Which preamp for Amp Camp?

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#63
I have received several private message asking about PC boards for the BZLS. Yes, I still have boards, the price is $10 each or $15 for the pair (line stage and power supply). They fit in a USPS priority mail small box which ships to anywhere in the USA for $7.20. I accept PayPal for payment. Overseas, I never ship overseas with Ebay, however, this forum is very different and I will make every effort to ship. However, please keep in mind, my local post office have workers who give you the "deer in the headlights look" every time I ask a question.
Nelson Pass sent the files to make the boards, you will find them in earlier posts.
Cheers!
 
#64
bbm3 said:
I will note that I have built three B1's all of which I purchased the boards and JFET's from Nelson Pass as a tiny token of my appreciation.

If he sold boards for the Balanced Zen I would buy from him rather than making my own in a heartbeat.

-BB
Click to expand...

What have you used for volume control? Is an ALPS pot good, or should I look at theattenuators with resistors. I’m a little intimidated by the tight work on the attenuators.
 
#65
I'm no expert on parts as far as good or bad. I'm following the article by N. Pass, he said four ganged pots using resistors was his recommendation. So, I found a company in China (along1986090) on Ebay, he sells four ganged 24 step pots with Vishay Dale resistors. I found a 10K and then asked him to make a 5k. It took about 2 weeks max to receive even the custom made one. I had no intention of trying to solder all those resistors on a diy version. Life is to short for some projects, like making my own PC boards. I've used enough bad chemicals for 46 years building cars.
He also sells enclosures which I've used for other projects. Now that I see diyAUDIO store has enclosures, I will probably buy them from them in the future.
Other parts such as connectors I bought from Parts Express in Ohio.
 
#69
Attenuator option

I used an EIZZ 24 step attenuator on a WHAMMY based preamp. It cost about $60 USD with shipping. I have no comparison for the sound, but the EIZZ attenuator is smooth in operation, with no pops. It has nice large posts for soldering your wiring. The aluminum body can be grounded providing some sheilding.

Prior to that I tried one of the cheap Valab attenuators (about $20 USD), the wiring is tricky because the hookup tabs are tiny. One of the tiny surface mount resistors broke off. I just couldnt deal with the surface mount soldering so decided it was a paperweight. Also in the part of the range that did work it had small pops when it was turned. Would not recommend the cheap ones over the ALPS. After I discovered the broken resistor I decided to spring for the EIZZ attenuator.



Next time I need to use a volume control I'll probably just use the ALPs pot.
 

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#70
A little help, please. Before I jump in too deep, can anyone direct me to a build guide for BZL or similar -- something that's really clear on the wiring from balanced inputs to the PCB, and then from the PCB to the pots to balanced output. I've only built the 2 ACAs previously, so this is a big undertaking for me. Thanks.
 
#71
My handy work is not worth documenting on this site, so I don't have a build guide. I'd be happy to mock up how I plan on building it. I plan on having four inputs:
1 - Balanced only
2 - Balanced and Single Ended
3 - Single Ended
4 - Single Ended
Using a DACT selector switch and a four ganged 10Kpot to the inputs on PC board. The output has the four ganged 5K pot to Balanced outputs with Single Ended outputs.
I have the hook up instructions for the DACT selector and the pots.
I'm not sure this is what your looking for, however I may do it just to make sure I'm doing it right.
 
#75
I was going to mount the output pot on the back case because I thought I would adjust once incorrectly and a second time to a listenable level. This would take care of the Rout issue, and the Voodoo part would explain my concerns of how and when to adjust.
If the output pot is deleted, is there a fixed resistor which should be substituted? What value?
 
#77
I'd rather have the input control, however, the article refers to P1 & P2 on the input, and P3 & P4 on the output. Along with P5 which I still don't understand. I decided on a fixed resistor for R15 and P 5. In regards to P3 & P4, I don't know what to use in place of the pots. I was building it according to the article.
So when you say build it with just the input attenuator, how?
 
#80
moe29 said:
I hooked up P5 when the boards were installed. Running wires from the front
panel to the unpopulated holes seen in the pic.

The BZLS is a VERY adjustable preamp! You can attenuate the Input signal with P1 and P2.
You can attenuate the Output signal with P3 and P4. And "P5 allows
intrinsic adjustment of the circuit gain without having to match the potentiometer
values, allowing adjustment from 10 t0 20 dB gain."
🙂
Click to expand...

I'm having a very tough time finding four-gang pots in 10K. There is an eBay seller, orexmen, offering an ALPS for $40 each. However, I don't see his part numbers on the ALPS website. Any other suggestions?
 
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