Wow. Yowza. Holy Mackeral, George.
LOTS to unpack here, George.
Just a LITTLE TOO COMPLEX for point-to-point or proto board, me thinks.
(A) Please put me on the Beta Testers/Early Adopters List. Ready when you are. In fact, just bought some NOS 45s and 2A3s, so need some more TSE-IIs while I'm at it.
(B) For a few seconds, thought I was looking at MOSFETs in Darlington Pairs. THEN, thought "paralleled". But the flip the MOSFET not the heatsink idea is excellent.
(C) I only see P-type MOSFETs; where's the N-FET at? I'm sure I'm staring right at it, SOMEWHERE.
(D) What's the spec for the MOSFETs and diodes? (Making a Mouser order.)
I was gonna ask if the TSE MOSFET (currently STF3LN80K5) could be used on the HV side (I have plenty) until you made the "P" comment. Arrows, old man, watch the arrows....
(E) Points of Clarification for the old mech engineer still learning about electrons:
Is Q1/Q2 a shunt regulator, governed by diode D3?
I would have assumed that D3 is a Zener, but the symbol is an "avalanche" diode, is that right? Same question for D4 in the driver screen supply.
Apropos of nothing in particular, I experimented years ago with a 6SL7 driver with the 10M45 CCS on the anode and battery bias (NiMH was the best IIRC).
Sounded superb.
Been meaning to revisit that topology; I think of it as "clamping" the tube between constant current source and sink, but not sure I'm using the terms correctly.
Of course, that was conventional grid-to-grid topology, which I can ALMOST fathom. "Cathode drive" is still a bit beyond me.
The Bartola Valve fellow has been noodling along similar lines (cathode drive – Bartola(R) Valves) but in ways that seem to me to be Unnecessarily Complex (to borrow a Millettism), which seems to be his thing. The TubeLab approach seems like better engineering.
[40+ years ago I had a professor (emeritus) named Fred Hooven who said that "engineering is doing with 50 cents what any jackass can do with five dollars." He had been a FORD guy for a long time, so he usually added "and the Mercedes Benz is what the jackass does with the five dollars." ]
LOTS to unpack here, George.
Just a LITTLE TOO COMPLEX for point-to-point or proto board, me thinks.
(A) Please put me on the Beta Testers/Early Adopters List. Ready when you are. In fact, just bought some NOS 45s and 2A3s, so need some more TSE-IIs while I'm at it.
(B) For a few seconds, thought I was looking at MOSFETs in Darlington Pairs. THEN, thought "paralleled". But the flip the MOSFET not the heatsink idea is excellent.
(C) I only see P-type MOSFETs; where's the N-FET at? I'm sure I'm staring right at it, SOMEWHERE.
(D) What's the spec for the MOSFETs and diodes? (Making a Mouser order.)
I was gonna ask if the TSE MOSFET (currently STF3LN80K5) could be used on the HV side (I have plenty) until you made the "P" comment. Arrows, old man, watch the arrows....
(E) Points of Clarification for the old mech engineer still learning about electrons:
Is Q1/Q2 a shunt regulator, governed by diode D3?
I would have assumed that D3 is a Zener, but the symbol is an "avalanche" diode, is that right? Same question for D4 in the driver screen supply.
Apropos of nothing in particular, I experimented years ago with a 6SL7 driver with the 10M45 CCS on the anode and battery bias (NiMH was the best IIRC).
Sounded superb.
Been meaning to revisit that topology; I think of it as "clamping" the tube between constant current source and sink, but not sure I'm using the terms correctly.
Of course, that was conventional grid-to-grid topology, which I can ALMOST fathom. "Cathode drive" is still a bit beyond me.
The Bartola Valve fellow has been noodling along similar lines (cathode drive – Bartola(R) Valves) but in ways that seem to me to be Unnecessarily Complex (to borrow a Millettism), which seems to be his thing. The TubeLab approach seems like better engineering.
[40+ years ago I had a professor (emeritus) named Fred Hooven who said that "engineering is doing with 50 cents what any jackass can do with five dollars." He had been a FORD guy for a long time, so he usually added "and the Mercedes Benz is what the jackass does with the five dollars." ]
The N-fet is Q1 or Q2. They are used as followers fed by a zener diode. The circuit of Q1 and D3 make a stable low impedance 180 volt source for the output tube screen grids, without the issues involved with a fully regulated supply. D4 is also a Zener but I used whatever library part my 10+ year old version of Eagle gives me. Autocad wants $600 per year to rent the version of Eagle that is capable of making large PC boards. They also require me to give up the ability to use the old version that I paid for several times. I started with the DOS version 2.62 of Eagle and paid for every upgrade. Not taking Autocad's dead end strategy.
I didn't know anything about the Bartola stuff until you just showed me. It seems that he has placed Copyright August 2020 notices in his schematics, some of which are quite similar to mine dated from 2019.
I have FQPF9P25's for the P-fets in this test amp since I tend to beat on test amps hard. Some of my smaller amps used smaller fets. The Nfet in the screen regulator position has a lot of voltage across it, and can see some serious current surges, especially with me turning knobs. I blew up several different kinds of fets with severe overdrive. The IXYS IXTP3N100D2 has withstood everything I have thrown at it so far, but I haven't plugged my guitar into this thing yet.
I did some testing tonight. Experiments in miswiring a 5K Hammond 1628SEA for 2.5K were disappointing. I hooked up a 1.5K Toroidy and ran both channels in PSE configuration from s single driver tube. I was exploring the power that this setup made when I just cranked the audio generator up full. The power meter read over 60 watts, busting my best for a SE tube amp. Granted it was a very ugly 60 watts. Things looked a bit better at 30 watts or so.
I didn't know anything about the Bartola stuff until you just showed me. It seems that he has placed Copyright August 2020 notices in his schematics, some of which are quite similar to mine dated from 2019.
I have FQPF9P25's for the P-fets in this test amp since I tend to beat on test amps hard. Some of my smaller amps used smaller fets. The Nfet in the screen regulator position has a lot of voltage across it, and can see some serious current surges, especially with me turning knobs. I blew up several different kinds of fets with severe overdrive. The IXYS IXTP3N100D2 has withstood everything I have thrown at it so far, but I haven't plugged my guitar into this thing yet.
I did some testing tonight. Experiments in miswiring a 5K Hammond 1628SEA for 2.5K were disappointing. I hooked up a 1.5K Toroidy and ran both channels in PSE configuration from s single driver tube. I was exploring the power that this setup made when I just cranked the audio generator up full. The power meter read over 60 watts, busting my best for a SE tube amp. Granted it was a very ugly 60 watts. Things looked a bit better at 30 watts or so.
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I just enjoyed myself so much reading this thread George. I truly enjoy the mix of your expertise, your unique and thorough ways of testing the hell out of anything (especially including the blowing up and glueing tubes to your hands), and getting to know you as a person all in the same time.
Wishing you and yours all the best. Might be interested in the final product (10-20W output would be fine), although with my ADD starting new projects is always easy, it's finishing them that's the problem.
Wishing you and yours all the best. Might be interested in the final product (10-20W output would be fine), although with my ADD starting new projects is always easy, it's finishing them that's the problem.
Reading the mail here and in other threads, I think George is busy trying to get some synthesizer (s) finished while he still has the dexterity for smd/smt work. A lot of parts are only available in smd these days. And they just keep getting smaller.
Plus it's mowing season.
A PCB would make the project a lot easier, no doubt, but it should be possible to make an UNSET on Veroboard or dead bug.
Plus it's mowing season.
A PCB would make the project a lot easier, no doubt, but it should be possible to make an UNSET on Veroboard or dead bug.
Is email ahead of the forum? Asking for an old friend, so to speak…
I got an email notice that Francois posted the following:
Yes, you are right. George is obviously busy with other things. But I notice that he writes about UNSET on other threads, if not here, so UNSET is not forgotten.
I thought if we start a list of people who anxiously waiting to buy an UNSET PCB’s George might have some basis for prioritizing his efforts. (If he can’t get the PCB’s ready for sale perhaps he would consider publishing the final schematic with part values, so that builders could go to the Veroboard approach).
So, in the next message I will start such a list, with my name first. Let’s help George to get an idea of the level of interest in UNSET.
(A) not seeing this post. Is email ahead of the forum? Did Francois retract?
(B) in any case (en tout cas) add my name to the list, if it isn’t already on there..
I got an email notice that Francois posted the following:
Yes, you are right. George is obviously busy with other things. But I notice that he writes about UNSET on other threads, if not here, so UNSET is not forgotten.
I thought if we start a list of people who anxiously waiting to buy an UNSET PCB’s George might have some basis for prioritizing his efforts. (If he can’t get the PCB’s ready for sale perhaps he would consider publishing the final schematic with part values, so that builders could go to the Veroboard approach).
So, in the next message I will start such a list, with my name first. Let’s help George to get an idea of the level of interest in UNSET.
(A) not seeing this post. Is email ahead of the forum? Did Francois retract?
(B) in any case (en tout cas) add my name to the list, if it isn’t already on there..
It's an exciting prospect and sitting on the hands is uncomfortable but . . We know he's busy and for sure he knows we're here.
Not just mowing season, it's "my wife wants to rearrange the whole back yard and we have an acre season." This has had me outside nearly every day since the snow melted, often in the rain. We now have a pool, and 192 square feet of deck about 75% finished, all built by me. She wants about 900 square.
Unhappy with my "slow progress" she has convinced me to contract out the remainder of the deck. This will be expensive, but may be worth it in order to get my life back to normal, so I reluctantly agreed.
The latest snag occurred Tuesday when we found out that we can't get a loan on this property without flood insurance, which costs about as much as the loan itself. Other avenues and possible size compromises are being explored.
Where we go from here is unknown, but what is known is that I will be outside working for much of today. At least the 95 degree heat has subsided temporarily.
I never saw it either, but I do see two removed posts from yesterday.
Summer is always the slow season for indoor DIY projects, including audio stuff. In March I had 25 orders for one or more boards. In May that was down to 7 with 3 total orders in June. This is typical, so I tend use summer time for other stuff including vacation trips. We even skipped our usual Florida vacation this year so I could play deck builder.
I received 25 UNSET boards in late April. There are three known mistakes in the silkscreen layer, all involving parts placement or numbering. There are NO electrical issues in the boards.
One board was built at the 15 to 20 WPC level it works fine but does get quite hot at 20 WPC. I have also run it as a PSE board with both channels feeding a single OPT where it makes 40 clean watts, and 60 very ugly watts. I have a paper list of every part that went into that board. This board has been in use for random listening for a couple months as a stereo amp at about 12 WPC with no issues.
Two more boards are about 80% populated. The plan was to make a stereo PSE amp with them, but the outdoor time needed to make a chassis is not available right now.
I also need to make a simple box for the synthesizer project to protect a nearly year long perf board build (one of two).
post # 187 here:
Post Pictures of Your Vero Board Designs Here.
I will try to get the paper parts list into Excel in the next few days. That takes some time on the Mouser and Digikey sites finding numbers for part that were ordered some time ago. I must also document the "errata list" so that these boards can be populated. there are one or two wrong numbers on the board, and two diodes are shown backwards on the silkscreen that will render the board mute (no plate current) if not noticed.
Three of the 25 boards are built or partially built. Two more are planned at different power levels as some resistor values need to change.
I never saw a "list" but if any "early adopters" or "beta testers" want these boards I will sell them for $25 each plus the usual $8 (US) or $15 (intl) shipping. Please limit orders to one or two boards so that there are enough for everyone. All funds collected from this sale will go for a new batch which will be ordered when I can fix the silkscreen and sufficient funds are in place.
I will start a new thread for this "beta" board build where board and amp builds for this board version can be discussed. The usual UNSET discussion should stay here. Post #1 should have the parts list.
@hareynolds,
Sorry about the confusion my message created. I deleted that message (just minutes after posting it) because I thought it might be distracting, and we certainly don’t want to disturb George in his development process.
Thanks, George, for the offer of the PCBs. I’ll take one (for a stereo amp). How do we send money?
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Same as with all of my boards. Send payment via Paypal to tech@tubelab.com
These boards are $25 each, my other boards are $25, $35 or $40 each. Shipping is $8 total for delivery in the US of 1 to 4 boards, and $15 for international delivery.
Use their "pay for goods or services" choice as their "send money to family or friends" option blocks the address and the use of their reduced rate (USPS) shipping which I use.
Verify that Paypal has your correct shipping address and state which board(s) you want and the quantity in the comments box. Boards are usually sent out the next business day.
There are a few countries where I usually do not ship to due to non delivery, extremely long delivery times, or customs fraud. Italy has been on that list since only one of three packages were ever delivered several years ago. In this case I will ship two boards to Italy. If they do not arrive within 45 days I will refund your money.
Due to several previous issues primarily in India or Russia with fraudsters using Paypal's "the customer is always right" policy to demand multiple reshipments followed by a refund, I can not afford to get caught in this loop again.
Hi George,
I just ordered one of the proto UNSET boards - if you get too many orders to immediately fill, it's OK to bump me to the back of the line until the next batch; I can wait. I'm eager to play with it, but I still have ongoing projects I have to wind down.
Awhile back, I went through an entire year where diodes were the absolute bane of my existence.
I had a piece of property that had a drainage ditch through it that didn't work very good, so I cleaned it up and fixed it. Later I found out it was some sort of stinky stream under some type of corps of engineers jurisdiction. That was awkward.
I just ordered one of the proto UNSET boards - if you get too many orders to immediately fill, it's OK to bump me to the back of the line until the next batch; I can wait. I'm eager to play with it, but I still have ongoing projects I have to wind down.
Awhile back, I went through an entire year where diodes were the absolute bane of my existence.
I had a piece of property that had a drainage ditch through it that didn't work very good, so I cleaned it up and fixed it. Later I found out it was some sort of stinky stream under some type of corps of engineers jurisdiction. That was awkward.
Hi George,
Thanks again. I also sent in my Paypal payment for one board. I’m about to leave on summer travels for several weeks, so, like w5jag, I could wait for a later batch of boards if necessary. Please note I also added one SPP board in the order. No hurry with the SPP either.
Thanks again. I also sent in my Paypal payment for one board. I’m about to leave on summer travels for several weeks, so, like w5jag, I could wait for a later batch of boards if necessary. Please note I also added one SPP board in the order. No hurry with the SPP either.
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