John Warren
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Posts posted by John Warren
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Quite pleased with the end results.
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Working an interesting project which I'll detail in the link below.
MC30 pair for restoration (northreadingeng.com)
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Agree with your assessment.
I would not purchase a McIntosh product today. McIntosh's best days are behind them.
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A few photos of a tube amp project completed recently. Two channels, about 20WRMS/ch into 8Ohms. Based somewhat on the Scott 299C output stage but using a solid-state, HV power supply design capable of substantially more power than is required for the push-pull 7591 pairs.
Chassis CAD files were sent out for quote, the supplier (New England based) responded with pricing for larger quantities than I was considering. Placed an order for a small lot of chassis assemblies. All metal chassis assemblies are best for RFI/EMI/noise immunity. The chassis assembly is the high-cost item in the build. Uses oversized Hammond or Lundahl output transformers. Still waiting on a few finishing touches (knobs, graphics). Was considering silk screening the top plate but perhaps some other time.
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Water should be either deionized or distilled.
A friend of mine uses distilled water and Simple Green surfactant solution. It's alcohol based. Chemical smell.
The u/s cleaners that sweep the frequency clean better than those that sit at a single frequency. With the surfactant and swept frequency embedded particles can usually be extracted.
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18 hours ago, HenningO said:
Hi Marvel, do you think another tweeter or diaphragm will fit my Palladium P-37f?
That would be awesome.
It may be possible to remove the transducers from the plastic horn section and find ones that would fit.
Can you provide photos of the rear of the assembly and, if possible, remove the transducers so we can have a peek?
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The WSJ had an article that talks to the concept of "health-span" rather than life-span. Health-span is the years one lives with good health and free of diseases that impact your quality of life and state of mind. The years past when the health-span ends are the years spent managing disease. Most medical interventions, especially for the 75+ crowd, increase life-span but not health-span.
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3 hours ago, hron61 said:
Interesting, never saw a portable GFCI before.
Common in industrial locations. If you have a portable water pump, wet-vac or using power tools in wet areas this is what you want.
If you work on vintage, old and/or faulty electronics, lots of "gotchas" and surprises. Here's my take, connect chassis directly to panel Earth.
Regarding Variac, the red, Chinese Amazon units are the POS. Can't run at rated kVA without getting hot AF. Wipers aren't accurate or don't function until the wick is turned halfway up then wham! The internal winding is likely a better fuse than the fuse.
A Staco 12A variable transformer runs about $650 and will source 1.4kVA all day and barely get warm.
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On 12/16/2023 at 9:45 AM, henry4841 said:
If you look at the price of a Pass Lab phono stage $12,075 for the XP-27 and $4,500 for the XP-17 you will understand the quality of sound you can expect from a phono stage designed by Wayne Colburn.
Texas Instruments published a 2-stage, phono preamplifier design based on the LM833. Flat RIAA response with noise floor lower than -100dBV. Can be fabricated for about 60 USD at the board level.
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On 2/1/2020 at 11:59 PM, rplace said:
I need balanced connections
Are you running long cables at line level signals?
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It's Damping, not Dampening.
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On 7/1/2023 at 6:59 PM, henry4841 said:
That said Mac transformers are more complicated to wind but I understand others are doing it the same way now. Found that out on this forum from our great members.
The unity coupled transformer offers improved performance for CL-B vacuum tube operation only. CL-B amplifiers are somewhat higher efficiency than CL-AB.
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4 hours ago, Marvel said:
She's on blood pressure meds, a statins, and I could see the future.
High BP can have nothing to do with weight. I recall a statistic that ~20% of the people on BP meds are at a good weight (i.e. BMI <24).
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It's dB (capital B for Bell as in Alexander Graham).
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18 hours ago, babadono said:
Ask your doctor to do a fasting insulin test, not a fasting blood glucose level test
A1C is the gold standard, most docs will prescribe an A1C if a couple of 12h fasting BG ratings are 105-115 (at least that was my experience). The correlation coefficient between BMI and A1C for the 50+y/o crowd is basically =1.0 so if you're heavy or obese you're most likely prediabetic or diabetic.
To your point, you can live into your early 90s with all sorts of metabolic issues. I've got family members there now.
And they're depressed, immobile (really crippled), fatigued, constantly panting and vision impaired. And that started 10-15 years ago. Not saying I won't experience same fate but if there's any opportunity to avoid it, I'll try.
Genetics loads the pistol but it's lifestyle that pulls the trigger.
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On 10/28/2023 at 11:09 AM, Montego said:
I don't miss 'real food' anymore. Occasionally I go to lunch with workmates and am always amazed at their choices but I keep my opinions to myself.
Yes, I know where you're coming from. Even guys I know with T2D with A1C in 7s and on meds eat like they're teenagers.
On 10/28/2023 at 12:55 PM, Marvel said:I love the brown rice, as does my Filipina wife, but she has cut out most of the rice and most of her snacks.
Oh yea, I love all forms of carbs, a classic carboholic. As Monty mentioned, I really don't miss them although it did take some getting used to. The wife was never really a big carb type which has been very helpful. What's been interesting is I've upped the red meat and expected to see a bump in the cholesterol numbers but nothing yet.
Still working at 74? I honestly hope you enjoy what you're doing!
37 minutes ago, RealMarkDeneen said:Over the years you may have developed some insulin resistance.
Agreed. Not sure it's reversible either but we shall see.
That said, thank you all for the words of encouragement! The other "trick" that's been working for me is making the morning run real early, like 6:30AM and making it a short duration, low preperation thing. I can do about 2.8mi. in 35min so it's no real time killer and easy to implement. Get up, coffee, read WSJ, NYTs (online), dress in running outfit and just go.
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For those of you struggling with sugar diabetes, a story.
I've retired from full time engineering work about 6 months ago. Devoting a ton of time to amplifier design.
One health issue that's always hassled me was blood sugar levels, A1C numbers hovering between 6.1-6.3%. Wasn't obese but always in the 25-27 BMI range. I'm 65y/o. I don't want to get T2D, it effects vision, hearing and motor function not to mention hammers the immune system.
About two years ago, I went practically no carb. And, after about 6 months of that. dropped 30 lbs. In my little world, no carb means no pasta, no rice, no grains, no breads, no sugar and no to most fruits. For many people it's very restrictive and given this stuff's in everything, difficult. For me it was an experiment.
Basically, when you come to the realization that white bread or whole wheat bread or brown rice or heart healthy plain oatmeal all turn into a gelatinous, sugar-rich "mass" in your gut, you start to get the picture. And don't take my word for it, just get a BG pin prick monitor and measure the results after eating say a cup of plain, "heart healthy" oatmeal with a bit of cinnamon and 1/2 a banana. There's NOTHING healthy about a spike from 102 before to 155 after, it's damaging and boosting the average BG levels. Not good.
After about 18 months (15 Oct 2022) of no-carb living my A1C was 6.0, a small trend towards better but nothing to get excited about. Hence, no-carb was only part of the solution. I was eating lots of meats, vegetables, nuts (I'd even strip all the cheese and toppings off pizza and toss the pie!). Greasy stuff, except for processed meats are ok however.
New strategy was needed. With a BMI of 22.5 thanks to no carb and a good EKG, in July I started running each and every day. First just to the end of the street, then a wee-bit more until about three months ago I was able to jog about 3mi each morning. Today, I can run at full stride over the same route. Many changes occur in the body, it transforms.
Last week, I had a physical so some data share:
The takeaway for me was it took three changes to get to a normal A1C
1. No-Carb enables weight loss
2. Weight loss enables running
3. Running lowers average BG levels
Even today, my 12h fasting BG isn't great at 115 BUT after a run it drops to low 90s which, averages out to good A1C numbers (A1C is a 3 month average).
That all said, there's hope if you want to reverse the trends. It's no easy but if I can do it, any clown can.
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I used the polypropylene orange drops (715P series) to replace the American Radionics foils. Tubes were new EL84M Sovteks. I thought the amp sounded respectable.
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Try EL84M
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On 3/13/2022 at 3:29 PM, captainbeefheart said:
Glad I have a ton of NOS tubes to play with and I never have to worry about getting 4,000 tubes like an amp company. Also very glad I have a ton of NOS Russian tubes i really like as we don't know when we'll have open trade with them again.
Sovteks have been available for some time. Purchased 4 5AR4s, 10 12AX7s earlier this year. Just purchased a quad of EL84Ms too, supplier as 90+ is stock.
So much for the Russian import ban.
MC30 pair
in Talkin' Tubes
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Thanks gents!