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May 20, 2019, 11:39:18 am

Author Topic: connections and compatibillity of system steps  (Read 630 times)

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Offline dvaugh

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connections and compatibillity of system steps
« on: May 27, 2018, 10:45:16 am »
years ago I purchased a pair of bottlehead kits, The Seduction phono pre and the Foreplay III line level amp. I had just finished
restoring a Thorens 125 turntable after two years of  researching and sourcing parts and upgrades for same, not being a
particularly knowledgable TT tech it was a difficult project in the extreme but one that I was very proud of the final product. needless to say errors were made along the way although I believe all were eventually identified and adjusted, The above mentioned pre amps were a miscalculation from the start of the project, they were not an error so much as a miss identification of needs for the planned final system. I believed I would need (and still do) the seduction phono stage and I also thought I would need the Foreplay III line level pre. my miss calculation came from not researching weather my Receiver was a good match for the TT and the signal stages up to the receiver.
I have a Integra DTR 9.1 receiver, it has a set of phono analog inputs with grd.connection,the specs indicate phono input sensitivity and impedence of 2.5mV at 50Kohms, now after more research I am of the opinion that to use these inputs I would need to not use the seduction stage as that would be incompatible with the integra phono inputs, and the Foreplay might or might not be compatible/necessary for proper pre amplification before the receivers amplifier section. Since the early days of this project the TT has been left sitting due to a failure of my interconnection needs and the final quality of sound.
Now some ten years later I have returned to my finished but not satisfactory TT to attempt to make this beautiful and quite expensive system play my carefully chosen collection of vinyl properly.
after more research I believe my miss calculation  is mainly in the choice of connections and inter connections.
and here is where I need your input: I dont wish to use the Integra phono inputs, I do believe the seduction to be superior
and most capable, I am using a Grado "Reference Platinum" cartridge with 5mV output, your websight and various other sources indicate this a good cartridge to pair with the Seduction pre. Because of the many comments online about "low"
amplification/output levels I feel the Foreplay should help with this possible problem, but what I am coming to conclude is that I should come out of the Foreplay and in to one of the Integras analog inputs (not Phono), these are all labled "Line".  they are all rated 200mV at 50Kohm. I think my best choice is: Grado to Seduction to Foreplay to Tape 2 analog in......
This is a lengthy post, as I think the included info is important, as well as I am a talky,retired,Industrial Electrician who is not sure of my facts, I would appreciate any comments and criticisms any one may have on my project/labor of love
thanks ..dvaugh

Offline Paul Birkeland

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Re: connections and compatibillity of system steps
« Reply #1 on: May 27, 2018, 10:51:03 am »
You'll want to plug your TT into the Seduction and the Seduction into the receiver.  The additional gain from a Foreplay is very likely unnecessary. 
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline 2wo

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Re: connections and compatibillity of system steps
« Reply #2 on: May 27, 2018, 02:59:47 pm »
And you want to plug the Sedution into one of the line level inputs of your receiver, not the phono input....John
John Scanlon

Offline dvaugh

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Re: connections and compatibillity of system steps
« Reply #3 on: May 28, 2018, 07:53:01 am »
Good Morning John....Thank you for your response, I understand that I should input my signal to the receiver
line level audio input and not into the "Phono" input, Question:do you think that the Seduction phono pre.
will give a noticably better sound then the receivers provided TT connections (Phono in)? to continue: in the
previous response Paul did not comment on the need or advisability of using the Forplay III line pre amp,and I find I am
curious about weather I need a line pre. in my system. when I was decideing if I would purchase one or both of the
Bottleheads kits they seemed to push the Foreplay pretty strongly,now after I have invested time and cash the
feeling is that the line pre amp is not necessary. many online forum posts comment about the Grado cartridge
and Seduction phono pre. combo as giving a gain/output that is "low". since my vinyl collection is mostly classic
rock and my system is built with loud output in mind this concerns me, could you advise me as to the need of a line
level pre amp?
Thank you for your help
Duane (dvaugh)
« Last Edit: May 29, 2018, 09:04:04 am by dvaugh »

Offline Paul Joppa

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Re: connections and compatibillity of system steps
« Reply #4 on: May 28, 2018, 09:14:58 am »
So, I found the Integra owner's manual online (92 pages!?!). It's a complex amp, all right.

But I see that the amp has separable preamp functions as well as the phono preamp. So, there is an internal phono preamp, an internal preamp, and power amps. There are jumpers between the preamp and the power amp, which can be removed to separate the functions. So here's the deal as I understand it:

The phono preamp section has an input sensitivity of 2.5mV, and is internally connected to the preamp section when "phono" is selected. I believe the phono pre output is available as the "rec out" and is rated 200mV. This section can be replaced with the Seduction. The gain of this section is 200/2.5, or a factor of 80, which is 38dB, basically identical to the Seduction.

The preamp section (which includes volume and tone controls, and the source selector switch) has a 200mV/50kOhm input rating. Its output is available at the "pre out" connections, and is rated 1.0v, giving a gain factor of 5, or 14dB - about the same as the Foreplay. This section can thus be replace by the Foreplay.

The power amp inputs are connected to the preamp outputs with the jumpers. The power amp input sensitivity is rated 1.0v/50kOhms. You can connect the Foreplay output to the  "amp in" jacks by removing the jumpers.

It appears that the gain structure of the Integra is very similar to that of the Seduction and Foreplay, so there should be no difference in gain or power capacity. As described above, you can replace the phono section with Seduction, the preamp section with Foreplay, or both. Note this gives you the opportunity to compare each section to the Bottlehead tube equivalents, so you can decide for yourself what sonic differences you hear. It will be fun!
Paul Joppa

Offline dvaugh

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Re: connections and compatibillity of system steps
« Reply #5 on: May 30, 2018, 09:07:27 am »
Paul...one final question and I will leave you alone, I dug out my Integra manual that you referenced and pondered your remarks, and the manual as I have many times in the past, you were able to make much more understandable a lot of
the setup I had not been clear on before. Looking at the rear panel connections in the manual, The section of analog inputs, specifically the ones without Video, is the pre.amp connections that are tied to the main amplifier section thru the removable jumpers......I believe......,so for me to tie in my Seduction phono I would remove the jumpers and connect the Seduction to the amplifier connections, BUT, if I read the manual and see the rear layout correctly, in doing so I am disconnecting all of the Integra analog pre amp connections as a set, not just whichever inputs I wish to replace, I/E phono in or one of the others, so I can not continue to use the remaining inputs that I have devices connected to. (Its all or nothing).
so as I understand I either give up all my bottlehead gear and connect my TT directly into the Integra Phono in, or I use the Seduction phono and go into one of the other Integra (non phono) device inputs. In my case as I am using most of the inputs already I would use the Tape 2 input. Does this sound correct? Anyway I thank you for your input, you have cleared
up much of that which has perplexed me with this complex reciever, if the bottlehead gear had been as complicated as my
Integra the two kits would have been stuck in a closet long ago.
Duane (dvaugh)

Offline Paul Birkeland

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Re: connections and compatibillity of system steps
« Reply #6 on: May 30, 2018, 10:36:35 am »
the pre.amp connections that are tied to the main amplifier section thru the removable jumpers......I believe......,so for me to tie in my Seduction phono I would remove the jumpers and connect the Seduction to the amplifier connections,
No.  The Seduction goes between your turntable and a line input. 

BUT, if I read the manual and see the rear layout correctly, in doing so I am disconnecting all of the Integra analog pre amp connections as a set, not just whichever inputs I wish to replace, I/E phono in or one of the others, so I can not continue to use the remaining inputs that I have devices connected to. (Its all or nothing).
PJ has mentioned that you could connect your sources to your Foreplay, then let your Foreplay drive the amplifier in of your Onkyo. (Turning your Onkyo into a power amplifier)  This is where the preamp/amplifier connections on the Onkyo come into play.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man