I have a dilemma that I am trying to solve...
I am hoping with the great help of all the great minds here I can get the answers I need... here it is.
I need to construct a 2-channel preamp/amp combo (stereo).
1. Needs to be as inexpensive as possible
2. Needs to be ROCK SOLID reliable
3. Must be able to use all current production tubes and parts!!!! (no NOS) There's a reason for this, and I don't like it any more than most of you NOS fans. (I LOVE NOS black plate 12ax7's myself so believe me I understand)
4. Try to avoid junk parts (low end Chinese or unknown brand Russian tubes)
5. The TOTAL COST of the project needs to be UNDER $200 (this includes ALL the iron, enclosure, tubes, everything... also, the further under the budget, the better) and that is buying parts at RETAIL cost (anything less than that is even better). Mouser, Digikey, etc are ok - no Ebay.
If it helps, imagine that you can order a custom made circuit board for your project. Predrilled, all traces in place and ready to solder. Count $5 for less than 6x6 or $10 for anything larger.
Transformers can be single output or tapped, doesn't matter. 8ohm load.
6. MOST IMPORTANTLY! It needs to sound good and tube-y, but I'm not seeking perfection here! PLEASE KEEP THAT IN MIND! I know we're all audiophiles here and we love our perfection, but in this particular project, perfection costs MONEY! 10W/ch is the baseline, extra is better if its within the budget! Please don't think of this as your listening room centerpiece, but rather a competition making you make do with what you have.
Some ideas that I've been throwing around:
Replicate the Musicians Amplifier, replace the tube rectification with SS, and ditch the 807's for a 6L6 and the 6SN7s for 12AX7s. Sadly, the tubes and transformer eat almost the entire budget for the project.
Tubelab's cathode follower has me intrigued! I can't find any schematics or a whole lot about it (the magazine article is a broken link now) so I can't estimate what it costs to build. I'm not against using solid state co-stars to bring the costs down, but the tube sound is the star of this project. Integrating a display, control buttons, etc into the PIC controller looks like a great way to build a nice preamp and keep the costs down.
I know some of us are anti-transistor, and there are others that are anti-tube. For this, I ask that we just agree to disagree and pursue what is most effective - even if it is a bit more modern than you'd normally appreciate.
Thanks for reading, and looking forward to hearing your ideas
Caleb
I am hoping with the great help of all the great minds here I can get the answers I need... here it is.
I need to construct a 2-channel preamp/amp combo (stereo).
1. Needs to be as inexpensive as possible
2. Needs to be ROCK SOLID reliable
3. Must be able to use all current production tubes and parts!!!! (no NOS) There's a reason for this, and I don't like it any more than most of you NOS fans. (I LOVE NOS black plate 12ax7's myself so believe me I understand)
4. Try to avoid junk parts (low end Chinese or unknown brand Russian tubes)
5. The TOTAL COST of the project needs to be UNDER $200 (this includes ALL the iron, enclosure, tubes, everything... also, the further under the budget, the better) and that is buying parts at RETAIL cost (anything less than that is even better). Mouser, Digikey, etc are ok - no Ebay.
If it helps, imagine that you can order a custom made circuit board for your project. Predrilled, all traces in place and ready to solder. Count $5 for less than 6x6 or $10 for anything larger.
Transformers can be single output or tapped, doesn't matter. 8ohm load.
6. MOST IMPORTANTLY! It needs to sound good and tube-y, but I'm not seeking perfection here! PLEASE KEEP THAT IN MIND! I know we're all audiophiles here and we love our perfection, but in this particular project, perfection costs MONEY! 10W/ch is the baseline, extra is better if its within the budget! Please don't think of this as your listening room centerpiece, but rather a competition making you make do with what you have.
Some ideas that I've been throwing around:
Replicate the Musicians Amplifier, replace the tube rectification with SS, and ditch the 807's for a 6L6 and the 6SN7s for 12AX7s. Sadly, the tubes and transformer eat almost the entire budget for the project.
Tubelab's cathode follower has me intrigued! I can't find any schematics or a whole lot about it (the magazine article is a broken link now) so I can't estimate what it costs to build. I'm not against using solid state co-stars to bring the costs down, but the tube sound is the star of this project. Integrating a display, control buttons, etc into the PIC controller looks like a great way to build a nice preamp and keep the costs down.
I know some of us are anti-transistor, and there are others that are anti-tube. For this, I ask that we just agree to disagree and pursue what is most effective - even if it is a bit more modern than you'd normally appreciate.
Thanks for reading, and looking forward to hearing your ideas
Caleb
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Caleb" Your best bet is to find an old ALLIED RADIO KNIGHT KIT integrated stereo amp and replace some worn out parts and all the cheap ceramic caps. They made a 20 watt (10 per channel) that used 6BM8 tubes for the output and 12ax7 for the phono preamp. The Russians still make the 6BM8. It was small and only had four knobs on the front in a nice steel case. The other possibility is to find a Roberts 770 tape preamp and do the same thing to it. It also used the 6BM8 tubes. It's not possible otherwise I don;t believe on your budget of building from scratch. First get some experience before you build from scratch. Ray
Amazon.com: Stereo Integrated Tube Amplifier DIY Kit: Electronics
So I guess they're taking a bath on each one sold Scott? Thanks for being the first to reply with a canned (and UBER negative) response.
I have always found that I can find the components cheaper (and usually better quality) when they're not all packaged into a el-cheapo kit.
grhughes> thanks for the advice, but not what I'm looking for. (off topic) I have less than $1500 tied up in my main system which is a Citation II, Fisher 400C, and a pair of Marin Logans. That includes a partial rebuild on the Citation and a recap on the Fisher. Vintage bargains are out there to be had, I know. I need help on the topic at hand.
Have found that Edcor has all 3 transformers needed available for less than $90!
So I guess they're taking a bath on each one sold Scott? Thanks for being the first to reply with a canned (and UBER negative) response.
I have always found that I can find the components cheaper (and usually better quality) when they're not all packaged into a el-cheapo kit.
grhughes> thanks for the advice, but not what I'm looking for. (off topic) I have less than $1500 tied up in my main system which is a Citation II, Fisher 400C, and a pair of Marin Logans. That includes a partial rebuild on the Citation and a recap on the Fisher. Vintage bargains are out there to be had, I know. I need help on the topic at hand.
Have found that Edcor has all 3 transformers needed available for less than $90!
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You're welcome but you are not following your own specs. Just being realistic. First of all, there is no case with that kit and it's more than $200.
11BM8 is not a current production tube.
If a design is developed to meet your specs, how much do you plan on selling them for?
11BM8 is not a current production tube.
If a design is developed to meet your specs, how much do you plan on selling them for?
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Retail pricing:
4x 6L6GC $70
2x 12AX7 $24.00 (12AX7 probably not the best choice here, but it is what you asked for)
2x Edcor PP OT $40
antek PT $35
hammond chassis $33
4x 8 pin socket $12
2x 9 pin socket $6
$220.00 not including shipping
not including jacks, resistors, caps, diodes, wiring
4x 6L6GC $70
2x 12AX7 $24.00 (12AX7 probably not the best choice here, but it is what you asked for)
2x Edcor PP OT $40
antek PT $35
hammond chassis $33
4x 8 pin socket $12
2x 9 pin socket $6
$220.00 not including shipping
not including jacks, resistors, caps, diodes, wiring
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EH 6L6 from Tube Store $14.95 ea ($10 saved)
Edcor Transformer kit $90 ($25 saved)
Hammond chassis... thats not very creative... $20-30 saved
That leaves about $50 for components... and sounds like you're envisioning a push pull? What about a single tube class A?
Edcor Transformer kit $90 ($25 saved)
Hammond chassis... thats not very creative... $20-30 saved
That leaves about $50 for components... and sounds like you're envisioning a push pull? What about a single tube class A?
Are you talking about the EH 6L6GC from the tubestore @ $14.25? You can't use those, they are rejects. Not normal production and probably not always available.
The transformers I listed are only $75.00 (40 + 35). How does $90 equate to a $25 savings?
What brand chassis are you pricing? Size?
You said 10W/ch is the baseline. You "might" get 10W from a 6L6GC or EL34 SE, doubtful if you want it to sound decent. The Edcors I priced are already bottom of the barrel XSE version. Unless you are talking about peak power and not RMS as it should be measured.
Why don't you post your working schematic(s)? It would be easier to see what you are envisioning.
The transformers I listed are only $75.00 (40 + 35). How does $90 equate to a $25 savings?
What brand chassis are you pricing? Size?
You said 10W/ch is the baseline. You "might" get 10W from a 6L6GC or EL34 SE, doubtful if you want it to sound decent. The Edcors I priced are already bottom of the barrel XSE version. Unless you are talking about peak power and not RMS as it should be measured.
Why don't you post your working schematic(s)? It would be easier to see what you are envisioning.
Don't have a working schematic yet, I'm trying to figure out which route to go.
I thought you had said $40 ea for the audio transformers... and thanks for the heads up on the rejects, I didn't realize.
For the base, a piece of sheet metal with a wooden box built around it. Very inexpensive.
I really didn't want to come out and say this, but right now I'm in college working on an EE degree. I really don't want to go back to working for another corporation. So I'm exploring my passions to see if there are some things I can pursue and eventually make a home grown business out of. One of them is electric cars, the other is tube amps.
I'm just now coming to grips with electrical circuits and what goes on inside a tube amp. I'm not yet knowledgeable about picking which resistors and caps go where and why they're there but I'm getting close.
Being as passionate as I am about what I'm working with, I REALLY don't want the vacuum tube industry to die. From my observations, it's been holding on by threads since the 70's. We are one foot in the grave already!
I have shown and demo'ed my setup to only a few people. My neighbors and a friend (a girl I've been friends with for a couple years - not electronically inclined at all). I played Lana Del Rey's new album for her and she was FLOORED by it! She is now trying to find her own tube gear!
I want to find a way to get tube gear back out in front of the public again. I want to find a way to make it affordable. I also want to find ways to make it more future friendly. When I first repaired the Citation, I was about to be completely content listening to iTunes through it. Then, I found a record player at a thrift store for $40. I never again want to buy a piece of off the shelf Hifi and now my friend is taking a similar interest. I can't point her to Best Buy, and she doesn't have a few grand to invest in a restored Citation from Jim McShane. So in other words, I'm trying to figure out if it is feasible to make a mass produced tube product of a good quality, that is also future friendly... to breathe some new life into the tube industry.
Music is one of the biggest conveyors of art and emotion. Tubes have become an obsession for me since I've started. The music industry is the biggest its ever been, and how could people walk by something that sounds as good as a tube (playing their favorite tune) and not stop to listen? The interest is infectious. Once you have a taste, you just have to have more.
If we don't act, the anti-tube propaganda and the transistor will triumph once and for all. Samsung has already thrown their billions into crashing the tube with this pile of you know
2.1 Channel Sound Bar System with Wireless Subwoofer | Samsung HW-F750
There needs to be an alternative! A GOOD ALTERNATIVE!
Before I start making a complete change in the direction my life is headed, I want to see if my dreams can become a reality of if they are best left as dreams.
I thought you had said $40 ea for the audio transformers... and thanks for the heads up on the rejects, I didn't realize.
For the base, a piece of sheet metal with a wooden box built around it. Very inexpensive.
I really didn't want to come out and say this, but right now I'm in college working on an EE degree. I really don't want to go back to working for another corporation. So I'm exploring my passions to see if there are some things I can pursue and eventually make a home grown business out of. One of them is electric cars, the other is tube amps.
I'm just now coming to grips with electrical circuits and what goes on inside a tube amp. I'm not yet knowledgeable about picking which resistors and caps go where and why they're there but I'm getting close.
Being as passionate as I am about what I'm working with, I REALLY don't want the vacuum tube industry to die. From my observations, it's been holding on by threads since the 70's. We are one foot in the grave already!
I have shown and demo'ed my setup to only a few people. My neighbors and a friend (a girl I've been friends with for a couple years - not electronically inclined at all). I played Lana Del Rey's new album for her and she was FLOORED by it! She is now trying to find her own tube gear!
I want to find a way to get tube gear back out in front of the public again. I want to find a way to make it affordable. I also want to find ways to make it more future friendly. When I first repaired the Citation, I was about to be completely content listening to iTunes through it. Then, I found a record player at a thrift store for $40. I never again want to buy a piece of off the shelf Hifi and now my friend is taking a similar interest. I can't point her to Best Buy, and she doesn't have a few grand to invest in a restored Citation from Jim McShane. So in other words, I'm trying to figure out if it is feasible to make a mass produced tube product of a good quality, that is also future friendly... to breathe some new life into the tube industry.
Music is one of the biggest conveyors of art and emotion. Tubes have become an obsession for me since I've started. The music industry is the biggest its ever been, and how could people walk by something that sounds as good as a tube (playing their favorite tune) and not stop to listen? The interest is infectious. Once you have a taste, you just have to have more.
If we don't act, the anti-tube propaganda and the transistor will triumph once and for all. Samsung has already thrown their billions into crashing the tube with this pile of you know
2.1 Channel Sound Bar System with Wireless Subwoofer | Samsung HW-F750
There needs to be an alternative! A GOOD ALTERNATIVE!
Before I start making a complete change in the direction my life is headed, I want to see if my dreams can become a reality of if they are best left as dreams.
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Look into the "El Cheapo" project I've been associated with for several years. If you're willing to live with approx. 6 WPC, Edcor's under $40 GXPP15-8-8K O/P trafo will be fine, with triode wired "finals". More costly O/P transformers allow the use of ultralinear mode "finals" and get you about 12 WPC. The Triode Electronics guitar amp O/P trafo shown on the graphic is no longer a good deal. 😡
Any 6V6 clan tube will work with the parts values shown. The current production ElectroHarmonix (EH) 6V6 is pretty decent and quite affordable.
Yes, 'AL5s are NOS only, but they are inexpensive and rate to last more than 10 years. 😉
A complete set of affordable power "iron" can be purchased from Allied. 2X N-68X will give you the same VA capability as a N-77U, at lower cost. Why sheats the bit out of me. The stock # is 70218526. So much for the bulk of the B+. Stock # 70218139 takes care of B+ boost and "12" V. heater power. Stock # 70218145 takes care of the B+ filter choke. Stock # 70009000 takes care of 12AT7 heater power and energizing the B- rail.
Jim McShane offers parts kits for the project.
Don't be fooled by the modest cost of the project. "El Cheapo" is a serious HIFI amp.
Any 6V6 clan tube will work with the parts values shown. The current production ElectroHarmonix (EH) 6V6 is pretty decent and quite affordable.
Yes, 'AL5s are NOS only, but they are inexpensive and rate to last more than 10 years. 😉
A complete set of affordable power "iron" can be purchased from Allied. 2X N-68X will give you the same VA capability as a N-77U, at lower cost. Why sheats the bit out of me. The stock # is 70218526. So much for the bulk of the B+. Stock # 70218139 takes care of B+ boost and "12" V. heater power. Stock # 70218145 takes care of the B+ filter choke. Stock # 70009000 takes care of 12AT7 heater power and energizing the B- rail.
Jim McShane offers parts kits for the project.
Don't be fooled by the modest cost of the project. "El Cheapo" is a serious HIFI amp.
Attachments
Eli> I was throwing around using a Switched mode power supply to do all of the voltages in the amp. You seem to get a lot of voltages and bang for your buck. Everybody seems to be dumping transformers in favor of them.
For those who aren't familiar with SMPS, here's an example
High Voltage Switch Mode Power Supply (SMPS)/Boost Converter for Nixie Tubes
They're in your Flatscreen TV, computer, Xbox, phone charger, anything not old. With the price of copper going through the roof, it might be time to start looking at alternatives to big transformer power supplies.
Your list of transformers is a proof of concept and thats kind of what I was hoping to find here. The output iron as far as I know is not a component that can be replaced or skimped on. I'm sure if this project got big enough that eventually custom stuff could be made and purchased for much less than retail.
I could definitely use some help from the more knowledgeable DIY'ers. I think its eminent that some new design techniques be tried in order to bring a polished product. I'm willing to scrounge up components and throw my extensive labors into soldering and prototyping as long something will conceivably work.
For those who aren't familiar with SMPS, here's an example
High Voltage Switch Mode Power Supply (SMPS)/Boost Converter for Nixie Tubes
They're in your Flatscreen TV, computer, Xbox, phone charger, anything not old. With the price of copper going through the roof, it might be time to start looking at alternatives to big transformer power supplies.
Your list of transformers is a proof of concept and thats kind of what I was hoping to find here. The output iron as far as I know is not a component that can be replaced or skimped on. I'm sure if this project got big enough that eventually custom stuff could be made and purchased for much less than retail.
I could definitely use some help from the more knowledgeable DIY'ers. I think its eminent that some new design techniques be tried in order to bring a polished product. I'm willing to scrounge up components and throw my extensive labors into soldering and prototyping as long something will conceivably work.
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Edcor DAP 201 package and an amp built around EL84 (or 6P14P) and 6N1P would be my recommendation.
I've used a smps in a tube amp before: http://www.diyaudio.com/forums/tubes-valves/213947-just-what-world-needs-another-el84-amp.htm
I've used a smps in a tube amp before: http://www.diyaudio.com/forums/tubes-valves/213947-just-what-world-needs-another-el84-amp.htm
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Well, I'm trying to hatch a plan to make a LOT of new converts... and revive the vacuum tube industry. I'm quite ambitious, and I don't take kindly to failing - so I don't.
One word, NOISE, is why SMPS is not a good idea. The cost of shielding and filtering to keep SMPS crud out of the audio signal path will be significant. TANSTAAFL!
Profit is, definitely, important. However, giving the customer what he/she pays for is important too. For good reason, value for value is time honored. Damn and blast the quick buck artists! Big business has lost sight of the fact that a satisfied clientele is GOOD for long term profitability.
I think that you are misinformed, the tube audio business is far larger and more advanced now than it has been for over 40 years. China sells plenty of low cost tube gear.
As a career move, EVs are much wiser.
If thats the plan you would be far better off becoming an agent for one of the chinese manufacturers. They will always beat you on price anyway, and if your target market is those buying $200 retail of tube gear, price is your single important differentiating factor.
Good luck either way
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