last moment then put say AU$10 on it in one hit. What this will do is start the proxy bidding process untill it reaches the $10 limit, which will up the ante against the other bidder at 0.50cent per bid. This way you have a good chance of getting it for a reasonable price...
Have fun,
tomcat
SSS,
Glad you found WES Comps. I was going to recommend them to you as well. They have a web site now: http://www.wescomponents.com/ The Sovteks they sell are quite good so you can't go wrong there. A peice of advice... I don't know if it's your bid on the Mullard, but leave it till the last moment then put say AU$10 on it in one hit. What this will do is start the proxy bidding process untill it reaches the $10 limit, which will up the ante against the other bidder at 0.50cent per bid. This way you have a good chance of getting it for a reasonable price...
Have fun,
tomcat
Tube amps
Thanks Tomcat,
The seller from E-bay has offered to supply with 5 6GW8 tube for an additional $50. I have bought a few things from E-bay and usually wait till the last minute to bid. If not, things can do an incredible run up because someone is trying find the top of your proxy bid. I will let you know what happens.
Surf, Sun & Sound
Thanks Tomcat,
The seller from E-bay has offered to supply with 5 6GW8 tube for an additional $50. I have bought a few things from E-bay and usually wait till the last minute to bid. If not, things can do an incredible run up because someone is trying find the top of your proxy bid. I will let you know what happens.
Surf, Sun & Sound
AE,
Is this the tube kit that is in Audioxpress?(www.tubeaudio.com) I didn't get Decembers issue. Does any one have any ideas on how this amp would sound. I want to build a tube amp but I can't afford to spend lots of money right now. (We're having our first child in March, never knew how expensive baby stuff is.)
Is this the tube kit that is in Audioxpress?(www.tubeaudio.com) I didn't get Decembers issue. Does any one have any ideas on how this amp would sound. I want to build a tube amp but I can't afford to spend lots of money right now. (We're having our first child in March, never knew how expensive baby stuff is.)
Hi All:
Just read this thread from the start, and had to toss in my two-bits worth...
If you are mystified by all this tube stuff but want to get your feet wet, a great way to start is to search your neighborhood junk shops, and everyone else's basement for old console stereos from the mid '50s. (You would be amazed how many people still have an old console in the corner gathering dust "because they just couldn't bear to throw out that nice furniture".)
I live in a very small and remote village, but when I went looking it took only three days to fine a 1954 Electrohome console with a nice little 15w 6BQ5 PP stereo amp in it.
The point is, start with something like that and get it running. Replace the caps and resistors. Get used to working with transformers, tube sockets and 300 plus volts.
Then, start building from scratch. You can spend the time and money with a lot more confidence.
I still have my little ehome 6BQ5, but have since built 3 other tube projects and, guess what: they have all worked!
Just a bit of encouragement from the wild BC coast.
Just read this thread from the start, and had to toss in my two-bits worth...
If you are mystified by all this tube stuff but want to get your feet wet, a great way to start is to search your neighborhood junk shops, and everyone else's basement for old console stereos from the mid '50s. (You would be amazed how many people still have an old console in the corner gathering dust "because they just couldn't bear to throw out that nice furniture".)
I live in a very small and remote village, but when I went looking it took only three days to fine a 1954 Electrohome console with a nice little 15w 6BQ5 PP stereo amp in it.
The point is, start with something like that and get it running. Replace the caps and resistors. Get used to working with transformers, tube sockets and 300 plus volts.
Then, start building from scratch. You can spend the time and money with a lot more confidence.
I still have my little ehome 6BQ5, but have since built 3 other tube projects and, guess what: they have all worked!
Just a bit of encouragement from the wild BC coast.
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