High Voltage Hijinks
- Thread starter Hal Harvey
- Start date
Hal Harvey
Well-known member
That’s very clean! I forgot the Wizard has led clippingAnd you must have quite a collection of transformers by now…
I am actually running out. After the Deliverance and X88R builds I'll have just one 320V toroid left. I do have 2 full amp sets after the Model T though. One is Park 75 spec and the other JTM50.
Asdrael
Well-known member
Time to order then
lucky for you, I guess you use like 100VA so it’s probably not that expensive. And not output trans…
Hal Harvey
Well-known member
Time to order then
The toroid transformers I get are like 50VA, 30 trump bucks each. So yeah pretty cheap
Made in China of course.I would not buy toroids for a full amp with OT though. I'll stick with Mercury Magnetics like the GT120 I built and coming T. Heyboer, I really like Heyboer. The odd Hammond here and there. I do see a Trainwreck build in my future and I'll likely get a OEM set from Pacific. But yeah laminated straight transformers. Less efficient but more forgiving running at the edge.
JohnnyCreepy
Well-known member
Seems like my Simms-Watts suffered from too much gain. Didn’t go with the plan I made before because after looking into topologies of triode stages I figured my second tube missed resistor before master volume and between halves. I also added extra grid stoppers, 10K on V1 and 22K on V2. Moved HTR center tap to more near main filter cap gnd lead, but that might be causing bad 60Hz buzz. Gonna look into it tomorrow. Make a mess and conquer??
JohnnyCreepy
Well-known member
@Hal Harvey I looked for AC ripple on bias circuit, but measurements were little weird as there was no signs about ripple after first filter cap, but the other tube pair bias lead had 0.3VAC presents occasinally and DMM made beep about OL few times. The suspected ripple was after second bias circuit cap. Meter was also showing 0.2VAC other measurement lead unconnected, which halved as I moved lead further away from the amp and bench…
Gonna look into it later today and give a mV mode measurement. Have to exclude EMF first as yesterday the amp was on my bench circuit side exposed and there was three potential EMF sources (geothermal heat pump, bench lights led strip & fluorescent light) within 1 meter from it.
BTW test play sounded really good and I was finally able to open up first volume pot in tonestack. Clean guitar sounded amazing. 60Hz noise dropped little when brite channel volume was opened, despite channels were not jumpered physically.
Edit. Might be nothing, but I just noticed I had amp power jack connected to same outlet as lights were. Gonna exclude that too.
Gonna look into it later today and give a mV mode measurement. Have to exclude EMF first as yesterday the amp was on my bench circuit side exposed and there was three potential EMF sources (geothermal heat pump, bench lights led strip & fluorescent light) within 1 meter from it.
BTW test play sounded really good and I was finally able to open up first volume pot in tonestack. Clean guitar sounded amazing. 60Hz noise dropped little when brite channel volume was opened, despite channels were not jumpered physically.
Edit. Might be nothing, but I just noticed I had amp power jack connected to same outlet as lights were. Gonna exclude that too.
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Hal Harvey
Well-known member
If it's working well I wouldn't worry about ripple on the bias.
Are you sure it's 60 Hz... not 120Hz? I guess I don't know much about Finnish power haha.
Does it go away without the guitar plugged in and the input grounded?
Are you sure it's 60 Hz... not 120Hz? I guess I don't know much about Finnish power haha.
Does it go away without the guitar plugged in and the input grounded?
Asdrael
Well-known member
Following a short exchange with @vigilante398 I did a couple of simulations on JLC for a custom chassis. C-shape, 2mm aluminium. 9cm high, 25cm deep, 45cm long, with 3cm folds to be able to screw the chassis to the headshell:
Base: 10€
Powdercoated: 13€ (!)
With enough holes for tube sockets, IEC, fuse, jacks, pots etc... wait for it... drum roll...
11.50€. Yes, the holes cost only 1.50€. They are laser cutting too so expect stuff to be exactly where it should be. That means 14.50€ if I powder coat that. I find it completely nuts.
Shipped to Germany, all included, I would be looking at 55€. For reference, a similar quality non-drilled chassis and powder coated only on a single face would cost me 50€ shipped from a european retailer (and it would be a pain to find anything else than 1.5mm which is too soft imo). I might also look into silkscreening it and not bothering with vynil but that would require more work on my end.
I am very much considering it. Very, very minor incovinience of having to model this compared to drilling massive holes in a powder coated enclosure, risking to melt the powder coat, plus the "joy" of filing squares for switches etc, for 5€? Yes sir.
Base: 10€
Powdercoated: 13€ (!)
With enough holes for tube sockets, IEC, fuse, jacks, pots etc... wait for it... drum roll...
11.50€. Yes, the holes cost only 1.50€. They are laser cutting too so expect stuff to be exactly where it should be. That means 14.50€ if I powder coat that. I find it completely nuts.
Shipped to Germany, all included, I would be looking at 55€. For reference, a similar quality non-drilled chassis and powder coated only on a single face would cost me 50€ shipped from a european retailer (and it would be a pain to find anything else than 1.5mm which is too soft imo). I might also look into silkscreening it and not bothering with vynil but that would require more work on my end.
I am very much considering it. Very, very minor incovinience of having to model this compared to drilling massive holes in a powder coated enclosure, risking to melt the powder coat, plus the "joy" of filing squares for switches etc, for 5€? Yes sir.
JohnnyCreepy
Well-known member
230-240V/50Hz mains here, but better to mention 60Hz to make it more easy for you weirdos with all kind of wacky wall voltages. Nope, it doesn’t go away without guitar/jack grounded. Added V2a cathode bypass cap to be sure few months old tube isn’t doing heater leakage via cathode, but no use. Made clean sound worse to be honest! Gonna remove that tomorrow and try setting bias colder to make sure it isn’t the cure here. Also tried to induce earlier cutoff experience with 2in1 fuzz pedal, but I’m happy it didn’t happen and buzz wasn’t really audible when raising volume enough to mask it into distortion. So I’m almost there with troubleshooting!
Hal Harvey
Well-known member
LOL ok. Have you tried elevating the heaters?
Hal Harvey
Well-known member
Heck yeah. It’d be nice to see more action around here
.What are you using to model it?
I could probably “live” with a templated mostly drilled enclosure too for some quantity discount action. Like for the larger enclosure preamps I made, most everything except the front is the same. And even the input and power switch could be the same too.
It might be cool to have some basic community designs for people.
Asdrael
Well-known member
I am using Fusion. Took my exactly 5 minutes from starting to model to getting the quote for the non-drilled enclosure. Obviously a drilled enclosure takes more time but nothing major, I would probably be done in 30min tops (kinda have to be precise so with my randomly placed PCB stand offs that's not that easy ).
For your case, ordering an enclosure with the classics already done like switch, fuse, IEC and a couple of tubes would be rather easy. Everything round and below like 16mm diameter can be easily drilled in aluminum anyway, it's the square and large stuff that is a pain.
If you give me your dimensions or a drawing, I'll produce a .step file for you if you want. I owe you one for the Diezel GAS
).For your case, ordering an enclosure with the classics already done like switch, fuse, IEC and a couple of tubes would be rather easy. Everything round and below like 16mm diameter can be easily drilled in aluminum anyway, it's the square and large stuff that is a pain.
If you give me your dimensions or a drawing, I'll produce a .step file for you if you want. I owe you one for the Diezel GAS
Guardians of the analog
Papi Fuego
I got a new set of output tubes in the mail yesterday. I got a set of new production Tung-Sol 5881s for a great price and decided to try them out. I'm my dirty Shirley build I've been using a set of JJ 5881s and while thile they function fine, I wanted to compare. Well, the Tung-Sol have it going on. Punchy, brighter and more aggressive. The amp really came alive with a nice sparkle. The JJs feel more flat. Gonna keep the TS in there and keep the JJs as a backup. Gonna have to get another set of these TS
Asdrael
Well-known member
Managed to catch JLC customer support today to ask if they could do masking before powder coating on their aluminium sheet metal.
Shanice told me “HU-uh Honey we can’t have none of that masking here”
I might be paraphrasing the answer slightly but the name is accurate
Still might be worth tho, always easy to sand powder coating away with a dremel sanding disk.
Hoh yeah and Nurul Ain (...wtf are those names) just told me it's a 100 micron thick powder coat so no big deal sanding it, won't have time to heat up.
Shanice told me “HU-uh Honey we can’t have none of that masking here”
I might be paraphrasing the answer slightly but the name is accurate
Still might be worth tho, always easy to sand powder coating away with a dremel sanding disk.
Hoh yeah and Nurul Ain (...wtf are those names) just told me it's a 100 micron thick powder coat so no big deal sanding it, won't have time to heat up.
Paradox916
Well-known member
I never priced a chassis job but that seems cheap to me.
Asdrael
Well-known member
The drilled and coated chassis shipped to me ends up being the same price as a raw piece of aluminum folded four time shipped to me from the same country. And that is using my trick of not ordering a chassis, but ordering a custom piece of gutter from an aluminum provider.
As most actual custom amp chassis makers still fold a sheet and drill/cut by hand (and have to make a living), the pieces usually end up being at least twice as expensive (without powder coating) before shipping. A classical Hammond is like 40€, but it flimsy as hell imo and not custom sized (and obviously raw and not drilled). So yeah. I will invest some time and see how far I can push it with a silkscreen etc but JLC is becoming crazy competitive for this. Imaging if I had ordered my PCBs in the same package - I would have saved an extra 30€ of shipping or so!
Hal Harvey
Well-known member
I agree with everything you said here except the Hammond enclosures are not flimsy if you order the the right thing. The 1441 (steel) series are very robust for example. Fairly cheap, especially with quantity. They were drop shipped to me, for free, in a matter of days. Great powered coating (grey or black). But like you said, various sizes that may not be ideal, and NOT drilled. I have invested in the tools to work the steel enclosures: Greenlee punches, a complete fractional Rotacut/Rotabroach set, Starret squares and punches, etc, etc. It adds up quick
.My experience with a custom folded aluminum amp chassis made in the US runs like this (Synaptic Amplification)
21" x 10" x 3" ($74) 2mm (chassis was completely masked with protective pvc)
Flanges IN
Open Side DOWN
STANDARD Layout
IEC @ 1.75 ($5)
PT KO - TWIN LL @ 3.5 , 5.0 to rear ($10)
OT KO - SVT LS @ 3.0 to input, 3.625 to rear ($10)
Add 10-32 mounts. ($10) (with a particle board drill template for when you make the cab)
Shipping $14
Total: $123 not including taxes. Delivered 4 weeks after payment.
The IEC hole, and two z mounted transformer holes were perfect. I drilled/punched everything else. This is the Model T chassis I posted in this thread.
Steel vs aluminum for amps is a interesting topic. If you are using big iron, aluminum can stress break. I'm using big fender washers to help spread the stress on the Model T chassis. The T is going to be beautiful but I don't know if it would survive throwing it down a flight of stairs like the Hilbish replica 14 gauge steel GT120 chassis likely would ($200 with roll bar hardware).
On the topic and a good comparison - Amplified Nation has a Dumble ODS chassis, 2mm aluminum, powder coated, predrilled for almost any ODS variation, silkscreened front. $200. $300 with eyelet boards. It's nice, I have one in my build queue (going to do Park 75 power amp with Dumble High Plate Skyline ODS pre). This is a great option for someone who wants a Dumble ODS (duh) but skill level between a kit and reinventing the wheel. https://amplifiednation.com/product/d-style-chassis/
I'm excited to see your JLC chassis @Asdrael!!! I think it's probably the best way forward for most scenarios - if you have skills to create the files they need (or a friend like you
).
JohnnyCreepy
Well-known member
Re-did HTR wiring for nothing.
Asdrael
Well-known member
Still missing my transformers so turned to 3D modelling.
Preamp:
Poweramp:
I should maybe have done this sooner. It may be that I have the KT77 heaters flying a bit close to some output transformer ins... we'll see.
As a bonus, I am spending some time reading up on amp design and started brainstorming on the possible "child" between a Deliverance and a VH4
Preamp:
Poweramp:
I should maybe have done this sooner. It may be that I have the KT77 heaters flying a bit close to some output transformer ins... we'll see.
As a bonus, I am spending some time reading up on amp design and started brainstorming on the possible "child" between a Deliverance and a VH4
Hal Harvey
Well-known member
This is why you need multiple (high volts tube) projects going.
As a bonus, I am spending some time reading up on amp design and started brainstorming on the possible "child" between a Deliverance and a VH4
Yeah building and deep diving into all these highish gain preamps has been teaching me what I like and don't like. The VH4 channel 3 is definitely in the like camp. On the other hand I may rebuild the Laney AOR pre into something else.