This amp will be for FrugelHorn XL speakers playing from PC via Cambridge Audio DAC with volume control.
Eric, I’m sure you’re right about the whole confidence builder thing. It looks like they do have the PCBs, but the thought of chasing down parts, keeping track of them, fixing the inevitable screw-up on something, either my fault or some vendors, just doesn’t sound like something I would enjoy very much. I think I’d rather build a little less confidence with a kit that takes those variables out of it. There will certainly be another one, probably right after the first one, and by then, maybe I’d be ready to go all DIY from scratch.
Eric, I’m sure you’re right about the whole confidence builder thing. It looks like they do have the PCBs, but the thought of chasing down parts, keeping track of them, fixing the inevitable screw-up on something, either my fault or some vendors, just doesn’t sound like something I would enjoy very much. I think I’d rather build a little less confidence with a kit that takes those variables out of it. There will certainly be another one, probably right after the first one, and by then, maybe I’d be ready to go all DIY from scratch.
Eric
Thanks for clarifying the volume pot situation. I will progress the build and continue reading builders comments and solutions.
Skylar88
That's great, I'll make sure to check and bookmark your posts.
Following assistance from you guys I will get down to ordering the required bits and pieces this weekend and then the fun will start.
I'll be back, I'm sure.
Graham
Thanks for clarifying the volume pot situation. I will progress the build and continue reading builders comments and solutions.
Skylar88
That's great, I'll make sure to check and bookmark your posts.
Following assistance from you guys I will get down to ordering the required bits and pieces this weekend and then the fun will start.
I'll be back, I'm sure.
Graham
My advice is a little different. We do not know your expertise level so I will go with the base line.
Build the basic ACA first. Just like the build guide schematic (Amp Camp Amp V1.6 Build Guide - diyAudio Guides)
If you are using the Store boards or parts kits R15 (2.2K) is standard. As is 39k R12.
Several of us have our power supply fitted internally. There are no issues with 'noise'. But you will have mains voltages inside the case and extra heat to dissipate. I believe the power brick outside the case is for safety reasons - so there is only low voltage inside the case.
The input pot should work fine. Try it. The standard ACA has 10 - 11dB of gain. So you will probably find it plays as loud as the EL84 amp. Your speakers are pretty efficient from the stats. You can reduce the feedback a little (make R12 68k again) and get a little more gain if you want it.
Many of us though prefer to have a pre-amp in front of the ACA. You only need 10dB to drive the ACA well into clipping. It just sound better, but that is my opinion.
Yes in standard (non bridged mode) there is a start up 'fart' as C1 is charged. This is a feature, not a fault, and does no harm to your speakers.
Once you have it up and running then is the time to 'improve' it. So make some contingency space in the chassis design...
I'm doing a 4-way active build with Two (2 pcs) Firstwatt M2's. One on midbass (2 x 15") and one on midrange (2 x 8"). Sub (2 x 21") will be powered by a Crown XLS. As tweeter I will use Beyma TPL-150B.
Would a Amp Camp Amp be suitable for the TPL's? Total system sensitivity will be around 100dB so I guess the power of the ACA is enough
Would a Amp Camp Amp be suitable for the TPL's? Total system sensitivity will be around 100dB so I guess the power of the ACA is enough
Skylar88
Didn't understand what dead-bug style was. Now I know. What the hell, if it works. It wouldn't bother me.
Alan4441
Agree with what you say.
Get it up and running, if possible, live with it, then tweak away as desired.
I'm definitely going with the separate power supply for all the good reasons suggested, for parts I have in stock and those just ordered.
I'll make sure to listen out for the 'fart'.
Thanks
Graham
Didn't understand what dead-bug style was. Now I know. What the hell, if it works. It wouldn't bother me.
Alan4441
Agree with what you say.
Get it up and running, if possible, live with it, then tweak away as desired.
I'm definitely going with the separate power supply for all the good reasons suggested, for parts I have in stock and those just ordered.
I'll make sure to listen out for the 'fart'.
Thanks
Graham
Dead bug is more like sculpture! You can make them look cool if you try..
An option to putting the PSU inside is to shorten the cord from the PSU to the amp and have the PSU sitting right behind the amp. Not saying one way or another whether putting the PSU inside the chassis or close to it improves the sound- I haven't tried it, and am in no hurry to try it!
And an external PSU is considered "high end" in some products! Would in theory keep 'noise" outside the chassis, but Pass amps are so quiet I wonder if it's an issue at all.
Another point is that since the ACA is class A single ended, it is always drawing almost full power so there aren't any "power surges" caused when reproducing drums, etc...
An option to putting the PSU inside is to shorten the cord from the PSU to the amp and have the PSU sitting right behind the amp. Not saying one way or another whether putting the PSU inside the chassis or close to it improves the sound- I haven't tried it, and am in no hurry to try it!
And an external PSU is considered "high end" in some products! Would in theory keep 'noise" outside the chassis, but Pass amps are so quiet I wonder if it's an issue at all.
Another point is that since the ACA is class A single ended, it is always drawing almost full power so there aren't any "power surges" caused when reproducing drums, etc...
been there done that......
Attachments
Someone just posted an ad over on AudioGon for a Amp Camp #1b kit. He has most of the parts. I have been trying to help him out. Only thing missing is the R15. He has both of the audio amplifier transistors and the output transistors, (actually extra ones even). Some aren't shown in the ad, but he has verified he has them. He has both power supplies also.
Nelson Pass Designed Amp Camp Amp (ACA) KIT | Solid state | Powers, Oregon 97466 | Audiogon
Seems like a GREAT deal for someone...
Nelson Pass Designed Amp Camp Amp (ACA) KIT | Solid state | Powers, Oregon 97466 | Audiogon
Seems like a GREAT deal for someone...
R15 is optional, if you wanted higher idle currents....
another way to do it is to use a lower value of 0.47 and 0.68 ohm,
what i did in mine was to use two 0.33 ohms in series,
if you wanted more idle current, you can use 0.27 in series with 0.22 ohms 5 watt resistors without the R15..
another way to do it is to use a lower value of 0.47 and 0.68 ohm,
what i did in mine was to use two 0.33 ohms in series,
if you wanted more idle current, you can use 0.27 in series with 0.22 ohms 5 watt resistors without the R15..
Thanks, mraudioguru,
I contacted the guy selling the partially completed ACA. That auction is also a month away. I’m a little impatient. I looked around for kits with all parts I could get NOW and one that popped up was the F5. Is that a good option for FrugelHorn XL sourced from FLAC on PC via CambrIdge Audio DAC? Any other recommendations?
Thanks,
Alan
I contacted the guy selling the partially completed ACA. That auction is also a month away. I’m a little impatient. I looked around for kits with all parts I could get NOW and one that popped up was the F5. Is that a good option for FrugelHorn XL sourced from FLAC on PC via CambrIdge Audio DAC? Any other recommendations?
Thanks,
Alan
Also, if I do decide to go with F5, does it make sense to get the big chassis with 32 volt transformer for further upgrade options? Turbo or ??
Any of the FirstWatt amps are light years better than the (extremely enjoyable) ACA.
Build them with the standard 18v transformer.
Build them with the standard 18v transformer.
Alan....the link I posted for the ACA parts kits above, is for sale right now. It's not an auction. I'm also pretty sure the seller will work a little bit of a deal on it.
Jim is right, the FirstWatt amps are amazing...