new build: 50w Bluesmaster HRM combo

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norburybrook
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Re: new build: 50w Bluesmaster HRM combo

Post by norburybrook »

erwin_ve wrote: Wed Jun 28, 2017 4:10 pm Lol that pesky relay thing.
The relay connections that are on the layout are the ones are ok.
The wiring for the backpanel switches are the ones that need to be reversed. Middle lugs stay the Same. Bottom and top wires are reversed, so the footswitch leds got ground connection when they are supposed to be on. Check if you can follow this thought. It should be right, but I'm doing this by what's in top of my mind and don't have a schem. in front.
Erwin the bottom wires on the switches all go to ground, the top wires go to the footswitch, if I swap them round aren't I just reversing the position of 'manual or pedal, i.e I'd be just turning the switch upside down not reversing the LED behaviour '?

My footswitch is wired like this with the exception of the 0.1uf caps, I don't have anything there.
footswitch.png


Marcus
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erwin_ve
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Re: new build: 50w Bluesmaster HRM combo

Post by erwin_ve »

Can you make some pics on what actually has been done on the relays and the back panel switches?
It's very easy to make a mistake when making assumptions.
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norburybrook
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Re: new build: 50w Bluesmaster HRM combo

Post by norburybrook »

relays and back panel switches are exatly the same as this
Bluesmaster Rev6.jpg





I have the diode on the OD reversed along with the wires to it so basically no change.

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erwin_ve
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Re: new build: 50w Bluesmaster HRM combo

Post by erwin_ve »

It looks ok on the layout, but it behaves like you wired the internals of the footswitch the other way around. Are you sure you did not wire the od footswitch like the pab? That could explain the reverse led function.
Edit: found IT. The wire coming from the manual switch to the chassis din is on the wrong pin in combination with the footswitch. Just reverse wire 2 and 4 on the chassis DIN.
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norburybrook
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Re: new build: 50w Bluesmaster HRM combo

Post by norburybrook »

Erwin, I'll give that a try in the morning I've left the studio now.

Thanks for your help [emoji16]

Marcus

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erwin_ve
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Re: new build: 50w Bluesmaster HRM combo

Post by erwin_ve »

Ceriatone footswitch wiring is not compatible with the "Tony" Blues master layout. :D :D :D
I'm pretty sure this reverse pin 2 and 4 on the DIN chassis will resolve the issue.
Nice puzzle isn't it?
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norburybrook
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Re: new build: 50w Bluesmaster HRM combo

Post by norburybrook »

erwin_ve wrote: Wed Jun 28, 2017 7:02 pm Ceriatone footswitch wiring is not compatible with the "Tony" Blues master layout. :D :D :D
I'm pretty sure this reverse pin 2 and 4 on the DIN chassis will resolve the issue.
Nice puzzle isn't it?
Erwin,

congratulations for solving the problem :D I now have a correctly working footswitch and LED's.

I've also been experimenting with V1 plates/cathodes.

as this amp is a bit of a mutt I've been trying things out with it.

I've changed v1 to a low plate, so I've got 100k plates and 1k5 on the cathodes with a 100k slope resistor , I've also added some LNFB too 0.05uF/2x 22M

It's subtly different, the clean is nice and fender as you would expect, the OD isn't as 'smooth' as before probably a bit more ragged but again subtle.

It's like the first stage of a low plate classic /wonderland now with the OD and P.I. from the Bluesmaster.

I don't think the very small open backed cabinet is letting the amp speak as much as it would through a traditional 1x12 or 2x12 but it's certainly an interesting little combo. I've just fit an extra parallel speaker out so it can be twined with another 1x12 if needed. Actually as it's underneath i'll have the combo speaker attached there and the regular output on the back will be extension.
DSC_1314.JPG




onwards and upwards.


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norburybrook
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Re: new build: 50w Bluesmaster HRM combo

Post by norburybrook »

Ok,all finished for now.

50w ODS , HRM. Hybrid low plate/High plate Bluesmaster 1x12 EVM force combo.

Here she is with a matching ported EVM 12L 1x 12 cab.
DSC_1318.JPG
DSC_1317.JPG
DSC_1316.JPG

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erwin_ve
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Re: new build: 50w Bluesmaster HRM combo

Post by erwin_ve »

:D nice! A fully functioning amp is a joy after much puzzle therapy 8) .
Do you like the 100k plates better or the higher plates?
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norburybrook
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Re: new build: 50w Bluesmaster HRM combo

Post by norburybrook »

I'm quite liking the 100k, 4.7uf/1k5 with the LNFB , it is the classic fender first stage. I chose it because my Wonderland I built has the same first stage and I really like it. This sounds different , but still a nice sound.

I'm going to live with it how it is for a while.

thanks for your help Erwin.

I've managed to get through this build without much hand holding from martin manning for the first time, I must be making progress :D


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martin manning
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Re: new build: 50w Bluesmaster HRM combo

Post by martin manning »

Good work Marcus, another Lojai! 100k/1k5 is typical 12AX7 bias point, but Fender would have a 22u bypass cap instead of 4u7 so you've reduced the bass a bit. On the relays and foot switch its a matter of understanding how the system works. Once you have that you wont be tripped up by the differences in layouts and opposite philosophies re relay engaged for OD or clean. The diode across the coil has nothing to do with that.
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Re: new build: 50w Bluesmaster HRM combo

Post by norburybrook »

thanks martin, so the smaller the bypass cap the higher the high pass filter? it's hard to tell much as it's a bit bass light due to the small cab. I might have to up the bass on the HRM as the OD is a bit thin without the boost as well.

maybe more tinkering is in order. I chose the 4.7uf because 1; they were already in there and 2; the wonderland has the same values and I really like the clean on that amp. It's my favourite amp I've built so far, there's just something I can't put my finger on about it. maybe it's the vintage well worn in Iron I used, who knows. This combo is OK, I'm not mad about it, I'm sure it will be a great little amp for something.

Marcus
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martin manning
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Re: new build: 50w Bluesmaster HRM combo

Post by martin manning »

The cathode bypass cap creates an approximately 6dB bass cut shelf. If you double the size of the cap you will slide the ramp down one octave and add more bass. You could easily tack or clip another 4u7 across the ones you have to see if 10u bypass is more to your liking. Try it on V1.
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norburybrook
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Re: new build: 50w Bluesmaster HRM combo

Post by norburybrook »

thanks Martin, that makes sense and is helpful for tuning your amps low end response.

may I ask you how it works as there are two bypass caps, one for each half of the valve, and what the effect would be if they were different regarding the filtering effect?

Marcus
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martin manning
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Re: new build: 50w Bluesmaster HRM combo

Post by martin manning »

On the ODS circuits documented here they seem to be either 4u7 or 10u, and matched on the clean and matched on the OD cathodes. You can certainly mix them if you like, and adjust the low-end response of each stage independently.
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