Ostrawa is a fully stereo four-channel voltage-controlled mixer featuring a stereo mixing bus, one stereo auxiliary send per channel (switchable between pre and post-VCA) with stereo returns, clickless muting, individual level meters, and a super-clean and DC-coupled signal path designed with high-quality VCA and opamp chips.
We have carefully crafted Ostrawa’s voltage control response to achieve what we believe to be the optimal user experience found in a Eurorack mixer. The design features an elaborate control circuit that combines the internal voltages generated by the panel potentiometers with external CV over volume and stereo balance.
The result is a natural attenuator response that constrains VCA gain to a usable range while minimizing distortion. Ostrawa, a sister module to Xaoc Devices Praga, features similar response characteristics and layout of controls with some functional differences due to its stereo inputs and limited panel space. Multiple Ostrawa and Praga units may be chained for a custom configurable mixing system.
Features
- Full stereo architecture
- Natural volume response
- Channel level indicators
- Stereo auxiliary send and stereo returns
- Clickless channel muting
- Expandable by chaining more units and optional expander modules
Expandability
Multiple Ostrawa and Praga units may be chained to provide a cascaded sub-mix setup.
A dedicated Bohumin expander adds a second full stereo AUX bus with voltage control over the amount of the effect on each channel of Ostrawa. Bohumin also features manual attenuators for stereo returns of both AUX buses, as well as four gate inputs for automated clickless muting of each stereo input channel.
Ustka is a simple passive expander module that offers direct access to four pairs of stereo signals before they are combined into the mixed signal at the output of Ostrawa. Ustka’s main application is interfacing with external multichannel devices like computer audio interfaces and hardware multitrack recorders.
- 20HP wide
- 46mm deep (including the ribbon cable and bracket)
- Current draw: +180mA/-150mA
- Reverse power protection
How much is my shipping?
Shipping is automatically calculated before you submit your payment information. Simply add items to your cart and proceed to the checkout page, where you'll be offered shipping options and their prices. In the UK it's normally around £4 for order values under £150, and free above that. Shipping to mainland EU is typically between £7 and £20, depending on the shipping method and the size and weight of the order.
Do you ship to my country?
Almost certainly - the site will give you an estimate of shipping costs if you add an item to the cart and then enter your country and postcode. If you have specific requirements (such as if you prefer UPS over FedEx, for example) then let us know in advance and we'll try to work something out for you.
Shipping methods
We use a combination of Parcelforce, DPD, Royal Mail and UPS for the UK, and for international orders it's either Royal Mail, UPS, DHL or FedEx depending on where you are in the world. If you have a particular preference then try to let us know BEFORE you order so we can look into it for you. Please note that there may occasionally be additional shipping charges if you live in a remote area, depending on what surcharges are applied by the shipper. We'll get in touch to discuss this with you in such cases.
Dispatch times
For UK orders, we normally dispatch the same working day if we get the order before 15:00. If you have a really urgent situation then of course drop us an email before ordering and we'll always do our absolute best to accommodate you.
For international orders, we normally dispatch the same day if we get the order before 13:00 but again, occasionally it might be the next day before we can send it out, and sometimes FedEx or UPS may come a little earlier than scheduled which would also push an order into the next day.
Shipping times
Since April 2020 the couriers we use have suspended guarantees for shipping times, so even though we're paying them for priority services - 24-48 hours for most of the world - in practice it's often an extra day on top and sometimes it can be longer.
There is absolutely nothing we can do about this unfortunately. If you are outside the UK and it's a life-or-death situation where you absolutely MUST have that passive mult for the next day then... it may be better to find a local supplier.
Saturday shipping
If you're in the UK and you order before 15:30 on a Friday then we can send something for a Saturday delivery (NB: this applies to UK mainland addresses only). The success rate with DPD is about 95% so it's worth a punt most of the time. Please note that if you select Saturday shipping on an order placed earlier in the week, we'll wait until Friday to ship it.
Pre-orders
If a product is listed as a pre-order, it means we've ordered it from the supplier but it's not physically in stock yet. The product listing will include an estimated shipping date based on the best information we have from the supplier, but do bear in mind this is subject to change and is not a guaranteed date.
If you place an order containing a mixture of in-stock and pre-order items, we'll normally hold off on shipping anything until the pre-order item(s) have arrived, rather than splitting it into multiple shipments. If you need the in-stock items sooner, we'd recommend placing separate orders. As always, please get in touch if you have questions.
Product Overview
Ostrawa is a fully stereo four-channel voltage-controlled mixer featuring a stereo mixing bus, one stereo auxiliary send per channel (switchable between pre and post-VCA) with stereo returns, clickless muting, individual level meters, and a super-clean and DC-coupled signal path designed with high-quality VCA and opamp chips.
We have carefully crafted Ostrawa’s voltage control response to achieve what we believe to be the optimal user experience found in a Eurorack mixer. The design features an elaborate control circuit that combines the internal voltages generated by the panel potentiometers with external CV over volume and stereo balance.
The result is a natural attenuator response that constrains VCA gain to a usable range while minimizing distortion. Ostrawa, a sister module to Xaoc Devices Praga, features similar response characteristics and layout of controls with some functional differences due to its stereo inputs and limited panel space. Multiple Ostrawa and Praga units may be chained for a custom configurable mixing system.
Features
- Full stereo architecture
- Natural volume response
- Channel level indicators
- Stereo auxiliary send and stereo returns
- Clickless channel muting
- Expandable by chaining more units and optional expander modules
Expandability
Multiple Ostrawa and Praga units may be chained to provide a cascaded sub-mix setup.
A dedicated Bohumin expander adds a second full stereo AUX bus with voltage control over the amount of the effect on each channel of Ostrawa. Bohumin also features manual attenuators for stereo returns of both AUX buses, as well as four gate inputs for automated clickless muting of each stereo input channel.
Ustka is a simple passive expander module that offers direct access to four pairs of stereo signals before they are combined into the mixed signal at the output of Ostrawa. Ustka’s main application is interfacing with external multichannel devices like computer audio interfaces and hardware multitrack recorders.
Technical Specs
Shipping Details
How much is my shipping?
Shipping is automatically calculated before you submit your payment information. Simply add items to your cart and proceed to the checkout page, where you'll be offered shipping options and their prices. In the UK it's normally around £4 for order values under £150, and free above that. Shipping to mainland EU is typically between £7 and £20, depending on the shipping method and the size and weight of the order.
Do you ship to my country?
Almost certainly - the site will give you an estimate of shipping costs if you add an item to the cart and then enter your country and postcode. If you have specific requirements (such as if you prefer UPS over FedEx, for example) then let us know in advance and we'll try to work something out for you.
Shipping methods
We use a combination of Parcelforce, DPD, Royal Mail and UPS for the UK, and for international orders it's either Royal Mail, UPS, DHL or FedEx depending on where you are in the world. If you have a particular preference then try to let us know BEFORE you order so we can look into it for you. Please note that there may occasionally be additional shipping charges if you live in a remote area, depending on what surcharges are applied by the shipper. We'll get in touch to discuss this with you in such cases.
Dispatch times
For UK orders, we normally dispatch the same working day if we get the order before 15:00. If you have a really urgent situation then of course drop us an email before ordering and we'll always do our absolute best to accommodate you.
For international orders, we normally dispatch the same day if we get the order before 13:00 but again, occasionally it might be the next day before we can send it out, and sometimes FedEx or UPS may come a little earlier than scheduled which would also push an order into the next day.
Shipping times
Since April 2020 the couriers we use have suspended guarantees for shipping times, so even though we're paying them for priority services - 24-48 hours for most of the world - in practice it's often an extra day on top and sometimes it can be longer.
There is absolutely nothing we can do about this unfortunately. If you are outside the UK and it's a life-or-death situation where you absolutely MUST have that passive mult for the next day then... it may be better to find a local supplier.
Saturday shipping
If you're in the UK and you order before 15:30 on a Friday then we can send something for a Saturday delivery (NB: this applies to UK mainland addresses only). The success rate with DPD is about 95% so it's worth a punt most of the time. Please note that if you select Saturday shipping on an order placed earlier in the week, we'll wait until Friday to ship it.
Pre-orders
If a product is listed as a pre-order, it means we've ordered it from the supplier but it's not physically in stock yet. The product listing will include an estimated shipping date based on the best information we have from the supplier, but do bear in mind this is subject to change and is not a guaranteed date.
If you place an order containing a mixture of in-stock and pre-order items, we'll normally hold off on shipping anything until the pre-order item(s) have arrived, rather than splitting it into multiple shipments. If you need the in-stock items sooner, we'd recommend placing separate orders. As always, please get in touch if you have questions.
