New HRM build

[CHIP]

Yes the plate values need to be reversed.

Also, don't most ODS have a bypassed 220K between the send and return jacks?

What value is the cap on the standby switch typically? .01uf?

That little filter on the send return jacks was more unique to #124 and was one of the neat features that made that amp so unique and nice. I think Funk said that he has seen a few other real ODS' with that passive RC network on the effects loop jacks before though.

That cap on the standby switch isn't critical in value. It's more voltage rating one if concerned about. I believe the cap is just there to reduce transient spikes.

What does that filter actually do? I might add to my loop on my d'lite.

[ic-racer]

What does that filter actually do? I might add to my loop on my d'lite.

I had posted in my #124 build thread that the send/return network smoothed out the sound with humbucker guitars. I have subsequently decided that the majority of that effect was from the length of the cord I placed between the jacks. I have a particular 12' cord that sounds best.

[ic-racer]

Any pictures of your new amp?

Happy new year to everybody at this forum!

So, far I have posted all that I have

The chassis is the 'standard-issue' Funk/Brandon chassis. I'm going to do a few modifications to it and I'll post some pictures as I go.

Today's big disappointment was finding that I had the proportions of the FET pc board all wrong. Somehow I got it all stretched out. The CTS pot didn't fit in the holes and the PC board certainly did not fit the holes in the chassis.

I totally re-proportioned my FET trace drawing and I'll go ahead and etch a new board.

Yesterdays mishap was in cutting the Formica. Just as I was ready to cut, I realized that if I rotated my piece 90 degrees, I could get both the top and the backing board from my last sheet of Formica.

Well....DUUUHH... now the wood grain is going in the wrong direction. So, I'm tracking down another piece of Formica.

I am developing a small collection of discarded boards, including the complete Funk/Brandon board set. I'll probably sell them all in the end, as they are all functionally fine.

[Structo]

Yes, I've had moments like that where everything seems to go wrong.
Best thing is to walk away for a day or two and come back fresh.
You'll get it and I'm sure it will be a very nice amp.

[ic-racer]

I was going over the schematic yesterday and I can't decide if I'm going to make that last 12ax7 section ( that feeds the HRM board) a cathode follower or not. I'll probably do it both ways and see if I can hear any difference.

It seems kind of like a 'no brainer' for HAD to have done it as a CF, just like the Marshall.

I also have noticed that the Sundown amp uses a tone stack nearly identical to the Marshall/HRM stack and it also has a CF just before the tone stack.

To make it into a CF, on the main board, you would only need to move one resistor and change a jumper wire. All this is under the HRM board and usually covered in goo, so unless you were looking for this subtle difference when examining a real amp with a multimeter you may not pick it up.

If someone has actually checked this out on a 'real' amp in the early 200 range I'd like to know what you found.

Also, if anyone has wired their HRM both ways, I'd be interested in what you found.

[talbany]

peaking of wiring. It has been quite a few months since I addressed wire type. I had a pretty good understanding of what was needed for #124, but I wonder if someone could give a recommendation on the wire likely used on this era amp. Size? Core? Casing?

The only stranded wire used seems to be for the filaments, the rest is solid core and looks like 20 AWG, high quality PVC (not teflon).

If you didn't know!

Taken from Gil's side notes on 124..Also in the comments section in layout we did

Tony

[ic-racer]

peaking of wiring. It has been quite a few months since I addressed wire type. I had a pretty good understanding of what was needed for #124, but I wonder if someone could give a recommendation on the wire likely used on this era amp. Size? Core? Casing?

The only stranded wire used seems to be for the filaments, the rest is solid core and looks like 20 AWG, high quality PVC (not teflon).

If you didn't know!

Taken from Gil's side notes on 124..Also in the comments section in layout we did

Tony

Yes, thanks. It has been almost 2 years since I built my #124...its all starting to come back to me

[ic-racer]

Ok, I got some more "Formica" to work with.
I put that in quotes because the stuff I found is a competing brand called "Wilsonart" They sell 8x10" samples for one dollar. So one sample should be enough for a main board and a backing board.

I did get some real Formica samples but they were about 3" x 6" and were too small to be used as a main board, unless spliced together somehow.

[benoit]

Ok, I got some more "Formica" to work with.
I put that in quotes because the stuff I found is a competing brand called "Wilsonart" They sell 8x10" samples for one dollar. So one sample should be enough for a main board and a backing board.

I did get some real Formica samples but they were about 3" x 6" and were too small to be used as a main board, unless spliced together somehow.

The offer stands for you and anyone else, for cost of shipping, I'll send as much formica as you want. Probably not worth it unless you plan on using a lot of it down the road, but PM if you're interested. Titanicslim used some in a build.

[ic-racer]

Ok, I got some more "Formica" to work with.
I put that in quotes because the stuff I found is a competing brand called "Wilsonart" They sell 8x10" samples for one dollar. So one sample should be enough for a main board and a backing board.

I did get some real Formica samples but they were about 3" x 6" and were too small to be used as a main board, unless spliced together somehow.

The offer stands for you and anyone else, for cost of shipping, I'll send as much formica as you want. Probably not worth it unless you plan on using a lot of it down the road, but PM if you're interested. Titanicslim used some in a build.

I presume it is woodgrain? I'll take 8x10" worth. Do you accept paypal? I can PM you with shipping details.

[Structo]

The laminate flooring I installed in my kitchen and dining room was made by Wilsonart.

[M Fowler]

Benoit dropped some off at my home a while back I used some for an 18w plexi into an Estey organ chassis and will use the rest in some new builds for fun.

[benoit]

Ok, I got some more "Formica" to work with.
I put that in quotes because the stuff I found is a competing brand called "Wilsonart" They sell 8x10" samples for one dollar. So one sample should be enough for a main board and a backing board.

I did get some real Formica samples but they were about 3" x 6" and were too small to be used as a main board, unless spliced together somehow.

The offer stands for you and anyone else, for cost of shipping, I'll send as much formica as you want. Probably not worth it unless you plan on using a lot of it down the road, but PM if you're interested. Titanicslim used some in a build.

I presume it is woodgrain? I'll take 8x10" worth. Do you accept paypal? I can PM you with shipping details.

Sorry, I just saw this. Not woodgrain. It's almost all faux-stone, in a variety of colors. Most of the pieces are 3.5" wide and anywhere from 2 to 8 feet long. As long as the woodgrain isn't a dealbreaker 8x10" should be easy to do.

[ic-racer]

I got my woodgrain boards cut and drilled. I did extra, in case of any problems.

I used a heavy duty paper cutter to cut the board. It worked great. I did all the holes with a borrowed medium-sized drill press. Worked great. (Don't think I'd do it with a hand drill again )

Pictures to follow.

[ic-racer]

Ok, now that I have my correct sized main board I see my nice HRM PC board is too small. It is all to correct scale, but just too small.

That is interesting because I sized it by using the manufacturer's size of the square pots and scaling the pictures to that size. It came out about 1/2 inch too short, though. I think that is from the fact the picture I used was taken at an angle.

I have corrected the PC trace graphic and will make a new board. Like the other spare boards, this one will likely get sold. It would work fine for someone.