Paralleling is not bridging.
It's no different than wiring up 2 speakers in parallel.
It' s as simple as the diagram Zen Mod posted (taken from F4 article).
Here is the article/manual. http://www.firstwatt.com/pdf/prod_f4_man.pdf
Sorry for not linking it earlier.
I do understand how simple it is now.
I figured it had to be complicated, along with misunderstanding the concept entirely, I had not heard of doing this before.
I do have an ulterior motive for doing the mono conversion.
I had used an isolation transformer at one time on the leads to the amplifiers. It is a giant SIGNAL device, it was up to the task, but it had two outputs, 110 and 120 volts. I used the latter. I think with the line voltage I have coming to my house that this combo gave these amps a bit more voltage than they wanted and I have detected a bit of dome on the electrolytics. Please note the past tense.
So for quite awhile I wanted to replace those caps. Getting to them is an involved operation that once done one is in a good place to go ahead and move one heatsink/PCB to the other chassis.
I feel it will be OK to replace the PLITRON with two ANTEKs since my SIT1s have ANTEs installed. I can get two ANTEKs much cheaper than one PLITRON. I am tempted to use a 270 VA HAMMOND split bobbin transformer but ZM is trying to assure me I do not want to do that. I do know these split bobbin things work great in my digital stuff but that is much lower power and I can remote mount them. I would never do that with a power amp just to assure!
And it will cost much less than half of a used J2. I will never sell the amplifiers so re-sale is not a concern. I would hate the idea of those outputs just idling.
Regarding parallel devices - did Mr. Pass say they were the best sounding amplifiers he had ever heard; if he did I missed it. If he is using them on a daily basis then that gives me lots to consider. I cannot remember how much trouble was taken to match the devices though one cannot imagine the task that would be - getting that many REAL close? I thought it was more a proof of concept than an assault on the art.
Of course, I know I can turn mole hills into mountains with these audio obsessions. I must think it is fun. It does seem to be a relatively harmless form of psychosis I try to reassure myself.
I figured it had to be complicated, along with misunderstanding the concept entirely, I had not heard of doing this before.
I do have an ulterior motive for doing the mono conversion.
I had used an isolation transformer at one time on the leads to the amplifiers. It is a giant SIGNAL device, it was up to the task, but it had two outputs, 110 and 120 volts. I used the latter. I think with the line voltage I have coming to my house that this combo gave these amps a bit more voltage than they wanted and I have detected a bit of dome on the electrolytics. Please note the past tense.
So for quite awhile I wanted to replace those caps. Getting to them is an involved operation that once done one is in a good place to go ahead and move one heatsink/PCB to the other chassis.
I feel it will be OK to replace the PLITRON with two ANTEKs since my SIT1s have ANTEs installed. I can get two ANTEKs much cheaper than one PLITRON. I am tempted to use a 270 VA HAMMOND split bobbin transformer but ZM is trying to assure me I do not want to do that. I do know these split bobbin things work great in my digital stuff but that is much lower power and I can remote mount them. I would never do that with a power amp just to assure!
And it will cost much less than half of a used J2. I will never sell the amplifiers so re-sale is not a concern. I would hate the idea of those outputs just idling.
Regarding parallel devices - did Mr. Pass say they were the best sounding amplifiers he had ever heard; if he did I missed it. If he is using them on a daily basis then that gives me lots to consider. I cannot remember how much trouble was taken to match the devices though one cannot imagine the task that would be - getting that many REAL close? I thought it was more a proof of concept than an assault on the art.
Of course, I know I can turn mole hills into mountains with these audio obsessions. I must think it is fun. It does seem to be a relatively harmless form of psychosis I try to reassure myself.
I'm not sure whether he has stated any amplifier is the best amplifier he has ever heard. It really depends in what application they will be used.
I do know he uses the BEAST regularly depending on the speakers and his mood.
He also stated that the inspiration for the F7 was to make it sound like the Beast of a thousand jfets but with obtainable parts. That sounds like a compliment to the beast of a thousand jfets if I ever heard one.
From what I understand he already is biamping (he also uses firstwatt SIT amp).
Just for the record, my day-to-day reference is the Tannoy 15" HPD's in the
upside-down Jensen Imperials with a rebuilt factory crossover. As Joe would
say, they aren't necessarily the best in the world, but they do reveal
differences in amplifiers, and for the FW designs, they have the sensitivity.
For evaluating higher power amps, I have a network that I can use with them
which drops the sensitivity of these speakers by about 12 dB and creates a
"Wilson-like" load for the amplifier while giving the speakers a DF of about 10.
At the moment I also have pairs of Zu Druids, Sony AR1's, and JBL 1400's
standing by. With biamping, I have LX-minis and the SLOBs with Lowthers,
Moths, Tangband, Fostex or SAL's.
That's in my "sound room". There's other equipment scattered about.
upside-down Jensen Imperials with a rebuilt factory crossover. As Joe would
say, they aren't necessarily the best in the world, but they do reveal
differences in amplifiers, and for the FW designs, they have the sensitivity.
For evaluating higher power amps, I have a network that I can use with them
which drops the sensitivity of these speakers by about 12 dB and creates a
"Wilson-like" load for the amplifier while giving the speakers a DF of about 10.
At the moment I also have pairs of Zu Druids, Sony AR1's, and JBL 1400's
standing by. With biamping, I have LX-minis and the SLOBs with Lowthers,
Moths, Tangband, Fostex or SAL's.
That's in my "sound room". There's other equipment scattered about.
Just for the record, my day-to-day reference is the Tannoy 15" HPD's in the
upside-down Jensen Imperials with a rebuilt factory crossover. As Joe would
say, they aren't necessarily the best in the world, but they do reveal
differences in amplifiers, and for the FW designs, they have the sensitivity.
For evaluating higher power amps, I have a network that I can use with them
which drops the sensitivity of these speakers by about 12 dB and creates a
"Wilson-like" load for the amplifier while giving the speakers a DF of about 10.
At the moment I also have pairs of Zu Druids, Sony AR1's, and JBL 1400's
standing by. With biamping, I have LX-minis and the SLOBs with Lowthers,
Moths, Tangband, Fostex or SAL's.
That's in my "sound room". There's other equipment scattered about.
I think you just gave half the forum readers an erection.............
Just for the record, my day-to-day reference is the Tannoy 15" HPD's in the
upside-down Jensen Imperials with a rebuilt factory crossover. As Joe would
say, they aren't necessarily the best in the world, but they do reveal
differences in amplifiers, and for the FW designs, they have the sensitivity.
For evaluating higher power amps, I have a network that I can use with them
which drops the sensitivity of these speakers by about 12 dB and creates a
"Wilson-like" load for the amplifier while giving the speakers a DF of about 10.
At the moment I also have pairs of Zu Druids, Sony AR1's, and JBL 1400's
standing by. With biamping, I have LX-minis and the SLOBs with Lowthers,
Moths, Tangband, Fostex or SAL's.
That's in my "sound room". There's other equipment scattered about.
I see you're going to be at Siegfried Linkwitz's open house this month. I wish I could be there to meet two famous audio gurus at once. I'm interested in possibly building the LX521.4 setup. Would be cool if there was a First Watt approved amp circuit alternative to the commercial offerings, capable of powering Linkwitz designs. One that can be built in 5 channel package for reasonable cost.
Last edited:
I built some amps just for this occasion, as the minidsp output needs at least
26 dB gain to get the 25 watts the amps will do. They play acceptably loud,
but not spectacularly so.
Very interesting! I'd be curious to hear your opinion about the mini DSP. Tranquility Bass, here on DIY is developing a DSP crossover with a bit more overhead which can hopefully do 4 way filtering at higher sample rates.
http://www.diyaudio.com/forums/digi...-integrated-preamp-crossover-dac-project.html
I built some amps just for this occasion, as the minidsp output needs at least
26 dB gain to get the 25 watts the amps will do. They play acceptably loud,
but not spectacularly so.
Hmh, now I am even more excited!
This is a somewhat embarrassing post since I worry I am infringing on some ethical aspect of FW, .... but,
I got the case from the guy in China for the mono J2 project and it is really strange seeing something that you know is a copy and is such a good copy - it even uses the same packing "stuff" as the real thing. I can only imagine Mr. Pass's first view of something like this.
The faceplate is a darker grey than my REAL First Watt amps but this means nothing to me. I have the amps backsides facing my listening chair since it is easier to connect things.
I asked for it to be SIT1 style since it is for a mono amp. No hole in the faceplate for a meter!
I expected there to be some glaring difference - even the heatsinks are exact.
Hope the holes all match to swap the heatsinks between the cases. Going to start from scratch on the power supplies.
I got the case from the guy in China for the mono J2 project and it is really strange seeing something that you know is a copy and is such a good copy - it even uses the same packing "stuff" as the real thing. I can only imagine Mr. Pass's first view of something like this.
The faceplate is a darker grey than my REAL First Watt amps but this means nothing to me. I have the amps backsides facing my listening chair since it is easier to connect things.
I asked for it to be SIT1 style since it is for a mono amp. No hole in the faceplate for a meter!
I expected there to be some glaring difference - even the heatsinks are exact.
Hope the holes all match to swap the heatsinks between the cases. Going to start from scratch on the power supplies.
I built some amps just for this occasion, as the minidsp output needs at least
26 dB gain to get the 25 watts the amps will do. They play acceptably loud,
but not spectacularly so.
....A few years ago when i built my Orions i sugested in SL's Forum that you were the one to do discreet active crossovers and amps for those magnificent speakers.
Now SL has moved on to even greener pastures and minidsp is much more flexible than hardware xovers.....it seems that my dream will come true.....sorry to say i cannor be there to hear it.
But very very happy to know it will happen.
Belleson SPHP reg in the J2
AS I plan my mono J2 project I intended to use a choke in place of the resistors between the capacitor banks and then I remembered that Brian Lowe is making a regulator with the ability to deliver 1000 watts of power is given enough heatsinking.
Well, I will have a bare heatsink with the mono J2 and wonder what y'all think of using a regulator here? I am not usually a regulator prone fellow but with this amp being used below 500 hz I am thinking it could be useful. They cost about the same as I was planning on spending for the filter chokes, will be immensely smaller and lighter, easier to package. Plenty of good things in that sense but I wonder what those I know to be much smarter than I think of the idea if any of you would be kind enough to opine.
A new raw supply is part of the project. This reg will require much more capacitance and a higher voltage power transformer. Again, I knew I had to get new transformers since PLITRON has that minimum order policy and the ANTEKs would be plenty good for this. So these considerations are not a problem.
Link to BELLESON: Superpower Super Regulator by Belleson
AS I plan my mono J2 project I intended to use a choke in place of the resistors between the capacitor banks and then I remembered that Brian Lowe is making a regulator with the ability to deliver 1000 watts of power is given enough heatsinking.
Well, I will have a bare heatsink with the mono J2 and wonder what y'all think of using a regulator here? I am not usually a regulator prone fellow but with this amp being used below 500 hz I am thinking it could be useful. They cost about the same as I was planning on spending for the filter chokes, will be immensely smaller and lighter, easier to package. Plenty of good things in that sense but I wonder what those I know to be much smarter than I think of the idea if any of you would be kind enough to opine.
A new raw supply is part of the project. This reg will require much more capacitance and a higher voltage power transformer. Again, I knew I had to get new transformers since PLITRON has that minimum order policy and the ANTEKs would be plenty good for this. So these considerations are not a problem.
Link to BELLESON: Superpower Super Regulator by Belleson