This is my good friends HRD. He wanted more out of it. So I fitted the Fromel mod kit for it. Next time you see this amp, it'll have a new speaker upgrade too.
The light behind the board makes things easy to see. I use a small flashlight (torch) to do the same when looking over my work. Great to see in a video tutorial! 🔮🌞🥁
Great vid. A small correction which I hope helps. When you biased the amp, you were measuring mV across the resister, not mA through the resister. It turns out that they are the same numerical value only because the resister is 1 ohm. using V = I x R, then 0.065mV = 0.065mA x 1ohm (likely a deliberate step by fender to make it easy to set the bias using mV because otherwise you would have to de-solder the resister to measure mA through it). Caution for other circuits - don't set your volt/ammeter to amps when measuring across a component - it effectively shorts out the resister through your meter. For other circuits, this could mean sparks and a dead meter! Amps are measured inline (amps = current flow = "through" vs. volts = potential difference = "across").
Correct. Normally I only ever measure bias using the shunt method style. Where I'll measure the resistance of both sides of the primary of the output transformer. Then measure the voltage drop across the same points. Then measure the plate voltage. This gives me the plate dissipation in Watts that will always be a better and more accurate indicator of what the power tubes are actually doing.
It does appear that way on camera, however I often leave a small gap so that air can circulate around them, especially underneath. The amp is my friends, and it has been in constant almost daily use since this mod was done. No issues yet.
@@pda041376 thank you kindly. I appreciate that mate. Yeah, I just watched the video and the resistors do appear flat against the PCB. I usually leave a gap about 2-3 business cards thick. I don’t go too high as a larger resistor like that can break off and this amp is a hard working touring amp, not a studio queen.
a cheap mod that makes a huge difference is to just replace V2 with a 12DW7. The result is a great overdrive and more drive channel. And it won't affect the warrenty.
Absolutely. A good affordable mod. Sometimes when a customer comes to you with a bag of parts and money, you figure they’ve already spent that on the parts and that’s what they want. I figured I’d take that opportunity and record fitting these popular kits. Thanks for watching.
Hi Stefano I'm looking at installing F&T's in my Hot rod amp too. Did you use a Variac to slowly increase the power after this installation? Or are they OK to receive full 240V straight away?
Hi there. Always a great idea to install high quality caps like F&T. Most of my clients, including myself notice a noticeable increase in clarity and volume. A clean and quality power supply is a no-brainer. To be honest, most caps are generally tested at manufacturing. So they have already been powered up to full power. But I do still bring them up slowly on a Variac. I don't really show that on the videos. But I might do a separate video of that one day. Thanks for your comment, and your support.
Definitely check your solder connections, especially since they may look fine but the solder pad on the circuit board can easily lift or break from heat. Also make sure your reverb RCA cables are around the correct way. I’ve plugged them in the wrong way 1000 times, and I’ll do it 1000’s more. Finally, inspect the thinner shielded cables inside the chassis. And maybe check the IC as the reverbs in these amps are not tube driven.
The light behind the board makes things easy to see. I use a small flashlight (torch) to do the same when looking over my work. Great to see in a video tutorial! 🔮🌞🥁
It does have its advantages.
Thank you for your comment.
Hi just had the Fromel Supreme done here in Australia sounds fantastic
I like the light behind the pcb! With that board laying down, it’s tough to see your traces and pads, especially if your an old hippie like myself!
Thanks man. Glad you enjoyed the different perspective.
Ooops.. Good technique tho!
Great vid. A small correction which I hope helps. When you biased the amp, you were measuring mV across the resister, not mA through the resister. It turns out that they are the same numerical value only because the resister is 1 ohm. using V = I x R, then 0.065mV = 0.065mA x 1ohm (likely a deliberate step by fender to make it easy to set the bias using mV because otherwise you would have to de-solder the resister to measure mA through it).
Caution for other circuits - don't set your volt/ammeter to amps when measuring across a component - it effectively shorts out the resister through your meter. For other circuits, this could mean sparks and a dead meter!
Amps are measured inline (amps = current flow = "through" vs. volts = potential difference = "across").
Correct.
Normally I only ever measure bias using the shunt method style. Where I'll measure the resistance of both sides of the primary of the output transformer. Then measure the voltage drop across the same points. Then measure the plate voltage. This gives me the plate dissipation in Watts that will always be a better and more accurate indicator of what the power tubes are actually doing.
It appears you flush mounted the 470 resistors, why? That will lead to more issues in the future.
It does appear that way on camera, however I often leave a small gap so that air can circulate around them, especially underneath. The amp is my friends, and it has been in constant almost daily use since this mod was done. No issues yet.
@@whatsstefon phew. Nice vid BTW.
@@pda041376 thank you kindly. I appreciate that mate.
Yeah, I just watched the video and the resistors do appear flat against the PCB. I usually leave a gap about 2-3 business cards thick. I don’t go too high as a larger resistor like that can break off and this amp is a hard working touring amp, not a studio queen.
a cheap mod that makes a huge difference is to just replace V2 with a 12DW7. The result is a great overdrive and more drive channel. And it won't affect the warrenty.
Absolutely. A good affordable mod. Sometimes when a customer comes to you with a bag of parts and money, you figure they’ve already spent that on the parts and that’s what they want. I figured I’d take that opportunity and record fitting these popular kits. Thanks for watching.
Before I start this Fromel Mod, Does the amp need to be bias if you are using the same tubes that came with the amp?
I don’t think so, but it’s worth checking the bias, especially as it’s so easy to check and adjust if necessary on this amp.
Hi Stefano I'm looking at installing F&T's in my Hot rod amp too. Did you use a Variac to slowly increase the power after this installation? Or are they OK to receive full 240V straight away?
Hi there. Always a great idea to install high quality caps like F&T. Most of my clients, including myself notice a noticeable increase in clarity and volume. A clean and quality power supply is a no-brainer.
To be honest, most caps are generally tested at manufacturing. So they have already been powered up to full power. But I do still bring them up slowly on a Variac. I don't really show that on the videos. But I might do a separate video of that one day.
Thanks for your comment, and your support.
Thanks for posting this. What would be a fair price to get this Mod doen to a HRD1?
If depends what country you live in.
Did you ever take a video testing the amp with a guitar?
Sadly not. The customer needed the amp back fast. So I put it back together and soak tested it then they came and picked it up.
anyone know why the reverb may not have fired up w the mod kit? or the drive?
Definitely check your solder connections, especially since they may look fine but the solder pad on the circuit board can easily lift or break from heat.
Also make sure your reverb RCA cables are around the correct way. I’ve plugged them in the wrong way 1000 times, and I’ll do it 1000’s more.
Finally, inspect the thinner shielded cables inside the chassis. And maybe check the IC as the reverbs in these amps are not tube driven.