Hi George-
I noticed that on your website, the buttons on the left hand panel don't display the text properly. This changed a few days ago, FAIK. Perhaps related to working on your web site?
Good one, tools you can see but an incompetent teacher is difficult to spot beforehand.
Anyway i'm not into doing chairs all i want to learn is to make a dovetail joint and a pro wood finish (think here guitar finish) and being able to use a table saw. By your description (thanks) guess that's not on the menu, well it may be but you'll have to wait... and i only have a couple of months. Back to metal.
I will check your joints and evaluate your work, maybe next step for you is master class.
I doubt that I will ever be a master at woodworking. In fact I am not even trying to, since I have too many other things to do. I must admit that my woodworking skills are far better than they were when I made the 845SE amp which is 4 pine boards screwed together with sheetrock screws. As long as I am learning something (and it doesn't get too expensive) I will keep at it.
I am sure that every one of these classes is different because they are highly dependent on the teachers preferences, but there has been no mention of wood finishing at all in this class. In fact I have built a solid body guitar and it remains unfinished for now. I haven't completed the vacuum tube based internal electronics yet either.
Yes, I am trying to post the first cut of the simple P-P instructions, but my web site was built using Microsoft Front Page, which nobody supports any more. The link buttons were pre-canned Front Page items. It looks like I will need to make my own and rebuild each page.
Hey George...I've managed a few websites over the past 10 years and I've been slowly migrating them all to modern content management systems. The days of authoring static web pages are pretty much in the past, thankfully, as I did them all with a text editor and it gets really old.
With some up-front effort, you can save a lot of time later and make updates so much easier by migrating to a system like this. You can then avoid the problem of what tools you need to keep your site updated and can update it from any PC with an Internet connection and a browser. I've use a few, but for your site something like Joomla or Drupal or maybe even WordPress would do the job nicely.
Just a thought, since I've been actively going through this over the past year or two.
With some up-front effort, you can save a lot of time later and make updates so much easier by migrating to a system like this. You can then avoid the problem of what tools you need to keep your site updated and can update it from any PC with an Internet connection and a browser. I've use a few, but for your site something like Joomla or Drupal or maybe even WordPress would do the job nicely.
Just a thought, since I've been actively going through this over the past year or two.
Second that. I still do a lot of web site work in text editors (yes, even "vi"), but where I can, I'll opt for a content management system. For anyone who must maintain a website, but is busy with other chores, these tools are a godsend provided the type of content can be adapted to the constraints of the new system.
Out of topic but I'm not the only one.
Going exotic is expensive. A woodworker like you might be interested in the work of others though. Check the link; too nice for me but interesting.
EWI Amps
Just wait, tropical forests are not that far away from where you live...it can't be that expensive.
Going exotic is expensive. A woodworker like you might be interested in the work of others though. Check the link; too nice for me but interesting.
EWI Amps
Just wait, tropical forests are not that far away from where you live...it can't be that expensive.
I dont think its a lot more expencive than to use aluminium
Besides, a small tubeamp doesnt take much wood
With regards to those very nice guitar amps, just think of all the other expencive stuff you would need to make it look like ordinary PRO amps
But to handle those special hardwoods is a different matter, and not easy at all
A very nice almost free side effect, handsome finish comes almost by itself
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This is where it gets expensive, no screw ups allowed. It is not fun working with exotic woods, you can't make mistakes. A bit like working in a bomb squad.
Wood and electronics:
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Practice Amp guitar woodworking tech gadget DIY hacks hacked
I haven't been here in a while so here is the update:
For the last two weeks I have been at work a lot trying hard to keep my job. There has been little time for work on the Simple P-P manual. The good news is that I have this week off. The Simple P-P is now a full time job.
Yes, the web site is busted. My hosting company was bought out by a larger company over the summer. My web site has been moved by them to their new servers, which don't handle many of the non standard features built into Front Page. This disabled the link bars that are built my site. I have found a few other things that don't work including Front Pages built in navigation system. The new pages don't even upload.
I don't claim to be a web designer, and I appreciate the suggestions, but the CMS programs mentioned seem over my head right now. I have several possible solutions to fixing the web site that are being narrowed down right now. Nothing has been confirmed as of yet but some changes are coming....SOON.
I don't know why, but I don't seem to have a problem blowing up electronics, sometimes I even do it on purpose. It bothers me when I screw up a piece of wood and wind up throwing it out. When I started I used scraps from the junk bin in the classroom. Then I graduated to pine (the cheapest wood you can get here). I stepped up to poplar for my guitar body and red oak for my amplifier chassis. I don't see myself using anything exotic anytime soon. The EWI guitar amps do look nice, too nice to actually use. Many of my amps get dragged around a lot, loaned out, experimented on, and taken apart.
For the last two weeks I have been at work a lot trying hard to keep my job. There has been little time for work on the Simple P-P manual. The good news is that I have this week off. The Simple P-P is now a full time job.
Yes, the web site is busted. My hosting company was bought out by a larger company over the summer. My web site has been moved by them to their new servers, which don't handle many of the non standard features built into Front Page. This disabled the link bars that are built my site. I have found a few other things that don't work including Front Pages built in navigation system. The new pages don't even upload.
I don't claim to be a web designer, and I appreciate the suggestions, but the CMS programs mentioned seem over my head right now. I have several possible solutions to fixing the web site that are being narrowed down right now. Nothing has been confirmed as of yet but some changes are coming....SOON.
I don't know why, but I don't seem to have a problem blowing up electronics, sometimes I even do it on purpose. It bothers me when I screw up a piece of wood and wind up throwing it out. When I started I used scraps from the junk bin in the classroom. Then I graduated to pine (the cheapest wood you can get here). I stepped up to poplar for my guitar body and red oak for my amplifier chassis. I don't see myself using anything exotic anytime soon. The EWI guitar amps do look nice, too nice to actually use. Many of my amps get dragged around a lot, loaned out, experimented on, and taken apart.
I have been beating on several Simple P-P amplifiers for the past few days. They have been tested in every way possible to verify performance under all conditions (including my guitar preamp). I have not blown anything up since I fried a cathode resistor early on (and since uprated the resistor wattage). The board is designed so that it can be wired in triode, UL or pentode mode in the same manner as the Simple SE. This puts the screen and the plate at similar voltages (again like the Simple SE). The maximum ratings for most 6BQ5/EL84 tubes show 300 volts max for plate and screen with the maximum output power occurring at 300 volts. This is how I have been testing the Simple P-P (well maybe a bit over 300 volts). It works quite well this way and this is the standard configuration that is already in the manual.
I have three amps nearing completion. Their construction is being added to the manual as they are finished. I have a fourth board all done that isn't being used. Today I decided to do a little experiment with that board.
Sometimes, when you aren't afraid to blow something up, you bend a few rules, and smoke happens. Other times you make a worthwhile discovery. There was no smoke today.
The 7189A tube is rated for 400 volts on the plate and 300 volts on the screen grid. Real 7189A's are extremely rare, and much of what is being sold as 7189A's today will have a short unhappy life at 400 volts. I have some of those relabled wonders, so I decided to hook a pair of variable power supplies up to a Simple P-P board and subject a few of these to their published ratings. The book says that a pair should make 24 watts, this should be fun.
I cranked up some Ei 7189A's and they were ready to explode whenever I got near the maximum ratings. No matter what combination of plate voltage, screen voltage, or cathode current I used, something began to glow at about 20 watts of output power.
The Russian 6P14P looks and acts the same. About 20 watts at the edge of glow.
I have a bunch of old used 6BQ5's of various manufacturers, and condition. Some of these could handle the voltage far better than the "7189A's" did.
I also have a brand new set of JJ EL84's. They were tested in the two EL84 based amps with good results. JJ's web site shows a set of specifications for their "EL84 RF output pentode." They show the same data that the old GE 6BQ5 data sheet shows. I decided to plug them in and turn some knobs.
SURPRISE. The JJ tubes cranked! I set the screen voltage at 300 volts and started turning up the plate voltage supply. With no signal applied I went to 420 volts without seeing any glow. With the amp cranked to the edge of clipping I started to get some screen glow in one tube when the plate voltage went over 410 volts. The amp was making 30 watts in one channel and 28 in the other. The distortion numbers were unbelievable.
OK, running an amp on bench type power supplies is needed to figure out what voltages you need, but it doesn't make for a good stand alone amp. I now know that I need about 400 volts on the plates and 300 volts on the screen. How do we get there using the existing PC board?
The answer turns out to be rather simple. We use a power transformer that produces about 400 volts of B+, and use rather large resistor for R1 so thet the board gets 300 volts. Then we connect the red wires from the OPT's to the input terminal on choke connector, so that they receive the 400 volts from before R1. NO choke can be used in this configuration.
I am sure that the experts can say that this unregulated screen supply will cause a lot of distortion, and the fairly poor filtering on the plate supply of the output tubes could cause hum, especially with unmatched tubes. I had these conerns too......until I fired this thing up.
There has been this crusty old power transformer sitting on my bench for about 10 years. It came from an old HP audio oscillator. I use it for experiments like this. In this amp it gave me 393 volts at idle and 389 volts with both channels driven to full power. It gets rather hot after 8 hours (yes I really "tested" this one) of continuous use.
Look carefully at the photo. You can see the red wires from the OPT going to the side of the board near the power transformer connections. You can see two 1.3 K ohm 5 watt resistors wired in series where R1 should be (on the right side of the 5AR4).
Does this amp rock? Would I have ran it for a total of 12 hours yesterday if it didn't?
I have three amps nearing completion. Their construction is being added to the manual as they are finished. I have a fourth board all done that isn't being used. Today I decided to do a little experiment with that board.
Sometimes, when you aren't afraid to blow something up, you bend a few rules, and smoke happens. Other times you make a worthwhile discovery. There was no smoke today.
The 7189A tube is rated for 400 volts on the plate and 300 volts on the screen grid. Real 7189A's are extremely rare, and much of what is being sold as 7189A's today will have a short unhappy life at 400 volts. I have some of those relabled wonders, so I decided to hook a pair of variable power supplies up to a Simple P-P board and subject a few of these to their published ratings. The book says that a pair should make 24 watts, this should be fun.
I cranked up some Ei 7189A's and they were ready to explode whenever I got near the maximum ratings. No matter what combination of plate voltage, screen voltage, or cathode current I used, something began to glow at about 20 watts of output power.
The Russian 6P14P looks and acts the same. About 20 watts at the edge of glow.
I have a bunch of old used 6BQ5's of various manufacturers, and condition. Some of these could handle the voltage far better than the "7189A's" did.
I also have a brand new set of JJ EL84's. They were tested in the two EL84 based amps with good results. JJ's web site shows a set of specifications for their "EL84 RF output pentode." They show the same data that the old GE 6BQ5 data sheet shows. I decided to plug them in and turn some knobs.
SURPRISE. The JJ tubes cranked! I set the screen voltage at 300 volts and started turning up the plate voltage supply. With no signal applied I went to 420 volts without seeing any glow. With the amp cranked to the edge of clipping I started to get some screen glow in one tube when the plate voltage went over 410 volts. The amp was making 30 watts in one channel and 28 in the other. The distortion numbers were unbelievable.
OK, running an amp on bench type power supplies is needed to figure out what voltages you need, but it doesn't make for a good stand alone amp. I now know that I need about 400 volts on the plates and 300 volts on the screen. How do we get there using the existing PC board?
The answer turns out to be rather simple. We use a power transformer that produces about 400 volts of B+, and use rather large resistor for R1 so thet the board gets 300 volts. Then we connect the red wires from the OPT's to the input terminal on choke connector, so that they receive the 400 volts from before R1. NO choke can be used in this configuration.
I am sure that the experts can say that this unregulated screen supply will cause a lot of distortion, and the fairly poor filtering on the plate supply of the output tubes could cause hum, especially with unmatched tubes. I had these conerns too......until I fired this thing up.
There has been this crusty old power transformer sitting on my bench for about 10 years. It came from an old HP audio oscillator. I use it for experiments like this. In this amp it gave me 393 volts at idle and 389 volts with both channels driven to full power. It gets rather hot after 8 hours (yes I really "tested" this one) of continuous use.
Look carefully at the photo. You can see the red wires from the OPT going to the side of the board near the power transformer connections. You can see two 1.3 K ohm 5 watt resistors wired in series where R1 should be (on the right side of the 5AR4).
Does this amp rock? Would I have ran it for a total of 12 hours yesterday if it didn't?
Attachments
I bought some "Schumaker 80 watt guitar amp OPT's" from a guy on Ebay about 10 years ago. He had about 1000+ of them, so I bought a bunch and began using them for making guitar amps. They worked very well in that application. I tested one and found that it worked fairly well in a Hifi application too. I took one apart and found no interleaving whatsoever. It is wound with one half primary, then the entire (0-4-8-16) secondary, then the other half primary. The two primaries have different winding lengths, and DCR's so a perfect balance between the two output tubes at all frequencies and power levels is impossible. This makes for some really good sreaming guitar amps, but it should suck for HiFi, right? So I thought.
I stuck a pair of these in my 300Beast amp when I first built it. That amp sounded great. I swapped the OPT's several times, but kept returning to the Schumakers. They are still in the amp. I like the sound of these transformers, I am familair with them, so I use them in all of my P-P experiments. I was sucking 125 watts through a pair when I had the "red board" hooked up. In fact I just removed the red board and put the Simple P-P board into the same test setup.
I performed my usual "good engineering practice" method of flip flopping between listening tests and test equipment measurements to get this amp tweaked up and I can report that in this case the two coincided to produce an amplifier that both measures very well and sounds fantastic. The only problem I have found so far is that the HP power transformer gets too hot. After 8 hours of nearly continuous use (powered off only to change components or connections) it was too hot to touch. A modern Hammond can live at this temperature but this thing was made in 1960.
I listened to music from mellow to rock and the amp sounds nice. Much of the punch and dynamics from the 300Beast has been captured here. Last night I played the entire " Pink Floyd Pulse" concert DVD and there were several "what was that" moments where some very realistic non musical sounds surprised me. I think that this amp might "vote my Simple SE off the island" as my everyday amp. It is much more dynamic.
The measured results are almost unbelievable. I verified that they are real and even re tested my old Simple SE for a reality check. Tube amps with cheap transformers and very little GNFB aren't supposed to measure like this. It measures better than some sand amps that I have created, but there is no silicon in this design, none.
The frequency response is +/- 0.4 db 20 Hz to 20KHz at 10 watts. 0.2 db at 1 watt. The 3db point is 60+ KHz.
The measured THD is 0.06 % at 1 watt and 1KHz, but well under 1% for all output powers and frequencies used in normal listening. The upturn in distortion at the frequency extremes can be atributed to my Ebay OPT's.
The GNFB compensation cap was tweaked for best square wave response at 10 KHz. This resulted in a gentle drop off in the HF response instead of the peaked response seen without a cap. This also removed the harshness from some of the high frequencies.
I stuck a pair of these in my 300Beast amp when I first built it. That amp sounded great. I swapped the OPT's several times, but kept returning to the Schumakers. They are still in the amp. I like the sound of these transformers, I am familair with them, so I use them in all of my P-P experiments. I was sucking 125 watts through a pair when I had the "red board" hooked up. In fact I just removed the red board and put the Simple P-P board into the same test setup.
I performed my usual "good engineering practice" method of flip flopping between listening tests and test equipment measurements to get this amp tweaked up and I can report that in this case the two coincided to produce an amplifier that both measures very well and sounds fantastic. The only problem I have found so far is that the HP power transformer gets too hot. After 8 hours of nearly continuous use (powered off only to change components or connections) it was too hot to touch. A modern Hammond can live at this temperature but this thing was made in 1960.
I listened to music from mellow to rock and the amp sounds nice. Much of the punch and dynamics from the 300Beast has been captured here. Last night I played the entire " Pink Floyd Pulse" concert DVD and there were several "what was that" moments where some very realistic non musical sounds surprised me. I think that this amp might "vote my Simple SE off the island" as my everyday amp. It is much more dynamic.
The measured results are almost unbelievable. I verified that they are real and even re tested my old Simple SE for a reality check. Tube amps with cheap transformers and very little GNFB aren't supposed to measure like this. It measures better than some sand amps that I have created, but there is no silicon in this design, none.
The frequency response is +/- 0.4 db 20 Hz to 20KHz at 10 watts. 0.2 db at 1 watt. The 3db point is 60+ KHz.
The measured THD is 0.06 % at 1 watt and 1KHz, but well under 1% for all output powers and frequencies used in normal listening. The upturn in distortion at the frequency extremes can be atributed to my Ebay OPT's.
The GNFB compensation cap was tweaked for best square wave response at 10 KHz. This resulted in a gentle drop off in the HF response instead of the peaked response seen without a cap. This also removed the harshness from some of the high frequencies.
Attachments
No such fun. More like finishing up the construction manual, and kitting up some bags of parts. I carefully stopped the previously mentioned experiments at the onset of glow. 6BQ5's / EL84's don't show up in the dollar menu any tube stores that I know of. I'll save the fireworks for the cheap sweep tubes. Maybe next time I hook the red board back up I'll toast some really ugly looking ones that I have that fit it.
Forgive me if my questions seem repetitive, but with the 6CW5, you mentioned that the Antek toroid you currently have may be slightly lacking to drive the tube to it's optimum, and the 230v version would have too much b+. What would my alternative be? A conventional power transformer? What kind of specs should I be trying to match?
I suppose I could always go with a different tube, but I got a good stock of Siemens and Motorola 6CW5's for a great price. I would like to push beyond the 14 watts (I think this is correct) that you got with the Antek, to around 18 watts if possible.
I also got a nice batch of GE 6201's for the front end, so I am all set on tubes.
Hope I am not being a pain in the ***, but I am chomping at the bit to get started.
Thanks!
Steve
I suppose I could always go with a different tube, but I got a good stock of Siemens and Motorola 6CW5's for a great price. I would like to push beyond the 14 watts (I think this is correct) that you got with the Antek, to around 18 watts if possible.
I also got a nice batch of GE 6201's for the front end, so I am all set on tubes.
Hope I am not being a pain in the ***, but I am chomping at the bit to get started.
Thanks!
Steve
How much of this do you attribute to the pairing of your amp to this iron? Since most folks will probably use Hammond or Edcor iron or similar, how does the amp fair in those cases?
Your "Industrial" amp with the Transcendars?
First off, I can assure you that you can't hear the difference between 14 and 18 watts. Conventional wisdom says that you need to double the audio power to notice a difference in loudness, and at takes 10 times the power level to double the apparent loudness. I am not sure that it is that simple, but it isn't far off.
OK, you twisted my arm.... I ordered an Antek 2T230 and I will report how much smoke it makes when I get it. Really, the 6CW5 has a specified maximum plate voltage of 250 volts and the screen is rated for 200 volts. Some tubes will work with more voltage, and some will not even live up to their specs. The tricks that I use with my tubes may not work with yours.
I am building three Simple P-P amplifiers. The chassis is completed for the first one. It is a 6CW5 amp. There is an Antek 1T200 in there now (under the deck) I will try the 2T230 when it shows up. I am sure that I can find a way to crank 20+ watts out of this thing. It may not be noticably louder than the 14 watt version, but numbers are important to many builders.
I do not have any Siemens 6CW5's to try. Where did you get yours and how much were they. Maybe I'll get some. Motorola never made tubes. They had someone else make them with their brand on them. Post a picture of your tubes showing the type number and maybe we can figure out who made them.
The cheap and ugly OPT's are by no means special. In most of my other experiments they work OK, but not great. They do have a sound quality that I like in just about any GOOD amp that I have listened to them in. I don't happen to have any Hammond P-P OPT's and the only Edcor units that I have are the little 10 watt units, which are easilly overpowered by this amp. My budget doesn't support purchasing any transformers right now, so testing with new iron must wait. I do have a vintage pair of UTC LS57's that I could hook up. I will try them when I get a chance. They are not considered "budget OPT's" though.
That's the one. It and the Lexan Tubelab SE are my only working amplifiers at the moment. It measures a consistent 1.4% at 5 watts with the original EH KT88's still going strong.
I got 19 NOS Siemens 6CW5's off ebay for about $2 each. 16 are identical in construction and three are matching each other but are slightly cosmetically different..
I knew the Motorolas were rebranded tubes. The only original markings (different ink color and font) read "6CW5" and "W. Germany". everything else is Motorola's markings. I have 5 of these.
I knew the Motorolas were rebranded tubes. The only original markings (different ink color and font) read "6CW5" and "W. Germany". everything else is Motorola's markings. I have 5 of these.