rainton's P2P LA2A chassis "original style" discussion thread

[weiss]

@Floti could you please make the payment for the meter so we can proceed with the order?

thanks

 

[Quayhog]

I'm not sure how long it will be before the metal work is ready.  I'm curious if there is enough interest in starting a Facebook group.  It would be a good format to show, pictures, troubleshooting discussions, parts trading etc.
If we do this group I'd only open it to the people who are in this group buy.

Are there any builders in the San Francisco area? 

 

[hymentoptera]

I would probably be interrested in the Facebook thing. It would give me a reason to log on every now and then. I just logged in for the first time in months!

I'm East Coast, but I'd still love to join in and post photos, etc.

 

[Quayhog]

I'm not sure what you all are doing for transformers.  I ordered a new power transformer from Heyboer, a clone to the original spec one.  It was only $88 USD.  Eight weeks to delivery.  The originals I saw on the bay cost more and some had very short leads.  Why set up to fail?

I'm going to use an A-24 for the output and I have an original HA-100x. Both are the grey ones with the riveted tags. 

I'm curious if an HA-133 would cause problems as an output on the LA2A?  Any comments from the gallery?  It's very large and may get in the way of the T4B.

Jonathan Horne
My gmail address is quayhog53

 

[weiss]

I am also using the A-24 on output. Unfortunately it seems that many people are building the La2a currently, didn't see any Ha-100x or A-10 for a long time now. Using the Hammond power trafo.

 

[nickhepfer]

The A-24 sounds great! Definitely a magic piece.
The input transformer has way less impact on the sound, so in fact I can not find any A-10 or HA100X for an acceptable price, I'll go for the Sowter 1009. A little bit modern sounding, but great quality at all!

How long we are going to wait for the last payment, before we proceed with the order…?

 

[Krutchy]

The last pair of A-10 ' s on Ebay went for a ridiculous amount of money especially since they were used, I think I might go sowter for input as well.

It's a shame I got my cases of Purusha about 2 weeks before this run started it looks like your cases are gonna be killer.

 

[DonnieDarko]

I have one UTC A-10 I recently bought for sale.

First  found a single one, then found a pair on ebay. As I´m building two units, I can spare one.

If someone´s interested: I paid 280,- Euro/310,- US$ with postage and import charges for the trannie, don´t want to make any money on this.

Unit is in Germany.

This is the original listing:

http://www.ebay.com/itm/171843243635

Yeah, this would be black market, but since this is the build thread…

 

[nickhepfer]

You paid 280€ for two or for a single one?

If it's 140€ for one, I'd be interested 

 

[weiss]

seems like one trafo only..

 

[Quayhog]

I opened up a Facebook group for this specific project.  I figured it would be a good forum to discuss issues, successes, photos, parts trading etc.

I want to keep it only open to the twenty-one members who bought a chassis from Rainton.  Search groups for title:  LA-2A Leveling Amplifier Group Build.
https://www.facebook.com/groups/1615927638648181/?ref=browser

When you ask for membership make sure I know what your GroupDiy handle is.
Keep it clean, polite and professional.  The more members we include the better the discussions will be.

Thanks
Jonathan A. Horne

 

[Quayhog]

We all talk about the transformers and the T4B and their impact on the overall sound.  How much of the magic comes from carbon comp resistors?  I have enough Alan Bradley's to accomplish the build but lately all my guitar amps have been built using 2 watt metal films.  My builds have all been dead quiet.

What are all of you going to use? What are your reasons for your choice?
What signal caps and electrolytics?  I'm thinking of using an FP type electrolytic.  I think they make for a cleaner layout, and I probably have some fresh ones in my stash.

 

[nickhepfer]

Of course transformers have a huge impact on the sound in tube-circuits.
Resistors in the audio circuit affecting the sound too, but not as much a transformers do (in my experience).
Using carbon composite gives you a little more "retro" kind of sound, maybe a little bit blurred. I perceived metal film always more direct and "modern" sounding.
Today I tend to use ca. 50% mf and 50% cc, depends on the build...

 

[Unit7]

Even though I'm not on FB I don't in any way disapprove you guys moving the discussion there. I'm just wondering why? I thought this was the ideal place for that. The old LA-2 thread is perhaps too chunky by now. I posted questions there when I built my LA-2 last year and didn't get much help. But we could start a new thread, either for LA-2 builds only with Rainton's case or LA-2 p2p builds in general. There are some seriously experienced members here and I wouldn't mind them joining in for an occasional comment

 

[weiss]

Even though I'm not on FB I don't in any way disapprove you guys moving the discussion there. I'm just wondering why? I thought this was the ideal place for that. The old LA-2 thread is perhaps too chunky by now. I posted questions there when I built my LA-2 last year and didn't get much help. But we could start a new thread, either for LA-2 builds only with Rainton's case or LA-2 p2p builds in general. There are some seriously experienced members here and I wouldn't mind them joining in for an occasional comment

a new p2p thread, that sounds good..

 

[Quayhog]

If there is no Facebook interest that's cool. I just think it's a slightly less cumbersome way to show pictures and have open discussions.  If there is no interest in a week I'll shut it down. 

After nine pages, this forum is getting hard to look back for information. 
If FB doesn't work I suggest we open a new thread here to discuss build issues and parts sources/trades etc.

 

[Quayhog]

I'm down to the last hard to source bit. The meter range selector switch. It a rotary 2 pole 3 position switch.  What are fellow group buy members doing for this part?  Any information on sources or part numbers?

 

[Unit7]

I'm down to the last hard to source bit. The meter range selector switch. It a rotary 2 pole 3 position switch.  What are fellow group buy members doing for this part?  Any information on sources or part numbers?

https://www.tubesandmore.com/products/P-H395

This is cheap but will do the job. It's three poles. Please correct me if I'm wrong but I'm pretty sure you could just use only two poles on it and it'll be fine. I actually used a 4 way switch on my build, and I believe it was 3 poles too, and working great.

edit: And I'd like to say it once again - I don't mind the slightest if you guys want to go FB. My last build, using the Cayocosta layout, worked with a minimum of issues. Sounds great and  very low noise/hum, so I'll just copy, except that I've been able to source UTC xformers this time (instead of Sowters) and also going to try Drip T4.

 

[Quayhog]

Thanks, I missed that one. The number of poles is less an issue than the number of positions.  I now have all the important bits.

A hint on the power transformer choice.  Heyboer has clones of the original Triad for $90.  Benefits are long leads and they adjusted the primary for 120VAC.  There are Chinese clones on eBay for $175 and some originals with stupid prices and short leads.  I should get mine next week.  I've built atleast ten amps using Heyboer. It's outstanding quality.

 

[Unit7]

Heyboer has clones of the original Triad for $90.  Benefits are long leads and they adjusted the primary for 120VAC.

Thanks for he tip! Are they painted gray? And, I see no product page at their homepage, so you just contact them to order?