Bi-amping Klipschorns, combining tubes and SS

[tromprof]

I am acquiring a 2A3 tube amp from Joessportster and have been playing around with some ideas of how to use it. I have a spare pair of Crites crossovers that I could modify to allow me to bi-amp. The thought is to use a spare Crown D-75 on the bass bins, and allow the 2A3 tube amp to do its thing on the mids and tweeters. Anyone have any experience doing this? Is there an issue because of the wide difference in power between the two amps (i.e. uneven volume control)?

I know that using an active crossover might have a better result, but I am trying to keep this system simple and use parts I have on hand.

[kevinmi]

I tried this years ago using a McIntosh 2125 ss amp and a Decware SE84 triode amp. The Mac puts out 125 w/channel, the Decware 1.8 w/channel. I could never get a good "blended" sound that I liked. I was using passive universal type crossovers. Maybe easier with active crossovers, but I didn't try that.

[tromprof]

Thanks for the response. The tube amp, a BEZ T3A-3, puts out around 8 watts (?), the Crown D-75 puts out 55 watts. So not as big a difference as your setup. I am rethinking using a passive crossover, and could use an Ashly crossover scavenged from my basement HT. That would allow me to time align as well as do so room correction. 

[kevinmi]

I'm using a Dennis Had Inspire single ended amp putting out between 6-8 watts driving my K-Horns, and have way more volume than I'll ever use. But my Horns aren't stock.

[ClaudeJ1]

It's a gain match issue, more than power.

 

[Coytee]

On 2/21/2020 at 2:27 PM, tromprof said:

I am acquiring a 2A3 tube amp from Joessportster and have been playing around with some ideas of how to use it. I have a spare pair of Crites crossovers that I could modify to allow me to bi-amp. The thought is to use a spare Crown D-75 on the bass bins, and allow the 2A3 tube amp to do its thing on the mids and tweeters. Anyone have any experience doing this? Is there an issue because of the wide difference in power between the two amps (i.e. uneven volume control)?

I know that using an active crossover might have a better result, but I am trying to keep this system simple and use parts I have on hand.

 

Years ago, I put a dbx BX-1 (monster solid state, something like 400 watts/channel) amp on the bass bins of the Jubilee's....  and had some 2A3 amps on the K402, later replaced with the McIntosh MC-2102 (100 watts channel)

 

Everything worked like a charm as per Claud, it's a gain match issue, not a power issue.....although if you DO use a smaller amp on top, I feel that's the limiting factor for the whole system.  

 

I was given the formula

 

20*log(v1/v2)

 

Where V1 and V2 are the input sensitivity values for each power amp.  Key to the formula is it will give you EITHER (for example)  "6" or "-6".  The number will be the same, the negative will depend on which amp you put on top/bottom of the formula so the only thing you need to recall is you need to adjust the lessor sensitive amp (with the LOWER input sensitivity value) by per this commentary, 6 db's to bring them into line with each other.

 

I've been informed there might be a better/different way of doing it.  I don't know, this is what I was told and it worked for me.

[tromprof]

2 hours ago, Coytee said:

 

I was given the formula

 

20*log(v1/v2)

 

Where V1 and V2 are the input sensitivity values for each power amp.  Key to the formula is it will give you EITHER (for example)  "6" or "-6".  The number will be the same, the negative will depend on which amp you put on top/bottom of the formula so the only thing you need to recall is you need to adjust the lessor sensitive amp (with the LOWER input sensitivity value) by per this commentary, 6 db's to bring them into line with each other.

 

 

 

Super helpful. thanks!