New guy needing help

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Resonance77
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New guy needing help

Post by Resonance77 »

Hello everyone. I am new to this forum and to amp building. I've repaired and/or modded a few amps in the past. I have some knowlege of electronics, can read and follow a schematic, solder half way decient and am well aware of HV safety (I used to build Tesla coils for fun). I'm a pretty quick learner as well.
I'm in the process of trying to put together an 18 watt version of a 2204. I would like to use 6v6's and an ss rectifier. I have a PT and an OT. They are Heyboer HTS-7048 and HTS-7046. I aquired them from a website called amppartsdirect.com. The plan is to use a JCM 800 preamp section and combine it with a 6v6 power section built from the HTS-7048 transformer.
Does anyone know if there is a schematic for something like what I'm talking about? My hang up right now is the power section. I don't know how to take the specs from the transformers and tubes and figure out the values for the resistors and capacitors in the power section and B+ rail. Can anyone point me in the right direction?
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geoff 1965
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Re: New guy needing help

Post by geoff 1965 »

Welcome to the forum,
Can you post the specs of the transformers?
Have a look through the downloads section,there is a lite2 with 18W power section using 6V6’s cathode biased.
Trinity amps also do a custom plexi 18W 6V6 amp which is worth checking out,go on their website and the schematic/layout are in the support section.
Good luck
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Bieworm
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Re: New guy needing help

Post by Bieworm »

Mark Huss' 6V6 plexi? That might be a good start.
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TriodeLuvr
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Re: New guy needing help

Post by TriodeLuvr »

I recently built a 2204 with a 36W power section (two EL34s). One difference, mine uses a 5AR4 instead of SS diodes. I really like the slow startup and simplicity of the tube rectifier, so that was my choice. Anyway, any power section with a 12AX7 long tailed pair phase inverter (like the Marshall) driving a pair of pentodes is easily adaptable. Circuit values for 6V6 are nearly identical to those for EL84. As someone else said, if you post the specs on the transformers, people here can help. I went to the manufacturer's site, but couldn't find those model numbers.

Jack
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Resonance77
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Re: New guy needing help

Post by Resonance77 »

geoff 1965 wrote:
Mon 07/05/21 9:57 pm
...Can you post the specs of the transformers?
TriodeLuvr wrote:
Tue 07/06/21 12:35 am
As someone else said, if you post the specs on the transformers, people here can help. I went to the manufacturer's site, but couldn't find those model numbers.
I couldn't find the manufacturer's specs either. The website I bought it from references Marshall 18W, 40-18035. I assume it is a direct replacement. Now that I think about it, I probably should email the manufacturer to confirm that assumption.
Bieworm wrote:
Mon 07/05/21 11:10 pm
Mark Huss' 6V6 plexi? That might be a good start.
Funny you mentioned that. I stumbled across that 6v6 plexi schematic earlier this morning and printed it out. It is sitting on my desk in front of me right now. The plan as of now is to merge the JCM 800 preamp section with the 6v6 plexi power section.

I downloaded a few schematic drawing programs to try out. I've never used one before. I have had a little difficulty finding one that has a decent selection of tube symbols in the default library. I think I've settled on a program called Jschem. It seems to have what I need. I'm open to suggestions if anyone knows of a better program to use.

I'm going to work on getting it all drawn out today. I'll post it here for comment and criticism once I have it drafted.
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TriodeLuvr
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Re: New guy needing help

Post by TriodeLuvr »

I'm currently using free software from Express PCB. They have two packages; one is proprietary layout software for ordering PCBs, the other is schematic drawing. The two link together for creating and ordering PCBs, but they each work fine independently.The schematic software doesn't come with vacuum tubes, but making new symbols is extremely easy. I was using Visio up until a few years ago. It was more cumbersome when new symbols were needed, and after Microsoft bought it, the program seemed to change for the worse. If you decide to try Express PCB, I can probably email my custom component file containing the tubes and transformers I made. The schematic below was drawn with this software.

Image

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geoff 1965
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Re: New guy needing help

Post by geoff 1965 »

40-18035 is a reference number for the 18W also used by classic tone,is the HT printed on the transformer next to the leads/lugs 290-0-290? heyboer make a lower B+ model as well.
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Resonance77
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Re: New guy needing help

Post by Resonance77 »

geoff 1965 wrote:
Tue 07/06/21 10:24 am
40-18035 is a reference number for the 18W also used by classic tone,is the HT printed on the transformer next to the leads/lugs 290-0-290? heyboer make a lower B+ model as well.
I can't find any markings referencing output voltage anywhere on the transformer. The website I purchased it from describes it as "Great vintage type upgrade/general replacement Power transformer! RadioSpares — 18 watt — Lower B+ With lugs like the original RS part." So I assume it is the lower B+ Heyboer model. Would you happen to know the HT Vout for this particular part?
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geoff 1965
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Re: New guy needing help

Post by geoff 1965 »

it could be 275-0-275 but not sure,if there are no markings then you need a schematic from the supplier for the colour codings of the wires.
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Resonance77
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Re: New guy needing help

Post by Resonance77 »

geoff 1965 wrote:
Tue 07/06/21 11:21 am
it could be 275-0-275 but not sure,if there are no markings then you need a schematic from the supplier for the colour codings of the wires.
I sent an email to Heyboer. I will let you know what I find out. Thanks for the help!
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Re: New guy needing help

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TriodeLuvr wrote:
Tue 07/06/21 10:21 am
I'm currently using free software from Express PCB.
Oh man. Get rid of that! I used to use it too, but it's not worth it. Try KiCad out. It's free and you can export Gerbers if you ever need to order anything. KiCad is great, and there's tons of stuff available for it, and what isn't available I designed in FreeCAD (not at all necessary, but I wanted a 3D halo inductor in my 3D view of my wah board). KiCad supports schematics, layouts, gerber viewers, and has trace calculators, etc...

Thanks,
Josh
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TriodeLuvr
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Re: New guy needing help

Post by TriodeLuvr »

JMPGuitars wrote:
Tue 07/06/21 12:57 pm
TriodeLuvr wrote:
Tue 07/06/21 10:21 am
I'm currently using free software from Express PCB.
Oh man. Get rid of that! I used to use it too, but it's not worth it. Try KiCad out. It's free and you can export Gerbers if you ever need to order anything. KiCad is great, and there's tons of stuff available for it, and what isn't available I designed in FreeCAD (not at all necessary, but I wanted a 3D halo inductor in my 3D view of my wah board). KiCad supports schematics, layouts, gerber viewers, and has trace calculators, etc...

Thanks,
Josh
I'll take a look, but our needs are probably very different. I only order boards from Express PCB (no Chinese boards or parts in my amps), so gerbers haven't been necessary. Also, I need to be able to design my own components quickly, such as transformers with five or six secondary windings in various configurations, or odd, one-off plugs and jacks, and the Express PCB software is really good for that. I can't think of a situation where I'm likely to need more capability, but I'll save a link to KiCad just in case. Thanks for the suggestion!

Jack
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Re: New guy needing help

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TriodeLuvr wrote:
Thu 07/08/21 2:21 am
I'll take a look, but our needs are probably very different. I only order boards from Express PCB (no Chinese boards or parts in my amps), so gerbers haven't been necessary. Also, I need to be able to design my own components quickly, such as transformers with five or six secondary windings in various configurations, or odd, one-off plugs and jacks, and the Express PCB software is really good for that. I can't think of a situation where I'm likely to need more capability, but I'll save a link to KiCad just in case. Thanks for the suggestion!

Jack
It's worth it, even for small stuff. And just about ALL domestic manufacturers will use Gerbers. There was only a very short learning period for me to switch from ExpressPCB to KiCad, thanks to tutorial videos on youtube. Anything you want to learn should be on there.

Some things I like are the global/hierarchical tags. I'm working on a tube tester design (beta testing it now), and two sections are identical. So I was able to make two schematic sheets, one an automatic copy of the other. Any change to sheet 1, automatically updates sheet 2. Then when I imported and designed the PCB for section 1, I was able to automatically generate section 2, traces intact and all. It was a great time / OCD saver.

There's also a TON of components loaded into it, including branded products. So if you want to make sure a specific part will fit, easy. And most of them have 3D models, so you can actually view the layout without a lot of guessing involved. That's great for spacing and hole tolerance.

This is my wah design, including the 3D inductor I made in FreeCAD:
JoshuWah.jpg
Thanks,
Josh
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Re: New guy needing help

Post by Bieworm »

That looks awesome!!!
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Re: New guy needing help

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Bieworm wrote:
Thu 07/08/21 12:50 pm
That looks awesome!!!
Thanks!

Check it out compared to the real thing:
JoshuWah.jpg
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Re: New guy needing help

Post by Bieworm »

Nice! I rarely use wahs though.. but then again. .. I have a cry baby.. crap!
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Re: New guy needing help

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Bieworm wrote:
Thu 07/08/21 3:37 pm
Nice! I rarely use wahs though.. but then again. .. I have a cry baby.. crap!
I'll send you a PCB, you can upgrade that crybaby and then maybe you will use a wah. ;)
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Resonance77
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Re: New guy needing help

Post by Resonance77 »

I sent emails to the seller and the manufacturer of the transformers.

Edit - my computer keyboard just started doing weird things and I accidentally posted before I was done with the post.
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Resonance77
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Re: New guy needing help

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Neither have replied to my emails. Heyboer Transformers is a couple miles from my house so I drove over there earlier this afternoon. There was nobody there at all. There was a sign on the door that said they are closed due to covid. I wonder if the shut down last year and never reopened?
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Re: New guy needing help

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I mentioned your experience on another forum. Several people replied that they've spoken with the factory in the last week or so. Just thought you might want to know. :)

Jack
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