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Tubelab SE: Removing MOSFETs?

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Not much new here - really hot this time of year out in the radio room.

Played around last week with some Rad Shack 70 volt line transformers, afaik, they are not air gapped, but at these low currents I'm not sure that makes much of a difference.

Performance was not that bad, low frequency response was markedly better than the OPT I have on it now, so I may swap them out. SMPTE IMD was about the same. I got best results with 46 and this transformer at what I calculated to be the 4K tap. I used the next tap down to energize the second grid. My real interest here was trying these as an OPT in a choke loaded configuration, but I don't seem to have any suitable chokes on hand. I suspect that at these low currents, a good line transformer is probably quite OK on its own.

I also jumpered in one of the 5K 10 watt Transcendars. No UL tap, so triode only - needless to say every aspect of performance was markedly better with this high quality transformer.

Win W5JAG

edit: I would also add, this thing remains hum free, which was totally unexpected to me. The 6.3 volt heater is not referenced to B+, or to ground with a virtual center tap. I've been meaning to do the latter. There is no provision for hum reduction on the 2.5 volt heater.

I jumpered in the Transcendar, just to see if it would go low enough to hum. It reproduces well below 60 Hz with that transformer, but there is no hum in my test speaker. It is capable of reproducing hum.
 
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Line transformers have caught my attention lately, for some reason.

In the first picture is an Atlas Sound HT-87. These are advertised as being made from audio grade laminations ( whatever that means ) and have a claimed frequency response of 50-15,000 Hz + 1 dB, and an 8 watt output rating. They weigh a bit more than a pound; the second picture shows it next to a typical ( Rad Shack ) 70 volt transformer. These are somewhat expensive for line transformers, but I got a case of them off eBay for $24 shipped to my door, so I figured it was worth a gamble to try them out. I am hoping that I can find a balanced center point on one of the taps so they can be used as push pull OPT's.

In the meantime, I rigged one up to the mule. I measured their frequency response, at 1 volt RMS input to the mule, as flat down to 40 Hz. It may go lower, I didn't try to measure below that. ( I also need to re measure the OPT that is currently on the mule, I think I've been doing it wrong and erroneously stated its low frequency response ).

For power levels up to 150 mw output or so, the HT-87 performance was as good as or better than the air gapped OPT that is on the mule. The two tone IMD went up pretty rapidly at higher outputs, however. This was using the 1 watt tap on the plate, and 2 watt tap on the second grid - all other combinations of taps were unacceptable. I also used it as a triode on the 1 watt tap with acceptable results.

I also tried choke loading the mule with the HT-87, even though I really don't have any suitable chokes. I set it up as a triode, and started sticking chokes in series with the plate. I used a .47uF output capacitor - values below that didn't show much output. Results were dismal below about 10 Henries. Results got better with increasing inductance up to about 23.5 Henries, the limit of chokes I had at the house to string together. Finally, I just used the primary of a 5K 10 watt Transcendar, which I think is 30 Henries, getting rid of all the mess and about six feet of jumpers in the process. I really didn't see any two tone IMD improvement by doing this. I think between about 20 and 30 henries is probably adequate for something like this.

At power levels to 100 mw output, choke loading did not provide any two tone IMD improvement. Above that level, it did show significant improvement, effectively doubling the power output, with no increase in the two tone IMD. If one could get suitable chokes and good line transformers on the cheap, this could be a viable methed of making an inexpensive low power amp. paying full price for chokes and line OPT's would probably be as much as just getting a Hammond 125xSE type transformer in the first place.

Win W5JAG

edit: what I call choke loading, the audiophiles call para feed. if that clears up any confusion.
 

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The Atlas Sound HT-87 as a push pull OPT

... I am hoping that I can find a balanced center point on one of the taps so they can be used as push pull OPT's.

They work well as a low power push pull OPT.

I have an Antique Electronic Supply 11BM8 push pull amp that has, for the last decade, resided under an eave on the deck at our primary residence. It's seen some hard times, including multiple hose blasts while in operation.

I pulled it, thinking I might liberate some good OPT's, freeing them up for something else, and replace them with mediocre OPTS more suitable for an outdoor deck amp. They are identical size with the stock OPT's.

The results were unexpected. My notes are in the last picture. The left channel was horrific with the stock OPT's, causing me to wonder if sheltered outdoor exposure and the occasional hose blast have damaged it. It looks OK. The right channel was somewhat better, but nothing to brag about. I did not record those measurements.

The HT-87 was a vast improvement on the left channel. It was a significant improvement on the right channel, but not as dramatic, probably due to tube mis match. The tubes in the left channel are the last of my "matched" 11BM8's. The tubes in the right channel are just random pulls from my warehouse to replace water blasted tubes.

The frequency response measurement was done on the right channel, at 1 watt output, since I expected it would be the worst case measurement. The sine wave is 1 kHz, 6 watts at onset of clipping. The square wave is at 10kHz, 1 watt.

These look to be pretty good as push pull OPT's.

edit: I haven't seen a voltage rating on these - they look to be good at the voltages in this amp and the mule, but they have very little time in operation, and caution is warranted here.

Win W5JAG
 

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The line transformer diversion is, temporarily, grinding to a close.

Re: the AES 11BM8 amp, I took off the HT-87's, and replaced them with the Radio Shack #32-1031 10 watt line transformers. The shared cathode resistors were also running scorching hot and had changed value, even though the amp really doesn't have a lot of hours on it, so I replaced those with 5 watt 270 ohm resistors. These still run hotter than I like.

I also verified that the distrortion and frequency response anomalies follow the unmatched tubes. The present B+ voltage is 215 volts, and Pd is 12.5 watts. Both line trannies seem to handle this voltage without difficulty.

The Radio Shack transformer is not as efficient as the Atlas Transformer, nor does it have the low distortion characteristic. Two tone IMD on the matched side was 1.5% at one quarter watt; 2.5% at one half watt, and 3.0% at one watt. Not good at all for a push pull amplifier. Freq resonse was spectacular for a cheap OPT, however. On the matched side, at 1 watt output, it was - 3dB at 35 Hz; -1 dB at 100 Hz; 0 db at 1 khz; 0 dB at 10 kHz; and -1.0 dB at 20 kHz. The bad side was similar, the - 3dB point being 60 Hz.

The square wave looks rough, however, these sound fine. Since they are on the deck amplifier, I've just left them in place.

Not sure if all line transformers work this way, but I've found with both the Atlas and the Rad Shack, the "center tap" is two taps down from the tap in current use. For those interested, the load is calculated thus: the line voltage is squared ( 70.7*70.7 = 5000) and this product is divided by the wattage tap to get a load resistance thus: 5000 / 1 watt = 5000 ohms. The center tap would be two taps down, at 4 watts.

Win W5JAG
 

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If you have a transformer, try it

Since it is easy to do, I've been hooking up anything that has windings to try out.

Filament transformers: work okay, over a narrow frequency range, which, happily covers speech pretty well. I have vague memories as a kid of using 6.3 volt filament transformers to "match' a 600 ohm line output to a typical speaker. Nowadays, I would use a PA line transformer for that.

Small, hamfest type, vintage OPT's: work well, provided relatively poor low frequency response is acceptable. Most are - 3 to -4 dB when you get much below 80 Hz. High frequency response is not a problem.

Push Pull transformers as Single Ended OPT's: Works, surprisingly, at least at these flea powers and currents, probably not at higher levels. Trying to use the end to end plate leads won't work well at all, but using the center tap as the B+lead, and a plate lead as the load, seems to work well, with good dstortion characteristics and good freq response. Trying this with a line transformer won't work at all.

This is the set up I have been using: I pull the 6X5 rectifier, and jumper B+ into the mule from the regulated power supply. I have a 25 watt 1k Clarostat potentiometer as the cathode resistor, and at a given B+, just twist the Clarostat for lowest distortion or highest output, or whatever.

For the 46, with the mule's onboard power supply, best distortion results are at a cathode resistance of 750 ohms. Distortion improves slightly up to about 300 volts B+, beyond which doesn't seem to make much difference.

Win W5JAG
 

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46 ( and 47 ) in the SSE

This SSE board was last seen running 6CD6's before being removed from its chassis to make way for the 801TSE board.

First pic is the SSE board with the octal sockets cut out, and five pin sockets installed, held in place by wavy washers.

It's easier to experiment with all components on the side of the board with the tubes, thus all but two resistors were so relocated, the resistors were all checked and new caps installed. The second pic shows the board set up with the components for 46 installed in one channel.

Third pic is testing the front end to make sure both sides still work properly before proceeding further - the pic shows each half of the 12AT7 putting about 75 volts RMS into a 1 meg load, 1 kHz input, about 300 volts to the CCS.

Fourth pic is the mule power supply jumpered to the SSE board, a Transcendar 5K OPT for the load.

Contrary to my intital belief, directly heated tubes on the SSE board looks to have real merit. I may follow through with a complete amp build. The TSE has nothing to fear from this, but it sure looks like it will be possible to out perform, by a large margin, a low power SSE built with indirectly heated tubes.

This was doing 0.8 % IMD at 1/10 watt, increasing to about 5% at 4/10 watt, with a 12AU7 / 46 combination. There is room for improvement yet to come. To put that in perspective, a well respected transformer winder, using new low IMD transformers and low IMD circuitry, got 2% at 1 watt from a Type 50 tube, IIRC, and my TSE 801 got down to 4% ( I can get it lower running the tubes harder ) at 1 watt with an RF final tube and cheap Hammond universal OPT's.

Win W5JAG
 

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Moving on, here is 307A / VT-225 in the mule. The perched transformer I picked up at the Joplin Hamfest; it should drop right in and do 400 volts, more or less, under load.

I have a half dozen used 307A, all came from Fair Radio for not much money. The first one I tried lit up like a neon sign inside the plate structure but, after a few hours, that resolved itself and it seems to work normally. 307A #2 has some wierd kind of on / off pulsation - mostly off - doesn't seem like oscillation, but I'm not ruling that out yet. 307A #3 is pictured, and it has a filament issue - one leg is visibly brighter as can be seen in the photo. It's burning in now to see if that will clear. I haven't tried the other three yet.

This is just a quickie circuit to get it going - I haven't measured anything except filament voltage. A 0.51 ohm resistor in each leg set it at 5.6 volts AC. Cathode bias. G2 and G3 are tied to plate. 470K grid resistor.

Win W5JAG
 

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Here is the underhood shot.

As a starter, I had the cathode resistor and bypass hooked to one leg of the heater. This worked, but hummed unacceptably at 8 mW with no signal input. I made a virtual center tap with two 22 ohm resistors, and connected the resistor and bypass to that, and this lowered the hum to 0.02 mW at idle. A lot better, but still barely audible with my ear against the test speaker. A real balance pot may be needed with more sensitive speakers.

The OPT wiring is wackadoo. Carelessly, I connected the screen/supressor to the 7K tap, and the anode to the 5K tap. It was some time before I noticed this obvious mistake. It seems to work really well this way. Maybe this is the way to get negative feedback to the screens with this OPT, and I was doing it wrong before.

Even with the crumby OPT, the mule sounds terrific wired this way, with this tube. As a utility amp, I'm not inclined to change anything about it. And to think, I was just going to stick an 807 in the socket. I may still, but I'm glad I tried these first.

Win W5JAG
 

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I was going to replace the PT on the mule with the larger one, but, even though the "chassis" is properly cut, this seemed like a fair amount of work, and I'm lazy, and, for a simple utility amp, not really needed.

The blindingly obvious solution, which for years I've managed to not notice ( like that Yaesu amp on my bench that has apparently not moved in years ) was to use one of my regulated high voltage bench supplies.

So I rigged up a cable with an eight pin plug to plug into the mule rectifier socket, emulating the pin out of the 6X5. The 6X5 / 6AX5 uses five of the eight octal pins. I used one of the free pins to tie the chassis/grounds together. I used another pin to bring in the adjustable negative bias for fixed bias. Banana plugs are expensive, and I'm cheap as well as lazy, so I used the test leads from old, free, HF VOM's that I had long ago blown up. The bias lead is longer with a shrink marker for positive identification.

The connection at the plug looks ( and is ) unacceptably fragile. It needs to be potted for strength, but I'm not sure what to use here. Suggestions welcomed; voltage is 400 max.

This will also work on SSE / TSE PCB's, provided they are modified for the 6AX5 pin out. Two jumpers are required; they are identified in the child resistant SSE thread. Or another specific umbilical could be made. This is needed as I am probably going to make a DHT SSE amp, possibly using 307A, maybe 46 or 47. Still undecided; but the board is done up and ready for direct experimenting, freeing up the mule for other exploits.

With a few new holes, the mule is now sporting an octal socket. I also have some loctal and 12 pin compactron sockets that will fit without more drilling, and with the 2.5 volt transformer gone, a new one can be installed for offbeat filament voltages.

Win W5JAG
 

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This is fascinating stuff, Win. Wish I had more substantive things to add, so I'll just cheerlead for now.

Earlier you said the 307A is a find sounding tube, but have you listened to the amp in its current state (with the HV bench supplies and 6Xf rectifier) or just tested it?

A DHT SSE was going through my mind the other day as a curiosity.
 
307A:

I listened to it quite a bit through the test speaker - enough to know that it probably has the most potential of the three DH tubes I've tried thus far. I haven't actually tried it on the modified SSE board, however. The front end may or may not have enough gain.

A DH SSE has merit, I think - for someone. I'm just not sure if I'm that someone. I just really don't need another amp. I already have the TSE 801A, the child resistant SSE, a "6AQ5" P-P chinese amp, and an Elekit TU-879S at our lake house. On top of that, I have an unbuilt Elekit TU-870 amp and matching TU-875 preamp. So, I'm SE amp rich. And, I'm not allergic to silicon - I still have some genuine 1980's Nat Semi LM1875's needing a purpose.

I also have a set of P-P OPT's with a tertiary winding that I want to play with - maybe in hot rod SPP, many unbuilt HF transceiver kits going back to the 70's and up to the present DZ kit, and I STILL want to do another homebrew SSB/CW transceiver in a hybrid format, which strated this traninwreck diversion in the first place.

A DHT SSE was going through my mind the other day as a curiosity.

Still, it's been said that 307A is a good 300B. Some have some real struggles with 300B in their TSE's. Assuming, without actually knowing as fact, that the front end has enough gain, A 307A SSE would not have the parts that seem to cause some TSE builders grief - the filament regulator, the adjustable negative bias supply, and the MOSFET's, but would introduce new issues of it's own. Cutting out the tube sockets and installing new ones is a pretty brutal mod. A tube socket adapter could be made, but it would be fiddly with the cathode wiring going in and out of it - and would add more height to an already tall tube(s). A separate filament transformer is needed for each power tube. You could go with DC on the cathodes, but then you start to get less simple. So, mixed bag.

I think enough of the merits to have hacked a board, and have thought about cake panning a proof of concept, but I'm not sure how much past that I would go with so many other projects needing attention. And, if I do that, I still might use 46 or 47 - haven't really decided. I have enough parts on hand to go either way, although the OPT's won't be that great.

To make a daily driver amp, to be usable at our primary residence, it would have to all be fit into a 12 x 10 inch chassis, and has to all fit under the existing Hammond cage. That is a difficult specification, given all the iron needed, but I've thought about it and have a plan in my head as to how it could be done, so who knows. Never say never.

Win W5JAG
 
For something a bit different- 3Q4, another directly heated pentode - something similar to this may make it into something else I'm working on.

This does a blistering 80 mW of output into an 8 ohm resistive load at first signs of clipping. This is the smallest tube OPT ( at least *I think* it's a tube OPT ) in my inventory. I was hoping it was 2.5K:3.2, but the 80 mW suggests it is 2K:8. 3Q4 needs 7.5K to 10K. The low end is - 1.5 dB at 300 Hz, which is good, the top end is about +1 dB at 100 Khz which is not so good and will have to be rolled off, a lot, but might make a good mosquito repellant as - is.

The input transformer is a transistor type, to make it easier to drive. I think it's 1K:10K. The square wave shows work is still needed. I think it was running about 50 volts on the plate when that was taken. The dh cathode is run off DC - the little LM317MP runs warmer than the tube ....

I think the next iteration of this will be push - pull, trying to use a small transistor type transformer to split the phase, and a small line transformer for the OPT.
 

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The mule outfitted as a push pull monobloc, the active, non power supply circuitry, being the SPP more or less, mostly more - a few component values changed to accomodate what I had in stock on a Friday night.

The power supply was moved into the back half, the hole for the filter cap was filed a bit and an octal socket was jammed ( literally ) into the opening. I removed the 60 ma choke and installed a much larger one of otherwise totally unknown specification.

The 12AT7 has one triode facing the input, the other facing the power tubes. That was about all the thought I gave to component layout.

I had a lot of trouble with the phase splitter. I wired the input triode - with a 10K plate load - measured the output with a VTVM, and it was fine. I wired the phase splitter triode, checked the outputs with a VTVM, and they were fine - near unity gain as expected. I connected everything up, checked for output, and got almost nothing. Checked everything again - lots of drive at the grides of the power tubes, virtually no output.

I disconnected one plate lead, and got a bunch of output. The OPT was cancelling the output instead of combining it. I got the scope and looked at the output of the phase splitter, and they were almost in perfect phase - off just enough to let a few milliwatts sneak out of the OPT.

After a couple of hours of struggling with something that consists of just two resistors, and getting absolutely nowhere, I was starting to feel like the poor bastard whose boomerang wouldn't come back. The problem was the 10K load resistor on the first triode, that I had picked to keep the gain down, as I have lots of drive available. I changed it to 100K, and bang, the following phase splitter worked as expected.

The power tubes are 6G6G, running about 7.5 watts each. This is more than double their rated dissipation, but they don't seem to care. This has also been my experience running them single ended. Cathode current is about 30 ma each side.

I just guessed at the feedback - I have a 2000 pf cap across a 5.6K resistor. It didn't seem to have much effect with the power tubes wired as triodes. It does seem to significantly lower distortion as power output increases in pentode mode. Frequency response seems unaffected either way, it's within about -2dB from 40 Hz or so to almost 50 kHz. Power output is about 1.25 watts before the first trace of sine wave distortion. B+ is about 260 volts loaded.

The OPT is the Atlas Sound HT87 line transformer. P-P 6G6G's want to see 15-20K plate to plate, the Atlas is 5K, so, way off. Performance would no doubt improve with the correct load.

Wn W5JAG
 

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SV811-10

I modeled the output stage in SE Amp Cad, but preliminary resuts were disappointing on the SSE, for several possible reasons. This could be hard. More work / experiments are needed. It was killa on the TSE board, at least before it set my board on fire. Maybe the zero bias transmit tubes could be persuaded to work here.

45

Worked pretty close to as modeled by SE Amp Cad. Produced more than a watt with a 5K transcendar as the load. Practically plug and play once you move past the drama of hacking out the existing power tube sockets. This would probably be a good amp for someone who wants a really simple DHT. The short bottle 45, and the stubby 5930, would fit under the Hammond cage on the CR SSE, making it easier to do a child resistant DHT.

2A3

I didn't have any at the house, so I haven't tried it. I'll try to bring home some 5930 next time I'm at the warehouse of junk, and try them. I expect them to be plug and play, like 45.

The red spots on the paper are an artifact of how tight a wavy washer holds these sockets to the board. There was a lot more than that, but it missed the paper.

Win W5JAG
 

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I changed the line transformer to a Stancor 10K plate to plate, which is still probably a little low, but a better match than the HT87 was.

I didn't take any notes, but IIRC, it was -2 dB at about 40 or 50Hz, and maybe - 1 dB at 20 KHz, so pretty well full range. Output is about 3.5 - 4 watts. Each tube in the push pull pair is running about 7 watts, so that seems like a reasonable enough output number, but I'm not really familiar with push pull amps.

I stuck a barrier strip on the "chassis" where the small choke used to be, and using some scrap pieces of wire, I brought the output of the first triode amp and grids of the power tubes to the barrier strip, also a ground connection. To make it easy to attach clip leads, I used scrap pieces of component ends and bent a little circle into one end, for the clip lead to get a good grip on. The straight end goes to the barrier strip. Waste not, want not.

This way I can easily use the output of the triode first stage, or the phase splitter, or the push pull power stage, as known good building blocks for working on other projects. The input tube could be pulled, and a differential input can easily be applied to the grids of the power tubes, to use just the power stage.

This is purely for convenience - the chassis could be flipped over to do all of this with clip leads - this just makes it a lot easier, neater, and faster. A blocking capacitor is needed for the output of the triode first stage, otherwise there would be a lot of DC at that terminal of the power strip. The power tube grids are already isolated from the splitter by the coupling capacitors, so bringing the signal out from the grids takes advantage of that. Feeding a signal into the power stage from the external strip would require blocking / coupling capacitors however.

The obvious first use here of the phase splitter outputs / inputs is making an SSE board push pull. I do recall at least one thread a few years ago on this. Should be easy, really - making one into a hot rod or top fuel psuedo SPP.

Also, it seems that this converts the mule into a tube tester of sorts. Since the output of the first stage is easily accessible, a signal of known ac voltage can be fed into the input, then measured at the output, and the gain of that section can be measured, also the noise, and since the AA-1 is quite sensitive, the IM distortion characteristic. Likewise with the phase splitter half, although I'm less sure about the validity of the data to be had there. More experiments will be needed, but it looks like it should be an easy way to match tubes for similar characteristics.

Since I had one pin on the barrier strip left over, I brought the cathode of one of the power tubes out to it. Measuring the cathode voltage here allows one to calculate the current, thus power tubes can be matched for current this way. While the onboard power supply is weak sauce, the external power supply can be easily plugged in to set whatever voltage is needed for the tube under "test". 6G6G uses the same pinout as the common stuff like 6V6, 6L6, etc., so it "should" be quite useful for this.

Anyway, Jeff, if you're still reading, thanks for the great idea, and sorry I've threadjacked your thread and trainwrecked it so badly!

Win W5JAG
 

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Hey, I'm still reading! Thanks, and no worries about the threadjacking. This is really fascinating and I've been watching it closely. I just don't have enough knowledge to chime in with.

One thing I've come to realize is that I prefer the sweet, warm, open, vintage sound that tends to get eliminated by ICs. I might try removing the MOSFET source followers but retaining the CCS chips, as originally suggested in this thread, just to see if it changes the sound. Also adding better coupling caps than the Auricaps that are in there now (like Mundorf Mcap silver-oils, maybe).

But in the spirit of frugality that you've inspired, I'm more interested in breadboarding a new 300B amp with the equipment I already have. Maybe I'll use a diode bridge in the PS section, but other than that it will be a non-transistor 5842-->300B with a double pi filter in the PS and the 5K:8ohm:15W Electra-Print OPTs, plus my existing PT. Maybe with a traditional circuit like the Williamson. I want to let the second-order harmonics sing!

Then I'll reassess. I once heard a 6SN7-->300B about 15 years ago that was revelatory. So, if the above project works, and I'm still wanting something different, then I'll invest in some new iron and a pair of 6SN7s and make a pair of mono blocks. I keep coming back to the 300B design in the Fi Primer and just want to try it.

Now that I've made and modified the TSE, I have enough knowledge to attempt it, and for that I thank George.
 
That preamp build you just finished looks terrific.

My metal working skills would have to improve a lot just to get to the point it could be said they really suck.

I take it you had no ground issue(s) to resolve with your split chassis build? I have a lot of old transciever supplies I've thought of pressing into audio amp service, but a dedicated external supply just for audio amps would have a lot of virtues. I've got the parts to build a pretty stiff one, just haven't done it.
 
Thanks! All I used was a step bit and various sizes of regular drill bits to make the holes. Oh, and a Black & Decker rotary tool with the Dremel #426 cutoff disk to make the rectangular opening for the IEC inlet.

The rest is Rustoleum all-surface spray paint (matte French cream).

The grounding is very strong. All the power conductors are 20 awg but I used 18 awg for the chassis grounds, and kept the wider bandwidth in the umbilical by soldering them to both the ground conductor and the cable shielding. There is a barely noticable 60hz hum but that's because the outlet it's plugged into is not grounded. I'm going to try the old "ground the outlet to the box" trick to see if that works.

300B ideas aside, I think my next project will actually be to make a line preamp, either with the 26 or 10Y tube, so I can drive mono blocks. The 26 is especially susceptible to hum, so I'd probably do a two-chassis build for that too.

It's more complicated and time consuming to pull off, but it's worked well so far.
 
a non-transistor 5842-->300B with a double pi filter in the PS and the 5K:8ohm:15W Electra-Print OPTs, plus my existing PT. Maybe with a traditional circuit like the Williamson. I want to let the second-order harmonics sing! ...

I wonder if there is enough gain out of the 5842 to drive the 300B to clipping.

An interstage transformer to boost the drive voltage might be useful, but I don't know much about them, vis-a-vis hi fi.

I have one, with adjustable ratios, but just haven't got around to experimenting with it. That SV811 on the SSE board is a likely first place to try it.

My four year old is at my office today, so .... work ..... is futile .....

Win W5JAG
 
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