F4 Billet Case is needing paint and polish. Boards done. P/S done. Other amps waiting on intall into their cases.
I'm at a bit of a loss to figure out how I can get anything done faster with stage 4 cancer. I am not allowed to be doing this especially out of a bedroom. Yet I am.
MoFo should be able to be driven harder. If it can't, it can't. Does not matter.
This is not about building amps. They will all be thrown out anyway. It is about keeping up what 'skills' I have left.
Yes it is.
Volume is not as I would expect. If it is not to be I have other amps to finish.
That will take some time. Everything is on temporary dissaray. It is doable. I need to bring down one set. Drag out the others and create another method of hooking them up in a space where a cat has trouble navigating!
I will ASAP
Yes, thank you!!!
I built a Dual Mono BA-3 with max gain. Almost done. Assumed the Pass FE 22 could handle it as reveiwed. In my case no.
Built a stock BA-3 Single P/S. That failed miserably due to the house wiring. One channel stole power from the other and could not bias. Tore that apart and built it Dual Mono. The board failed and other parts as well again due to the way this house is wired. Basically whole house is on one circuit. Pass FE blew parts, wiring and one channel. Now that summer is over the house is a bit more stable. Maybe.
That brings it to the point where we are at now. I have 3 pre's all apart from troubleshooting.
I need to finish D/M BA-3 with gain pre. See how that works.
Or find as 6L6 has proven another FE with more gain.
Yes, you are correct. The F4 and MoFo have the same gain.... 1....
Iv'e tried running the B1 and B1K with the F4 and it just doesn't dance... but the tube preamps (both running 20V with lots of gain) do the F4 a lot of justice.
So long as the speakers have at least 90 db/w efficiency.
BTW, your numbers would be far more useful if you used the units... as in Vpp, Vrms, A, ohms, watts, etc...
Where did you get that "4.14"?
The B1 has no gain. What the source outputs in voltage into the B1 is what the B1 outputs into the amplifier. So if the source outputs 1.0V, the F4 sees 1.0V at its input which results in 1.0V or less at the amplifier output. Into 8 Ohms that is 1/8W.
The B1 Korg has some gain but it does not have much voltage output, and the THD is high. According to the specs, the B1 Korg's maximum output is about 5V at 7% THD. Into 8 Ohm, that is 3.1W.
So that is why both the B1 and the B1 Korg are unsuitable for the F4, MoFo, or any power amplifiers with no voltage gain.
The B1 Korg has some gain but it does not have much voltage output, and the THD is high. According to the specs, the B1 Korg's maximum output is about 5V at 7% THD. Into 8 Ohm, that is 3.1W.
So that is why both the B1 and the B1 Korg are unsuitable for the F4, MoFo, or any power amplifiers with no voltage gain.
The original observation was MOFO and Pass FE 22 do not produce the Volume in my case that is needed.
Measurements were taken asap on source output. FE was put into a usable condition to run MOFO.
Data conclude by accomplished forum member(s) the above original statement.
Not to end it at this in case others may plan on driving MOFO harder. In my case I have D/M BA-3 max gain on bench and Aska Lender that is said to drive MOFO in bits.
Measurements were taken asap on source output. FE was put into a usable condition to run MOFO.
Data conclude by accomplished forum member(s) the above original statement.
Not to end it at this in case others may plan on driving MOFO harder. In my case I have D/M BA-3 max gain on bench and Aska Lender that is said to drive MOFO in bits.
Whatever speakers that have been attached. If somebody was using 105db efficient speakers we wouldn’t be having this conversation.… 
The point is that Holzarbeiter’s source is outputting 0.59V, it’s 5.9V coming out if the 2022FE, and 5.9V at the output of the follower power amp. (MoFo, in this case)
The math was done twice as the output wasn’t speciefied as 5.9Vpk, or 5.9Vpk-pk.
In his example the output at the speaker posts is either 2W or 1/2W as currently configured. Probably 1/2W.
The point is that Holzarbeiter’s source is outputting 0.59V, it’s 5.9V coming out if the 2022FE, and 5.9V at the output of the follower power amp. (MoFo, in this case)
The math was done twice as the output wasn’t speciefied as 5.9Vpk, or 5.9Vpk-pk.
In his example the output at the speaker posts is either 2W or 1/2W as currently configured. Probably 1/2W.
I work under 2 60W incandescent bulbs. Basically blind in this 'lab'.
I have to pull things out to read.
These are work speakers bought 45 years ago.
Technics Model SB-CR33
2 Way
8 ohm
Input 140W
I have no idea as to the measurement on output. Readings taken from Fluke set at V variable Hz. in V AC.
I have never studied the tech on amp design and speakers. Never came across the method to determine what power ratings are required to discuss on the forum.
I restore, used to, Vintage aircraft and race cars. Ran many maschine shops and restoraiton shops.
I have not found the time to buy books to learn this subject.
Ask me about racing in 1961 in S Ca or T33 and F-86 Sabrejets. Aerobatic biplanes, Competition aerobatics.
In a way I should not have brought this up.
It has caused much angst.
I will have to pull speakers and data on all to see if any are rated at near 105db.Whatever speakers that have been attached. If somebody was using 105db efficient speakers we wouldn’t be having this conversation.…
Hook them up and end this conversation as obviously the 105db units are required for MOFO. I have not read on forum best speakers for MOFO.
Or find and buy speakers with 105db spec if I don't have anything close.
Again must apologize this will take time to do.
I will attempt to research V structures relating to amps so to not bring any more confusion due to major ignorance on this end.
The only speakers I have at hand that come close to what is needed for MOFO is a pr of Audio Nirvana 15 inch Ferrite at 100db.
In the fastest search I can do tonight Klipschorn have 105db Speakers. Getting to the point I will not be buying Klip.
I'm on a bit of borrowed time. I am doing these amps as physical theropy. As NP has said it is not dialysis but entertainment. It litterally for me is becoming dialysis.
The A/N can be shifted and hooked up as soon as I can do it. See how they sound. It is not the best solution but the only one I can infer from the thread I am able to do.
In the fastest search I can do tonight Klipschorn have 105db Speakers. Getting to the point I will not be buying Klip.
I'm on a bit of borrowed time. I am doing these amps as physical theropy. As NP has said it is not dialysis but entertainment. It litterally for me is becoming dialysis.
The A/N can be shifted and hooked up as soon as I can do it. See how they sound. It is not the best solution but the only one I can infer from the thread I am able to do.
It is not exactly like that. Not sure you want the details, but in case you are interested I will try to make a parallel based on where you are coming from.
We are in 66 and you are building a Group 7 / Can-Am racer.
You have a chassis and no power train. The chassis is a T70. It is not the lightest available vs some other specials or some Cooper / Lotus / Chevron,& Co lightweight, but it is stable (long wheel base), stiff, and can handle power, is made for the fast circuits rather than short European hillclimbs. You are now looking for a power train.
The T70 is your loudspeakers, the powertrain say in that case "preamp + amp". This is where things are getting a bit different as preamp is upstream (I skipped the source here) and amp comes after that, whereas on cars engine is upstream and gearbox + final drive comes after that.
The MOFO and F4 are the engines. They are light enough to not unsettle your car, nimble enough to fit and capable (enough power, nice torque curve, nice mpg) to propel your T70 (Technics louspeakers) to 190mph on any track or so. In short: all is fine engine wise. So these power amps (read engines), the MOFO and F4 are capable to drive many loudspeakers without problem hence no one mentioning a problem.
Now, what you ave is a gearbox problem. Your gearbox are desesperately short, ways too short, when you rev your engine in top gear to the redline you barely touch 60mph! You have a top engine but such a bad gearing that you can not really use it (or only at very low speed as you will hit the redline). Your gearbox are your preamps. They do not provide enough gain to drive your power amps, to make use of their available power (obviously things are different in cars where you would end up with bags of torque at the wheel but no end speed, but be able to have the power at the wheel... but so much slip you can't use it anyway).
To summarise, the amps are fine to drive your loudspeakers probably. But you need the appropriate gain structure, that is with these power amps you need a preamp with a lot of voltage gain as they don't have enough intrinsic gain. It is true that with other type of amps, more conventional ones, you would have less problems as they provide a voltage gain and that can be enough "gearing", or close to it. Read most amps are like electrical motors that give you torque "immediately" and you don't need a gearbox, or just 2 ratios.
I hope this helps at least understanding the issue, even if not really needed and just academic, and I wish you all the best.
Claude
We are in 66 and you are building a Group 7 / Can-Am racer.
You have a chassis and no power train. The chassis is a T70. It is not the lightest available vs some other specials or some Cooper / Lotus / Chevron,& Co lightweight, but it is stable (long wheel base), stiff, and can handle power, is made for the fast circuits rather than short European hillclimbs. You are now looking for a power train.
The T70 is your loudspeakers, the powertrain say in that case "preamp + amp". This is where things are getting a bit different as preamp is upstream (I skipped the source here) and amp comes after that, whereas on cars engine is upstream and gearbox + final drive comes after that.
The MOFO and F4 are the engines. They are light enough to not unsettle your car, nimble enough to fit and capable (enough power, nice torque curve, nice mpg) to propel your T70 (Technics louspeakers) to 190mph on any track or so. In short: all is fine engine wise. So these power amps (read engines), the MOFO and F4 are capable to drive many loudspeakers without problem hence no one mentioning a problem.
Now, what you ave is a gearbox problem. Your gearbox are desesperately short, ways too short, when you rev your engine in top gear to the redline you barely touch 60mph! You have a top engine but such a bad gearing that you can not really use it (or only at very low speed as you will hit the redline). Your gearbox are your preamps. They do not provide enough gain to drive your power amps, to make use of their available power (obviously things are different in cars where you would end up with bags of torque at the wheel but no end speed, but be able to have the power at the wheel... but so much slip you can't use it anyway).
To summarise, the amps are fine to drive your loudspeakers probably. But you need the appropriate gain structure, that is with these power amps you need a preamp with a lot of voltage gain as they don't have enough intrinsic gain. It is true that with other type of amps, more conventional ones, you would have less problems as they provide a voltage gain and that can be enough "gearing", or close to it. Read most amps are like electrical motors that give you torque "immediately" and you don't need a gearbox, or just 2 ratios.
I hope this helps at least understanding the issue, even if not really needed and just academic, and I wish you all the best.
Claude
If the issue is insufficient gain, and, on the assumption that there are two correctly functioning 'Front End 2022' units with 10X (20dB) gain, could the two FE units be daisy-chained to deliver 20X gain for one channel to demonstrate the issue. It's not an end-solution but might at least bring some clarity and identify a way forward.
That is an interesting take on it. We could talk hours. Even more specifically the way it was taken care of the transition of front to mid-engine config.
I appreciate it.
Still all talk of which torque multiplyer is best does not help as it didn't in period with Custom Modifieds to the Early Can Am.
The MOFO is, was, recomended to be able to produce lap times with Pass FE 22 with high gain. Even a Gear Chart was provided for us gearheads to chose for each track. Some of us here pitside chose the highest gain gearset. Based on our engine character and wheel/tire aspect ratio. Others needed unity gain and chose the opposite.
Race starts and some are left on the field passed up left and right.
In my case MOFO and FE 22 failed on this CM class special.
Yet others on track that combo with what is said to be needed 105db Hewland we can't afford or even buy as they are that rare due to construction, case strentgh, etc. But mainly $$$.
I chose based on advice it would produce. I empirically found out it can not.
I lost the race. Choose poorly and now will decide what to do with them and build another special.
Thanks for your story.
Frankly I should have never brought up the observation and at this point in time kidney function is more interesting to me then how V structure is measured and discussed in context to amp character!
Best regards,
Charles
