F5 power amplifier

dedicated RIAA

Thanks, guys...I would never have found this. I love the idea of using optics for a nice clean signal. If there is a thread dedicated to topology, please advise, and I'll move to there.

I also was browsing SY's Heretical writeup, and saw that he uses a dedicated RIAA amp. I think that I will head in that direction as well. I saw many references to Pearl, I will look for others.

Thanks, again,
Andy
 
The F4 has no voltage gain. To reach it's maximum peak voltage output you will need a preamp cappable of about 20Vpk (14Vrms). The B1 also has no voltage gain and I would think not the best combination with F4 also due to it's max output being about 8Vpk.
The F5 has a gain of about 5 I think. Therefore an input signal of 4V pk (2.8Vrms) will drive it to it's maximum. A B1 would have no trouble operating in this range without loss of available headroom in the system.
If you are looking to incorperate an attenuator into your system, source output and pwr-amp input levels need to be considered.
:Pawprint:
 
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The F4 has no voltage gain. To reach it's maximum peak voltage output you will need a preamp cappable of about 20Vpk (14Vrms). The B1 also has no voltage gain and I would think not the best combination with F4 also due to it's max output being about 8Vpk.
The F5 has a gain of about 5 I think. Therefore an input signal of 4V pk (2.8Vrms) will drive it to it's maximum. A B1 would have no trouble operating in this range without loss of available headroom in the system.
If you are looking to incorperate an attenuator into your system, source output and pwr-amp input levels need to be considered.
:Pawprint:

F-5 gain is 15. My B-1 will drive it fairly loud as long as the speakers are over 90 db efficiency. I can drive my Ewaves ( approx 91 db efficient or so )
At full volume. Its pretty loud, mid 90's or so at the listening position. With an a preamp with gain, they can get very loud!

Russellc
 
I am also considering building an F5, I think I would actually prefer to build the F5. However, I don't see any consensus on which preamp is optimum for it. Maybe it is not a big deal...just use any old preamp? B1? Impasse? Pumpkin? Heretical?

Thanks in advance for any advice.

Andy

You should try with any preamp you might have, I needed some gain in my preamp so I opted for NS10 with Shiny PSU.
 
pcb availability

Thanks, Stein. I'll take a look at this. I looked at the DCB1 last evening and it looks like I just missed the boat on the last group buy for the pcb.

One of the things that I think is important is availability of a nice pcb for construction. None of these things look very expensive or hard to build, but it looks like you need the right timing to get in on the group buys, etc.

So, I think I'll see if there is a waiting list for the DCB1 and in the meantime, see if I can find parts for NS10.

BTW, the reason why I have "nothing" right now is because my "quality manufacturer" integrated amp fried, and I have it in parts right now. When I saw how it was put together I decided that the diy amps that I see here are higher quality!

Andy
 
Arg, still having problems with my amp.

I've replaced 2x 5k trim pots, I've put back in the 22k ohm that I mistakenly removed.

I've zeroed the pots (turned them fully counter clockwise -checked r3 + r4 too), re-attached everything again.

When I powered it up my fuse popped and blackens my R11 + R12 resistors.

Any suggestions?
 
Arg, still having problems with my amp.

I've replaced 2x 5k trim pots, I've put back in the 22k ohm that I mistakenly removed.

I've zeroed the pots (turned them fully counter clockwise -checked r3 + r4 too), re-attached everything again.

When I powered it up my fuse popped and blackens my R11 + R12 resistors.

Any suggestions?

I had this happen to me. I checked all my solder joints and traces and everything was perfect. In the end, it turned out I'd put the outputs on the wrong sides of the circuit. In my case I was lucky and only lost one of the outputs. Have you double checked the N and P output and their position in the circuit?
 
Hi ,
I am in a bit of a mess with the F5 project. I purchased my boards back in September 2009. I have only just got around to (starting) to build them... too many other projects.
Firstly I have found that the resistors provided do not match what is on the F5 BOM (from TechDIY). I was about to ask for replacements when I found that I do not have a current schematic showing what resistor values are actually wanted (this is a V1.0a 2009-03-14 board.)
Can anyone point me to a schematic for the V1.0a which defines which resistors should have been provided?
Thanks for the help