[FallenAngel]

$53 for transformer for 2 boards form SumR does look VERY good, probably even cheaper considering shipping within Toronto than A.L. with shipping from US.

 

[BoilermakerFan]

Yes, I had him do two boards per transformer, so a balanced build still needs two transformers, but they are in fact two separate SE builds and can always be separated and sold off that way. 

  Plus I like having the option of wiring the amp with two separate pots for balance control and wire the outputs to either speaker posts, dual TRS jacks, or a 4-pin XLR.  It also makes it really easy to audition tweaks side by side with a switch box. 

 

[bada bing]

    Quote:

6N27Pi is a 100 Mu tube.  6GM8 is 14...  Way too much gain. 
 
EDIT:  I'm finding conflicting reports of the Mu, some sites list 100, other list 16.

I've got a quad of 6n27p that I've used on a balanced EHHA. The tube has a similar Mu to a 6gm8, so no way it's a 100 mU tube. It is a good but not superior alternative to 6gm8's I've tried in the EHHA. I have a quad of Telefunkin and a quad of Sylvania 6gm8's. The 6n27 sounds like most other Russian dual triodes I've listened to, mostly in a Soha II. It has a neutral kind of solid state sound to it without much tube flavor. I would put in a recommendation for the 6n27p for the EHHA except for it is pretty expensive compared to 6gm8 versions. Seems like the availability of 6gm8, especailly as quads, is down lately though.
 
My experience with the EHHA is that it doesn't do it's best with anything other than the 6gm8 or 6n27p. I never had much enthusiasm for the sound of any 6dj8's or 6H30dr. I found the 6H30 in particular to be a disapointment considering the cost of the tube, the cost of a beefed up heater supply for it, and how impressive they sound in a SOHA II. The EHHA isn't a tube roller at all, it just needs a good pair (quad) of 6gm8's. I didn't get much, if any, changes going from different brands of 6gm8's either.  
 

 

[keyid]

i got a box of hammond lopro 16 VAC @ 3A
http://parts.digikey.com/1/parts/997967-transformer-lopro-16vct-3a-229d16.html
 
Can i use two of these? one for each board?

 

[fishski13]

Quote:

i got a box of hammond lopro 16 VAC @ 3A
http://parts.digikey.com/1/parts/997967-transformer-lopro-16vct-3a-229d16.html
 
Can i use two of these? one for each board?

Alex talked about this on pg. 16.  

 

[fishski13]

i have a couple of Richard's TX and think they're great.  $53 for a single TX compared to $43 for 2 TX from A.L. is compelling for space and chassis layout reasons.  
 
BMF,
when you say 60V C.T./200mV, why not just spec a 30-0-30/400mA or a 30V+30V/400mA?  wouldn't this be a little cheaper without the extra secondary leads?
 
i want to get a BOM put together before buying the TX(s).  right now, the Par-Metals 20-series 12"x12" looks like a nice little pre-fab chassis.

 

[BoilermakerFan]

Quote:

i have a couple of Richard's TX and think they're great.  $53 for a single TX compared to $43 for 2 TX from A.L. is compelling for space and chassis layout reasons.  
 
BMF,
when you say 60V C.T./200mV, why not just spec a 30-0-30/400mA or a 30V+30V/400mA?  wouldn't this be a little cheaper without the extra secondary leads?
 
i want to get a BOM put together before buying the TX(s).  right now, the Par-Metals 20-series 12"x12" looks like a nice little pre-fab chassis.

It needs to be a CT trafo.  It might be $5 more for the two windings versus one, but I asked to see.  The two windings make it easy to wire the amp boards too, the leads are long enough for run straight to the amp boards in most cases. 

 

[fishski13]

so it's just for ease of wiring, i see.  i'm going to get a quote for a 30V+30V/400mA with 7V heater windings and a single primary.

 

[FallenAngel]

Dual primary has some serious advantages in case the amp ever gets sold to someone.

 

[cobaltmute]

And you can always wire the primaries in parallel.

BMF, I know you already have dome most of the work, but do you mind if I ask SumR for a quote on the same but in Canadian dollar? I hate paying the extra charge that the credit card companies tack on, not counting the bad exchanges rates they give you.

 

[FallenAngel]

Yes please.

 

[jdkJake]

Okay, so, whats the trick for posting attachments? It keeps saying I don't have permission.
 
I have the latest layout, schematic and first release BOM ready to post...

 

[BoilermakerFan]

Quote:

And you can always wire the primaries in parallel.

BMF, I know you already have dome most of the work, but do you mind if I ask SumR for a quote on the same but in Canadian dollar? I hate paying the extra charge that the credit card companies tack on, not counting the bad exchanges rates they give you.

No worries guys.  I only did the work because I'm working with SumR on 4 other amps and two side projects, so I email him pretty regularly.  I was just trying to make it easy on him and you guys. 
 
As I said earlier, the dual primaries is to cover most of the worldwide voltages so the amp can be sold to most anyone if you guys decide to sell an amp. 
 
The dual secondaries makes wiring so much cleaner and easier, but if there is a $5 savings and the build budget is that tight, it's a good place to save $5 and put it towards a Nobel pot instead of a RK27 for instance.  I'd personally go with the cheaper rotary power switch and skip the TDR boards to save even more money, but that's just me, everyone has different priorities. 
 
I need to acquire a few more of my new preferred vintage chassis.  Scored a killer deal on eBay, but there aren't too many of these lower models out their bigger brothers or other models in the same chassis is uber pricey. 

 

[jdkJake]

BMF,
 
For those of us in the USA, did you get a part number? I like it just the way you spec'ed it.

 

[fishski13]

Quote:

Okay, so, whats the trick for posting attachments? It keeps saying I don't have permission.
 
I have the latest layout, schematic and first release BOM ready to post...

can you email it to me?
 
fishski13 at hotmail dot com
 
thanks!